Historical simulation of photovoltaic potential over China within the CORDEX-EA-II framework

This study evaluates historical simulation of solar photovoltaic potential (PVpot) during 1989-2008 over China against the ERA5 reanalysis, using the Weather Research and Forecasting (WRF) model and Regional Climate Model version 4 (RegCM4) within the framework of the Coordinated Regional Downscaling Experiment-East Asia second phase (CORDEX-EA-II). The impacts of spectral nudging technique and land surface model on the simulated PVpot are investigated as well. Results indicate that the observed PVpot is abundant over western China, which can reach up to 26% in summer particularly. The WRF simulations significantly overestimate the PVpot over most areas of China, with the bias about 9% over southeastern China, while the utilization of spectral nudging method and CLM4 land surface model can greatly reduce the deviation. The RegCM4 simulations generate underestimation of PVpot over Northwest China and overestimation over Southeast China. As for the interannual variation, the observed PVpot features an increase of 0.9%/decade over southeastern China. The WRF and RegCM4 simulations can reproduce the rising trend of PVpot, while the magnitude is much lower than ERA5. The WRF simulations can properly portray the characteristics of seasonal cycle of PVpot, with the peaks in May over entire China and most subregions, while RegCM4 exhibits poor skill in reproducing the intra-annual variation. Moreover, the simulated bias in the clear-sky solar radiation (RSDSCS), low-level cloud fraction, and light rain during the daylight may contribute to the deficiency of PVpot.