This is a short biography of a man whose life was filled with enough experiences, friendships, and drama to serve the lives of several men. Father, husband, friend, scientist, educator, researcher, mentor, aeronaut, and warrior, he comes as close to a true "Man for All Seasons" as many of us could likely imagine. His experiences in wartime, as a uniformed civil service official in the Luftwaffe and flight meteorologist in combat and later as director of the Luftwaffe’s principal forecast agency, would have been the high points of most men’s lives, as wartime service undoubtedly was for many of his comrades.

Doctor Werner Schwerdtfeger Source: Richard Savage

Not one to settle for dwelling on the past, Doctor Werner Schwerdtfeger went on to become a world-famous atmospheric scientist. He became if not the leading authority on weather and climate in South America and the Antarctic, then certainly a principal authority on those regions as well as on weather in the Arctic. Settling in the United States for the last part of his life, he continued his interests in polar climates while educating new generations of atmospheric scientists at the University of Wisconsin in Madison, Wisconsin until his passing in 1985.

Doctor Richard Savage has managed a project regarding a book published after the war by Schwerdtfeger and Franz Selinger, "Wetterflieger in der Arktis 1940-1944. The collective "we" or "us" used in the following refers to participants or interested parties in that project.

Initially, we thought the book, in German, was about Schwerdtfeger’s own experiences in wartime. Savage soon realized that the book was instead a memorial to the wartime experiences of Schwerdtfeger’s long-time friend and wartime comrade, the highly-decorated pilot Rudolf Schütze, the Wetterflieger. Based on a journal kept by Schütze during the war and on other materials, Schütze’s saga is a fascinating and detailed story of combat and flying from Norway into some of the world’s worst weather and of exploring, landing, and operating at inhospitable locations north and east of Norway.

While researching, we discovered various materials dealing with Schwerdtfeger’s own service as the chief flight meteorologist in the principal 'wettererkundungsstaffel' (weather reconnaissance squadron), usually abbreviated as wekusta or westa. He served in Wekusta 1 of the Luftwaffe’s High Command from its organization in 1938 until he was transferred to become the Chief (Chef) of the Luftwaffe’s Central Weather Service Group (Zentral Wetterdienst Gruppe or ZWG) in August 1943.

'Wekusta 1, Ob.d.L.' (Oberbefehlshaber der Luftwaffe or Commander-in-Chief of the Luftwaffe) flew combat weather reconnaissance, provided technical training for meteorologists and other aircrew members, and developed equipment and procedures for aircraft weather reconnaissance operations. Schwerdtfeger led those activities and flew 250 combat missions from 1939 until 1943.

Werner Schwerdtfeger

On this planet’s coldest and most barren continent are monuments to two gentleman scientists from the University of Wisconsin. Once known to many German meteorologists of the early 1930s as "The Austausch Twins,"[1] together they used manned hydrogen balloons to collect data for assessing the fine structure of vertical winds in studying Austausch Theory[2] and atmospheric turbulence. The "Twins," Dr Werner Schwerdtfeger and Dr Heinz Lettau, became friends at the 'Institut fur Geophysik und Meteorologie' in Leipzig where they received their doctorates under the direction of the famed German meteorologist Professor Ludwig Weickmann They remained friends and frequently colleagues for more than five decades.

Lettau’s legacy is honored by a University of Wisconsin automatic weather station (AWS)[3] on the Ross Ice Shelf not far from a similar AWS named for Schwerdtfeger. The Lettau Bluff[4] is a rock and ice bluff that forms the central part of the western edge of Beaufort Island. Named for Lettau, an authority on Antarctic meteorology, the bluff rises some 660 feet above the Ross Sea of Antarctica.

In the Royal Society Range[5] at the head of the Renegar Glacier near the Ross Ice Shelf and McMurdo Station rises Mount Schwerdtfeger, a 9860 foot ice-and-snow-covered peak named for the subject of this biography, Doctor Werner Schwerdtfeger[6]Schwerdtfeger, a senior meteorological researcher at the University of Wisconsin late in his life, was a driving force in the study of Antarctic meteorology, particularly the barrier winds east of the Antarctic Peninsula. He lived a life filled with adventures, pioneering science, huge challenges, defeats and victories, and great and lasting friendships.


German air force.
Oberbefehlshaber der Luftwaffe
Supreme commander of the German air force.
A military unit in the Belgian navy usually six to eight small ships operating together under one command. The smallest military unit in the Dutch air force of about 350 men. In most countries is the designation of a military unit thesize of a company. It is either an independent unit, such as a battery, or part of a bigger Calvary unit. In the air force it is the designation of a unit of aircrafts.

Early Years

Werner Schwerdtfeger’s early life was marked by tragedy, privations, hardships, love, and scientific achievements. This time in his life spanned The Great War to End All Wars, World War I, as a boy, as well as the rise of Adolph Hitler and National Socialism while he was a young adult. These large events in Germany formed the background in his life, intruding into it in his early years as they did for all Germans, and ultimately forced hard choices after the next war as well.


Werner Schwerdtfeger was born on July 12, 1909 in Köln, Kalk District, in a Germany ruled by Kaiser Wilhelm II. He was the son of a Prussian Major, Otto Dietrich Schwerdtfeger[7][8] and his wife, Helene Laura Hueck. 1909 would prove to be an important year in his life for another reason: three of the most important people in his life were also born in that year. Rudolf Schütze was born December 6, 1909 in Königsberg, East Prussia; Heinz Helmut Lettau was born November 4, 1909, also in Königsberg; and, most importantly, his future wife Marianne Margarithe Noack was born May 11, 1909 in Leipzig, and all proved seminal influences in the development of Werner in the years before and after the second world war.

Tragedy struck early in his young life when he was just five years old. His father, Major Schwerdtfeger, a tall and imposing figure of a man, was killed early in the war on December 10, 1914 near Lowicz, Poland at the start of the German campaigns against Russia. He is buried in Göttingen, home to the Schwerdtfegers and where young Werner grew to manhood with his mother and older brother Hans.

Major Otto Schwerdtfeger, third from left, and his brothers Erich, Heinrich, and Ernst Source: Schwerdtfeger Versuch einer Genealogie
Living conditions in Germany steadily deteriorated as the war was prolonged and the Allied blockade in particular had an ever-increasing negative economic effect on both the home front and the armed forces. Conditions improved some after the war but privations continued and the Weimar Republic struggled to maintain stability in the face of increasing labor agitation and the growing strength of the Communists and other factions during the Twenties.

The National Socialist German Workers' Party, or Nazi Party, emerged during this time from the German nationalist, racist and populist Freikorps paramilitary culture, which fought against the Communist uprisings in post-World War I Germany. The party was created to draw workers away from Communism and into völkisch nationalism. A charismatic young leader, Adolph Hitler, began to assume a greater and greater role in party politics.

Against this background, young Werner attended Göttingen’s prestigious Humanitisches Gymnasium[9], with its very demanding high school curriculum. In 1927, he began university studies at the University of Freiberg and then transferred in 1929 to the University of Leipzig where he studied under the direction of Professor Ludwig Friedrich Weickmann at the Institut für Geophysik und Meteorologie.

He later told Heinz Lettau how he became interested in the atmospheric sciences. Bored with the abstract subject matter of mathematics[10], he was browsing through the library stacks at Freiberg when he found the 400-page "Textbook on Meteorology"[11] by Julius von Hann and Reinhard Suring. Fascinated by the subject that applied mathematics to nature, he decided to matriculate at the University of Leipzig.

Part of his time there as a student included mandatory service in data collection and observations from the Institut’s mountaintop tower observatory, under construction and somewhat primitive, at Collmberg ("Hill, mound")[12] about 30 miles west of Leipzig at an altitude of 312.8 m (1026.3 ft). In 1931 he earned a Doctor of rerum naturalium (Doctor of Natural Sciences) degree at the Institut. His doctoral thesis analyzed pulsating outbreaks of polar airmasses during a Northern Hemispheric winter season.

Professor Ludwig Weickmann and the Collmberg Observatory as it is today Source: Borngen, Michael, and Ziemann, Astrid
In Leipzig during this time, he met at university and became friends with Heinz Helmut Lettau who also received his doctorate in 1931 under Weickman’s direction. It was while at the Institut that Schwerdtfeger first met his future wife, Marianne Margarithe Noack, and that Lettau met his future wife, Katherine.[13]

Researcher, Aeronaut, Teacher

In the 1920s and 1930s, civilian and military meteorological and weather forecasting activities were rapidly evolving as was technology for observing weather conditions. Upper air observing techniques were developed using pibals and vertical data-collection ascents by aircraft in weather flights from selected airfields. Radiosondes were designed and developed although they did not reach limited operational use until the very late Thirties. Weather forecasting techniques became more sophisticated as knowledge of atmospheric structure and climatological weather patterns grew in greater detail. International cooperation in exchanging weather observations and data became common, especially in Europe. It was an exciting and challenging time to be a meteorologist.

The rise of the Nazi Party continued apace in the 1930’s and by 1932 it was the largest political party in Germany. On January 30, 1933 Hitler was appointed Chancellor by President Hindenburg. Shortly after, the Reichstag passed the Enabling Act of 1933 which began the process of legally transforming the Weimar Republic into Nazi Germany. When Hindenburg died in August 1934, Hitler became both President and Chancellor, thus becoming both head of state as well as head of government and essentially the de facto legal dictator of Germany.

The rise of Nazism led Werner’s older brother Hans, an outspoken critic of the Nazis, to leave Germany clandestinely in 1934, settling his family first in Prague, then Zurich, and then Grenoble. He and his family finally managed to emigrate from war-torn Europe to Sydney, Australia; he was later appointed a lecturer in mathematics in Adelaide in 1940 where he taught for many years.[14][15]

Meteorology in Germany had largely been a conglomeration of local state services and activities at universities. At the instigation of Professor Franz Linke from Frankfurt, one of the first German aeronautical meteorologists and a pioneer in observations from manned free balloons, the Reichswetterdienst.

Werner Schwerdtfeger began his professional career as a meteorologist with the German government’s weather service at Berlin-Tempelhof aerodrome in 1931, followed by in-house service with the German equivalent of the US Civil Aeronautics Board (CAB). During this time Schwerdtfeger and Lettau, "supported by the venerable Suring," began collecting weather data in manned hydrogen balloon flights for researching atmospheric phenomena such as turbulence

They were perhaps influenced by the weather research ballooning adventures of their mentor, Professor Weickmann, Director of the Institut fur Geophysik und Meteorologie during its two-decade heyday beginning in 1923. Likely Weickman’s most famous such exploit was his participation as director of meteorological activities during the five-stage, over-one-month-long 1931 polar flight of the airship LZ-127, the famed Graf Zeppelin, sister ship to the LZ-129 Hindenburg.

Route of the Graf Zeppelin on its 1931 polar flight Source: Borngen, Michael, and Ziemann, Astrid

Schwerdtfeger and Lettau’s most interesting ballooning experiment was possibly their measurement of air motions below 4 kilometers using instrumented manned hydrogen balloons in free flight. The experiment was motivated by the work of Wilhelm Schmidt and Ludwig Prandtl on 'Austausch' (Exchange) Theory a in the 20’s and 30’s.[16]

The first known experiments to determine Austausch coefficients (and associated turbulent structures) were conducted by Schwerdtfeger and Lettau in a series of flights in 1933 and 1934, with results published in a set of co-authored papers in the Meteorologische Zeitschrift. At the 1933 Annual Meeting of the German Meteorological Society in Hamburg, Professor Schmidt dubbed the pair the "Austausch Twins" for their exploits. Their method for determining vertical motion, does not appear to have been used by others although it appears that the accuracy of their method has also not been equaled by aircraft sensing or other techniques.[17]

Their open-gondola ballooning exploits were further enhanced by the participation of Werner’s wife, Marianne, who served as a technical assistant in the gondola while Schwerdtfeger and Lettau were busy reading instruments that measured the fine scale structures of fluctuating vertical winds.[18] Werner and Marianne Margarithe Noack were married in Leipzig in 1933.[19]

Crew and ground support team prior to the 25 Feb 1934 launch. The four crewmembers are on the right: Marianne and Werner Schwerdtfeger; Robert Petschow, the pilot on the flights; and Heinz Lettau Source: H. Lettau

Liftoff from Bitterfield Aerodrome on 25 Feb 1934 Source: H. Lettau

While continuing his meteorological research activities, Schwerdtfeger took over the aerological station at Königsberg in 1935. Königsberg was one of five such wetterflugstellen (meteorological flight stations) in service at the time at airfields in Germany that collected daily weather data in vertical ascents by aircraft to at least 5000 meters (16,400 feet). Eight such stations formed a network later in the 1930’s: Darmstadt, Hamburg, Königsberg, Munich, Berlin, Breslau, Köln, and Frankfurt. Schwerdtfeger accumulated over 1000 such aircraft ascents to the neighborhood of 500 mb (just over 18,000 ft above sea level), many of them in open-cockpit biplanes, while stationed at Königsberg. It was there that he met and flew with Rudolf Schütze, pilot for many of those flights and a lasting friend of the Schwerdtfegers in peace and at war.[20] And it was there that the Schwerdtfeger’s first child, son Dietrich, was born on June 16, 1936.[21]

Schwerdtfeger’s goal was to become an academic, a professor teaching at a university. He lectured in meteorology at the universities at Königsberg and Vienna while continuing his research. To become a full professor and teach independently at the university level in Germany then, as now, required a second degree not based upon coursework; the candidate had to habilitate and be awarded the second degree, a Doctor habilitatus. The Doctor habilitatus could be awarded based either upon a second doctoral thesis or upon a significant body of research, the latter path followed by Schwerdtfeger. He completed habilitation in 1937 at Königsberg, prepared to assume a career as an academic, teacher, and researcher.

It was not to be. He was denied a teaching appointment because of politics. In his own words:

"Under these conditions, my personal situation became threatened. Through all the years since 1933 I had been under pressure to join the NS party, but nobody could convince me, which appeared to some people to be suspicious per se. My older brother, a mathematician, foresaw a new and terrible world war as early as 1934, though at that time nobody wanted to believe him. A few months later he left Germany for good, and finally found an academic position at the University of Adelaide, Australia. His departure from Germany without permit was known in 1937, when I was weather-flying at Königsberg and began teaching courses at the ‘Albertus Universität’. I had fulfilled all requirements for admission to an academic career but was informed rudely that I had not shown the right Weltanschauung (political principles), and therefore had no chance for any teaching appointment. I sought safety in the military world (in which my father had died in 1914), and weather reconnaissance aviation had become not only my devotion, but also my refuge."[22]


Political ideology originating from the work of Karl Marx “Das Kapital” written in 1848 as a reaction to the so-called class struggle between the proletariat (labourers) and the bourgeoisie. According to Marx the proletariat would take over power from the well-to-do classes though a revolution. The communist movement aspires an ideal situation where the means of production and the means of consumption are common property of all citizens. This should end poverty and inequality (communis = common).
German paramilitary units established directly after the Great War by former front soldiers. These groups were often named after their commander. Freikorps formed the basis of the eventual SA or Sturmabteilung.
Largest Soviet ground formation. It was attached to a certain area which gave its name to the units involved. For instance the Voronezh front.
National Socialism
A political ideology drawn up by Hitler based on the superiority of the German race, the leader principle and fierce nationalism that was fed by the hard Peace of Versailles. National socialism was anti-democratic and racist. The doctrine was elaborated in Mein Kampf and organised in the NSDAP. From 1933 to 1945 National socialism was the basis of totalitarian Germany.
The pursuit of a people to become politically independence or securing such independence.
Abbreviation of a national socialist.
Abbreviation of national socialism.
The Reichswetterdienst primarily carried out weather observation and auxiliary tasks for aviation. Most of the weather observing stations were located at airports.
Political ideology aiming at slight or no class differences. Means of production are owned by the state. Evolved as a response to capitalism. Karl Marx tried to substantiate socialism scientific.
Weimar Republic
Name for the German republic from 1919 until 1933. Hitler ended the Weimar republic and founded the Third Reich.
This expression has often been used to refer to the "wide worldview" or "wide world perception" of a people, family, or person.

Warrior Years

In 1938 Werner Schwerdtfeger became a member of the world’s first dedicated weather reconnaissance squadron based at Berlin-Gatow Aerodrome: the Luftwaffe’s Grossraum Wettererkundungsstaffel (Long-range Weather Reconnaissance Squadron), later in June 1939 designated Wettererkundungsstaffel, Oberbefehlshaber der Luftwaffe (Weather Reconnaissance Squadron, Commander-in-Chief Luftwaffe) and abbreviated as Wekusta (Wettererkundungsstaffel or Westa, Ob.d.L.) Both Rudolf Schütze and Schwerdtfeger continued their close association in the new unit, which developed weather reconnaissance equipment and operational procedures, evaluated aircraft for weather reconnaissance service, trained aircrews including flight meteorologists, and flew operational missions. Meteorologists in the Luftwaffe were Beamte , or civil servants, in military uniform and subject to military discipline and control.[23] Schwerdtfeger’s initial rank was Regierungsrat, the equivalent of a Luftwaffe or USAAF Major.

Starting rank among Luftwaffe uniformed civil servants in technical fields such as civil engineering, air traffic control, medical, firefighting, etc., and in meteorology and other sciences typically was based upon education level or on demonstrated expertise. Individuals with a doctorate typically started with equivalent rank to a Major; a bachelor’s degree earned a starting rank equal to a Leutnant, equivalent to a USAAF Second Lieutenant. Pilot cadres were largely filled with enlisted ranks, with officers in lead, command, and staff positions. Rudolf Schütze, despite his extensive prewar wetterflugstellen experience, began his service in Wekusta, Ob.d.L. as a civil servant in uniform; when the unit was "militarized" in August 1939 his rank was Unteroffizier, equivalent to a Corporal in the US Army. Promotion was usually based on merit and accomplishment; by 1942 he was a Leutnant and by March 1943 an Oberleutnant (First Lieutenant), highly decorated and with extensive combat service. He flew more than 1000 weather reconnaissance missions.

Prior to World War 2, the German military was very aware that when hostilities commenced Germany would be cut off from "upstream" weather data by its adversaries. Several measures were implemented to mitigate that impact prior to and during the war, including extensive use of weather reconnaissance aircraft, automatic weather stations and weather buoys, weather ships, and observations from submarines and other warships. An extensive "weather war" was fought in the Arctic and North Atlantic regions during the war, by the Germans to obtain weather data and by the Allies to keep weather data from them. Weather reconnaissance squadrons were essential sources of weather data for both the Allies and Germany throughout the war in Europe.

Meteorologists in the Luftwaffe were nicknamed "wetterfrosche" ("weather frogs") by their comrades. Frogs and weather have had a close association in German lore and several emblems of Wekusta units featured winged frogs as part of them. Wekusta "wetterfrosche," Met. Beobachtern (meteorological observers), were trained as weather observers, aircraft navigators, and aerial gunners. Twin-engine bomber cockpits were crowded, with the Met. B. sitting in what was normally the navigator’s seat next to the pilot and navigating as well as observing weather. Crews normally consisted of one pilot (Flugzeugfuhrer), one meteorologist (Met. B.), one or more flight engineers (Bordmechaniker), and one or more radio operators (Bordfunker). For self- defense, the meteorologist also manned the nose-mounted machine gun while the flight engineer(s) and radio operator(s) operated machine guns in other positions.[24]

Schwerdtfeger was no stranger to hazardous flight operations, beginning with flights in balloons filled with explosive hydrogen lifting gas in addition to the ever-present hazards from weather and mechanical failures. In over 1000 near-daily aircraft flights to collect data in vertical ascents at Königsberg, he had routinely dealt with hazardous weather and the always possible mechanical failures associated with biplane and early monoplane aircraft operations. Wetterflugstelle pilots, such as Rudolph Schütze, and flight meteorologists quickly became highly experienced in dangerous aircraft operations.

Wartime operations added the dangers from combat, with many Wekusta aircraft and crews lost to enemy aircraft and antiaircraft fire. Single-engine performance of most of the modified twin- engine bombers was marginal at best; engine failures on long overwater flights frequently resulted in ditching the aircraft with little or no chance of survival in the frigid North Atlantic and Arctic regions. Rescue after ditching or crashing was unlikely, especially in areas routinely patrolled by Allied aircraft and ships.

Some 302 meteorologists, many with doctorates, were assigned to Wekusta; at least 158 of them, over half, are known killed or missing in action during the war. Fourteen flight meteorologists from Schwerdtfeger’s squadron (staffel) were killed during the war, including seven with doctorates. Valor was a strong suit; Wekusta had 75 crewmembers (out of several thousand in some 11 staffeln) earn the German Cross in Gold (Deutsches Kreuz in Gold or DKG) for combat service. The DKG was only awarded to personnel who had previously earned the Iron Cross First Class for combat service. Twenty-one Wekusta DKG holders were meteorologists, including Werner Schwerdtfeger.[25]

After serving in weather reconnaissance since 1938, toward the end of the war Schwerdtfeger suddenly found himself transferred and in charge of the Luftwaffe’s principal forecast center.[26],[27] Fortunately, we have his own summary of his service as the Chief (Chef) of the Zentral Wetterdienst Gruppe (ZWG) to draw upon for this biography. Those with experience as forecasters will readily recognize the difficulties he describes with demanding "customers" and with unrealistic customer expectations. Schwerdtfeger ended the war in charge of ZWG, having survived several demanding forecast challenges and the collapse of Nazi Germany.


Luftwaffe Beamte, or military officials, were civil servants that served in the Luftwaffe in technical, administrative, legal, and other positions.
Iron Cross
English translation of the German decoration Eisernes Kreuz.
German air force.
machine gun
Machine gun, an automatic heavy quick firearm.
Abbreviation of a national socialist.
Oberbefehlshaber der Luftwaffe
Supreme commander of the German air force.
A military unit in the Belgian navy usually six to eight small ships operating together under one command. The smallest military unit in the Dutch air force of about 350 men. In most countries is the designation of a military unit thesize of a company. It is either an independent unit, such as a battery, or part of a bigger Calvary unit. In the air force it is the designation of a unit of aircrafts.

Weather Reconnaissance Meteorologist

Schwerdtfeger entered Luftwaffe service as a uniformed civil servant in early 1938 as a Meteorologische Beobachter Leiter (Senior Meteorological Observer) in the Grossraum Wekusta at Berlin. He would serve in the unit in its various designations until his sudden transfer to the ZWG in August 1943. The unit was formally activated on March 15, 1938 at Berlin-Gatow airport and was equipped with Heinkel He 111 and Junkers Ju 86 P converted twin-engine bombers for operational missions; some twenty additional aircraft types were assigned for research and training. The mission of the Wekusta was to gain experience and develop procedures for weather missions over broad areas; to test suitable aircraft and equipment; to train specialized personnel, particularly meteorologists as both observers and navigators; and to conduct operational weather reconnaissance missions. Those roles would remain with the Wekusta throughout the war.[28]

Dr. Walther Kopp, a highly-experienced pilot and scientist, was the initial civil service commander of the unit. Kopp was the former leader of the wetterflugstelle at Berlin-Tempelhof and had been a key member of Alfred Wegener’s Greenland Expedition and of the 1936-1937 Lufthansa Afghanistan Expedition. Oberregierungsrat (Lieutenant Colonel) Kopp led the unit into the start of the European war in September 1939. In September, the unit was further militarized and a regular Luftwaffe officer, Oberleutnant Kurt Jonas, became the commander, replacing Kopp. Kopp continued to serve as the senior meteorological observer in the unit until he was replaced on November 11 th by Schwerdtfeger. Kopp later transferred to Wekusta 26 at Munster-Loddenheide. Schwerdtfeger was likely promoted to Oberregierungsrat at that time (although there is some uncertainty as to exactly when in the records available to us).[29]

Just as the dedicated weather reconnaissance squadrons of the Germans were innovative, so were the procedures used and developed by the Wekusta. Development of weather reconnaissance procedures had begun before the war and were further refined during the Wekusta years by Dr. Schwerdtfeger and others in the Grossraum Wekusta, etc. A principal technique was the "saw-toothed" flight profile, or sagezahn-flugprofil, first devised in the mid-thirties by Dr. Rudolf Reidat and Walter Schulze-Ekardt on meteorological flights between Berlin, Königsberg, and Munich in a Junkers Ju W 34 transport aircraft. In the "saw-toothed" profile, the altitude was changed several times during the flight to obtain vertical soundings along the track.[30] At selected points, the aircraft would descend to near sea level to determine surface pressure. At least one wekusta aircraft descended so close to the sea surface that the propeller blades were damaged by contact with the waves! After collecting surface data, the aircraft would then climb to collect sounding data before descending again to the mission flight level, which usually varied from one leg of the track to another.

Collected weather observations were transmitted following the flight, as in early Wekusta missions, or were enciphered by the radio operator and transmitted by the aircraft inflight as was the more common practice for most of the war. Weather data were summarized in a special format, or "code," similar in part to that developed by the wetterflugstellen in the mid-thirties. John Fuller was the highly-regarded long-time historian for the US Air Force’s Air Weather Service and author of Thor’s Legions, a history of weather support to the US Air Force and Army from 1937 to 1987. He credits Schwerdtfeger with developing the Zenit ("Zenith") weather code used by the Wekusta.[31]

Fuller, who described Dr. Schwerdtfeger as "Germany’s foremost weather reconnaissance expert," wrote that the observations were encoded in the Zenit code and then enciphered using ciphers changed daily before being transmitted to a ground site where they were edited. The observations were then retransmitted to the Luftwaffe’s main weather central, the Zentral Wetterdienst Gruppe (ZWG), at Wildpark near Berlin. All weather reconnaissance reports plus all data from about 325 Luftwaffe weather reporting stations were channeled to the ZWG.[32] The Zenit code, in three successive versions, was used by the Wekusta throughout the war.[33]

After the flight, the Met. B. would compile a report in "clear text" entries in which the essential details of the cloud and weather observed were summarized. These reports included vertical cross-section sketches and temperature-height graphs. After any transmission errors from the flight were corrected, the reports were sent to ZWG and other centers for analysis and forecasting use.[34]

Schwerdtfeger used much of the collected weather reconnaissance data in scientific work during and after the war. In 1942, he presented a report about the characteristic formations of frontal clouds based on observations made over a two-year period by Wekusta in northern and western European sea areas. The results were presented in schematic cross-sections of warm fronts, cold fronts, and occlusions. Six years later he expanded his ideas in a comprehensive analysis of the structure of fronts and cold pools in an official report to the reconstituted German weather service.[35]

For many weather reconnaissance missions, especially tropical cyclone missions, customers want surface wind data. Before the development of the microwave stepped-frequency radiometers used today and capable of measuring surface winds throughout the weather reconnaissance mission, US Air Force weather reconnaissance crews estimated surface winds visually using techniques originally developed by the US Navy. Sea surface visual characteristics such as foam patches from breaking waves and the foaming crests of wind-driven waves could be used to estimate wind direction and speed with good accuracy, especially when at or below 1500 feet of the sea surface. Luftwaffe Wekusta used a more esoteric observing method.

Years after the war, Schwerdtfeger would write about the Wekusta method for surface wind estimation. The method, supposedly well-known to veteran seaplane pilots with a vested interest in knowing the surface winds before landing, was tested for Wekusta use and adopted at Schwerdtfeger’s suggestion in 1939. Wekusta meteorologists were not only weather observers and mission navigators but also aerial gunners, operating the nose-mounted machine gun for defensive purposes.

As Schwerdtfeger described the method, near the sea surface (not above more than 100 meters), the meteorologist would fire the machine gun downward at a slight angle of about 15 degrees. The impact of the bullets would create concentric patterns and slowly expanding circles on the surface. From each point of impact would rise a small cloud of spray carried away by the surface wind. By adjusting the downward angle of fire and airspeed, the aircraft would pass over the expanding reference circles; the meteorologist could easily determine the horizontal angle between the aircraft course and the direction of the sinking spray from bullet impacts. The surface wind could then be estimated for light winds.[36]

While not as accurate as the use of smoke bombs, etc., the method was simple and repeatable as long as ammunition remained. Schwerdtfeger noted that he used the method on flights across high pressure ridges over northern seas where he could study the location of the divergence line and winds surrounding it from observations taken every half-minute, roughly every two miles. He also noted that the method offered one of the "... few opportunities to apply a deadly weapon to a useful and peaceful purpose."[37]

With the formation of other Wekusta for operational wartime service, the Grossraum Wekusta was redesignated as Wekusta, Ob.d.L. on June 1, 1939. The mission remained the same. Shortly after, Werner and his wife Marianne welcomed a new member of their family, daughter Antje, on July 30th. 25 World War II in Europe began on September 1, 1939 with the invasion of Poland and declarations of war against Germany by both the United Kingdom and France.

Wekusta, Ob.d.L entered the war with at least 23 different types of aircraft, most used for training or research or for evaluation for operational mission suitability. Personnel consisted of 12 pilots, 10 meteorologists, six radio operators, and six flight engineers. The unit’s first operational sorties were flown using twin-engine bombers, nine He 111 J-1s and a single Ju 86 P. Meteorological data were collected using a "meteorograph" which recorded pressure, temperature, and relative humidity. Initially externally-mounted under the wing, the data could only be read after the flight ended. The meteorographs were soon relocated under the cockpit nose where they could be accessed inflight by the meteorologist for weather observations.[38]

Wekusta, Ob.d.L., formerly the Grossraum Wekusta, and later Wekusta 1, Ob.d.L., was the nucleus for all meteorological reconnaissance developments, providing new staffeln with experienced and trained personnel as well as specially-equipped aircraft. The new staffeln were assigned to regional air commands (Luftkriegskommando) of the respective "air fleets" (Luftflotten). On the eve of war, on September 1, 1939, there were five operational Wekusta trained and ready for combat weather reconnaissance.[39]

The period from September 1939 to May 1940 became known to many in the West as the "phony war" or "sitzkrieg" since combat operations were rare on both sides. That changed with the invasion of France and the Low Countries on May 10, 1940. More Wekusta were formed and the need for a second Ob.d.L staffel led to the formation of Wekusta 2, Ob.d.L. and the redesignation of Wekusta, Ob.d.L. as Wekusta 1, Ob.d.L. in July 1940. The mission remained the same. On July 3, 1940, the unit moved to Oldenburg in northwest Germany. The grass field proved too soft for sustained operations, and in January 1941 the unit transferred to Bad Zwischenahn west of Oldenburg. A meteorological observer training school was established at that time as part of the unit.[40]

Ehrenpokal awarded to Oberregierungsrat Werner Schwerdtfeger in January 1942. The obverse depicts two eagles in mortal combat; the reverse bears an Iron Cross in high relief. Oak leaves and acorns adorn the stem Source: Wulf Schwerdtfeger

On December 26, 1941, the Schwerdtfeger’s third child, Wulf, was born in Berlin. Then, at age 33 and with more than two years of wartime service, on January 19, 1942 Doctor Schwerdtfeger was awarded the Honor Goblet of the Luftwaffe (Ehrenpokal der Luftwaffe) for special achievement in combat in the air war. The Ehrenpokal award, established in February 1940, was made to honor aircrew that had already been awarded the Iron Cross First Class; it was unique to the Luftwaffe. Not long after, on May 27, 1942, Schwerdtfeger was awarded the Deutsches Kreuz in Gold for sustained combat service, one of only 75 Wekusta crewmembers so honored throughout the entire war.[41] On August 20, 1942, Wekusta 1, Ob.d.L. completed its 1000 th weather reconnaissance mission.

The base of Schwerdtfeger’s Ehrenpokal, inscribed with his name and "12 1 42," 12 January 1942; records of the award indicate 19 January 1942, the date the award was announced publicly Source: Wulf Schwerdtfeger

Schwerdtfeger continued to serve as the Chief Meteorological Observer of Wekusta 1, Ob.d.L. throughout 1942. He was joined in that capacity by Dr. Otto Krug, former Chief Meteorological Observer of Wekusta 26, in September 1942. Dr. Krug substituted for Schwerdtfeger when he lectured in meteorology at the University of Vienna during late 1942 and early 1943. Schwerdtfeger continued to lead the development of operational and weather observing procedures, development of meteorological equipment, evaluation of new aircraft for weather reconnaissance, and the training of weather reconnaissance aircrews throughout his assignment to the lead weather reconnaissance staffel. In 1943, the staffel organized instruction classes numbers 14 to 17 for meteorological observers that were university-educated.[42]

During June and July of 1942, Schwerdtfeger inspected all the Wekusta for Ob.d.L. to exchange information about experiences, investigate operational standards, and evaluate personnel. He then repeated the inspection assignment in June 1943; for the inspections, he was temporarily assigned to the Luftwaffe Wetterdienst staff as deputy chief. Following his inspection tour, Schwerdtfeger was sent to Greece. On August 3, 1943, he flew his 250 th combat weather reconnaissance mission from Athens-Tatoi as a meteorological observer in a Junkers Ju 88 piloted by Hauptman Hans Bonath, the staffelkapitan (squadron commander) of Wekusta 27. It was his last weather reconnaissance mission as he found himself suddenly transferred a few days later to Kurfurst, at Wildpark-Werder near Potsdam, Germany as the new Chef of the ZWG.[43]

He was replaced by Dr. Otto Krug as Chief Meteorological Observer in Wekusta 1, Ob.d.L. Dr. Krug’s service in that position proved short as he was killed in action in a Ju 88 on August 23, 1943. On August 26, 1943, Schwerdtfeger’s close friend, one of only three Wekusta crewmembers to hold the Ritterkreuz f (Knight’s Cross) during the war, Oberleutnant Rudolf Schütze of Wekusta 5 was killed in the crash of an Arado 232 twin-engine transport following engine failure shortly after takeoff in bad weather from Banak, Norway.[44]


Armed incursion.
Iron Cross
English translation of the German decoration Eisernes Kreuz.
German air force.
machine gun
Machine gun, an automatic heavy quick firearm.
Military intelligence service.
A military unit in the Belgian navy usually six to eight small ships operating together under one command. The smallest military unit in the Dutch air force of about 350 men. In most countries is the designation of a military unit thesize of a company. It is either an independent unit, such as a battery, or part of a bigger Calvary unit. In the air force it is the designation of a unit of aircrafts.
The track of a tank.

Zentral Wetterdienst Gruppe

During 1934, the Reichsamt fur Wetterdienst (RfW) was created in Berlin as a department of the Reichsluftfarhtministerium (RLM), the German Air Ministry. For the RLM, the RfW acted as the central controlling authority for all meteorological activities in Germany except those at universities and research institutes. The RLM directed the establishment of the Grossraum Wekusta in March 1938, led by Dr Walther Kopp.[45]

Coinciding with the establishment of the Grossraum Wekusta, the RLM directed the establishment at a higher administrative level of the Zentrale Wetterdienst Gruppe (ZWG) (Central Weather- service Group) of the Luftwaffe, headed by Doctor Kurt Diesing and subordinate for administrative purposes to the Chef Wetterdienst (Director of Weather Services) at Kurfurst, codename for the Oberkommando der Luftwaffe (OKL), or Headquarters of the Luftwaffe, at Potsdam-Eiche. Two ZWG meteorologists, Schuster and Bauer, were permanently detached to Wolfsschanze (Wolf’s Lair), Hitler’s personal headquarters.[46]

At the general officer level, Chef Wetterdienst played no direct role in weather analysis and forecasting activity; that was the province of the ZWG. The ZWG advised the OKL on all meteorological matters concerning operations and strategic planning. ZWG analyses and forecasts were based upon data from weather stations, weather reconnaissance missions, ships, dedicated weather ships (at the start of the war), and U-boats. Climatological analysis heavily influenced medium- and long-range forecasts. Doctor Diesing was a devoted and expert career meteorologist with over 30 years’ experience in synoptic analysis and forecasting. Beginning in 1938, Diesing quickly built the ZWG into an efficient and smoothly working organization.

Weather forecasting in Germany as elsewhere was still developing as the war began, possibly no longer in its infancy but certainly not much beyond adolescence. Forecasting practices beyond 24-36 hours were heavily dependent upon climatology, especially the long-range forecasts demanded then as now by military commanders and planners. The ZWG experienced great success with forecasts for the invasion of France and the Low Countries; Diesing’s ZWG forecast for good weather was largely based upon a typical high pressure over Western Europe in mid- May. For those forecasts and subsequent favorable weather, Diesing was promoted to Ministerialrat (Colonel) and received an engraved gold pocket watch from Hitler. The continued good weather throughout the summer of 1940 and the Battle of Britain further highlighted success by the ZWG. However, the Luftwaffe campaign failure during the Battle of Britain made Chef ZWG a convenient target for dissatisfaction when the weather was bad and prevented bomber and fighter operations over Britain.

The Luftwaffe’s failure in the Battle of Britain coupled with the onset of autumnal weather over Britain, the Channel, and the North Sea turned German interests toward the East and Russia. Hitler had long planned to invade Russia and military planning for the invasion had begun well before the invasion of Western Europe. The timetable was shortened and the invasion set for the onset of suitable weather in Eastern Europe. Fortunately for the Russians, Mussolini’s abortive invasion of Greece coupled with the later Yugoslav uprising compelled Hitler to rescue his Italian ally by in turn invading and occupying Greece, Crete, Yugoslavia, and several Aegean Islands. Despite German success, the delay and serious losses in personnel and materiel, especially the heavy losses of Luftwaffe paratroops and transport aircraft in Crete, critically delayed the 1941 Russia invasion and arguably cost Germany the war.

Success can breed unreasonable expectations among "customers." Diesing and ZWG were heavily involved in planning for the invasion and its aftermath. The delayed start to the invasion coupled with logistical failures stalled the invading forces barely outside Moscow as a severe winter began. During the following summer of 1942, Wolfsschanze requested temperature conditions for the coming winter of 1942-3. A comprehensive study by climatologists using up to 150 years of data showed that statistically three very cold winters in four had never occurred; a very cold winter was not to be expected following three years with two very cold ones. Diesing signed the short version, condensed from the study, and became a lightning rod for dissatisfaction when Nature paid no attention to statistics and the subsequent winter again proved very cold instead.[47]

The daily stress of briefing the high command at Kurfurst and supporting Wolfsschanze over nearly four years of war took a severe toll on Kurt Diesing and during early 1943 his health rapidly failed. He died in July. His deputy, who had to assume daily briefings of the high command generals, did not perform satisfactorily. A new Chef ZWG had to be found who could quickly regain the trust of the generals as well as maintaining the confidence of his colleagues.[48]


Armed incursion.
German air force.
Military intelligence service.
“Oberkommando der Luftwaffe”. German supreme command of the air force.
Headquarters of Adolf Hitler in East Prussia.

Chef, Zentral Wetterdienst Gruppe

Into that unwelcomed assignment walked Doctor Werner Schwerdtfeger, at age 34 already an accomplished meteorologist and researcher as well as a highly-decorated combat weather reconnaissance veteran. He later wrote that his first task was to get acquainted with the twelve meteorologists for whose professional output he was suddenly responsible. He noted that three of them had already achieved strong reputations in scientific meteorology: Richard Scherhag, Horst Phillips, and Herman Flohn. Scherhag had developed a semi-empirical method for forecasting tomorrow’s surface chart using today’s surface analysis and transplanting the 24- hourly isallobar field to today’s 500 mb flow fields, a method apparently later adopted by American and British weather centers. Phillips, a theoretician, developed a new aeronautical almanac particularly useful for navigating on long polar flights. Flohn, successor to Regierungsrat (Major) Heinz Lettau who left ZWG in early 1943 for another assignment, was one of the top climatologists of his generation.[49]

Schwerdtfeger’s other key task in his first month at ZWG was to learn the correct form, level of detail, and amount of information to present at the intense briefing sessions chaired by the commander at Kurfurst and attended by other generals and selected staff. He noted that: "An important point...was that I should rigorously confine myself to talk about weather features and forecasts of changes. Never should I say anything about the possibilities of flying. That was the prerogative of the ‘real’ air force officers."[50]

As sometimes happens, given his extensive operational experience, he inadvertently stepped across that boundary. On a day in September, the weather in Jutland was poor and expected to remain so into the next day. The commanding general inquired if a group of Ju 88s could land under such weather at Aalborg, a large airfield on flat land with no major obstacles around. The question was certainly addressed to the "1A," the executive officer. Since Schwerdtfeger had landed at least ten times at Aalborg under far worse conditions, he responded without thinking, "Yes sir, no fog to be expected." He drew an immediate and nasty reprimand. The next day brought a measure of vindication. While the Ju 88s were enroute to Aalborg, a new question arose: can they land tomorrow at Banak? Banak, Norway was home to part of Wekusta 5 and several bomber units, and was one of the few forward bases for launching attacks on Allied convoys carrying supplies to Murmansk. An awkward silence ensued with all eyes on the "1A." He was obviously unprepared for a pro or con decision and finally said "never been there."[51]

Unlike Aalborg, Banak lay at the southeastern end of a fjord surrounded by mountains with steep escarpments. Offering few amenities, also unlike Aalborg, it was seldom visited and none of the staff officers present knew the place. The weather forecast for Banak was worse but similar to that for Aalborg a day earlier although with strong winds from the northwest. The awkward silence continued, finally broken by an angry general, "Anybody familiar up there?" No one responded. Uncertain as to what might result, Schwerdtfeger looked at the general and nodded very slightly. To his surprise, the general suddenly and humorously said, "You win, doctor, go on – tell us." There was relief all around as Schwerdtfeger, who had been at Banak three months earlier, explained the terrain so it was obvious that the flight of Ju 88s should be postponed. His forecast for improved weather at Banak for the flight the next day also came true. From then on, he was accepted as a real member of the Kurfurst briefing team. [52]

Nevertheless, friction continued at times with disagreement most often involving forecast reliability past a couple of days. The pressure of an increasingly gloomy outlook for Germany in the war contributed to the tensions as well. The differences between two- or even three-day forecasts based upon synoptic surface and upper air charts, given at any time and updated as necessary, and the twice-weekly five day "outlooks" prepared by Flohn and Phillips from current data coupled with climatology were frequent sources of displeasure from Kurfurst and Wolfsschanze. Constant efforts were necessary to distinguish between outlooks and forecasts and to stress that no one could forecast details reliably for more than two or three days. It didn’t help that the weather service of the Kriegsmarine (Navy) routinely issued ten-day forecasts, especially for the coasts of Norway and the English Channel, regardless of their accuracy. [53]


Germa navy. Part of the Wehrmacht next to Heer and Luftwaffe.
Headquarters of Adolf Hitler in East Prussia.

Normandy and the D-Day Forecast

Paraphrasing Samuel Butler, Schwerdtfeger has noted: "God cannot alter the past, but historians can."[54] Much has been claimed and written about the Allied forecasts for the D-Day landings in Normandy. Many authors have claimed Allied forecasting successes versus failures of German forecasting for that event, particularly in accounts written immediately following the war by the Allied principals involved. These accounts, often incomplete and frequently self- serving or even blatantly in error, have persisted in some more recent histories. Over the years, more comprehensive work, while acknowledging the overall success of the Allied forecast for June 6 th , tends to credit the successful landings more to the overwhelming Allied forces employed despite adverse cloud, wind, and sea conditions worse than forecast and that seriously impacted efforts to land troops and equipment under enemy fire.

Allied assault landing craft were capsized or swamped in large numbers attempting to land in the face of enemy fire. Many of the unwieldy small craft were lost when tossed upon beach obstacles, many of them with explosive mines attached, or into other vessels. Almost all of the US "swimming" duplex-drive M4 Sherman tanks, never tested in such sea conditions, sank taking their crews with them. Most of the light artillery carried by amphibious DUKWs toward Omaha Beach was similarly lost at sea.[55]

Heavy bombers were unable to bomb visually, releasing their bombs well inland instead of on the beach defenses. The lack of bomb craters on Omaha Beach, expected by the landing troops, deprived the landing force of shelter from the intense German fire from the overlooking cliffs. Paratroops of the 82 nd and 101 st Airborne Divisions were scattered away from their landing zones when their transport aircraft broke formation in unexpected dense cloud cover over Normandy inland from Omaha and Utah Beaches.

Accounts by individual soldiers stress the rough seas and seasickness as well as the difficulties of getting ashore in wave action edging the broadly-exposed and difficult to cross sea bed at low tide.[56] Some units had to use their helmets as bailers to keep their landing craft from swamping, bailing while seasick. Troops landed already exhausted from seasickness. Accounts by naval officers emphasize the difficulties of the small craft, "swimming" tanks, and amphibious vehicles in getting ashore. John Fuller in Thor’s Legions pointed out the politics involved with the D-Day forecast and in achieving a consensus of sorts between individuals at the three independent Allied forecast centers in England, one American (USAAF) and two British (RAF and RN).[57]

William Logan, author of Air: The Restless Shaper of the World, noted that the Allied forecast succeeded "... not because of the brilliant work of any forecaster, but because a group of forecasters imitated the weather. They jostled, yelled, scribbled, and cast malevolent looks at one another. They fought it out and voted. And in the end, they were just right enough."[58] "Just right enough" ...that might seem a bit harsh. Yet the same teams and individuals were involved in the disastrous forecasts two weeks later that led to the loss due to weather of the Mulberry Harbors necessary for logistical support to the invasion.[59] The consensus forecasting effort that largely worked for D-Day did not work well at all two weeks later. It was a forecast system primed for error as at least one staff meteorologist had quietly pointed out.[60]

Many Allied naval officers, including Eisenhower’s naval aide, Captain Butcher, were dismayed by the differences between forecast and actual wind and sea conditions on June 6 th and that largely remained on June 7 th .[61] Those conditions accounted for significant losses before assault troops and equipment could be landed. Nevertheless, the invasion succeeded, in large part because it had begun at low tide, timed to expose most of the beach obstacles and take advantage of darkness to hide the ships and assault boats for the initial approach, and also because Hitler and most of his key generals thought it was a feint and expected the "real" landings to take place further east at the Pas de Calais.[62][63][64]

German planners had expected any invasion to begin at high tide to get landing forces past the obstacles and then only after several days of suitable weather. The assault landings had originally been planned for May, and were expected by the Germans then due to the typically good weather over the Channel and France in May (recall the Diesing forecast for the invasion of France and the Low Countries). Delayed a month by Eisenhower and Montgomery to add more troops and accumulate more landing craft, etc., Allied timing surprised German leaders and large-scale deceptions led them to look further east away from Normandy and toward Calais.[65]

Accounts by Schwerdtfeger, Lettau, and in some cases, Fuller, contradict the idea of poor German forecasting for D-Day.[66][67][68], Schwerdtfeger stressed that the ZWG forecasts passed to Kurfurst, Wolfsschanze, and Luftflotte 2 (in Paris) and by them to the Army during the critical period happened to be good, specifying winds of Beaufort Force 5, varying from 4 to 6, equivalent to 15 - 23 knots. Actual winds closely matched the ZWG forecast as the day progressed; the Allied forecast remained for Force 3 or less as opposed to an actual increase to Beaufort 4/5 by afternoon.[69][70]

Note that Beaufort Force 3 tends to produce large "wavelets" with scattered whitecaps; Force 4 waves 1-4 feet with numerous whitecaps; and Force 5 moderate waves 4-8 feet with many whitecaps. Four-to-eight-foot seas severely batter small craft; as one result, the numerous German e-boats, desperately needed for attacking the landing forces, were unable to sortie due to the rough seas in the Channel and to tidal conditions.

The ZWG forecasts, as usual, were for weather only with no judgments regarding the probability of an invasion (then as now, that was the exclusive province of the commanders involved and not the meteorologists). Fuller reported that many of the more unreliable D-Day German forecasts came from Kriegsmarine and other sources, and Schwerdtfeger admitted that he did not know if different forecasts from other sources had been passed on to Army commanders, influencing their thinking.[71]

Given the pre-invasion German planning and expectations, there’s little wonder that their commanders were caught by surprise not by bad weather forecasting but rather due to failure early on to recognize the seriousness of the invasion reports and act accordingly. A weather forecast is only one element in a command decision. To suggest that D-Day occurred or succeeded because of a weather forecast is naive. No commander then or now risks success or failure solely on a weather forecast.

Misinformation about German meteorological intelligence and forecasting continues to enter the literature, regrettably from British and American sources, and continues to be quoted by military historians. In 1979, however, the Polish historian Januscz Pielkalkiewicz discovered captured documents in US military archives that contradicted the notion that German weather forecasts in June 1944 were inaccurate.[72] That report from Kington and Selinger has not been confirmed by us as of this writing.

A measure of the success of ZWG’s forecasting at the time comes from Schwerdtfeger’s own words:

"Regarding my own position, I can add that after the landing of the Allies my daily contact with members of the general staff at Kurfurst indicated more appreciation for the work of meteorologists than I had felt in my first nine months at ZWG. And there was another personal experience: General der Flieger (three-star general in the Air Force) v. Seidel [ed.: Hans-Georg von Seidel (1891–1955)] had frequently been present at the daily briefings. Older than most of the staff members, he was a man who inspired trust at the first glance. He had spoken little, but when he did, his judgment was respected by everybody. A few weeks after D-Day he had to leave Kurfurst. To my complete surprise, he gave me a photo of himself; on the back, handwritten, a very friendly dedication to me, his name, dated 30 June 1944. I was deeply moved by this unexpected gesture and, frankly, I still am. I value it at least as highly as any of my military decorations and medals, all still in my possession. It is just inconceivable that v. Seidel would have given me such recognition if a few weeks earlier I had substantially contributed to Germany’s disaster at the beaches of Normandy by a wrong forecast of weather conditions."[73]

Picture of General der Flieger von Seidel presented to Doctor Schwerdtfeger on June 20, 1944 at Kurfurst Source: Wulf Schwerdtfeger

Another measure of the success of ZWG’s forecasting over the Normandy invasion is more indirect but perhaps more suggestive. Five months later, Schwerdtfeger was charged under great secrecy with preparing a highly important forecast for an operation critically dependent upon weather for any chance of success. He suggested that he would not have been selected for that task if ZWG forecasts for the first week of June 1944 "had been deficient."[74]


The day of the long awaited invasion of western Europe in Normandy, France, 6 June 1944. After a long campaign of deception the allies attacked the coast of Normandy on five beaches to begin their march on Nazi Germany. Often explained as Decision Day, though this is entirely correct. The D stands for Day as generally used in military language. In this case it means an operation beginning on day D at hour H. Hence “Jour J“ in French.
Armed incursion.
Germa navy. Part of the Wehrmacht next to Heer and Luftwaffe.
Royal Air Force. British air force
Headquarters of Adolf Hitler in East Prussia.

Ardennes Counteroffensive Forecast

Heinz Lettau introduced Part 3 of Schwerdtfeger’s ZWG (Zentral Wetterdienst Gruppe) account with the following:

"The Allied invasion of Normandy, codenamed Overlord, had succeeded despite marginal weather conditions during the critical period. The forecast supplied by the German ZWG at the time of the landings had been accurate, and the prestige of its meteorologists had risen. As the allied armies closed in upon Germany the Wehrmacht made its last desperate attempt to ward off the inevitable. This action, to become known as the Battle of the Bulge, took place in the Ardennes and its timing was dependent upon the forecast issued by the Chef ZWG, Werner Schwerdtfeger."[75]

Schwerdtfeger noted that the initial assignment was a "true mission impossible":

"Two days before occurrence in the coming month of December, you have to forecast the date of a period of five days or more in which fog and/or low clouds will cover continuously a wide area west of the River Rhine north of the 50 o N parallel approximately, including the region of the Ardennes."[76]

Even with today’s technologies and forecasting techniques, that forecast would be a challenge to produce for such a large-scale, shrouded-in-secrecy military operation. Seventy-five years ago, it was indeed a virtually impossible forecast challenge with the data, techniques, and technologies available to the ZWG. Indirectly, it soon became obvious that such weather was needed for a last counterattack by the Wehrmacht against Allied forces advancing through France and Belgium. Since Allied air forces dominated the skies, success for such an operation depended upon keeping Allied air forces grounded long enough for a rapid and dominating advance by German panzers and infantry.

Schwerdtfeger noted that the "two-plus-five-day" forecast was "uncommon and really a severe challenge." He had previously been successful at times convincing the commanding general that such long-range forecasts were not worth the paper on which they were written. Some on the Wolfsschanze staff, perhaps even Hitler, may have recalled Dr. Diesing’s success using "singularities," synoptic conditions (cyclonic or anticyclonic) tending to occur on or near a specific date with significant probability. That had worked well for the invasion of France and the Low Countries in mid-May 1940; December in the Ardennes was a different matter altogether. Schwerdtfeger tried a couple of times without success to get the general, who apparently had orders directly from Wolfsschanze, to change to a more reasonable order.[77]

Schwerdtfeger later could not remember how many prior Decembers he and Flohn reviewed, but recalled the result: five-day periods none; four-day periods one doubtful; three-day periods a few. He found the statistics convincing; the general did not. He then decided, for the only time during his 20 months at ZWG, to ask Dr. Burkendorff, the Chef Wetterdienst or chief administrator of Luftwaffe weather services, for help. Burkendorff had connections at Wolfsschanze and two days later ZWG received "absolute minimum" requirements of a "forecast at least one day ahead, for three days or more of no-flight weather conditions."[78] It was the best ZWG was to get, and still a serious, and at that time in Nazi Germany, personally hazardous challenge.

Over the remaining weeks, ZWG worked hard to find guidance on the development and persistence of the desired fog and low cloud over the Ardennes, Eifel, and surrounding terrain. Lack of upper air data was the most serious challenge even with aircraft weather reconnaissance; except for data from Köln, about 100 km northeast, and places further to the east, no data were available. Success of any forecast beyond 24 hours would depend more on pure luck than anything else; it was still "mission impossible" for a 72-hour forecast.

Beginning the first day in December, Schwerdtfeger was required to contact both Kurfurst and Wolfsschanze every evening. Each time he politely submitted a "not yet," implying that a positive forecast would perhaps come before Allied forces reached the Rhine. In the evening of the 14 th , he said: "...probably yes, confirmation tomorrow at noon."[79]

The next morning, controlling weather was dominated by relatively warm and moist air and weak winds, presumably throughout the whole troposphere over Western Europe. Without cold advection from the northeast, it looked promising for the 16 th and 17 th but "...none of my synopticians dared to say anything about the third day." Shortly before noon on the 15 th , Schwerdtfeger called his two prime customers with the message: "Fog and/or persisting low-level cloud deck with poor visibility underneath to be expected in entire region, for 16-18 December, W.S., ORR, ZWG."[80]

Schwerdtfeger later wrote:

"Strange things can happen in nature. It really was unbelievable. The three days came and passed. According to all information we could gather, the weather was exactly like the guessed forecast. The fourth day still was quite similar, only in the afternoon some rise of cloud-deck occurred and a few airplanes were visible or audible; even on the fifth day, apparently with stronger winds, thick low clouds prevailed over most of the critical region. We had found not one case of five continuous days of this kind in all the Decembers we had checked - but here it was. From the meteorologist’s viewpoint the entire event became even more bizarre because almost everybody forgot that we had restricted the number of forecast-days to one-plus-three."[81]

Even with favorable weather for five days, the Ardennes offensive failed and German forces soon retreated under relentless Allied attack. Schwerdtfeger was somewhat astonished that "...superfluous administrative functions were carried on as if nothing of importance was happening beyond them." In the third week of January 1945, Schwerdtfeger and Chef Wetterdienst were summoned to the commanding general’s office at Kurfurst. In the presence of other officers, there was a short address recognizing the work done by ZWG at the start of the counteroffensive, and announcing Schwerdtfeger’s promotion to Ministerialrat (or full colonel). The second recognition and promotion, to the rank of Oberregierungsrat (lieutenant colonel), went to Oskar Schuster who through five years had served as meteorologist at Wolfsschanze.[82]


Ardennes offensive
Battle of the Bulge, “Von Rundstedt offensive“ or “die Wacht am Rhein“. Final large German offensive in the west from December 1944 through January 1945.
Foot soldiers of a given army.
Armed incursion.
German air force.
Military intelligence service.
Abbreviation of a national socialist.
Attack on a smaller or larger scale.
German armed military forces, divided in ground forces, air force and navy.
Headquarters of Adolf Hitler in East Prussia.

Last Days of War

The bitter end approached not long after. With Russian forces approaching Berlin from the east and the Americans, British and French at the Rhine, ZWG had to move to remain operational. Sufficient electrical power had to be available to maintain radio transmission of meteorological information to weather units closer to the front. Telephone and teletype service had become less and less reliable. The second week in February, ZWG was ordered to prepare to move by special train from Wildpark to Neubiberg, a military airfield a few miles southeast of Munich in Upper Bavaria. The first step in uninterrupted ZWG services was to temporarily establish about a quarter of ZWG’s personnel under Richard Scherhag at Quickborn near Hamburg. A large radio station there was still in working order.[83]

The main ZWG group prepared for its railroad journey in three passenger cars and fourteen freight cars. The special train left Wildpark on February 24, 1945 also with Chef Wetterdienst and staff, and with numerous stops and changes of rail lines, arrived in Neubiberg on March 2 nd . There was plenty of room in unused barracks. A few days later, ZWG was again in full operation. There was no Kurfurst general staff and no daily briefings. The number of weather reports continued to decrease, the number of customers diminished, and so did ZWG morale..[84]

Morale particularly decreased among the some 60 "communications girls" who still worked for ZWG. Some had already been discharged at Kurfurst if they could reach home easily by rail. To those remaining, and who had any chance of reaching home and family, Schwerdtfeger arranged to issue official travel orders. Chef Wetterdienst had refused to do so, but the commander of the airfield (a Luftwaffe major) gave Schwerdtfeger the necessary authority and forms..[85]

Chef Wetterdienst and staff left a week later for southeastern Bavaria where many generals and their staffs began to congregate near Hitler’s lodge (Berghoff) above Berchtesgaden. The only orders received by ZWG were to incorporate two motorized weather units and to remain in touch with Kurfurst by telephone. No further orders were received and Schwerdtfeger had to plan what to do when American soldiers approached Munich. There were three basic problems to consider:

  1. How to prevent the remaining communication girls being made prisoners-of-war;
  2. How to preserve the daily weather charts and other valuable meteorological material, because of their historical value;
  3. What to do with the men who were obviously neither prepared nor willing for senseless fighting on the last days of the war..[86]

The forty communications girls still at Neubiberg were called in for departure in civilian clothes. Guided by two native Bavarians, a meteorologist, and a technician, they left on foot and with a few bicycles, moving south. Almost everywhere the female ex-soldiers found refuge with local people. After the war, Schwerdtfeger heard from several of them that they had come to no harm..[87]

The preservation of daily weather maps and other material of the past six years proved hopeless. Herman Flohn volunteered to remain at Neubiberg, where everything of value was stored in a basement. He tried in vain to convince an American officer that the maps were of significant value to meteorologists of any nationality. Flohn was carried off with other prisoners of war and told Schwerdtfeger about the loss about twelve months later. The loss was already known; wrapping paper was scarce in Germany at that time and one of the technicians found a purchase wrapped in half of an original 1944 ZWG surface analysis. Despite efforts, nothing was recovered.[88]

ZWG’s plan was to conceal the remainder of the unit for at least the first few days of the occupation of the southernmost portion of Bavaria. The hideout selected was a heavily-wooded area difficult to access from the main roads but not too close to the northernmost slopes of the Alps where many units had already gathered. An appropriate spot had been located not more than 30 km south-southeast of Munich. Sonderdilching is enclosed on three sides by the sharply-turning Mangfall, a deep cut, narrow, fast-moving river with a timber forest close to and on the steep slopes. The rough road from Holzkirchen eastward became an obstacle course down an old wooden bridge and up to higher countryside. The vehicles could be targets in an open field so the four drivers of the "wrecks" moved them on their final trip to hide up in the nearest woods. That essentially established the "graveyard" of the ZWG.[89]

For the next two days they almost constantly heard the noise of nearby American units moving southeast. It then became quiet in Sonderdilching. They had food for two weeks and were sleeping in two buses and the barns of local farms. Schwerdtfeger spent much of his time in the radio truck, waiting for news of the surrender. Finally it came on May 8, 1945. Schwerdtfeger called everyone to report the next morning on the meadow above the vehicles. On a brilliant spring morning, he told everyone what had been prepared for them: a document (of doubtful value) stamped and signed and declaring that the bearer was honorably discharged; a just portion of the remaining food; and his salary prepaid for May to July from the "ZWG war chest". And then: "I hereby declare ZWG terminated and everybody now his own boss. I wish the very best for everyone."[90]


Largest Soviet ground formation. It was attached to a certain area which gave its name to the units involved. For instance the Voronezh front.
German air force.

New Beginnings

Schwerdtfeger’s war ended in early May 1945 although its effects lingered long after. He became a prisoner of war and eventually was interrogated by a USAAF weather officer, Captain Gilbert Woods, of Detachment C, 21 st Weather Squadron, who reported the results to his commander in mid-September.[91] In autumn of 1945, Schwerdtfeger was freed and transferred by the Americans to direct civilian weather services for southern Bavaria.[92][93]

Postwar Germany was a living nightmare for most Germans. Food, shelter, and basic services were in severely short supply and would remain so, especially in the Russian sector, for several years. A decimated Germany struggled to survive and recover. Divided into four sectors, American, British, French, and Russian, each had different military "governments," governing policies, and weather services. Starting in 1946, civilian weather centers manned by German meteorologists were established by the French at a small town in the Black Forest, by the British at Hamburg, and by the Americans at Bad Kissingen in extreme northwestern Bavaria. Bad Kissingen was one of the few German towns not destroyed in the war.[94]

The Bad Kissingen weather center was initially directed by Gerhart Schinze and then by Schwerdtfeger’s mentor from the 1930’s, Ludwig Weickmann. Weickmann was dedicated to reestablishing weather services and meteorological science in Germany. His efforts were largely successful in the American sector. Then in 1949, the Federal Republic of Germany (FRG) was established, consolidating the American, British, and French sectors into what became known as West Germany. Weickmann and other German meteorologists were then successful in establishing the Deutscher Wetterdienst, the German Weather Service, in 1952. [95]

Schwerdtfeger remained in charge of civilian weather services in southern Bavaria until 1948 and also taught at the University of Munich starting in 1947. His oldest son’s health suffered, in part due to the poor diet experienced by most Germans at that time. Concern for Dietrich and other issues in postwar Germany led Schwerdtfeger to look for other options. Finally, in 1948 and to the dismay of Weickmann, Schwerdtfeger left with his family and settled in Argentina. Lettau, in an interview after he had retired with his wife to South Carolina near Charleston, said that Schwerdtfeger’s departure was "clandestine," apparently unannounced beforehand. The Schwerdtfeger family went to Genoa, and from there traveled by ship to Buenos Aires.[96]


Military intelligence service.
A military unit in the Belgian navy usually six to eight small ships operating together under one command. The smallest military unit in the Dutch air force of about 350 men. In most countries is the designation of a military unit thesize of a company. It is either an independent unit, such as a battery, or part of a bigger Calvary unit. In the air force it is the designation of a unit of aircrafts.

Scientist and Teacher

Beginning in 1948, Schwerdtfeger was the scientific advisor to the Argentino Servicio Meteorologico Nacional in Buenos Aires. He also taught at the Escuelo Superior de Meteorologica de la Nacion. In 1957, he became the scientific advisor to the Hydrographic Office of the Argentine Navy and taught meteorology and atmospheric physics at the local university. He maintained his association with the hydrographic office until 1961. In 1950, he published the diary of his friend Rudolf Schütze. In 1982, with Franz Selinger, an aeronautical engineer and established author, he republished the diary as Wetterflieger in der Arktis 1940-1944, a memorial to Schütze that details his experiences as a wartime Luftwaffe wekusta pilot. He published his first meteorological book in 1952, containing over 100 scientific publications in Spanish, German, and English.

In 1957 and 1958, during the International Geophysical Year, Schwerdtfeger was a visiting professor in Australia at the University of Melbourne and then later at UCLA and in Boulder, Colorado. In 1962, Schwerdtfeger was appointed professor at the University of Wisconsin; he was to remain at Madison after his retirement as Professor Emeritus in 1980. In 1979, he was elected a Fellow of the American Meteorological Society.

Schwerdtfeger’s love of books was reflected in his abiding interest in and loving care of the Meteorology Department’s reading room. From modest beginnings, he prepared the ground for establishing an official University of Wisconsin branch library.[97] Upon his retirement, it was officially named the Schwerdtfeger Library. In 1983, the Schwerdtfeger Academic Award was established at the university; each year it is awarded to the first-year graduate student who has performed at the highest level academically during the intensive first year of core course work

Doctor Werner Schwerdtfeger suffered a massive stroke at his home and the next day, January 17, 1985, died at the University of Wisconsin Medical Center, six months after his seventy-fifth birthday. He was survived by his wife, Marianne, daughter Antje, sons Dietrich and Wulf, several grandchildren, and his older brother Hans.

During his eventful life, he had lectured at many universities in German, Spanish, and then English, including:

  1. Universities in Königsberg (1936-38), Vienna (1942-43), and Munich (1947) in German;
  2. Escuela Superior de Meteorologica de la Nacion, Buenos Aires (1949-51), and University of Buenos Aires (1957) in Spanish;
  3. University of Melbourne in 1957/58 in English;
  4. And finally in English, at the University of Wisconsin where he was appointed Professor in 1962 and where he retired as Professor Emeritus in 1980.

A list of his publications includes over 100 titles in German, Spanish, and English. His major works include:

  1. El Problema de la Prevision del Tiempo, 1952, in Buenos Aires;
  2. "The Climate of Antarctica," a chapter in Volume 14 of the World Survey of Climatology series;
  3. Editor of Volume 12 of The Climate of Central and South America, in 1976, in the World Survey of Climatology series;
  4. and Weather and Climate of Antarctica, written and published in 1984.

Husband, father, friend; scientist and researcher; prolific author; aeronaut and flight meteorologist; teacher, professor, lecturer; leader and manager; warrior and combat flight meteorologist, aircraft navigator, and gunner. World-class meteorologist and recognized expert on weather and climatology of South America, Antarctica, and the Arctic. Read, wrote, and taught in three languages. Bibliophile. Strong of character and will yet gentle and patient when needed. Dedicated to excellence in everything he attempted and accepting no less from those he led and those he taught on four continents in three languages. He earned respect by deeds and not words, and was a staunch comrade and leader in a brutal war forced upon his nation by a brutal dictatorship.

Werner Schwerdtfeger was a Man for All Seasons.


  1. Lewis, John M.: "The Lettau-Schwerdtfeger Balloon Experiment: Measurement of Turbulence via Austausch Theory"; Bulletin of the American Meteorological Society; Vol 78, No11; November 1997; pp 2619-2635
  2. Austausch Theory. The determination of the virtual or eddy viscosity of air in the lowest levels of the atmosphere was a dominant theme for research during the first two decades of the 20th century.
  3. UW Automatic Weather Stations 2018
  4. Lettau Bluff at Wikipedia
  5. Mount Schwerdtfeger at Wikipedia
  6. USGS - Antarctica Detail; Mount Schwerdtfeger.
  7. Schwerdtfeger Versuch einer Genealogie
  8. Selinger, Franz: "Schwerdtfeger, Werner"; Neue Deutsche Biographie 24 (2010) S.72-73
  9. Nicholson, Sharon: Tape Recorder Interview Project; Interview with: Heinz Lettau, March 10,2002; American Meteorological Society; UCAR.
  10. ibid.
  11. Lehrbuch der Meteorologie ("Textbook of Meteorology"). Written by Julius von Hann and Reinhard Suring; Schwerdtfeger probably read the 1926 Fourth Edition.
  12. Collmberg .
  13. Nicholson, Sharon: Tape Recorder Interview Project; Interview with: Heinz Lettau, March 10,2002; American Meteorological Society; UCAR.
  14. Biography of Hans Wilhelm Edward Schwerdtfeger
  15. Nicholson, Sharon: Tape Recorder Interview Project; Interview with: Heinz Lettau, March 10,2002; American Meteorological Society; UCAR.
  16. Lewis, John M.: The Lettau-Schwerdtfeger Balloon Experiment: Measurement of Turbulence via Austausch Theory; Bulletin of the American Meteorological Society; Vol 78, No11; November 1997; pp 2619-2635.
  17. ibid.
  18. ibid.
  19. Selinger, Franz "Schwerdtfeger, Werner"; Neue Deutsche Biographie 24 (2010) S.72-73;
  20. Kington, John A. and Selinger, Franz: 'WEKUSTA', Luftwaffe Meteorological Reconnaissance Units & Operations 1938-1945; Flight Recorder Publications Ltd.; Ottringham, East Yorkshire; 2006; 256 pp.
  21. Selinger, Franz "Schwerdtfeger, Werner"; Neue Deutsche Biographie 24 (2010) S.72-73;
  22. Schwerdtfeger, Werner: "The last two years of Z-W-G (part 1)". Weather, Volume: 41, Issue: 4, 1986, pp.129-133. Reprint # 718.
  23. Kington, John A. and Selinger, Franz: WEKUSTA, Luftwaffe Meteorological Reconnaissance Units & Operations 1938-1945; Flight Recorder Publications Ltd.; Ottringham, East Yorkshire; 2006; 256 pp.
  24. ibid.
  25. ibid.
  26. ibid.
  27. Schwerdtfeger,Werner: "The last two years of Z-W-G (part 1)". Weather, Volume: 41, Issue: 4, 1986, pp.129-133. Reprint # 718.
  28. Kington, John A. and Selinger, Franz: WEKUSTA, Luftwaffe Meteorological Reconnaissance Units & Operations 1938-1945; Flight Recorder Publications Ltd.; Ottringham, East Yorkshire; 2006; 256 pp.
  29. ibid.
  30. ibid.
  31. Fuller, John F.: Thor’s Legions, Weather Support to the U.S. Air Force and Army, 1937- 1987; American Meteorological Society; Boston, 1990; 443 pp.
  32. ibid.
  33. Kington, John A. and Selinger, Franz: WEKUSTA, Luftwaffe Meteorological Reconnaissance Units & Operations 1938-1945; Flight Recorder Publications Ltd.; Ottringham, East Yorkshire; 2006; 256 pp.
  34. ibid.
  35. ibid.
  36. Schwerdtfeger, Werner: "A Rapid Method to Determine Light Surface Wind During Reconnaissance Flights"; Bulletin of the American Meteorological Society; Vol 37, No 7; Sept 1956; p. 369.
  37. ibid.
  38. Kington, John A. and Selinger, Franz: WEKUSTA, Luftwaffe Meteorological Reconnaissance Units & Operations 1938-1945; Flight Recorder Publications Ltd.; Ottringham, East Yorkshire; 2006; 256 pp.
  39. ibid.
  40. ibid.
  41. deZeng, Henry L, IV and Sankey, Douglas G.: Luftwaffe Officer Career Summaries; 1 April 2015; online web publication with extensive references.
  42. ibid.
  43. ibid.
  44. ibid.
  45. ibid.
  46. ibid.
  47. Schwerdtfeger, Werner: "The last two years of Z-W-G (part 1)". Weather, Volume: 41, Issue: 4, 1986, pp.129-133. Reprint # 718.
  48. ibid.
  49. ibid., 719
  50. ibid., 719
  51. ibid., 719
  52. ibid., 719
  53. ibid, 719
  54. ibid., 718
  55. Mueller, Gordon H.: "Everything We Have", D-Day 6.6.44; The National WWII Museum, New Orleans; Ande Deutsch, New Orleans; 2019; 256 pp.
  56. ibid.
  57. Fuller, John F.: Thor’s Legions, Weather Support to the U.S. Air Force and Army, 1937-1987; American Meteorological Society; Boston, 1990; 443 pp.
  58. Logan, William Bryant: Air, The Restless Shaper of the World; W.W. Norton & Co.; New York; 2012; 417 pp.
  59. Atkinson, Rick: D-Day, The Invasion of Normandy, 1944; Henry Holt and Company, New York; 2014; 202 pp.
  60. Fuller, John F.: Thor’s Legions, Weather Support to the U.S. Air Force and Army, 1937-1987; American Meteorological Society; Boston, 1990; 443 pp.
  61. ibid.
  62. ibid.
  63. Atkinson, Rick: D-Day, The Invasion of Normandy, 1944; Henry Holt and Company, New York; 2014; 202 pp.
  64. Mueller, Gordon H.: "Everything We Have", D-Day 6.6.44; The National WWII Museum, New Orleans; Ande Deutsch, New Orleans; 2019; 256 pp.
  65. Fuller, John F.: Thor’s Legions, Weather Support to the U.S. Air Force and Army, 1937- 1987; American Meteorological Society; Boston, 1990; 443 pp.
  66. ibid.
  67. Lettau, Heinz : History of the Schwerdtfeger Library; Schwerdtfeger Library .
  68. Schwerdtfeger, Werner: "The last two years of Z-W-G (part 2)". Weather, Volume: 41, Issue: 5, 1986, pp.157-161. Reprint # 719.
  69. Fuller, John F. : Thor’s Legions, Weather Support to the U.S. Air Force and Army, 1937- 1987; American Meteorological Society; Boston, 1990; 443 pp.
  70. Schwerdtfeger,Werner : "The last two years of Z-W-G (part 2)". Weather, Volume: 41, Issue: 5,1986, pp.157-161. Reprint # 719.
  71. ibid.
  72. Kington, John A. and Selinger, Franz: WEKUSTA, Luftwaffe Meteorological Reconnaissance Units & Operations 1938-1945; Flight Recorder Publications Ltd.; Ottringham, East Yorkshire; 2006; 256 pp.
  73. Schwerdtfeger, Werner: "The last two years of Z-W-G (part 2)". Weather, Volume: 41, Issue: 5, 1986, pp.157-161. Reprint # 719.
  74. ibid.
  75. Schwerdtfeger, Werner "The last two years of Z-W-G (part 3)". Weather, Volume: 41, Issue: 6, 1986, pp.187-191. Reprint # 720.
  76. ibid.
  77. ibid.
  78. ibid.
  79. ibid.
  80. ibid.
  81. ibid.
  82. ibid.
  83. ibid..
  84. ibid.
  85. ibid.
  86. ibid.
  87. ibid.
  88. ibid.
  89. ibid.
  90. ibid.
  91. Woods, Capt. Gilbert N., Weather Intelligence Officer, Det C, 21 WS: "Interrogation of Dr. Werner Schwerdtfeger"; 12 Sep 1945.
  92. Lettau, Heinz: History of the Schwerdtfeger Library; Schwerdtfeger Library .
  93. Taba, Hessam "The Bulletin Interviews: Professor H.Flohn": Reprints of the 32 interviews with eminent personalities in meteorology and hydrology that appeared in the WMO Bulletin between 1981 and 1988; World Meteorological Organizations; 1988.
  94. ibid.
  95. ibid.
  96. Nicholson, Sharon: Tape Recorder Interview Project; Interview with: Heinz Lettau, March 10, 2002; American Meteorological Society; UCAR.
  97. Lettau, Heinz: History of the Schwerdtfeger Library; Schwerdtfeger Library.


The day of the long awaited invasion of western Europe in Normandy, France, 6 June 1944. After a long campaign of deception the allies attacked the coast of Normandy on five beaches to begin their march on Nazi Germany. Often explained as Decision Day, though this is entirely correct. The D stands for Day as generally used in military language. In this case it means an operation beginning on day D at hour H. Hence “Jour J“ in French.
A form of government where the power in a country is in the hands of one person, the dictator. Originally a Roman regime in case of an emergency where total power would rest with one person during six months in order to face a crisis.
Armed incursion.
German air force.