南水北调中线工程水源区蒸散发计算方法比较及影响因素分析

COMPARATIVE STUDY AND INFLUENCING FACTORS OF LAND SURFACE EVAPOTRANSPIRATION IN THE MIDDLE ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

以南水北调中线工程水源区为研究区域,采用1961～2007年9个气象站点气象观测数据和黄家港水文站实测径流资料,以FAO彭曼蒙特斯公式和水文模拟法为标准分别对多种潜在蒸散发计算方法和实际蒸散发计算方法进行比较研究,并分析了陆面蒸散发的影响因素。研究表明:南水北调中线工程水源区存在"蒸发悖论"现象,Priestley-Taylor公式计算结果偏大,但与FAO彭曼蒙特斯公式存在良好的相关关系,在气象资料较少时可以考虑建立相关方程进行推求。傅抱璞公式与水文模拟法计算结果较为接近,相关关系最优。潜在蒸散发与平均温度、气温日较差、实际水汽压、降雨量、风速、净太阳辐射、日照时数呈正相关,而实际蒸散发与平均温度、气温日较差、实际水汽压、降雨量、净太阳辐射、日照时数呈正相关,与风速呈负相关。净太阳辐射是影响陆面蒸散发的核心因素。

In this paper,the water source area of the Middle Route of South-to-North Water Transfer Project was chosen as the study area,and the meteorological data series of 9 meteorological stations and runoff data of Huangjiagang Hydrological Station have been collected.Based on these data,we have done comparative researches on several potential and actual evapotranspiration calculation methods with FAO Penman-Monteith equation and hydrological simulation via SWAT model as the benchmark,and also analyzed the influencing factors of land surface evapotranspiration.The conclusions are as follows.First of all,'evapotranspiration paradox' phenomenon exists in the Middle Route of South-to-North Water Transfer Project.Secondly,given that the results of Priestley-Taylor formula have a good linear correlation with those of FAO Penman-Monteith equation,we can build relevant equations to get evaporation information when there are less meteorological data series.Thirdly,the results of Fubaopu formula are close to the results of hydrological simulation.Besides,via correlation analysis between land surface evapotranspiration and meteorological factors,we have obtained that potential evapotranspiration have positive correlation with average temperature,diurnal temperature range,saturated vapor pressure,precipitation,net solar radiation and sunshine duration;Actual evapotranspiration have positive correlation with average temperature,diurnal temperature range,saturated vapor pressure,precipitation,net solar radiation,sunshine duration,and have negatively correlation with wind speed.The net solar radiation is a key factor affecting the land surface evapotranspiration.