The Acquisition Of The Impervious Surface Fraction And The Land Surface Energy Flux And The Disscussion Of The Relationship Between Them

Impervious surface is an anthropogenic feature which water cannot infiltrate the soil, including roads, driveways, sidewalks, parking lots, rooftops, and so on. And is an important part of the city surfaces. Impervious surface prevents water from entering soil effectively, thus it can increases the rain-wash and has higher heat-conduction and heat store ability, then form the urban tropical island effect. The fast development of the impervious surface shows the expansion urbanization directly and indirectly. The estimated of impervious surface has offered a index which the river degraded, surface temperature change and land life environmental quality reduce.Land surface energy flux influences the nearly stratum atmosphere energy with the lower cushion to exchange with the moisture directly, thereby influence structure and climate in storey of atmospheric border. Sensible heat flux and latent heat flux is regional climate model and important input parameter of the regional hydrology model, it is also an important index while studying the ecological effect of city. So study the characteristic of the non-uniform surface energy flux in the urban amd draw the regional distribution map of the energy flux surface, have important meanings. This paper regards Guangzhou region as study area, use LandsatTM(1990,2006)/ETM+(2000)image, 1:50,000 DEM data, the vector graph of Guangzhou canton region in 1:100,000, weather data of ground observation station of Guangzhou and the vegetation height of ground observation station data as the main data source, and other geographical information data as assistant data source. First, through image enhance, registration and resampling and other image preparation, and then in virtue of normalized linearity spectral mixture analysis model to extrate the scale image of impervious surface. Second, based on the data of surface temperature and ground observation station weather data by SEBAL computation to gain the study area's land surface energy flux. At the same time, use the land surface energy flux and impervious surface image on 14 Sep 2000 as an example, analyze the coupling relation between Impervious surface and Land surface energy flux. The conclusion is: The fraction of impervious surface and sensible heat flux present positive correlation, the correlation coefficient is 0.56573; the correlation coefficient between the fraction of impervious surface and latent heat flux is -0.58964;There is different correlation between the fraction impervious surface and surface energy in different pixel scale,but the ratio of desending is relatively small; with the increasing of the fraction of impervious surface, the average latent heat flux takes the desending trend(except the one or two areas ).