High resolution surface radiation products for studies of regional energy, hydrologic and ecological processes over Heihe river basin, northwest China

This paper presents a framework to obtain high spatial resolution regional surface photosynthetically active radiation (PAR), solar radiation (SSR) and net radiation (NR) products through combining Geostationary Meteorological Satellite (GMS) data, polar-orbiting satellite Moderate Resolution Imaging Spectrometer (MODIS) products and ground meteorological sites' observations. Huang et al. (2011) approach was adopted and improved to directly retrieve instantaneous PAR and SSR from GMS data; while for NR the relationship between net radiation and net solar radiation was analyzed and calibrated using ground observations and Normalized Difference Vegetation Index (NDVI). Then these instantaneous estimates with temporal resolution of half hour would be averaged or integrated to acquire hourly and daytime accumulated PAR, SSR and NR. Taking Heihe river basin in northwest China, a typical oasis-desert area, as an example, the methodology was applied to produce year 2012 PAR, SSR and NR products. Ground measurements from Watershed Allied Telemetry Experimental Research (WATER, Li et al. (2009)) and Heihe Watershed Allied Telemetry Experimental Research (HiWATER, Li et al. (2013)) were used to perform the accuracy assessments. The results indicate highly reliable products at 1 km resolution have been produced over this basin, and are applicable to the researches of the regional surface energy, hydrological and ecological processes.