滇中地区昆明市潜在蒸发量的时空变化特征

Spatial and Temporal Change of the Potential Evapotranspiration in Kunming,the Middle of Yunnan Province

基于昆明市12个气象站1970-2013年的气象资料,采用世界粮农组织(FAO)推荐的彭曼公式估算了12个气象站的潜在蒸发量(Potential Evapotranspiration,PET),采用空间内插统计得到昆明市区域平均气象因子和潜在蒸发量,分析了潜在蒸发量的时空变化特征及成因.研究结果表明,昆明市区域多年平均潜在蒸发量为1 150.5mm,年和季节空间分布相一致,总体呈北高中南部低、高值集中分布在金沙江干热河谷;1970-2013年期间区域年潜在蒸发量显著下降(α=0.05),下降幅度为16.3mm/10a;同期年平均气温、最高气温、最低气温显著增加(α=0.05),年平均风速、年相对湿度和年日照时数显著减少(α=0.05);区域存在"蒸发悖论"现象,体现在1970-2008年期间8个单站;区域年平均风速和年日照时数的减少是造成年潜在蒸发量减少的主要原因,同时区域气温的升高和年相对湿度的减少使得年潜在蒸发量减少的趋势有所减缓,但未改变其减少趋势.春、秋和冬季潜在蒸发量的减少主要受平均风速的影响,夏季潜在蒸发量的减少主要受日照时数的影响.

Based on the daily data of 12 meteorological stations of Kunming city in 1970-2013 and combined with FAO Penman-Monteith model,spatial and temporal changes of potential evapotranspiration （PET） were analyzed.It was showed that the average areal PET was around 1 150.5 mm,and the spatial distribution with high value in the north part and low value in the middle and south part was observed both at the annual and seasonal level.A significant decreasing trend was tested in annual areal PET over the period of 1970-2013 with a speed of 16.3 mm/10 a,companying with significant increased mean,maximum minimum temperature,decreased wind speed,relative humidity and sunshine hours.Evaporation paradox was observed at 8 stations,over the period of 1970-2008.Wind speed,sunshine hours and temperature were the dominant factors influencing the annual areal PET,wind speed and sunshine hours were positive factors,and temperature was a negative factor in the annual PET decreasing trend.Decreasing PET in spring,autumn and winter was mainly determined by the wind speed,and sunshine hours was dominant in summer.