宁夏地区潜在蒸散发变化特征及成因分析

Characteristics and causes of potential evapotranspiration in Ningxia region

根据宁夏地区1962—2017年11个国家级气象站的逐日气象资料,采用Penman-Monteith公式计算宁夏地区潜在蒸散发(potential evapotranspiration,ET 0)日值系列,采用气候倾向率、Mann-Kendall突变检验、ArcGIS反距离权重空间插值、敏感性分析和贡献率等方法对宁夏地区ET 0时空变化特征及影响因素进行分析.结果表明:宁夏地区1962—2017年多年平均ET 0为1073 mm,其中,中部干旱带最高(1135 mm),引黄灌区次之(1095 mm),南部山区最低(893 mm);宁夏地区ET 0在1986年发生了突变,突变前以0.571 mm/a的幅度下降,突变后以0.109 mm/a的幅度递增,整个周期内,以0.523 mm/a幅度递增,但变化幅度均不显著.ET 0对不同区域气象要素的敏感性不同,引黄灌区和中部干旱带对最高温度最敏感,敏感性系数分别为0.41和0.43,南部山区为相对湿度(-0.45);不同气象要素对ET 0的贡献率不同,引黄灌区和南部山区主导因子是最低温度,中部干旱带是平均风速.突变前后,对引黄灌区、中部干旱带和南部山区ET 0贡献率最高的气象要素分别由平均风速、相对湿度和最低温度,变为相对湿度、平均风速和最低温度.

According to the daily meteorological data of 11 national meteorological stations in Ningxia from 1962 to 2017,the Penman-Monteith formula was used to calculate the potential evapotranspira-tion(ET 0)daily value series in Ningxia,using climate tendency rate and Mann-kendall mutation test.ArcGIS inverse distance weighted spatial interpolation,sensitivity analysis and contribution rate were used to analyze the temporal and spatial variation characteristics and influencing factors of ET 0 in Ningxia.The results show that the average ET 0 of Ningxia region from 1962 to 2017 is 1073 mm,of which the highest in the central arid zone(1135 mm),the third in the Yellow River irrigation area(1095 mm),the lowest in the southern mountainous area(893 mm);the Ningxia ET 0 in 1986 occurs the mutation,and the amplitude decreases by 0.571 mm/a before the mutation,and increases by 0.109 mm/a after the mutation.The whole period increases by 0.523 mm/a,but the variation range is not significant.ET 0 has different sensitivity to meteorological elements in different regions.The Yellow River irrigation area and the central arid zone are most sensitive to the highest temperature,the sensitivity coefficients are 0.41 and 0.43 respectively,and the southern mountainous areas are relative humidity(-0.45).The contribution rate of ET 0 is different.The dominant factor in the Yellow River irrigation area and the southern mountain area is the lowest temperature,and the central arid zone is the average wind speed.Before and after the mutation,the meteorological elements with the highest contribution rate to ET 0 in the Yellow River irrigation district,the central arid zone and the southern mountain region were changed from average wind speed,relative humidity and minimum temperature to relative humidity,average wind speed and minimum temperature.