Vapor Source Characteristics of Precipitation in South China during May

Based on monthly precipitation datasets of 89 meteorological stations and 38 hydrological rain gauges from 1961 to 2005 in Xinjiang, China, differences in temporal-spatial variations of Xinjiang precipitation detected by these two precipitation observations have been compared and causations for these differences have been analyzed. Meanwhile, the relationships between precipitations with topography features (altitude, slope, and aspect) under increasing warming background have been discussed. The results indicate that: 1) Multiyear mean annual precipitation in Xinjiang observed by hydrological rain gauges is 221.4 mm, which is 69.3 mm more than that observed by meteorological stations (152.1 mm). However, meteorological and hydrological observations show the same spatial-temporal change characteristics; 2) Differences between meteorological and hydrological observations are mainly affected by altitude. Besides, slope and aspect are also crucial factors. Precipitation shows huge spatial-temporal variations in Xinjiang because of complicated landform. As a result of uneven distribution of rainfall gauges, there exists great bias in precipitation estimation. In the future, it would be an effective method to objectively assess precipitation in Xinjiang that multi-source precipitation datasets combine together.