Abstract:With soil moisture dataset derived from China Land Data Assimilation System of China Meteorological Administration(CLDAS-CMA),the spatiotemporal and vertical distribution of soil moisture over the Tibetan Plateau(TP) and its typical areas with influencing factors have been investigated for period of July 1,2009 to June 30,2010.Results show that soil moisture corresponds well to the precipitation over the Tibetan Plateau.Soil tends to be wet during the rainy season with large precipitation and vice versa.Soil moisture persists significant seasonal variation,which is highest in summer,followed by that in spring and autumn,while it is lowest in winter.With the rise of air temperature,March to August has become the period with increasing soil moisture and the areas with high soil moisture has expanded from the southeast part of Tibet to the northwest part of the Plateau,as well as from Tarim Basin to the northeastern of Tibet.As for the vertical distribution,soil moisture tends to be high at interlayer,and low at shallow layer and deep layer,with a gradual decreasing trend in variation magnitude from shallow layer to deep layer.The distribution of soil moisture at typical areas over the TP presents similar temporal variation tendency as the regional average soil moisture for the entire Plateau.Season with large precipitation is corresponding to the season with large soil moisture in humid and semi-arid areas.Humid areas has bigger vertical gradient in soil moisture compared with arid and semi-arid areas.Meteorological variables such as evaporation,wind speed,average air temperature and vegetation coverage have some influence on the distribution of soil moisture.