Research On Urban Heat Island Of Zhengzhou Based On Remote Sensing

With the development of the urbanization process, human is facing the increasingly serious problems of the urban environment at present. Because of the environmental heat pollution problems and the underling surfaces changes, how to ease the urban heat island (UHI) has become an urgent urban environment problem. In recent decades, domestic and foreign experts have made a lot of researches and explorations about the causes of UHI, influences of UHI, change rules of UHI, mitigation measures of UHI. More traditional research methods use the ground-based observatories' meteorological data in studying the thermal environment of urban change, but this research method is time-consuming and labor-intensive, it can no longer meet today's research requirements about the UHI. A wide use of remote sensing technology can be used to make large-scale, simultaneous and dynamic monitoring of surface thermal field's distribution and changes. So the technology of remote sensing is becoming the most important research method in studying the contemporary UHI.In this study, the primary research material is based on two Landsat remote sensing images: May 14, 1988 of TM sensor and May 10, 2001 of ETM+ sensor. These images are about Zhengzhou, and also weather information of Zhengzhou is necessary. In this paper, the study introduced the development of UHI as the breakthrough point, and analyzes the causes of UHI through the analysis of the impact of UHI. It describes the main topic of this study, introduces the idiographic technical line, and focuses on the cause of UHI. This paper introduces the concept and steps of image pre-processing, and this part is used to dispose the main data of Zhengzhou. Through the study of inversion method about land surface temperature, this paper confirmed the single-window algorithm about this study and calculated the surface emissivity, the average atmospheric temperature and the atmospheric transmittance, and then created the temperature classification and grading maps of Zhengzhou, this part is the core of this article. At last this paper combined land surface temperature distribution maps, land-use type classification maps and NDVI analysis maps of Zhengzhou, then obtained the trends of UHI and the evolution reasons of UHI, and then put forward a reasonable measures to mitigate the UHI, it's the extended part of this study.