黄土高原地区生长季参考作物蒸散量对主要气象要素的敏感性分析

Sensitivity Analysis of Reference Crop Evapotranspiration to Key Meteorological Factors during Growing Season in Loess Plateau

为预测气候因子变化引起的区域参考作物蒸散量(ET0)的变化,以黄土高原地区为研究区,运用FAO Penman-Montieth方程计算了68个站点1961-2010年生长季参考作物蒸散量,并计算其对平均气温、太阳辐射、风速和实际水汽压的敏感系数,最后分析了敏感系数的时空变化特征。结果表明,黄土高原地区生长季ET0对实际水汽压最敏感,其次是太阳辐射和平均气温,对风速的敏感性最低;平均气温的敏感系数和实际水汽压敏感系数绝对值呈单峰型分布,二者分别在7月、9月达到最大值,太阳辐射敏感系数表现为持续上升趋势,风速敏感系数波动幅度最小,其值在4月最大;生长季气候因子敏感系数的空间差异性显著,平均气温敏感系数西部明显大于东部,太阳辐射敏感系数在高海拔地区形成高值区,风速敏感系数在西风带Ⅳ区形成高值区,实际水汽压敏感系数在黄土高原湿润地带最大。

In order to predict the responses of reference crop evapotranspiration （ET0 ） to climate factors change, growing seasonal ET0 of 68 meteorological stations in the Loess Plateau from 1961 to 2010 was estimated by using of FAO -56 Penman - Monteith equation. Sensitivity coefficients of ET0 to average temperature, shortwave radiation, wind speed, and vapor pressure were calculated and their temporal - spatial distributions were analyzed. The results showed that vapor pressure was the most sensitive factor to ET0 in the region, followed by shortwave radiation and averagetemperature and wind speed. During growing season, the highest sensitive coefficient to average temperature was in July, while the absolute sensitive coefficient to vapor pressure was in September, the sensitive coefficient to shortwave radiation increased from April to October, the highest sensitive coefficient to wind speed was in April. The sensitive coefficients to all climate factors indicated large spatial variability. The sensitive coefficient to average temperature was higher in the eastern than in the western. The peak value of sensitive coefficient to shortwave radiation was in high elevation area, the peak value of sensitive coefficient to wind speed was in the western, while the peak value of sensitive coefficient to vapor pressure was in the relatively moist region.