陕西省潜在蒸散发的敏感性及变化成因分析

潜在蒸散发(ET_0)是准确估计作物需水量和合理制定农田管理制度的重要参考依据,分析其对气象要素的敏感性对评估区域陆地水资源利用效率具有重要意义。根据陕西省1955-2015年的20个气象站的逐日实测气象数据,利用Penman-Monteith方程计算逐日ET_0,应用敏感性公式计算ET_0对最高气温、最低气温、相对湿度、平均风速、日照时数等5个关键气候要素的敏感系数,探究敏感系数的时空分布规律及变化趋势;并结合气象要素的多年变化定量分析的变化ET_0成因。结果表明:(1)ET_0对气象要素的敏感系数年内变化幅度依次为:相对湿度日照时数最低气温风速最高气温。(2)陕西省年均ET_0对气象要素的敏感程度均在"中"等级以上,相对湿度最为敏感;年际敏感系数显著增减变化趋势南北差异大,且空间分布特征表现不一。(3)ET_0与关键气候要素之间呈现的复杂非线性关系,使各气象站ET_0变化的主导气象要素也不尽相同,存在明显空间差异。

Sensitivity of potential evapotranspiration in Shaanxi Province and attribution of its variation

Po tent ial ev apo transpiratio n( ET0 ) is an important refer ence fo r the accurat e estimatio n of cro psc w ater dem and and fo r the reasonable formulatio n o f a farmland m anag ement system. Analy sis of the sensitivit y of ET 0 to m eteo ro log ical factors is of g reat significance fo r assessing the utilizat ion efficiency of land w ater resour ces in a reg ion. Based o n the daily w eather data from 20 m eteo ro log ical statio ns in Shaanx i Pr ov ince from 1955 to 2015, w e used the FAO256 Penman2M onteith equatio n to calculate daily E T0 . T hen w e used the sensitiv ity formula to calculate the sensitiv ity coefficients of ET 0 to the main meteo rolog i2 cal facto rs, such as the daily max imum temperature ( ST H ) , da ily minimum temperature ( ST L ) , relative humidity ( SRH ) , w ind speed ( S A W ) , and sunshine dur ation ( SSD ) . We ex plor ed the tem po ral and spatial distributio n featur es and v ariation tr ends o f the sensitivity coefficients and quantitativ ely ana lyzed the contributing factors to ET0 v ariation in view o f the multi2year va riatio n of the meteo ro log ical facto rs. Results show ed that t he meteoro lo gical facto rs so rted by the annual variation amplitude o f the sen2 sit ivity coefficient o f ET0 to these factors wer e SRH > SSD > STL > SA W > ST H . The sensitivit y o f annual averag e ET 0 in Shaanx i Pro vince to the meteor olog ical facto rs all r eached the middle o r abov e level. It was the most sensitiv e to SRH . The interannual variatio n tr ends of sensit ivity coefficients show ed a big differ ence between the nort h and south, and they also show ed differ ent spatial distribution characteristics. The complicat ed no nlinear relationship between E T0 and the key meteor olog ical factors caused the dominant meteoro lo gical factors o f ET0 to differ acr oss differ ent meteo rolog ical stations and to show obvio us spatial differ ence