甘肃省农业干旱对多尺度气象干旱的响应

Response of Agricultural Drought to Multi-Scale Meteorological Drought in Gansu Province

基于气象站点和卫星遥感数据,以标准化降水蒸散发指数(SPEI)和植被状态指数(VCI)分别表征气象干旱和农业干旱,利用统计方法和Arcgis技术分析了甘肃省气象及农业干旱的时间变化趋势和空间分布特征,采用最大相关系数法分析了不同时间尺度的SPEI指数对VCI指数的响应关系。结果表明:气象干旱在春、夏、秋及生长季干旱发生频率最高的地区分别为:陇东地区、河西地区、陇东与河西地区、陇东地区。大部分地区气象干旱呈增加趋势,而农业干旱呈减缓的趋势。农业干旱发生频率表现出西北部和东部高,中部和南部低的空间格局。SPEI与VCI相关性特征表明,空间上SPEI与VCI在林地和草地的相关性最大;时间上VCI指数与SPEI-3相关性最大,即农业干旱对3个月尺度的气象干旱响应最灵敏。研究结果可为甘肃省的农业防旱工作提供参考。

Based on meteorological stations and satellite remote sensing data,statistical methods and Arcgis techniques were used to analyze the temporal and spatial distribution characteristics of meteorological and agricultural droughts.The response coefficient of SPEI index at different time scales to VCI index was analyzed by the maximum correlation coefficient method.The results showed that the drought frequency in spring,summer,autumn and growing season was highest in Longdong,Hexi,Longdong and Hexi,Longdong,respectively.Meteorological drought increased in most areas,while agricultural drought decreased.The frequency of agricultural drought showed high spatial pattern in northwest and east,low in central and south.The correlation between SPEI and VCI indicates that the spatial correlation between SPEI and VCI is the largest in woodland and grassland.In terms of time,the VCI index has the greatest correlation with SPEI-3,that is,agricultural drought is the most sensitive to meteorological drought on a 3-month scale.The results can provide reference for agricultural drought prevention in Gansu province.