A LUT-based approach to estimate surface solar irradiance by combining MODIS and MTSAT data

In this paper, a new satellite-derived approach for obtaining instantaneous surface solar irradiance (SSI) by combining Moderate Resolution Imaging Spectroradiometer (MODIS) and Multifunctional Transport Satellite (MTSAT) data is presented and validated using one year pyranometer measurements from five stations in northern China. The approach is based on look-up tables created via comprehensive radiative transfer modeling to achieve high accuracy and high computational efficiency. The synergy of the multispectral sensor MODIS and the high-temporal-resolution geostationary satellite MTSAT enables the adequate use of multisource remote sensing information to determine the atmosphere and surface states, and thereby complements shortcomings of their own. Here we use MTSAT data to capture the changes of cloud fields in the atmosphere and use MODIS products to obtain the dynamic aerosol loading, water vapor content, surface reflectance, and other information. Meanwhile, on the basis of instantaneous retrieval results, the calculation of hourly average SSI is also explored. The preliminary validation demonstrates that both instantaneous and hourly SSIs can be produced accurately over northern China using this approach, and the retrieval quality of hourly SSI data is slightly better than that of instantaneous SSI data. However, in mountainous areas the results need further refinement.