资源环境科技发展态势分析平台

The temporal and spatial variations in precipitation, and the relationships between precipitation and elevation/latitude are analyzed. The following results are derived from the analysis: (1) Unimodal and bimodal precipitation regimes are observed for 19 and 11 stations, respectively, of which the Type 1 and Type 2 bimodal precipitation regime is observed for three and eight stations, respectively. The primary flood season of the Type 1 bimodal precipitation regime is around July, except for Gongshan station that is relatively long flood season. The primary flood season of the Type 2 bimodal precipitation regime is around June. The precipitation peaks are negatively correlated with latitude/elevation for each bimodal precipitation regime. (2) Basically similar spatial distributions are observed for the annual and seasonal average precipitation - the southern part of the Hengduan Mountains region experiences relatively high precipitation, whereas the central and northeastern parts experience relatively low precipitation; in addition, the precipitation trends are nonsignificant for most of the stations. A decreasing trend is observed for the annual, summer and drought season precipitation for most of the stations located in the area south of 28 degrees N, whereas an increasing trend is observed for most of the stations located in other areas. Most stations experience an increasing in spring precipitation, and in autumn, the opposite is observed. A decreasing trend is observed for winter precipitation for most of the stations except for the northeastern part of the study area. An increasing trend is observed for precipitation in the rain season for most of the stations except for the northeastern and southern parts of the study area. Significantly negative correlations are observed between the annual and seasonal with relatively high precipitation (summer, autumn and the rain season) average precipitation and elevation/latitude (3) Negative correlations, mostly significant, are evident between the standard deviations of the annual, seasonal and monthly precipitation and elevation/latitude.