Tuesday, 11 February 2003
The Impact of Climatic Conditions on Seasonal River Discharges in Siberia
Abstract Seasonal variations of river basin discharges over the Ob, Yenisei, and Lena River during the 1936-95 have been associated with atmospheric climatic variables and Arctic Oscillation index. The climatic variables include seasonal basin-averaged surface air temperatures, precipitation, maximum snow accumulation depth, starting and ending dates of the basinís continuous snow cover. These climatic variables together with the AO index explain about 31% to 55% of the variance of annual total discharges in these rivers. On average, climatic and atmospheric variables explain 35% to 69% variance of spring discharges, 34% to 47% variance of summer discharges, 21%-50% variance of fall discharges, 18% to 36% variance of winter discharges. As expected, spring thermal condition is the most significant for spring discharge and also negatively affects summer discharge. The climate conditions during winter through fall have influences on fall discharges. Winter discharges are associated with previous summer and fall atmospheric conditions. Also, snow depth significantly influences summer and fall discharge in Ob, Yenisei river basins but affects winter and spring discharges in Lena River basin, suggesting the potential importance of the permafrost condition to the river discharges.
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