Aerological observations in the Tropics in the Early Twentieth Century

Brönnimann, Stefan; Stickler, Alexander (2013). Aerological observations in the Tropics in the Early Twentieth Century. Meteorologische Zeitschrift, 22(3), pp. 349-358. Borntraeger 10.1127/0941-2948/2013/0458

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In the first decades of the 20th century, aerological observations were for the first time performed in tropical regions. One of the most prominent endeavours in this respect was ARTHUR BERSON’s aerological expedition to East Africa. Although the main target was the East African monsoon circulation, the expedition provided also other insights that profoundly changed meteorology and climatology. BERSON observed that the tropical tropopause was much higher and colder than that over midlatitudes. Moreover, westerly winds were observed in the lower stratosphere, apparently contradicting the high-altitude equatorial easterly winds that were known since the Krakatoa eruption (‘‘Krakatoa easterlies’’). The puzzle was only resolved five decades later with the discovery of the Quasi-Biennial Oscillation (QBO). In this paper we briefly summarize the expedition of BERSON and review the results in a historical context and in the light of the current research. In the second part of the paper we re-visit BERSON’s early aerological observations, which we have digitized. We compare the observed wind profiles with corresponding profiles extracted from the ‘‘Twentieth Century Reanalysis’’, which provides global three-dimensional weather information back to 1871 based on an assimilation of sea-level and surface pressure data. The comparison shows a good agreement at the coast but less good agreement further inland, at the shore of Lake Victoria, where the circulation is more complex. These results demonstrate that BERSON’s observations are still valuable today as input to current reanalysis systems or for their validation.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geography > Physical Geography > Unit Climatology
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geography

UniBE Contributor:

Brönnimann, Stefan and Stickler, Alexander Nicolas

Subjects:

900 History > 910 Geography & travel

ISSN:

0941-2948

Publisher:

Borntraeger

Language:

English

Submitter:

Monika Wälti-Stampfli

Date Deposited:

16 Jan 2014 10:15

Last Modified:

23 Nov 2015 13:28

Publisher DOI:

10.1127/0941-2948/2013/0458

Uncontrolled Keywords:

BERSON WESTERLIES, HISTORICAL AEROLOGY, QUASI-BIENNIAL OSCILLATION, TROPICAL TROPOPAUSE

BORIS DOI:

10.7892/boris.39435

URI:

https://boris.unibe.ch/id/eprint/39435

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