Processes of intraseasonal snow cover variations over the eastern China during boreal winter

• Published in: Atmospheric Science Letters
• Main Authors: Song, Lei, Wu, Renguang, Zhu, Jialei
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: John Wiley & Sons, Ltd. 2019
• Subjects: the eastern China; moisture fluxes; intraseasonal snow cover variation; the Arctic Oscillation; Atmospheric and Oceanic Sciences; Engineering; Arctic
• Online Access: http://hdl.handle.net/2027.42/149343; https://doi.org/10.1002/asl.901

This study reveals that the dominant time scale of intraseasonal snow cover variation over the eastern China is within 30 days by using the latest satellite snow cover data from the moderate resolution imaging spectroradiometer (MODIS)/Terra product. The leading empirical orthogonal function (EOF) mode of 10–30‐day snow cover variation during boreal winter from 2004 to 2018 over the eastern China has two centers: northwest part of the eastern China and north of the Yangtze River. Composite analysis based on 25 snow events identified from normalized leading principal time series (PC1) indicates that the southeastward intrusion of surface anticyclonic anomalies and accompanying low temperature anomalies provide the temperature condition for snow events. Negative Arctic Oscillation induces mid‐latitude wave train and leads to the development of surface anticyclonic anomalies and upper‐level cyclonic anomalies over East Asia. The cyclonic anomalies induce ascending motion and anomalous convergence of water vapor fluxes over the eastern China, which supplies moisture for snowfall.(a) Time evolution of composite NAO index (pink curve), AO index (blue curve), regional mean surface air temperature anomalies (°C) (black curve) and snow cover anomalies (%) (red curve) in the region of 20–40°N, 105–120°E. (b) Time evolution of composite anomalies of regional mean snow cover tendency (%/day) (black curve), vertical velocity (Pa/s) (blue curve), and divergence of water vapor flux integral from 1,000 to 100‐hPa (*10−6 kg/(m2*s)) (pink curve) in the region of 20–40°N, 105–120°E. Dots on the curves indicate anomalies significant at the 95% confidence level. Peer Reviewed https://deepblue.lib.umich.edu/bitstream/2027.42/149343/1/asl2901_am.pdf https://deepblue.lib.umich.edu/bitstream/2027.42/149343/2/asl2901.pdf