title: Downscaling Thermal Infrared Radiance for Subpixel Land Surface Temperature Retrieval.
abstract: Land surface temperature (LST) retrieved from satellite thermal sensors often consists of mixed temperature components. Retrieving subpixel LST is therefore needed in various environmental and ecological studies. In this paper, we developed two methods for downscaling coarse resolution thermal infrared (TIR) radiance for the purpose of subpixel temperature retrieval. The first method was developed on the basis of a scale-invariant physical model on TIR radiance. The second method was based on a statistical relationship between TIR radiance and land cover fraction at high spatial resolution. The two methods were applied to downscale simulated 990-m ASTER TIR data to 90-m resolution. When validated against the original 90-m ASTER TIR data, the results revealed that both downscaling methods were successful in capturing the general patterns of the original data and resolving considerable spatial details. Further quantitative assessments indicated a strong agreement between the true values and the estimated values by both methods.
authors.affiliation: Department of Geography and Department of Statistics, The Ohio State University, 1036 Derby Hall, 154 North Oval Mall, Columbus, OH 43210 USA. liu.738@osu.edu.
authors.forename: Desheng
authors.initials: D
authors.lastname: Liu
authors.affiliation: Department of Geography, University of South Florida, 4202 E. Fowler Ave., NES 107, Tampa, FL 33620 USA. rpu@cas.usf.edu.
authors.forename: Ruiliang
authors.initials: R
authors.lastname: Pu
keywords: ASTER; Land surface temperature; downscaling; subpixel; thermal infrared radiance