土地利用对湘江流域蒸散发的影响

Impact of Land Use on Evapotranspiration in Xiangjiang River Basin

以湘江流域湖南段为例,基于2000、2010、2020年土地利用和蒸散发等数据,通过土地利用转移矩阵、综合/单一动态度模型和GIS空间分析等方法,探讨2000~2020年湘江流域土地利用类型、面积变化和转换特征,揭示研究区土地利用类型、面积和转换对蒸散发的影响。结果表明,研究期内湘江流域土地利用类型的面积、占比和空间格局均发生了较大变化,尤其是土地利用类型之间相互转换频繁,但近20年主要土地利用类型的面积排序基本保持稳定,即林地>耕地>草地>建设用地>水域;湘江流域基于土地利用类型的年蒸散量排序为林地>草地>耕地>建设用地,相较于基于土地利用面积的实际年蒸散总量排序(林地>耕地>草地>建设用地)存在差异,因此分析研究区土地利用对蒸散量的贡献要综合考虑土地利用类型及所占面积;研究区各土地利用类型的相互转换,引起了不同趋势和程度的年蒸散量变化,其中,建设用地与其他土地利用类型的相互转换对研究区蒸散量的影响相对较大,其余土地利用类型转换对于区域蒸散发的影响相对较小。研究成果可为流域土地利用规划和水资源管理提供参考。

Taking the section of Hunan in Xiangjiang River Basin(XRB)as an example,bases on the land use and vapotranspiration e-data in 2000,2010 and 2020,this study discusses the characteristics of land use type,area change and mutual conversion in the XRB by using the methods of land use transfer matrix,integrated and single dynamic attitude model and GIS spatial analysis.The effects of land use type,area and conversion on evapotranspiration in the study area were revealed.The results show that the area,proportion and spatial pattern of land use types in the XRB have undergone great changes,especially the frequent conversion among land use types.However,in the past 20 years,the order of main land use areas in the XRB remained stable:forest>farmland>grassland>construction land>water area.The order of theoretical annual evapotranspiration based on land use type in the XRB is forest>grassland>farmland>tion construc-land,which is different from the order of actual annual total evapotranspiration based on land use area:forest>farmland>grassland>construction land.Therefore,the land use type and land use area to evapotranspiration in the study area should be considered comprehensively.The conversion of different land use types in the XRB caused the change of evapotranspiration in different trends and degrees.The conversion between construction land and other land use types has a relatively large impact on evapotranspiration in the study area,while the conversion of other land use types has a small impact on regional evapotranspiration.The research results can provide scientific reference for land use planning and water resources management in the basin.