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| Titel |
More Variable and Stronger Winds during the Last Glacial |
| VerfasserIn |
Stephan Dietrich, Martin Werner, Gerrit Lohmann |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250114682
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| Publikation (Nr.) |
 EGU/EGU2015-15486.pdf |
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| Zusammenfassung |
| Changes of wind systems and thus of atmospheric circulation patterns are an essential feature
of fast climate changes that explain hemispheric wide teleconnections. Here, we present the
synoptic interpretation of prevailing paleo wind systems for Central Europe during
glacial times and compare the results with a proxy record of changes from easterly to
westerly wind directions from maar lake sediments (Germany). This record indicates a
high amount of east wind and a high variability on a millennial time scale of wind
direction changes for the last glacial period. The basic observations, made on the
proxy record, are also shown in the 10 m-wind vectors in ECHAM3 and ECHAM4
model experiments under glacial conditions with different prescribed sea surface
temperature patterns. However, all glacial experiments show a lower frequency of east
wind in comparison to the present-day control runs. But all glacial runs show a
high variability of wind direction changes and stronger winds in comparison to the
present-day control runs. Furthermore, the analysis of long-persisting east wind conditions
(so-called LEWIC events) in the AGCM data shows a stronger seasonality during
glacial conditions: all different experiments are characterized by an increase of the
relative importance during spring and summer. Synoptic analysis of the air flows with
prevailing east wind over Central Europe are given for the spring which is the most
important season for dust emission. Under present-day conditions easterly wind
directions are mainly forced by a strong high over the Baltic Sea realm. The different
glacial experiments show in good agreement a shift from a long-lasting high from
the Baltic Sea towards NW, directly above the Scandinavian Ice Sheet, together
with the contemporary occurrence of enhanced westerly circulation at the North
Atlantic. |
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