Evaluation of Himawari-8 surface downwelling solar radiation by ground-based measurements

Abstract

Abstract. Observations from the new Japanese geostationary satellite Himawari-8 permit quasi-real-time estimation of global shortwave radiation at an unprecedented temporal resolution. However, accurate comparisons with groundtruthing observations are essential to assess their uncertainty. In this study, we evaluated the Himawari-8 global radiation product AMATERASS using observations recorded at four SKYNET stations in Japan and, for certain analyses, from the surface network of the Japanese Meteorological Agency in 2016. We found that the spatiotemporal variability of the satellite estimates was smaller than that of the ground observations; variability decreased with increases in the time step and spatial domain. Cloud variability was the main source of uncertainty in the satellite radiation estimates, followed by direct effects caused by aerosols and bright albedo. Under all-sky conditions, good agreement was found between satellite and ground-based data, with a mean bias in the range of 20-30 W m −2 (i.e., AMATERASS overestimated ground observations) and a root mean square error (RMSE) of approximately 70-80 W m −2 . However, results depended on the time step used in the validation exercise, on the spatial domain, and on the different climatological regions. In particular, the validation performed at 2.5 min showed largest deviations and RMSE values ranging from about 110 W m −2 for the mainland to a maximum of 150 W m −2 in the subtropical region. We also detected a limited overestimation in the number of clear-sky episodes, particularly at the pixel level. Overall, satellite-based estimates were higher under overcast conditions, whereas frequent episodes of cloud-induced enhanced surface radiation (i.e., measured radiation was greater than expected clear-sky radiation) tended to reduce this difference. Finally, the total mean bias was approximately 10-15 W m −2 under clear-sky conditions, mainly because of overall instantaneous direct aerosol forcing efficiency in the range of 120-150 W m −2 per unit of aerosol optical depth (AOD). A seasonal anticorrelation between AOD and global radiation differences was evident at all stations and was also observed within the diurnal cycle.

Solar Irradiance Forecasts by Mesoscale Numerical Weather Prediction Models with Different Horizontal Resolutions

“…Aerosol information (e.g., optical depth of aerosol) has not been considered in the current satellite algorithms for surface GHI value (see Section 2.2). For further verification of satellite-derived GHI values using surface GHI observations, see the previous publication by Damiani et al [24].…”

“…AMATERASS datasets from Himawari-8 were also used to validate spatial distributions in GHI model simulations. Validation of the satellite-derived GHI data with ground-based data resulted in a mean bias error (MBE) within the range of 20-30 W m −2 under all-sky conditions (10-15 W m −2 under clear-sky conditions) and a root mean square error (RMSE) of approximately 80 W m −2 (Damiani et al [24]).…”

Improving the UAV-based yield estimation of paddy rice by using the solar radiation of geostationary satellite Himawari-8

“…The Advanced Himawari Imagers aboard the Himawari-8 acquire full-disk observations in 16 bands (three for visible, three for NIR, and 10 for infrared wavelengths) every 10 min (and over Japan, every 2.5 min), with a spatial resolution ranging from 0.5 km to 2.0 km (Bessho et al, 2016;Damiani et al, 2018). Using the EXAM algorithm, one can leverage these observations to estimate surface downwelling global shortwave radiation over Japan at a 2.5-min temporal resolution and a nominal 1-km spatial resolution (Takenaka et al, 2011;Damiani et al, 2018). In this study, we used a solar radiation dataset with a 30-min temporal resolution.…”

A Method for the Detection of Decrease in Power in PV Systems Using Satellite Data

“…Errors in satellite-based data have been observed in some previous studies [10] Smart Grid and Renewable Energy [11] [12]. The difference between measured irradiance and that derived from Himawari-8, a Japanese stationary weather satellite, has been evaluated [10]. Although the accuracy of estimation based on Himawari-8 observation has improved compared to the estimation based on Himawari-7, problems such as the influence of albedo and radiation enhancement have remained.…”