基于遥感的区域热环境分析

Regional Thermal Environment Analysis of the Qinling Mountain Area Based on Remote Sensing Data

为研究城市及其周边区域大范围热环境变化,以秦岭山脉南坡和北坡为例,采用遥感数据反演地表温度、植被指数和地表通量,不仅从传统地表温度参数理解区域热环境问题,还着重分析了秦岭两侧地表通量空间分布格局。研究表明,秦岭山脉南坡与北坡气候、地形和地表覆被状况的差异导致地表温度和热通量等热环境均存在显著差异。北坡的西安和咸阳市平均地表温度比其他行政区显著偏高,而在南坡植被覆盖较好的周至县境内,地表温度平均值则显著下降;裸地和居民地的地表温度平均值较高,而潜热通量和蒸散发平均值则较低。遥感估算区域热通量和蒸散发信息与地表温度同样是区域热环境研究中不可忽视的重要表征变量之一,而大范围区域热环境变化对于研究城市热岛效应的形成机制具有重要推动作用。

Land surface temperature,NDVI and land surface fluxes were estimated from Landsat ETM＋ image in order to understand the mechanism of urban and large-scale thermal environment over the north and south slope of the Qinling Mountain Area.The results showed that there were remarkable differences of the thermal environment on the southern and northern slope of the Qinling Mountain.It was found that the average land surface temperature,which can reach to 30.27℃,was higher in Xi′an and Xianyang City where urban built-in area dominated than in other administrative districts, on the contrary, in Zhouzhi County where the vegetation coverage is higher, there was lower mean and less heterogeneous spatially of land surface temperature. Moreover, higher land surface temperature and less latent heat flux and actual evapotranspiration appeared in bare soil and settlement area which resulted in the emergence of urban heat island. So it could be concluded that large-scale thermal environment will promote the production of urban heat island,and it was very important for understanding the inner mechanism of urban heat island to monitor the spatial distribution of large-scale land surface temperature and flux using remote sensing.