Dynamic Monitoring Of Urban Expansion, Land Use Change And Urban Heat Environment In Quanzhou City Based On Remotely-Sensing Images

Urban has changed the landscape of the Earth with unexpreeding speed. On onehand, the rapid expansion of urban resulted in the change of the regional landscape,on the other hand, it made the regional environment worser and worser. All of thesechanges make an important impact on urban long-term and sustainable development.This study takes Quanzhou city of South Fujian Province as an example, which isone of three cities comprising the famous Golden Triangele Area of South Fujian.Based on three satellite images of Landsat TM/ETM+ and with the help of GIStechnology and scio-economic data, we monitor and analyse the urbanization processof Quanzhou city during the reform period from 1989 to 2000. The study reveals that the land use chaged rapidly in Quanzhou city during the11 study years. The main land use, such as built-up land, arable land and forest landhas changed at various degrees, which stimulated the competiton between build-upland and arable land, and caused the decrease of arable land in quantity and quality. Itis found that the main driving forces to land use change in Quanzhou are theurbanization and industrilization. The rapid increase in urban areas is a remarkable character in urbanizationprocess of Quanzhou city. The urban area in 2000 is three times more than that in1989 approximately. The urban expanded mainly surrounding the urban area andalong the major traffic roads, and the trend is quickening. The main dring force tourban expansion are the increase of population, the high-speed development ofeconomy and the vast investment of the foreign businessman. The direction and rateof urban sprawl were determined by policy executed in Quanzhou and georaphiccondition. The rapid urbanization results in the great changes of environment in Quanzhou IICity. This study takes the advantage of the inherent heat information in the remotesensing imagery to study the change process of the Urban Heat Island (UHI) effect inthe study area between 1989 and 2000, and analyze the key factors and consequencesof the UHI effect. The key factors of the UHI effect in Quanzhou City are proved tobe urban surface property, impervious area, urban runoff, the local weather, etc.Furthermore, this study reveals that the change of land surface humidity andevaporation are also important factors of the UHI effect in Quanzhou City and cannot be ignored. Thus, these two factors are further studied in the aspects of theirenvironmental consequences and derived from the remote sensing images by usingthe methods of Spectrum of Soil Water Contents and Surface Energy BalanceAlgorithm for Land respectively. The results of the study show that the amounts ofland surface humidity and evaporation in the urban are generally smaller than that inthe suburb, this represents a phenomena of "dry island", which goes against thereduce of the UHI effect. Finally, the interactive relationship among the urban area expansion, land usechanges and urban heat island effect is studied and analyzed in this study.