2001—2020年渭北黄土台塬区农业干旱变化特征及影响因素分析

Characteristics of agricultural drought and its influencing factors in the Loess Tableland of the north of the Wei River from 2001—2020

为明晰渭北黄土台塬区2001—2020年间农业干旱的时空变化特征及影响因素,利用MODIS遥感数据构建了Ts-NDVI特征空间,计算出温度植被干旱指数(TVDI),以揭示干旱的时空演变规律。同时,借助地理探测器分析了干旱与自然因素及人类活动之间的关联,确定了影响TVDI空间分异性的关键因子。结果表明:该区域平均每年有65.04%的区域遭受不同程度的干旱,多年平均TVDI值为0.52,整体处于中旱状态,且春季干旱尤为严重;2001—2020年,该区域TVDI值呈现波动下降趋势,并表现出强持续性特征,约有91.38%的区域干旱情况得到缓解或保持稳定;TVDI的空间分异性显著,主要受到高程、气温、人口密度和NDVI等多个因子的综合影响;在不同年份,影响TVDI的主导因子组合有所变化,这反映出自然因素和人类活动对干旱影响的复杂性。需综合运用气候监测、生态恢复、优化农业生产结构和提高水资源利用效率等措施,以更精准地预测和缓解干旱对区域农业生产和社会经济的影响。

To clarify the spatio-temporal variations of agricultural droughts in the Loess Tableland on the North of the Wei River(LTNWR)from 2001 to 2020,we employed MODIS data to construct Ts-NDVI feature space.Subsequently,the temperature vegetation dryness index(TVDI)was obtained,and the spatio-temporal evolution of droughts was thoroughly examined.Meanwhile,the relationship between droughts and natural factors as well as human activities was analyzed by GeoDetector,and the key driving factors of the spatial differentiation of TVDI were identified.Our findings reveal that 65.04%of the region experienced varying degrees of drought annually,with an average TVDI value over multiple years standing at 0.52,indicating a state of moderate drought across the entire region.Notably,drought conditions were particularly severe during spring.In the study period,TVDI values exhibited fluctuating and declining trends with strong persistence.In turn,approximately 91.38%of regional drought conditions either improved or remained stable during this period.Furthermore,the spatial differentiation of TVDI was pronounced and primarily influenced by factors such as elevation,temperature,population density,and normalized difference vegetation index.The leading factors affecting TVDI varied across different years,reflecting the multifaceted impacts of natural factors and human activities on drought conditions.To address these challenges,integrated measures including climate monitoring,ecological restoration,optimization of agricultural production structures,and improvement of water resources utilization efficiency are essential.These measures will facilitate more accurate prediction and mitigation of the impacts of droughts on regional agricultural production and socio-economic development.