Correlations of snow depth over the Tibetan Plateau in winter and spring with precipitation in summer over China.

The spatotemporal distributions of snow depth on the Tibetan Plateau are revealed by the monthly snow depth data from satellite remote sensing i.e.SSMR and SSM/I in December 1978—December 2005 and the monthly station observations in 1960—1998.The contrast analyses of snow depth with summer precipitation anomalies and atmospheric circulations in anomalous snow years,show that the satellite remote sensing data is able to reflect the actual condition of snow cover over the plateau and the snow change over the western Plateau;there is a good uniformity between the distributive characteristics of south-flood and north-drought of summer precipitation and the increase in snow depth over the plateau in winter and spring in the late—1980s.After the EOF decomposition of snow depth over the plateau in winter and spring,the first modes in both seasons show the same spatial distribution,which reflects the distribution of snow depth over the Plateau in winter is considerable consistent with that in spring.But the second EOF mode over the Tibetan Plateau in spring reflects difference of snow depth between the western and eastern Plateau.The correlation analysis between the summer precipitation over China and the time series of the first mode of snow depth on the Tibetan Plateau in winter and spring shows that the primary pattern of summer precipitation is a south-flood(the area south of the Yangtze River) and north-drought(the area north of the river) distribution over eastern China.Differences of composite summer precipitation between years when spring snow cover was thicker in the eastern of the Tibetan Plateau than in the western and years when spring snow cover was thicker in the western than in the eastern also reveal a south-more and north-less pattern of summer precipitation anomalies.