First assessment of surface solar irradiance derived from Himawari-8 across China

The Advanced Himawari Imager (AHI) aboard Himawari-8, a new generation geostationary satellite with high spatiotemporal resolution, was launched in 2014 and operated by the Japan Meteorological Agency. The released AHI surface solar irradiance (SSI) product by the Japan Aerospace Agency (JAXA) has great potential in application of study on energy budget, solar energy and ecosystem etc. In this study, the JAXA AHI SSI products are evaluated using the Chinese Ecosystem Research Network (CERN) pyranometer measurements during March-December 2016 at 36 sites in China. The AHI SSI products are correlated to surface measurements very well. The daily and monthly AHI SSI products on all-sky conditions show mean bias errors of 13.8 and 13.3 W m(-2) relative to corresponding CERN measurements. The AHI SSI products are close to CERN data in summer, however they are significantly lower in winter. The significant positive bias of AHI SSI in the North China Plain very likely resulted from the underestimation of aerosol optical depth (AOD) by AHI. In contrast, the negative bias of SSI in high elevation stations is likely related to the improper input of atmospheric profile. All these error factors need further improvement in the AHI SSI algorithm.