Droughts characteristics of the hilly areas in southern China

Understanding of seasonal drought characteristics of the hilly areas in southern China is helpful to guide reasonably the local environment management. In this paper, the seasonal drought is divided into spring drought (SPD), spring-summer continuous drought (SSD), summer drought (SUD), summer-autumn continuous drought (SAD), autumn drought (AUD), autumn-winter continuous drought (AWD), winter drought (WID) and winter-spring continuous drought (WSD). Based on the monthly precipitation data of the 295 ground-based meteorological stations of southern China and its surrounding regions from 1961 to 2005, a Drought Severity index (DSI) is built firstly and graded into Mild, Moderate, Severe and Extreme, to reflect the spatial patterns of the various drought occurrences in 1961-2005 under the support of GIS technique. The results indicate that: (1) WID, WSD and SPD mainly occur in the west of southern China, SAD and AUD in the southeast. AWD mainly occurs in the west and southeast. SUD is most extensive in the regions. (2) In the SPD, SUD, AUD, AWD and WSD regions, the seasonal drought events always occur along with higher air temperature. Almost all seasons have a trend to become hot. SPD, SAD, WID and WSD are gradually alleviative. SUD and AUD have a trend to become severe. AWD is gradually alleviative until 1983.