Land Surface Temperature Retrieval From FY-3C/VIRR Data and Its Cross-Validation With Terra/MODIS

Accurate inversion of land surface temperature (LST) from remote sensing data is an essential and challenging topic for earth observation applications. This paper successfully retrieves the LST from FY-3C/VIRR data with split-window method. With the simulated data, the algorithm coefficients are acquired with root mean square errors lower than 1.0 K for all subranges when view zenith angle (VZA) <; 30° and the water vapor content (WVC) <; 4.25 g/cm², as well as those in which the VZA <; 30° and the LST <; 307.5 K. In addition, a detailed sensitivity analysis is carried out. The analysis result indicates that the total LST uncertainty caused by the standard error of the algorithm, the uncertainties of land surface emissivity and WVC, and the instrument noise would be 1.22 K and 0.94 K for dry and wet atmosphere, respectively. Furthermore, LST retrieval method is applied to the visible and infrared radiometer measurements over the study area covering the geographical latitude of 31.671°N to 44.211°N and longitude of 10.739°W to 1.898°E, and the derived LST is cross-validated with Terra/MODIS LST product. The preliminary validation result shows that the split-window method determines the LST within 2.0 K for vegetation and soil areas.

I. Introduction

Land surface temperature (LST) is one of the most important parameters in the physical processes of surface energy and water balance. Knowledge of the LST provides information on the temporal and spatial variations of the surface equilibrium state and is of fundamental importance in many applications, such as evapotranspiration, climate change, hydrological cycle, vegetation monitoring, urban climate and environmental studies, among others [1]. Due to the strong heterogeneity of land surface characteristics such as vegetation, topography, and soil, LST changes rapidly in space as well as in time, and an adequate characterization of LST spatial and temporal distribution are extremely important [2]. Thus, the in situ LST measurements are no longer valuable over large areas. Satellite thermal infrared (TIR) imagery is the primary source, from which LST is retrieved at the regional and global scales.