Study On The Relationships Between Land Use And Urban Heat Island In Laizhou City Based On TM Data

With the rapid development of economy and society and expansion of city-size, the levelof urbanization keeps increasing. Landscapes such as architecture, roads and so onaccumulate quickly in the limited space in cities. The cities expand outside continuously. Atthe same time, the population has been centralized into city and anthropogenic heat rises uprapidly, which makes the urban heat island attract extensive attentions. Urban heat island cancause a number of questions in many aspects such as decrease in comfort level, aggravationin energy consuming, deterioration of environmental quality, disease of respiratory system,meteorological disaster and so on. During the urbanization, from a natural state to artificiallandscape including architecture and roads, the change of urban land coverage is one of themain reasons for Urban Heat Island.Based on the Landsat TM images in1995and2009and Artis&Camahan’s inversionmethod of temperature of radiometric correction adopted in it, two periods of the temperaturelayout of Laizhou city have been got. Meanwhile, the average temperature in the samehistorical period is used to test the precision of Inversion results， which turns out to beeffective. Then the Urban Heat Island is divided into five levels through the equidistantmethod, namely strong UHI, weak UHI, no UHI, weakly negative UHI and strong negativeUHI. The location and the distribution of Laizhou’s UHI is determined according to that theregion of UHI contain the strong UHI and the weak UHI. Then the types of land cover areextracted by the classification of gradually layer by layer based on remote sensing images, toget the four types of land cover pictures which is including water body, vegetation, buildingand hardened road, and one else. When combined with the two-phase inversion of surfacetemperature distribution, surface temperature classification pictures, land cover type picturesand statistics related properties, namely by means of the calculation,such as MNDWI, NDVIand ISA, by collecting samples of pixel temperature properties of linear to do the correlationanalysis, analysis of the relationships between three land cover types,including water body,vegetation, building and hardened road, and Laizhou’s UHI. This paper also uses a bufferanalysis, statistics buffer land cover types each pixel average temperature values to obtain theinfluence that the coastal impacts on the urban heat island. Conclusions are as follows:（1）When the two-phase inversion temperature pictures of the surface are all exhibited thephenomenon, including uneven distribution of surface temperature and the heat gathered inthe local area, it is indicated that the urban heat island phenomenon of the two phases areboth very obvious.（2）Urban temperature is obviously higher than suburban temperature, and it shows that theheat gatherers to Urban from the surrounding.（3）According to the results of counting the areas of the UHI, the range of the UHI ofLaizhou City in2009is larger than that in1995. Meanwhile the feature that the heataccumulating is more and more obviously, and the urban heat island intensity significantlystrengthened.（4）According to the land cover type pictures, the range of building and hardened road ofLaizhou City in2009increases obviously compared with that in1995, and the region of urbanexpands around obviously.（5）Based on the comprehensive change of each picture, the expansion direction of urbanheat island of Laizhou city and building and hardened road, shows a strong consistency.at the same time,the distribution of the urban heat island and building and hardened road is alsoshowing a strong consistency.（6）Based on the collecting sample as pixel per the average temperature, surface temperatureand NDWI show a significant negative correlation. Besides, when it is with the NDVI, theresult shows a significant negative correlation. But when it is with the impermeable rate, theresult shows a significant positive correlation. In other word, there is a negative correlationbetween water body, vegetation and urban heat island but a positive correlation betweenbuilding and hardened road and urban heat island.（7）The average surface temperature of each type of land cover overall manifested asincreasing tendency from the coast to the inland, that shows that the coastal can weaken theUHI.