西辽河流域潜在蒸散量时空格局

Spatial-temporal Pattern of Potential Evapotranspirations in Xiliaohe Watershed

利用地处北方农牧交错带的西辽河流域及其周边45个地面气象台站1974-2005年的月平均气象资料(温度、湿度、风速和太阳辐射等),采用先计算后插值(CI)的方法,选用彭曼—蒙特斯(Penman-Monteith)(98)模型,对45个站点的多年平均潜在蒸散量进行了计算,在ArcGIS 9.0软件平台的地统计模块下,运用普通克里格法,对西辽河流域的多年平均潜在蒸散量逐月进行空间插值。在此基础上对全流域多年平均潜在蒸散量进行了时空格局分析,结果表明:西辽河流域潜在蒸散量ET0与气温、日照时数和风速显著正相关,与平均相对湿度为显著负相关;受各气象要素影响,ET0的逐月变化曲线为一条单峰曲线,冬季ET0普遍较低,春末、秋初及夏季ET0则较高;西辽河流域潜在蒸散量空间分布格局呈现以科尔沁沙地为中心区域向东北、西南两侧逐渐递减的总体趋势。

In China,the farming-pastoral zone of northern China has become one of the academic research hot spots.Xiliaohe watershed is a part of the farming-pastoral zone of northern China,located in the east of Three-North Area of China.Horqin sandy land is in this watershed,which is well known as the biggest sandy in China.Xiliaohe watershed’s weather is meteorological drought with less rain.And the evapotranspiration is strong.The situation of water shortage is serious.Water shortage has become the bottleneck to the development of local in-dustry and agriculture.Also,Xiliaohe watershed is considered as a vulnerable eco-region because of water shortage.Potential evapotranspiration,seen as the basis for the actual evapotranspiration research,is important not only to the water resources research but also to the study of the relationship between vegetation and mois-ture.This study aims at analyzing the spatial-temporal pattern of potential evapotranspiration in the Xiliaohe watershed.Based on the climatic data from 45 meteorological stations throughout the Xiliaohe watershed during 1974 and 2005,potentia1 evapotranspirations（ET0） are calculated using the CI method（Calculate first,Interpo-late later）.Firstly,potentia1 evapotranspirations of 45 meteorological stations are calculated using the Penman-Monteith（98） Model recommended by FAO.Secondly,based on the ArcGIS 9.0 software,using the Ordinary Kriging method,potentia1 evapotranspirations in Xiliaohe watershed are interpolated month by month.Conclu-sions are as follows： 1） ET0 is positively related to temperature,sunshine hours and wind speed but inversely re-lated to average relative humidity.2） Affected by the impact of various meteorological elements,the monthly ET0 change curve is a single peak curve.ET0 is always lower in winter and higher in summer,the end of spring and the beginning of autumn.3） The spatial distributional trend of potential evapotranspirations in Xiliaohe water-shed is that ET0 decreases gradually from the Horqin sandy land（the middle of the Xiliaohe watershed） to the northeastern side and southwestern side.