基于Landsat-8影像的西安市地表温度遥感反演与影响因子研究

Land surface temperature retrieval and influential factor analysis in Xi’an based on Landsat-8 image

基于西安市的Landsat-8数据,采用单通道算法进行了地表温度(LST)的反演,并通过实测LST值对反演精度进行了评价,同时分析了LST与不同地表类型、归一化植被指数(NDVI)以及归一化建筑指数(NDBI)之间的关系.结果表明,单通道算法反演LST精度较高,反演结果能较好地反演西安市LST的空间分布特征;不同地表类型对应的LST有明显的差异,城镇建设用地LST最高,农用地LST最低;通过在东西方向/南北方向剖面线上分别对NDVI、NDBI与LST进行线性拟合,发现NDVI与LST呈负相关线性关系, NDBI与LST呈正相关线性关系,进一步说明植被对地表起到了一定的降温作用,城镇建筑则加剧了城市热岛效应.

Based on Landsat-8 image of Xi’an,the single-channel algorithm was used to retrieve the land surface temperature(LST)and the retrieval accuracy was validated by the simultaneously measured surface temperature.The relationships between various surface types,normalized difference vegetation index(NDVI),normalized difference built-up index(NDBI)and LST were analyzed respectively.The results indicated that the single-channel algorithm manifested relatively high retrieval accuracy,and the retrieved surface temperature could effectively reflect the spatial distribution of LST in Xi’an.Distinct LST differences were detected between various surface types,where the LST of urban development land was the highest,while agricultural land was the lowest.The linear fitting of NDVI and NDBI with LST in both the east-west and north-south profile lines demonstrated that NDVI was negatively correlated with the LST,while NDBI was positively correlated,suggesting that vegetation had a cooling effect on the land surface,while urban constructions could markedly exacerbate the effect of urban heat island.