Impacts of radiometric calibration on land surface temperature retrieval over urban areas

摘要

In this paper, the impact of radiometric calibration on land surface temperature (LST) retrieval from a single thermal channel, particularly over urban areas, was investigated. To measure the impact, an error coefficient (EC) was defined as the ratio of LST error to radiometric calibration uncertainty. The EC was estimated based on a sensitivity model, with focusing on HJ-1B thermal channel. Generally, under a moderate condition, a 0.1 (W·m^{-2·sr-1·μm-1) uncertainty in radiometric calibration may result in an error of 1.1 K in LST retrieval. Further investigations on the spatial and temporal variations of EC were based on MODIS/Terra MOD11_C3 and MOD08_M3 as well as a yearly land cover product (MCD12_C1). In addition, discussions for urban areas were demonstrated. Major findings include: (1) the EC over urban areas located in low latitudes are larger than those in middle latitudes; (2) seasonal variation of the ECs over urban is visible, which is associated with the backgrounds of geography and climatology; (3) the EC differences between urban and non-urban vary spatially and temporally, which show significant contribution to LST retrieval, especially over the transition region of middle and low latitudes.}