Research on the method for estimating emissivity of land surface using Landsat TM

Land surface emissivity is one of key parameters in land surface temperature retrieval using remote sensing data. However, most methods are too complex to practical application. It is essential to create an easy method for retrieving land surface emissivity. The land surface emissivity retrieval mainly lies on land surface substance structure and wave band of sensors. This paper divides land cover into four types and induces the formula for each land cover based on heat radiation balance of land surface. The emissivity of study area is estimated and the results show that average is 0.979. The emissivity of cropland is high when corp well grow, and low contrarily. The emissivity of natural vegetation universally is lower because the vegetation has not grown fully in this period. The emissivity of building is mostly between 0.980 and 0.985, and road value is also relatively high. The results are reasonable in spatial distribution. The method used to estimate emissivity is simple and practical, and easily be applied in other area.