HR: 1340h
AN: A13E-1603    [Abstracts]
TI: Structures of moisture transport to Norway associated with winter cyclones in the North Atlantic
AU: * Sodemann, H
EM: hso@nilu.no
AF: Norwegian Institute for Air Research, P.O. Box 100, Kjeller, 2027, Norway
AU: Stohl, A
EM: ast@nilu.no
AF: Norwegian Institute for Air Research, P.O. Box 100, Kjeller, 2027, Norway
AB: Understanding of the atmospheric processes leading to periods of extreme precipitation is still limited. Previous studies have shown that both, remote and local moisture transport contribute to heavy precipitation events in Norway and the American West coast via moisture conveyor belts or 'atmospheric rivers', which are linked to mid- latitude cyclones. In this work we want to gain more insight into the processes and the structures of moisture transport associated with mid-latitude cyclones. We studied a period of above-average precipitation in southern Norway during winter 2006/07, which was related to a series of mid-latitude cyclones moving into the Scandinavian land mass. A number of high-resolution simulations was conducted with a limited-area NWP model, using ECMWF's high-resolution operational data. The limited-area model has been fitted with water vapour tracers, which allow to tag water vapor at its area of evaporation, and to follow it's movement through the model's hydrological cycle. We determined the evaporation sources for precipitation in southern Norway for several of the mid-latitude cyclones. In addition, the spatial structure in the cyclones the and temporal evolution of the moisture from different evaporation sources are presented. A variety of latitude-longitude sectors provide substantial amounts of moisture to different sectors of the cyclones, including the sub-tropcial North Atlantic. Our results have implications for understanding the role of SST anomalies, and provide new insight into the mechanisms of moisture transport in and precipitation from mid-latitude cyclones.
DE: 0368 Troposphere: constituent transport and chemistry
DE: 1655 Water cycles (1836)
DE: 1840 Hydrometeorology
DE: 3355 Regional modeling
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting