A dataset of topographic correction coefficients for shortwave downward radiation over the Pan-Third Pole

Abstract

AbstractPrevalent Shortwave downward radiation (SWDR) estimates assume a flat surface, neglecting topographic effects and leading to significant errors in mountainous regions. We introduce SWDR topography correction coefficients (TCCs), based on the mountain radiative transfer model tailored for the Pan-Third Pole region. This dataset effectively bridges the disparities between flat-surface SWDR and rugged-surface SWDR, forming part of the Long-term Earth System spatiotemporally Seamless Radiation budget dataset (LessRad). Validation results using a three-dimensional radiative transfer model demonstrate the efficacy of this method in correcting solar direct radiation, sky diffuse radiation, and SWDR under diverse conditions. At a spatial resolution of 2.5 arc-minutes, the correction accuracy for solar direct radiation is characterized by a coefficient of determination (R²) of 0.998, a relative root mean square error (rRMSE) of 2.4%, and a relative bias (rbias) of 0.8%. For sky diffused radiation, an R² of 0.965, a rRMSE of 1.2%, and a rbias of −0.8%. SWDR corrections under clear and cloudy skies also show high accuracy, demonstrating the robustness of the TCCs approach.