不同流域下农业干旱和水文干旱的影响、变化及成因

Effects,Changes and Causes of Agricultural Drought and Hydrological Drought in Different Watersheds

随着全球变暖,水文循环过程发生变化,干旱时空分布特征同样随之改变,因此探讨干旱产生的影响、变化特征和驱动因素具有重要的意义。因此,研究应用模型模拟干旱指数(self-calibrating Palmer Drought Severity Index)、降水、径流数据和土壤湿度的长时间序列数据。利用相关系数、干旱分级和Lindeman–Merenda–Gold(LGM)分别研究干旱的传播、不同级别干旱变化特征和干旱驱动因素。结果表明中国夏季、秋季和生长季的水文干旱对农业干旱的响应关系空间分布较为相似,但春季的松辽流域和海河流域水文干旱的响应程度低于其他季节。在松辽、海河、黄河和内陆河流域,轻度和重度干旱分别是农业和水文干旱发生频率最高的干旱等级,极度干旱为频率最低的干旱等级;不同等级的农业干旱频率总体上呈现增加的趋势,而水文干旱频率总体上呈现保持稳定不变的趋势。在不同流域的土壤湿度均为农业干旱的首要驱动因素。南方流域的参考作物蒸散量为水文干旱的首要驱动因素,松辽河流和内陆河流域的降水和土壤湿度为首要驱动因素,黄河、海河和西南诸河流域的土壤湿度和参考作物蒸散量为首要驱动因素。

With global warming,the hydrological cycle changes in regions.Meanwhile,the temporal and spatial distribution characteristics of drought also changed.Therefore,it has great significance to explore the impact,change characteristics and driving factors of drought.Therefore,this study applies the model to simulate the long-time series data of self-calibrating Palmer Drought Severity index,precipitation,runoff data and soil moisture.The correlation coefficient,drought classification and Lindeman-Merenda-gold(LGM)were used to study the propagation of drought,the variation characteristics of drought at different levels and the drought driving factors.The results show that the spatial distribution of hydrological drought response to agricultural drought in summer,autumn and growing season is similar,but the response degree of hydrological drought in Songliao and Haihe river basin in spring is lower than other seasons.In Songliao,Haihe,Yellow River and inland river basins,mild and severe drought had the highest frequency in different drought classification of agricultural and hydrological drought;meanwhile,extreme drought had the lowest frequency in different drought classification of agricultural and hydrological drought.The agricultural drought frequency of different classification generally showed an increasing trend,while the hydrological drought frequency generally showed a stable trend.Soil moisture was the primary driving factor of agricultural drought in different river basins.The reference crop evapotranspiration was the primary driving factor of hydrological drought in southern China river basins;precipitation and soil moisture were the primary driving factors in the Songliao and inland river basins;soil moisture and reference crop evapotranspiration were the primary driving factors in the Yellow River,Haihe,and southwest river basins.