基于MODIS数据的近8年长三角城市群热岛特征及演变分析

Characteristics Analysis on Heat Island Effect in Yangtze Delta Urban Agglomerations in Recent 8 Years by MODIS Data

利用MODIS hdf数据来反演地表温度,首先通过数据挑选少云覆盖图像,再经多波段综合法去云,用近8年的MODIS历史资料选择劈窗算法反演计算给出了长三角平均地表温度分布图,以长三角作为区域整体研究热岛效应,分析了城市群热岛分布特征,指出主要城市热岛分布呈"Z"字型分布格局。长三角地区热岛强度季节变化是夏季最强,春季次之,秋冬季除少数地区为较强热岛外,大部分地区都显示为弱热岛或无热岛。采用GIS地理统计方法比较16城市的强热岛面积分布,分析了2001—2008年夏季各城市热岛强度的年际变化趋势。

Retrieving the land surface temperature by hdf data in MODIS receiver system,first the few cloudy data were selected,and then cloud be removed by means of multiband combination.The average temperature figures of Yangtze Delta were retrieved by split window algorithm,the distribution characteristics of Yangtze Delta area were analyzed,and the heat islands are arranged in ＂Z＂ distribution.In Yangtze Delta area,the heat island intensity is the strongest in summer,then in spring and most areas are in weak or no heat island except few areas in strong heat island in winter.By GIS geographic statistics,the strong heat island areas were compared.And the change trend of heat island of each city from 2001 to 2008 were also being analyzed.The data were processed in Delphi and IDL languages including data projection, inversion,cartography.The analysis of island heats was independently conducted,and average retrieval results were more objective.