云南省四季潜在蒸散量时空演变的主导气象因子分析

基于1981—2011年云南省52个站点气象数据，通过敏感系数和贡献率法，定量分析了各站点冬春夏秋季潜在蒸散量变化的成因。结果表明:（1）1981—1990年、1991—2011年春、夏、秋季，云南省各站点潜在蒸散量均对平均气温最敏感，其次是相对湿度和日照时数，对风速的敏感性最低；冬季有部分站点以相对湿度的敏感系数最大。（2）蒸散量变化的主导因子因季节不同而不同。1981—1990年，绝大多数站点冬季蒸散量变化主导因子为平均气温，其他季节多数站点主导因子为日照时数；1991—2011年，冬、春、秋季，多数站点以平均气温为主导因子，夏季则以日照时数为主导因子的站点居多。（3）主导因子空间分布格局有差异。平均气温是云南省东部地区冬季蒸散量变化的主导因子，日照时数是中南部地区夏季蒸散量变化的主导因子，春、秋季节，前后时间段主导因子区域差异较大。这些结果表明云南省蒸散量变化的主导因子具有阶段性、季节性和区域差异性。

Dominant Meteorological Factors of Spatiotemporal Variations of Seasonal Potential Evapotranspiration in Yunnan Province During the Period from 1981 to 2011

Based on the data of 52 meteorological stations in Yunnan Province from 1981 to 2011, we quantitatively analyzed the main factors affecting the change of seasonal potential evapotranspiration in each station by sensitivity coefficient and the contribution rate. The results show that:(1) the average temperature was the most sensitive variable for seasonal ET₀ in each station, and then followed by relative humidity, sunshine hours in spring, summer and autumn in the period from 1981 to 1990 and from 1991 to 2011, the sensitive of wind speed was the lowest; in winter, relative humidity was the most sensitive factor in a few stations; (2) the main factor of ET₀ change in most stations was different with seasons; from 1981 to 1990 in most stations, the determining factor of winter ET_0w was average temperature, and sunshine hours were the determining factor of other three seasons; from 1991 to 2011 in most stations, the ET₀ changed in summer mainly due to the sunshine hours, and other seasons were average temperature; (3) the spatial distribution patterns of main factors were different. The rise of average temperature was the dominating factor leading to the increase of winter ET_0w in the eastern region, and the sunshine hour was the main factor of summer ET_0e change in south-central area; in spring and summer, the regional diversity of the dominating factor was relatively obvious in different periods. The above results indicated that the dominating factor affecting the ET₀ in Yunnan Province had the characteristics of stage, season and region.