河套灌区参考作物蒸发蒸腾量估算方法研究

参考作物蒸发蒸腾量（ET₀）是计算作物需水量的基础，一般用FAO推荐的Penman-Monteith公式（PM公式）计算。但是在河套灌区部分地区缺少辐射数据的观测，因而无法利用PM公式计算ET₀。本文选用河套灌区临河气象站1990—2012年的气象资料，分析了利用PM公式计算参考作物蒸发蒸腾量ET₀与气象要素的关系，发现对ET₀影响最大的气象因素为净辐射，其次为饱和水气压差和平均温度。建立了基于饱和水气压差、温度和风速的ET₀估算公式，验证结算显示相关系数、纳什效率系数和总量平衡系数分别为0.96、0.92、1.00。在风速缺测的条件下，也建立了基于饱和水汽压差和温度的ET₀估算公式。以上两个公式为河套灌区缺资料条件下ET₀的估算提供了简单且准确的估算方法。

Research on the estimating methods for reference crop evapotranspiration in Hetao Irrigation District

Reference crop evapotranspiration (ET₀) is the base for calculating crop water requirements, and it generally uses the Penman-Monteith Formula (PM formula) recommended by FAO to calculate. But this method cannot be used in some regions in Hetao irrigation district, due to lack of the measured radiation data. Herein in this paper, we selected and used the daily climatic data at Linhe Meteorological Station from 1990 to 2012, analyzed the relation between the reference crop evapotranspiration (ET₀) estimated by the PM formula to the climatic factors, has found the net radiation that was the dominated factor greatly influencing ET₀, the second factors were the saturated vapor pressure deficit and mean temperature. Also has established the ET₀ estimating formula based on the saturated vapor pressure deficit, temperature and wind speed. By the confirmation, the correlation coefficient, Nash Efficiency Coefficient and overall equilibrium coefficient were 0.96, 0.92 and 1.00, respectively. Under the condition of lack the measured wind speed, another estimated ET₀ formula by considering the saturated vapor press deficit and temperature was established. These two formulas can be provided the simple and accurate methods for estimating ET₀ in Hetao irrigation district when the measured meteorological data was limited.