首页|基于Copula函数的千米尺度综合干旱指数构建与应用——以重庆市为例

基于Copula函数的千米尺度综合干旱指数构建与应用——以重庆市为例

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  • 国家科技期刊平台
  • NETL
  • NSTL
  • 万方数据
干旱是影响农业生产最大的自然灾害之一,开发综合干旱指数对于评估干旱具有现实意义.该文耦合XG-Boost算法降尺度后的土壤水分和降水Z指数数据,在空间上以重庆市行政区县边界分区,时间上以旬为单位分段,基于Copula函数构建千米尺度网格化的综合干旱指数(meteorology-agriculture composite standardized dranght in-dex,CSDIM-A),评估干旱的时空特征.结果表明,降尺度提高了遥感产品的空间连续性,为后续构建千米尺度的CSDIM-A提供支持;广义极值分布和t位置尺度分布分别适用于拟合重庆市大多数区县土壤水分和降水变量数据分布,Frank-copula函数适用于拟合旬尺度下二元变量的联合分布;基于土壤墒情数据验证构建的CSDIM-A比降水Z指数能更好地反映干旱信息,基于各区县得到CSDIM-A的空间分布与实际旱情资料相符,说明所构建的CSDIM-A可为干旱评估提供参考.
Construction and application of a comprehensive drought index based on Copula function on a kilometer scale:A case study of Chongqing,China
Drought is identified as one type of the most serious natural disasters affecting agricultural production,and developing a comprehensive drought index holds practical significance for the assessment of drought in various districts and counties in Chongqing.By coupling the soil moisture and precipitation Z-index data downscaled using the XGBoost algorithm and using the Copula function,this study developed a gridded comprehensive drought index CSDIM-A on a kilometer scale with the boundaries of various districts and counties of Chongqing as the spatial division criteria and decades of a month as time units.Using this index,this study assessed the spatiotemporal characteristics of drought and performed an experimental demonstration of the index using Chongqing as the study area.The results indicate that the downscaling enhanced the spatial continuity of remote sensing-based products,thus providing support for the subsequent construction of a comprehensive drought index on a kilometer scale.The generalized extreme value distribution and the t location-scale distribution applied to the fitting of the data distributions of soil moisture and precipitation in most districts and counties of Chongqing,respectively,while the Frank-copula function suited for the fitting of the joint distribution of binary variables on a scale of a month decade.As validated based on soil moisture content,CSDIM-A can more effectively reflect drought than the precipitation Z-index,with its spatial distribution in various districts and counties consistent with the actual drought data.This indicates that the CSDIM-A can be used as a reference for drought assessment.

droughtsoil moistureprecipitation Z-indexdownscalingcomprehensive drought index

杨辰飞、吴田军、王长鹏、杨丽娟、骆剑承、张新

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长安大学理学院,西安 710064

长安大学土地工程学院,西安 710064

中国科学院空天信息创新研究院遥感科学国家重点实验室,北京 100101

中国科学院大学资源与环境学院,北京 100049

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干旱 土壤水分 降水Z指数 降尺度 综合干旱指数

内蒙古自治区科技重大专项项目国家自然科学基金项目国家重点研发计划项目第三次新疆综合科学考察项目国家自然科学基金项目重庆市农业信息中心项目

2021ZD0045420713162021YFB39009052021xjkk14001200105721C00346

2024

10.6046/zrzyyg.2023097

自然资源遥感
中国国土资源航空物探遥感中心

自然资源遥感

CSTPCD北大核心
影响因子：1.275
ISSN：2097-034X
年,卷(期)：2024.36(3)