摘要
揭示耕地与林地转换对地表温度的影响对于认识人类活动的气候与环境效应具有重要意义。基于卫星遥感数据的统计分析是揭示土地利用/覆盖变化对地表温度影响的重要手段。但是,在景观破碎度较高地区,混合像元问题成为使用这一技术手段的主要限制性因素,中国南方长江流域尤为典型。为突破这一限制,论文基于Google Earth高清影像,在1 km尺度上辨识了200对耕地与林地纯像元,进而利用MODIS陆地数据产品,对比分析了耕地与林地的地表温度(LST)、叶面积指数(LAI)、地表反照率(Albedo)之差。结果表明:耕地的LST高于林地,白天和夜间温度分别约偏高2.75℃和1.15℃,并且温差因季节而异,白昼温差呈双峰(分别是5月和10月,温差约3.18℃和3.33℃),夜间温差为单峰(7月,约2.46℃)。同时,温差因地而异,总体表现为西高东低,陕甘交界处的白昼温差最大,年平均约为3.83℃;安徽中南部温差最小,约为1.1℃。耕地与林地的LST之差主要由蒸散发的差异所致。林地的LAI较大,蒸散发较强,地表向大气的潜热通量较大,用于直接加热地表的感热相对偏少,因而LST相对偏低。上述结果表明近年来长江流域及毗邻地区的耕地转为林地通过增加蒸发产生了一定的致冷效应。
Revealing the impact of land conversion on land surface temperature is of great significance for understanding the climatic and environmental effects of human activities. Statistical analysis based on satellite remote sensing data is an important method to reveal the impact of land use/cover change on land surface temperature. However, in areas with high landscape fragmentation, the mixed pixel problem has become the main limiting factor for the use of this technology, especially in the Yangtze River Basin in southern China. In order to break through this limitation, 200 pairs of pure pixels of cropland and woodland were identified on the 1 km scale based on Google Earth high-definition images. Then, the differences of land surface temperature(LST),leaf area index(LAI), and albedo between cropland and woodland were compared and analyzed by MODIS land data products. The results show that the LST of cropland was higher than that of woodland, and the temperature differences between daytime and nighttime were about 2.75 ℃ and 1.15 ℃, respectively. Daytime temperature difference between cropland and woodland showed double peaks(May and October, with temperature differences about 3.18 ℃ and 3.33 ℃), and nighttime temperature difference showed a single peak(July, about2.46 ℃). Temperature difference varied from place to place. The highest temperature difference was in the west-in the area bordering Shaanxi and Gansu Provinces, annual average temperature difference was about 3.83 ℃;and temperature difference was the smallest between central and southern Anhui Province(about 1.1 ℃). The difference of LST between cropland and woodland is mainly caused by the difference of evapotranspiration. The LAI of woodland is larger, the evapotranspiration is stronger, the latent heat flux from the surface to the atmosphere is higher, and the sensible heat used to directly heat the surface is relatively less, so the LST is relatively low. The above results show that the conversion of cropland to woodland in the Yangtze R
作者
赵彩杉
曾刚
张丽娟
张学珍
ZHAO Caishan;ZENG Gang;ZHANG Lijuan;ZHANG Xuezhen(Heilongjiang Province Key Laboratory of Geographical Environment Monitoring and Spatial Information Service in Cold Regions,Harbin Normal University,Harbin 150025,China;Key Laboratory of Meteorological Disaster,Ministry of Education,Nanjing University of Information Science & Technology,Nanjing 210044,China;Key Laboratory of Land Surface Pattern and Simulation,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China)
出处
《地理科学进展》
CSSCI
CSCD
北大核心
2019年第5期698-708,共11页
Progress in Geography
基金
中国科学院前沿科学重点研究项目(QYZDB-SSW-DQC005)
中国科学院青年创新促进会资助项目(2015038)
国家自然科学基金项目(41790424)
气象灾害教育部重点实验室开放课题(KLME1506)~~
关键词
耕地与林地转换
地表温度
长江中下游地区
cropland and woodland conversion
land surface temperature
middle and lower reaches of the Yangtze River Basin
