Wladimir Peter Koppen
Köppen, Wladimir Peter
KöPPEN, WLADIMIR PETER
(b. St. Petersburg, Russia, 25 September 1846, d. Graz, Austria, 22 June 1940)
climatology, meteorology, paleoclimatology.
Köppen was a principal founder of modern meteorology and climatology. The word founder is used here in both its conceptual and organizational sense: Köppen produced a useful and durable scheme of descriptive climatology; a modified version of the system bearing his name remains in use more than a century after he proposed it. He was an early proponent of synoptic meteorology, and an active worker in developing the international network of observing stations that made this approach to meteorology possible. He was also the founding editor of the Meteorologische Zeitschrift and, during the half century of his contributions, maintained its position as the leading meteorology periodical in the world. In 1924 he produced a major survey of the climates of the Earth’s past, and he is rightly considered one of the founders of modern paleoclimatology. The list of his publications includes more than five hundred journal articles and books, and his lifetime as a working scientist is one of the longest on record: His first publication appeared in 1868, and his last in 1940.
Childhood and Education . Köppen was born and raised in Russia. His grandfather had emigrated from Germany, in the time of Catherine II, to help set up a public health system. Köppen’s father was a regional governor, economic officer, and epidemiologist in the service of the czar, and he was a member of the Imperial Academy of Sciences. Köppen’s uncle, his father’s brother, was later tutor to the young czar Alexander III. Köppen was thus a part of a hereditary caste of culturally and linguistically German scientists and civil officials permanently resident in Russia.
Until the age of fifteen Köppen lived in St. Petersburg, at which time his father, then sixty-seven years old, retired and took his family to his estate at Karabagh, in the Crimea. Köppen recalled, in a memoir written in 1931, being struck by the changes in the vegetation he encountered from the windows of the train as the family traveled south: from the boreal coniferous forests around St. Petersburg, to the Mediterranean, arid, and subtropical climate of the Crimea. Many subsequent trips between St. Petersburg and the Crimea confirmed his intuition that vegetation is controlled to a large degree by latitude. Completing his high school education in the Crimea, he returned to St. Petersburg for his university degree before continuing to the University of Heidelberg in Germany for his PhD—a path well trodden by Russian students with an interest in the sciences. Transferring to the University of Leipzig he produced (in 1870) a doctoral dissertation on “Heat and Plant Germination.”
The German Marine Observatory . After a brief stint as a schoolteacher, Köppen began work in 1872 as an assistant at the Central Observatory in St. Petersburg, where he helped prepare the daily synoptic weather map, and he began to correspond with his counterparts elsewhere in Europe. Synoptic maps, which plot simultaneous values of meteorological elements at stations widely separated, are a staple of modern meteorology, but were just beginning to be produced at this time. In 1873 he attended the first international meteorological congress in Vienna and began his lifelong friendship with the Austrian meteorologist Julius Hann. Prospects for permanent employment in St. Petersburg pursuing meteorology were slim, and in 1875 Köppen accepted an offer from Georg Neumayer to head the meteorological section of the newly founded Deutschen Seewarte, the German Marine Observatory in Hamburg; he would remain there for the rest of his working life. From 1879 until 1919 he held the post of meteorologist of the Marine Observatory, which allowed him wide scope to pursue theoretical as well as practical investigations.
In addition to his practical work in maritime meteorology and his role in helping to establish an international network of meteorological stations, his publications in the 1870s and 1880s reveal a strong interest in the periodicity of meteorological phenomena, looking for patterns in rainfall amounts, wind, and barometric pressure on all time scales from daily through weekly and monthly up to annual and multiyear periods. He also worked (unsuccessfully) to establish the possible influence of the Moon and of the eleven-year sunspot cycle on weather phenomena.
Köppen was a night owl his whole life—a man who slept little and made a slow start in the morning. He would remain at the observatory late into the evening after his official duties were complete, compiling and plotting temperature data from the thousands of ships’ logs for which the Marine Observatory was the official depository.
The Köppen Climate System . In 1884 he took the bold step of founding his own scientific journal, the Meteorologische Zeitschrift, and he edited it either alone or in combination with Julius Hann until 1891. He used this journal to publish his first climate scheme in 1884: “Die Wärmezonen der Erde, nach der Dauer der heissen, gemässigten und kalten Zeit, und nach der Wirkung der Wärme auf die organische Welt betrachtet” (The heat zones of the Earth, based on the duration of hot, temperate and cold periods and on the action of heat on the organic world). This article appeared almost simultaneously with two other significant contributions to climatology, Julius Hann’s 1883 Handbuch der Klimatologie (Handbook of Climatology) and Alexsandr Ivanovich Voeikov’s Klimaty zemnago shara, v osobennosti Rossii (Climates of Our Globe and Particularly Russia, 1884).
Köppen’s initial climate system was the basis of every subsequent modification of his work until 1936. It was a latitude-zone scheme, which took as its basis the temperatures during the warmest month of the year (at a given latitude), deriving isothermal maps based on this data. The approach reflects his own PhD work in botany, as well as his experiences growing up in Russia: the intuition, acquired in childhood, that vegetation is largely determined by latitude. There are, of course, many ways to organize a climate scheme: One could use topographies and land forms, or soil types, or the nature and character of the air masses—that is, the dynamic weather—that passes over them. Köppen chose botany as his discriminating criterion, based on a particular discovery that he had made, that of the Baumgrenze, the “tree limit.” The northernmost latitude for the growth of trees is well defined by the temperature of the warmest month. Where the mean monthly temperature is 10°C or less in the warmest month, trees cannot grow. Moreover, definable suites of vegetation show up when the mean monthly temperature remains above 10°C (50°F) for one, four, and twelve months. Using a 10°C (50°F) and a 20°C (68°F) isotherm denoting the warmest temperature for periods of one, four, and twelve months, he developed a seven-zone system of climate representing the whole globe. The initial version thus had seven zones per hemisphere: one tropical, one subtropical, three temperate, one cold, and one polar.
Throughout the 1880s and 1890s Köppen continued to work on practically every aspect of climate and weather, with increasing attention to cloud types and precipitation regimes around the world, constantly collating and bringing together work on the climate of all the continents. In 1887 he worked with Julius Hann to produce an Atlas der Meteorologie (Atlas of meteorology), and in 1890 published a Wolkenatlas (Atlas of cloud forms) with Neumayer and Hugo Hildebrandson.
By the later 1890s Köppen had become convinced that climate zones were differentiated not just by their temperature but by the entire weather picture, with a special attention to the amount and seasonal distribution of precipitation. This led to a new and more complex climate scheme, published in 1901 as Versuch einer Klassifikation der Klimate. Vorzugsweise nach iheren Beziehungen zur Pflanzenwelt (An attempt at a classification of climates chiefly according to their relation to the plant kingdom). Here Köppen discerned six basic climate types, five based on temperature and one based on aridity. When combined with different precipitation regimes, this led to twenty-four distinct climates, all with botanical and zoological names, and exact limits based on the temperature of the hottest and coldest months and the amount of precipitation.
Family Life and Personality . Simultaneously with this immense scientific labor, Köppen and his wife Marie raised a large family, with five children of their own, plus the two children of Marie’s sister Sophie, who merged households with them in 1888, first in Hamburg proper and later in their large and rambling house in the suburb of Grossborstel close to the Marine Observatory’s aerological station, from which Köppen launched both free and captive balloons and meteorological kites of his own design, carrying instrument packets up to altitudes of several kilometers. Köppen was quite gregarious and kept “open house” year-round, with a steady stream of friends and scientific visitors welcomed into the family circle; the Köppen home was also often filled with collateral relatives who had come for long visits.
Köppen was well known for his generosity to younger colleagues; he promoted their ideas and took an interest in their lives as well as their work. He seems to have been universally liked and admired for his good humor and his immense capacity for concentrated hard work, and his epithet “the Nestor of meteorology” refers to both his reputation for giving sage advice and his extremely prolific written output. He was a committed pacifist and internationalist, and he argued strenuously for the adoption of Esperanto as an international scientific language to help overcome national differences. His linguistic gifts were immense, and in addition to Greek, Latin, French, German, English, and Russian, he was also competent in Spanish and Italian. His promotion of the international language movement was a reflection not only of his belief that his ability to read in many scientific literatures had advanced his scientific understanding, but also of his desire for peace.
Köppen and Wegener . While Köppen remained committed to the basic plan of his descriptive climatology, he was not estranged from developments in dynamical meteorology, and indeed he was one of its great patrons; he had close ties to the Bergen School. Köppen was keenly aware of the growing pull of physics on studies of the Earth in all its aspects in the first decade of the twentieth century, and he vigorously promoted it. In fact, he worked extensively with a young atmospheric physicist for two years between 1908 and 1910, helping to write a textbook on thermodynamics of the atmosphere, and constantly insisting to the young man that it had to be about real gases in a real atmosphere. This work, Thermodynamik der Atmosphäre (Thermodynamics of the atmosphere), became the standard text in the subject for the next twenty years. Its young author married Köppen’s daughter Else, and the two men forged a powerful scientific partnership. The younger man was Alfred Wegener.
The collaboration of Köppen and Wegener is of some scientific interest. It combined the sagacity, deep reading, and wide knowledge of the literature of the older man with the energy and strong physical intuition of the younger. While Köppen originally discouraged Wegener from pursuing his ideas about continental drift, he was gradually won over to his son-in-law’s hypothesis, for which he became a strong advocate.
Paleoclimates . In the difficult period following World War I, the Wegeners and the Köppens merged households in Hamburg. Köppen used his influence to have Wegener named meteorologist at the Marine Observatory and procured for him an appointment at the new University of Hamburg. In these years, from 1920 to 1924, Köppen and Wegener collaborated in the production of a very significant work in paleoclimatology: Die Klimate der geologischen Vorzeit (The climates of the geological past). At some point Köppen and Wegener realized that a shift of latitude zones through geological time would be a necessary consequence of continental displacement, and would perhaps explain the anomalous appearance of tropical flora at very high latitudes; they therefore set about to reconstruct this history, which was not aimed as a proof of continental drift, but assumed its existence in order to map paleoclimates.
Die Klimate der geologischen Vorzeit relied on a simplified version of the Köppen zone system, with seven belts: a tropical equatorial belt, paralleled to the north and south by arid belts, these paralleled to the north and south by temperate moist zones, and each hemisphere capped by a cold polar climate zone. The climate reconstruction used reef limestones as proxies for equatorial climate; aeolian sandstones and evaporites for arid regions; peat, coal, and plant fossils for the temperate zones; and the glacial tills for the polar regions.
Using the stratigraphical data from the multivolume and internationally produced Handbuch der regionalen Geologie (Handbook of regional geology), Wegener and Köppen calculated paleopole positions and paleoequators for every period of the Paleozoic, Mesozoic, and Cenozoic eras. Notably, the book contained the first widely distributed version of the insolation theory of continental glaciations of Milutin Milankovitch.
In 1924 Wegener obtained a professorship of meteorology and geophysics at the University of Graz in Austria, and the Wegener and Köppen families moved to Austria that year. Köppen brought with him his quite considerable library, many thousand volumes in size, and continued to work on his climate system.
In the 1920s, with the appearance of a dynamic meteorology with real predictive power in the form of the theory of frontal weather, there was a great deal of interest in shifting the basis of climatology from descriptive to causal and dynamic, with climatology following meteorology in its proud mathematization. Much work in the 1920s shows the theoretical shift of climatology: Whereas previously the end products were climate maps, now the climate maps were the data and the end products were equations.
Ideal Climates . Köppen’s response to this pressure to put climate into abstract form was interesting, and it had a lasting effect on climatology, which preserved his descriptive approach in the face of the challenge from dynamic meteorology. Köppen dealt with the question of theory not by putting climate in motion, but by inventing the idea of an ideal climate on an ideal continent on an ideal Earth and then showing how real climates departed from this ideal. This version of climatology and its idealization is an interesting version of the Germanic preference in these decades for theories of ideal type, whether climatological or sociological, as in the theories of Max Weber. It retained its influence in the depiction of climate and the aim of climatology until the appearance of electronic calculators and computers after World War II.
Köppen continued to expand and modify his climate system, with major revisions appearing in 1918, 1923, 1930, 1931, 1936, and 1939, the latter two versions appearing as part of a multivolume Handbuch der Klimatologie (Handbook of climatology) for which Köppen was the general editor, along with Rudolf Geiger. His final publication, a revised and enlarged version of his Die Kli-mate der geologischen Vorzeit appeared in 1940, shortly before his death. His daughter Else recalled in her biography of her father, published in 1955, that he sent an urgent telegram to the publishing house that was setting type for the enlarged edition, which read: “Please send corrections immediately, I am dying.” He died a week later, in repose, at the age of ninety-three.
The Köppen system of descriptive climatology, based in temperature and rainfall and their effect upon vegetation, has survived for more than a hundred years and has been described as the least objectionable system ever devised. It has built into it Köppen’s childhood, his employment history and his work habits, his feeling for plants, his background in Russian science, his commitment to theoretical idealization, and his relationship with his son-in-law. It was advanced and maintained by the length of his career, his placement in the world, his control of periodicals, and perhaps above all by its real and constructive utility in describing the climates of Earth.
Köppen’s correspondence to 1919 is housed in the Prussian State Library, Berlin; his later correspondence is lost. A preliminary and incomplete list of Köppen’s scientific papers and his bound book publications may be found in Else Wegener-Köppen (1955), below. This list does not include Köppen’s occasional and popular pieces or his publications in advocacy of Esperanto. Köppen’s works remain untranslated into English.
WORKS BY KÖPPEN
“Die Wärmezonen der Erde, nach der Dauer der heissen, gemässigten und kalten Zeit, und nach der Wirkung der Wärme auf die organische Welt betrachtet.” Meteorologische Zeitschrift 1 (1884): 215–226.
Versuch einer Klassifikation der Klimate. Vorzugsweise nach iheren Beziehungen zur Pflanzenwelt. Leipzig: B. G. Teubner, 1901. Die Klimate der Erde. Berlin and Leipzig: Walter de Gruyter, 1923.
With Alfred Wegener. Die Klimate der geologischen Vorzeit. Berlin: Gebrüder Bornträger, 1924.
With Rudolf Geiger. Handbuch der Klimatologie. 5 vols. Berlin: Gebrüder Bornträger, 1940.
Wegener-Köppen, Else. “Wladimir Köppen. Ein Gelehrtenleben für die Meteorologie.” In Grosse Naturforscher, edited by Hans Walter Frickhinger. Stuttgart: Wissenschaftliche Verlagsgesellschaft, 1955. The only biography of Köppen, written by his daughter, Alfred Wegener’s widow.
Mott T. Greene