Spatial-temporal characteristics and synoptic significance of deep convective clouds over the physiognomy transition region of western Huanghuai

Topography is complex over the physiognomy transition region (30°-38°N,109°-118°E) of western Huanghuai where severe connective weather occurs frequently.Based on the database observed by the gcostationary satellites from May to August during 1996-2010 and the weather phenomena data from the surface observatory stations in Henan Province, spatial-temporal characteristics and synoptic significance of deep connective clouds in the area are researehed.The results show that spatial-temporal characteristics of deep connective clouds in the area are closely related to the climate zone and affected obviously by the terrain and the atmospheric circulation.Deep convection happens along the Huaihe river and its south areas most frequently, and secondly over the mountain areas of northern and western Henan province.The comparative analysis shows that deep convection in the northern and western mountain areas are mainly in the form of thurderstorm and hail,which in lower-elevation areas such as the Huaihe river valley and the Nanyang Basin, are mainly in the form of short-time rainstorm.With the moving northward of the subtropical anti-cyclonic, deep convection shows the different monthly and inter-diurnal variations.Its frequency has obvious volatility in the middle-south areas from the end of May to early August.The diurnal variation of deep connective frequency in northern Henan province is of single peak type, which propagates from northwest to southeast, while it in southern Henan province is of double peak type.