水利学报2017，Vol.48Issue(9)：1055-1063,9.DOI:10.13243/j.cnki.slxb.20170002
西藏高海拔地区气象数据缺失条件下的ET0计算研究
Simplified limited data ET0 equation adapted for high-elevation locations in Tibet
摘要
Abstract
The Food and Agriculture Organization of the United Nations (FAO) has recommended the Penman-Monteith (FAO56 P-M) method as a standard method for estimating reference evapotranspiration (ET0) and for evaluating other methods.But the FAO56 P-M method requires many parameters that are not available in many developing regions of high elevation in Tibet.Meanwhile,the low pressure,strong solar radiation,intensive evaporation,and frequent heat transfer are special meteorological phenomena in high-elevation areas.Accordingly,the basic objective of this study is to develop a new equation requiring fewer parameters for simulating the ET0 at high-elevation stations.When solar radiation,relative humidity and/or wind speed data are missing,a possible exception is the Hargreaves-Samani (HS) method which has shown reasonable ET0 results with a global validity according to the FAO's Irrigation and Drainage Paper No.56.Therefore,the new equation (HS-E) based on HS equation and elevation was developed using the meteorological data of nine stations in the Tibet Plateau from 1981 to 1990.Then the HS-E and HS equation,which requires less meteorological data to calculate ET0,were evaluated as compared to the FAO56 P-M method.Results indicate that the computations of the improved HS-E model are obviously better than the HS model for the areas of higher than 2000m under the conditions of different time scale.The new mode,which enhanced the practical applications and computational accuracy of ET0,can nake up the shortage of HS model that the ET0 would have negative values in arctic-alpine region of Tibet.Compared with the ET0 calculated by FAO56 P-M equation,the daily ET0 and monthly ET0 calculated by HS-E model were analyzed.The Nash-Sutcliffe efficiency coefficient (NSE),root-mean-square error (RMSE) and Mean Relative Error(MRE)for the daily ET0 calculated by HS-E model are 0.8,0.53 mm/d and 13.80％ and for the monthly ET0 are 0.84,11.90 mm/month and 12.50 ％,respectively,which indicated that the HS-E model is high-quality and can calculate the ET0 more exactly.Considering the error result of different time scales,the larger the time scale,the better the results can be obtained by the HS-E model.In conclusion,the HS-E model is suitable and accurate in the high-altitude district,which can be recommended as a simple method for calculating ET0 in the area higher than 2000m.关键词
参照作物腾发量/西藏高海拔地区/Hargreaves-Elevation改进模型/Penman-Monteith方程/Hargreaves模型Key words
reference evapotranspiration/high elevation of Tibet/Hargreaves-Elevation equation/Penman-Monteith equation/Hargreaves equation分类
农业科技引用本文复制引用
汤鹏程,徐冰,高占义,高晓瑜..西藏高海拔地区气象数据缺失条件下的ET0计算研究[J].水利学报,2017,48(9):1055-1063,9.基金项目
国家自然科学基金项目(51579158,51609154) （51579158,51609154）
中国水利水电科学研究院科研专项(MK2016J13,MK2017J02) （MK2016J13,MK2017J02）
