湖南年蒸发量时空演变特征及气象影响因子分析

利用湖南省地面气象站点1971—2012 年的地面气象观测数据，采用线性趋势、经验正交函数分 解、相关分析法和相对权重法，分析了湖南省蒸发皿年蒸发量时空变化及主要气象影响因子。结果表明：在过去的42 年，湖南全省年平均蒸发量呈不显著下降趋势；大部分地区年蒸发量有比较明显的年代际波动，在湘中及湘东大部分地区表现为显著的下降趋势，湘东南的东部地区表现为显著上升趋势，其余区域变化趋势不明显；蒸发量与日照时数、降水量、平均气温、气温日较差和饱和水汽压差等多个气象因子都存在显著的相关关系，与日照时数的正相关程度最大，与降水量的负相关程度最大；在年蒸发量下降的区域的主导因素是日照时数的减少，在年蒸发量上升的区域的主导因素是降水量的减少。

Spatiotemporal Variability of Annual Evaporation and the Impact of Meteorological Factors in Hunan Province

Based on surface observation data of meteorological stations in Hunan Province from 1971 to 2012, the spatiotemporal variability of annual pan evaporation (PE) and the major meteorological factors were analyzed by using linear regression, EOF, correlation analysis and relative weighting method. The results showed that: the annual mean total PE in Hunan Province presented an insignificant decreasing trend in the past 42 years; the annual mean PE had an evident interdecadal fluctuation in most regions, it had significant decreasing trends in the central of Hunan and most areas of east Hunan, but significant increasing trends in eastern part of southwest Hunan, and there was no significant trends in other areas. In addition, there were significant relationship between PE with sunshine duration, precipitation, mean air temperature, diurnal temperature range and vapor pressure deficit. PE had the highest positive correlation with sunshine duration and the highest negative correlation with precipitation; furthermore, the leading factors in regions with decreasing PE and increasing PE were the reduction in sunshine duration and precipitation, respectively.