LONG-TERM CHANGES IN COVARIABILITY BETWEEN CONTINENTAL-SCALE SNOW COVER AND ATMOSPHERIC CIRCULATION IN THE NORTHERN HEMISPHERE

• Main Authors: Kazuyuki Saito, Tetsuzo Yasunari, Takeshi Yamazaki, Kooiti Masuda, Judah Cohen
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Climate change
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.587.2625; http://las.physik.uni-oldenburg.de/eProceedings/vol04_2/04_2_saito1.pdf

Large-scale snow cover extent and the atmospheric circulation have recently been recognized to interact mutually. Understanding the snow-atmosphere interaction is important for a better predict-ability of the cryospheric climate variability under the future climate change. We investigated interactions between continental snow cover extent and the large-scale atmos-pheric circulation variability in the Northern Hemisphere, on a climatic scale (from seasonal to sub-decadal) for the recent three decades. Both observations and numerical simulations were used. Utilized snow cover data were derived from the visible sensor (AVHRR). The indices to present the atmospheric circulation variability, such as the Arctic Oscillation (AO), were computed from the re-analysis data. Statistical analyses showed that the Eurasian snow cover extent (SCEEUR) and the AO have a significant coherency in sub-decadal periods, with the former leading the latter by several months. A more detailed inspection revealed a climatological change in the sub-decadal covariability between snow and the atmosphere in the mid 1980s. The change may be attributed to changes in the seasonal persistency of SCEEUR, from autumn to winter, and in strength of winter-to-spring in-teraction between SCEEUR and the AO. A series of numerical experiments was performed with an