Total Net Downward Surface Solar Irradiance for Himawari-8/9 (HIM_SSI_Netdown) 

As part of the surface solar irradiance (SSI) collection, this product is the net downward total (diffuse and direct) irradiance, i.e., the difference between irradiance from above (downwelling) and reflected irradiance from below (upwelling), integrated over the solar spectral range (300 to 3500 nm). The product was generated for daytime Himawari-8/9 imagery using the Qin et al. (2021a) algorithm for the Australian continent and surrounding waters. While it is provided here in a regular latitude/longitude grid, the product is also available in the original Himawari (geostationary) projection (WGS84, sub-satellite longitude = 140.7°E and satellite altitude = 35785863 meters). Please contact the authors for accessing the data, which is located on the Australian National Computational Infrastructure (NCI). Currently, a near-real-time algorithm/processor is being developed to improve data availability, and to extend production to Himawari-10 (2028-2045). 

We at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging. We at the Terrestrial Ecosystem Research Network (TERN) acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging. This work was funded by TERN, an Australian Government NCRIS (National Collaborative Research Infrastructure Strategy) enabled project, and is supported using TERN infrastructure. The research was undertaken at CSIRO (Commonwealth Scientific and Industrial Research Organisation) collaboratively among research units (Environment, Energy, Agriculture and Food). The authors acknowledge the resources and services received from NCI and CSIRO HPC (High Performance Computing). We appreciate the support by Japan Meteorology Agency (JMA) and Australian Bureau of Meteorology (BoM) in providing Himawari data. 

The Himawari satellite series offers a unique opportunity to monitor sub-daily processes on Earth and in its atmosphere over Asia and Oceania, due to its unprecedented 10-minute temporal resolution as well as improved spatial and spectral resolutions compared to the previous generations of Japanese geostationary satellites and sensors (i.e., MTSAT series) which Australian researchers are kindly provided access through a JMA-BoM agreement. This product provides an instantaneous estimation of the total net downward surface solar irradiance (W/m²) every 10 minutes on a pixel (~2 km) level. Here “net downward” means the downward irradiance minus the irradiance reflected upward by the Earth’s surface. “total” means all solar irradiance that passed through the atmosphere without being absorbed or reflected back to space by the atmosphere before reaching the Earth’s surface in downward direction. The irradiance was integrated with respect to wavelength from 300 nm to 3500 nm when the sun is 15° above the horizon. This product may be used, for examples, in assessing plant health and productivity in agriculture and forestry, in monitoring and mitigating environmental impacts, and in improving climate models. 

As part of the downward surface solar irradiance (SSI) collection, this product was generated using an algorithm independently developed by CSIRO based on radiative transfer, using the cloud properties products generated by Qin et al. (2019). Discussion of the algorithm can be found in Qin et al. (2021a, 2021b and 2022).