SSM/Iに基づく北半球積雪深の長期変動

概要

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In the past, many of the relationships between Arctic oscillations and snow cover in the Eurasian Continent were discussed assuming a decadal cycle. However, the possibility of an annual rotation of the relationship was not discussed. The target of our study is the investigation of an annual variation of snow quantity in the Northern Hemisphere.In 2007, we developed a snow depth retrieval algorithm for AMSR and AMSR-E. In this paper, that algorithm was adjusted to make it applicable to the Special Sensor Microwave Imager (SSM/I) data which have been collected continuously since 1987. Then, snow depth in the Northern Hemisphere by using our improved algorithm is estimated, and the interannual variation of the long-term distribution of snow depth in the Northern Hemisphere is discussed. Next, the relevance of our estimations of March snow depth and Arctic oscillation (AO) is confirmed. Then the estimation accuracy of snow depth as compared with a few in situ observations, concluding that its accuracy is comparatively good is discussed. Furthermore, the interannual fluctuation of the distribution of snow depth is discussed. Our result shows a tendency toward a converse fluctuation between the Siberia and the Alaska/Canada snow depths in January and February, which has been confirmed from 1995 to 1999.
2009-01-31