Arctic Winds in the “Twentieth Century Reanalysis”

Brönnimann, Stefan; Wegmann, Martin; Wartenburger, Richard; Stickler, Alexander (2013). Arctic Winds in the “Twentieth Century Reanalysis”. In: Brönnimann, Stefan; Martius, Olivia (eds.) Weather extremes during the past 140 years. Grundlagenforschung: Vol. G89 (pp. 59-67). Bern: Geographica Bernensia 10.4480/GB2013.G89.07

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Climate in the European part of the Arctic underwent a rapid warming between the 1910s and the 1930s. Previous studies have addressed the role of atmospheric circulation in this period based on geopotential height fields because observations of upper-level winds in the Arctic are rare. Here we analyse winds over the Arctic and specifically over Spitsbergen in the “Twentieth Century Reanalyses” (20CR). We compare in situ upper-air wind measurements performed in 1912 and 1913 in Spitsbergen with six-hourly 20CR data. Furthermore, we compare monthly-to-seasonal 20CR winds at 700 hPa over the European Arctic with statistically reconstructed winds at 3 km altitude. Finally, we analyse long-term trends in Arctic winds in 20CR. The general agreement between observed upper-air winds and 20CR on the day-to-day scale is rather poor, which is not surprising given the paucity of observations in the Arctic at that time that constrain 20CR. In contrast, the seasonally averaged winds (which represent a larger spatial scale) in 20CR compare well with statistically reconstructed winds. The analysis of long term near-surface wind time series in 20CR shows arguably artificial trends from 1871 to around the 1950s over sparsely observed regions, particularly oceanic regions. Densely observed regions such as Europe or the USA show no such trends. This analysis shows that great care needs to be taken when working with 20CR in the Arctic and other sparsely observed regions.

Item Type:

Book Section (Book Chapter)

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

Graduate School:

Graduate School of Climate Sciences

UniBE Contributor:

Brönnimann, Stefan; Wegmann, Martin; Wartenburger, Richard and Stickler, Alexander Nicolas

Subjects:

500 Science > 550 Earth sciences & geology
900 History > 910 Geography & travel

Series:

Grundlagenforschung

Publisher:

Geographica Bernensia

Language:

English

Submitter:

Monika Wälti-Stampfli

Date Deposited:

13 Nov 2013 17:00

Last Modified:

25 Mar 2019 13:41

Publisher DOI:

10.4480/GB2013.G89.07

BORIS DOI:

10.7892/boris.39147

URI:

https://boris.unibe.ch/id/eprint/39147

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