The spatial character of regional heat island in Pearl River Delta using MODIS remote sensing data

Abstract

The purpose of this paper is to study regional large scale temperature elevation phenomenon in the Pearl River Delta using MODIS(Moderate-resolution Imaging Spetroradiometer) land surface temperature data.The result shows that MODIS data can reflect the change of regional land surface thermal environment in the rapid urbanization process.Land surface temperature(LST) relates to land cover types and NDVI.Corresponding temperature of urban land use is the highest,while that of the woodland is the lowest.The higher the NDVI,the lower the LST is.This trend is similar to the air temperature change.In the large-scale continuous urbanization process,non-urban land around urban areas is impacted by urban land use,causing LST rising and then large area of the regional temperature rising,thus regional heat island forms.In this study,there are about 46% of the non-urban areas where regional heat island effect occurs,while the percentage is about 75% for urban areas where RHI effect happens.The space pattern of RHI is highly interrelated with space layout of urban land use.Large cities or city groups are often the center of RHI.The circumferences of these regions have evident RHI phenomena.Towns in the southwest and northeast of the research region are distributed separately,where the RHI phenomena are not so evident.Therefore,regional urban pattern has an important effect on the intensity and spatial form of RHI.The result is useful for urban planning.Obviously,the better pattern for the metropolitan areas is small towns with large area green belts,which can mitigate the RHI effect.The result of the study also indicates that the MODIS data have some merits for monitoring the RHI effect,which includes large area coverage,high resolution,and easy access to the data.However,the shortage for MODIS is that it is likely to be affected by the cloud.Only when the air temperature is derived from the land surface temperature with MODIS data,can the study on urban heat island and regional heat island make a sound progress.