基于MODIS数据的重庆市地表热环境效应研究

利用2000—2006年EOS/MODIS卫星资料反演的地表温度(LST)和植被指数(NDVI)资料，分析了重庆市夏季地表热场分布状况，并对重庆市夏季地表热场变化规律及成因进行了研究. 结果表明:①重庆市夏季LST分布区域特征明显，东北部LST最低，西部LST最高；2000—2003年重庆市除了中部地区LST升高外，其他地区降温明显；2003—2006年重庆市中部和西部地区LST明显升高. ②2000年以来，重庆市热岛效应明显增强，重庆市中心强热岛区(城郊温差大于8 ℃)面积由2000年的53 km2增至2006年的313 km2；城郊最高温差由2000年的10.8 ℃增至2006年的14.5 ℃. ③重庆市的LST和NDVI具有显著的负相关关系，相关系数均在-0.7以上；在植被长势较好的2000和2003年，重庆市NDVI每升高0.1，LST降低约4 ℃；而在植被长势较差的2006年，NDVI每升高0.1，LST降低约5 ℃. ④在2006年大气环流异常背景下，NDVI的急剧降低和城市热岛效应的显著增强进一步促进了重庆市高温伏旱天气的形成. 

Research on Land Surface Thermal Field Change in Chongqing City from MODIS Data

Using Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) retrieved by EOS/MODIS data from 2000 to 2006, distributionandchange of land surface thermal field of Chongqing in summer were analyzed. Results showed that: ① regional distribution of LST of Chongqing was obvious, the maximum and minimum of LST lied in the west and northeast respectively. From 2000to 2003, the LST in most areas of Chongqing raised except the middle area decreased, and from 2003 to 2006, the LST in the middle and west areas increased obviously. ② urban heat island (UHI) intensity of Chongqing increased distinctly since 2000. Urban heat island areas whose intensity is more than 8 ℃ in the center of Chongqing increased from 53 km2 in 2000 to 313 km2 in 2006, the highestLST difference between the center of Chongqing and countryside raised from 10.8 ℃ in 2000 to 14.5 ℃ in 2006. ③ LST and NDVI of Chongqing showed significant negative correlation, the correlation coefficients were more than-0.7. In 2000 and 2003 vegetation grew better and NDVI raised per 0.1, LST decreased about 4 ℃. In 2006 vegetation grew worse; NDVI raised per 0.1, LST decreased about 5 ℃. ④ On the background of atmospheric circulation anomalies, the changes of NDVI decreasing and UHI intensity increasing both contributed to the formation of high temperature weather in 2006.