科尔沁沙地参考作物蒸散发估算及影响因子分析
李 霞1, 刘廷玺1,2, 段利民1,2, 王冠丽1,2, 周亚军1

(1.内蒙古农业大学 水利与土木建筑工程学院, 呼和浩特 010018; 2.内蒙古农业大学 内蒙古自治区水资源保护与利用重点实验室, 呼和浩特 010018)

参考作物蒸散量; Penman-Monteith模型; 通径分析; 科尔沁沙地

Estimation of Reference Crop Evapotranspiration and Analysis of Impact Factors in Horqin Sandy Land
LI Xia1, LIU Tingxi1,2, DUAN Limin1,2, WANG Guanli1,2, ZHOU Yajun1

(1.Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot 010018, China; 2.Inner Mongolia Key Laboratory of Water Resource Protection and Utilization, Inner Mongolia Agricultural University, Hohhot 010018, China)

reference crop evapotranspiration; Penman-Monteith model; path analysis; Horqin sandy land

备注

为了准确评估区域气候干湿状况以及保护半干旱区生态环境,基于科尔沁地区草甸地、半流动沙丘、半固定沙丘、水稻地及玉米地5个典型景观类型2015—2018年日气象资料,通过FAO56 Penman-Monteith公式计算参考作物蒸散发(ET0),了解不同时间尺度上ET0变化特征,并利用通径分析与指标敏感性分析相结合剖析了ET0的驱动因素。结果 表明:(1)4年的年平均ET0为1 051 mm,不同样地ET0年值在922～1 257 mm波动,最大值出现在2017年;(2)ET0季节变化表现为夏季>春季>秋季>冬季;(3)ET0月际变化呈抛物线型,3—10月贡献最大,占全年ET0的80%以上;(4)通径分析中,气象因子对ET0的通径系数表现为VPD>Rn>u2>Tmax,直接作用系数最大为0.614,即VPD是影响ET0最重要的因子; Tmax对ET0的间接作用最大,间接作用系数为0.936,且主要通过VPD路径对ET0产生作用,间接作用系数为0.554; 指标敏感性分析中,去除VPD后E由0.993减小为0.877,进一步说明ET0对VPD的变化最为敏感。总体而言,VPD为科尔沁沙地参考作物蒸散发变化的主导因子。

In order to accurately assess the regional climate condition and protect the ecological environment in semi-arid areas, based on the daily meteorological data of five typical landscape types including meadow land, semi-mobile sand dune, semi-fixed sand dune, rice and maize land from 2015 to 2018 in Horqin area, reference crop evapotranspiration(ET0)was calculated by using FAO56 Penman-Monteith model. Changes in ET0 on different time scales was analyzed, and then causes of ET0 changes were analyzed through path analysis and index sensitivity analysis. The results showed that:(1)the 4-year average ET0 was 1 051 mm, the annual value of ET0 fluctuated between 922 mm and 1 257 mm at different sample plots, and the maximum value appeared in 2017;(2)the seasonal change of ET0 decreased in the order: summer>spring>autumn>winter;(3)inter-monthly changes of ET0 were parabolic, with the largest contribution from March to October and accounting for more than 80% of ET0 in the whole year;(4)In path analysis, the path coefficients of meteorological factors to ET0 decreased in the order: VPD>Rn>u2>Tmax, and the maximum direct action coefficient was 0.614. indicating that VPD was the most important factor to affecting ET0, Tmax had the largest indirect effect on ET0, and the indirect action coefficient was 0.936, and it mainly affected ET0 through VPD path, and the indirect action coefficient was 0.554; in the index sensitivity analysis, E decreased from 0.993 to 0.877 after removing VPD, which further indicated that ET0 was the most sensitive to the change of VPD. In general, VPD was the main factor for evapotranspiration in Horqin sandy land.