Spatio-temporal distribution and general circulation of heavy rainfall
in rainy season over Tibetan Plateau

Using daily rainfall dataset in rainy seasons of May to September during 1980 to 2011, the spatio-temporal distribution of heavy rainfall over Tibetan Plateau is analyzed, including the spatial distribution of the heavy rainfall days, its seasonal differences and interannual variation. The results are as follows. The number of heavy rainfall days has its maximum near the Yarlung Zangbo River and the Nujiang River Basins. Its annual distribution showed a single peak only in July. Heavy rain days showed no significant increasing trend in the recent 32 years; the trend shows a 2.6 point-times per 10 a increase before 1998, followed by a 12 point-times per 10 a decrease. Total 88 typical heavy rainfall weather cases are analyzed with composite method using the NCAR/NCEP daily reanalysis dataset and FY2 series Geostationary Meteorological Satellite data. Of them, 4 general models of atmospheric circulation can be classified, i.e., subtropical high model (SHM), Indian Low model (ILM), south-north sub troughs model (STM) and Tibetan Plateau vortex/shear-line model (VSL). SHM constitutes 36%, ILM 17%, STM 21% and VSL 25% of the total cases, respectively. SHM is further classified into 3 subtypes named West Pacific subtropical high model, Iran subtropical high model and low pressure in between the two highs model.