Eurasian snow can influence the Indian summer monsoon and the East Asian climate. Variability of autumn Eurasian snow is a contributing factor in wintertime Artic Oscillation variation – an important climate system in the Northern Hemisphere. Studying the changes in autumn Eurasian snow and the factors involved is important for our understanding of the Eurasian climate variability in subsequent seasons.
Dr. Kunhui Ye, who has recently graduated from the Chinese University of Hong Kong, worked with Prof. Renguang Wu of CAS Institute of Atmospheric Physics to investigate the autumn Eurasian snow variability, with the intent to provide a better understanding of the factors involved in Eurasian snow changes and their impacts on the wintertime Arctic Oscillation. Their study shows that both snowfall and surface air temperature contribute to the snow variability via different pathways, and they exhibit differing levels of importance in different regions (Fig. 1). Further analysis reveals accompanying changes in surface heat fluxes and atmospheric circulations. The atmospheric water vapor transport and its divergence/convergence are important in the snowfall and longwave radiation changes. The anomalous downward longwave radiation and anomalous wind advection contribute to surface temperature changes.
Fig. 1 Schematic diagram outlining the main atmospheric processes through which snow anomalies are induced. SAT: surface air temperature; SC: snow cover; SWE: snow water equivalent. (Image by WU Renguang)
The study concludes that atmospheric circulation and associated changes in the land-surface state are essential factors of influence for the autumn Eurasian snow variability. This complicates the prediction of autumn Eurasian snow anomalies and their climatic impacts.
The study is recently published in Advances in Atmospheric Sciences.
Ye. K. H., and R. G. Wu, 2017: Autumn snow cover variability over northern Eurasia and roles of atmospheric circulation. Adv. Atmos. Sci., 34(7), doi: 10.1007/s00376-017-6287-z.
Contact: WU Renguang, email@example.com