摘要
土地利用/覆盖变化对气候具有重要影响,为探讨耕地扩张的气候效应,基于土地利用数据及MODIS遥感资料,采用窗口搜索法,利用能量平衡的原理,研究2000−2018年东北地区耕地扩张的潜热和净短波辐射通量变化,分析耕地扩张对地表温度的影响。结果表明:(1)研究期内东北地区耕地面积增加1.6×10^(4)km^(2),主要来自林地和草地,分别占耕地扩增面积的16.33%和76.24%。(2)与林地相比,耕地白天对地表具有增温作用,夜间具有降温作用,全天具有增温作用,并具有明显的季节特征。夏秋季节耕地的蒸散发弱于林地,潜热通量比林地少,导致耕地对地表具有增温作用,冬季耕地的净短波辐射远少于林地,导致耕地对地表降温。(3)与草地相比,耕地夜间总体的降温效应稍强于白天的增温效应,使耕地全天对地表具有降温效应,并具有不同的季节特征。夏秋季节耕地的蒸散发强于草地,耕地的潜热通量比草地多,成为耕地对地表降温的主要原因,而在春冬季节,耕地与草地吸收的净短波辐射差异较小,同时潜热差异也较小,因此对地表的增温/降温效应不明显。
Land use and land cover change significantly affects climate.To explore the climate effects of cropland expansion,the window search method and the principle of energy balance were used to quantify how the cropland expansion in Northeast china changes the surface energy balance,thereby affecting the land surface temperature based on multi-source remote sensing data in 2000−2018.The results showed that:(1)the area of cropland increased by 1.64×10^(4)km^(2) in Northeast China,mainly from forestland and grassland,accounting for 16.33%and 76.24%of cropland expansion area,respectively.(2)Compared with forestland,cropland has a warming effect on the surface during the daytime,a cooling effect at nighttime,and a warming effect throughout the day with obvious seasonal variation.In summer and autumn,the evapotranspiration of cropland is weaker than that of forestland,and the latent heat flux is less than that of forestland,resulting in a warming effect on the surface.In winter,the net shortwave radiation of cropland is far less than that of forestland,resulting in a cooling effect on the surface.(3)Compared with grassland,the cooling effect of cropland at nighttime is slightly stronger than that during the day,resulting in a cooling effect on the surface throughout the day with obvious seasonal variation.In summer and autumn,the evapotranspiration of cropland is stronger than that of grassland,and the latent heat flux of cropland is more than that of grassland,which has become the main reason for the cooling of cropland to the surface.In spring and winter,the difference of net shortwave radiation absorbed by cropland and grassland is small,leading that the warming/cooling effect on the surface is not obvious.
作者
狄文丽
沈润平
黄安奇
韩慧敏
DI Wen-li;SHEN Run-ping;HUANG An-qi;HAN Hui-min(School of Geographical Sciences,Nanjing University of Information Science&Technology,Nanjing 210044,China)
出处
《中国农业气象》
CSCD
北大核心
2022年第6期450-463,共14页
Chinese Journal of Agrometeorology
基金
国家重点研发计划(2018YFC1506602)
国家自然科学基金重点项目(91437220)。
关键词
东北地区
耕地扩张
生物物理
能量变化
Northeast China
Cropland expansion
Biophysical
Energy change
