基于SWAT模型的区域农业干旱模拟研究

Study on Simulation of Agricultural Drought in a Region Based on SWAT Model

近年来,干旱在我国呈现出广发和频发态势,已经成为我国主要的自然灾害之一,尤其是农业干旱,其成灾机理最复杂、涉及范围最广、灾害影响最严重。以贾鲁河流域为典型研究区域,利用水文气象、社会经济、土地利用、DEM等数据,构建了基于SWAT的区域农业干旱模拟模型,选取土壤相对湿度作为农业干旱指标进行模型的适用性评价,并系统分析贾鲁河流域的农业干旱特征。结果显示:(1)所建模型对贾鲁河流域农业干旱的模拟效果良好,农业干旱模拟结果与历史记录基本吻合,且空间分布基本一致;(2)贾鲁河流域轻度干旱主要发生于初春、春末及夏初;中度干旱主要发生于初春及春末;重度干旱主要发生于春夏之交及夏秋之交;特大干旱主要发生于春季及春夏之交;(3)贾鲁河流域农业干旱整体呈现9 a的周期性特征,季节性特征明显;(4)春旱、春末夏初旱是贾鲁河流域农业干旱的主要类型,流域上游地区及下游地区发生春末夏初旱的频率最高,中游地区发生初春旱的频率最高。

In recent years,drought has become one of the foremost natural disasters in China with a wide range and a high frequency,especially agricultural drought with the characteristics of the most complex disaster-becoming mechanism,the most extensively involved and the most severely affected.This paper took the Jialu River Basin as a typical research area to construct a regional agricultural drought simulation model based on SWAT using the data of hydro-meteorology,social economy,land use,DEM,etc.We selected the relative humidity of the soil as an agricultural drought index to evaluate the applicability of the model,and the characteristics of agricultural drought in the Jialu River basin were systematically analyzed.The results show:①The model has a perfect simulation effect on agricultural drought in the Jialu River basin,the simulation results of droughts and their spatial distribution are basically consistent with the historical data;②The mild droughts mainly occur in early spring,late spring and early summer,the moderate droughts mainly occur in early spring and late spring,the severe droughts mainly occur at the end of spring and summer,the beginning of summer and autumn,the extreme droughts mainly occur in spring and the beginning of summer;③The agricultural drought in the Jialu River basin has the characteristic of 9-year cycle and obvious seasonal feature;④The main types of agricultural droughts in the Jialu River basin are spring droughts,droughts at the ending of spring and the beginning of summer.In the upper and lower reaches of the basin,the frequency of the droughts at the ending of spring and the beginning of summer is the highest;in the middle reaches,the frequency of the early spring droughts is the highest.