Daily Exposure of Diffusely Transmitted Downward Surface Solar Irradiance for Himawari-8/9 (HIM_SSI_DE_Diffuse)

Brief description

This product is part of the downward Earth’s surface solar irradiance (SSI) collection, which was generated for daytime Himawari-8/9 imagery using the Qin et al. (2021a) algorithm for the Australian continent and surrounding waters. The product is provided here in a regular latitude/longitude grid. It 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).

Notes

Standard name:
integral_wrt_time_of_surface_diffuse_downwelling_shortwave_flux_in_air

Description:
The phrase "integral_wrt_X_of_Y" means int Y dX. The phrase "wrt" means with respect to. The limits of the integral is from sun rise to sun set local time. The surface called "surface" means the lower boundary of the atmosphere. The term "shortwave" means shortwave radiation. Downwelling radiation is radiation from above. It does not mean "net downward". The sign convention is that "upwelling" is positive upwards and "downwelling" is positive downwards. "Diffuse" radiation is radiation that has been scattered by gas molecules in the atmosphere and by particles such as cloud droplets and aerosols. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. Units conversion: 1 MJ = 10^6 Watt-second = 0.2778 kWh.

Units:
MJ/m^2/day

Lineage

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).

Qin, Y., Steven, A.D.L., Schroeder, T., McVicar, T.R., Huang, J., Cope, M. and Zhou, S.Z. (2019) Cloud cover in the Australian region: Development and validation of a cloud masking, classification and optical depth retrieval algorithm for the Advanced Himawari Imager. Frontiers in Environmental Science. 7(20) doi:10.3389/fenvs.2019.00020

Qin, Y.; Huang, J.; McVicar, T.R.; West, S.; Khan, M.; Steven, A.D.L. (2021a): Estimating surface solar irradiance from geostationary Himawari-8 over Australia: A physics-based method with calibration. Solar Energy 220, 119–129. DOI: 10.1016/j.solener.2021.03.029.

Qin, Y.; McVicar, T.R.; Huang, J.; West, S.; Steven, A.D.L. (2021b): Application of small angle approximation in circumsolar irradiance modelling. Solar Energy Advances 1, 100001. DOI: 10.1016/j.seja.2021.100001.

Qin, Y.; McVicar, T.R.; Huang, J.; West, S.; Steven, A.D.L. (2022): On the validity of using ground-based observations to validate geostationary-satellite-derived direct and diffuse surface solar irradiance: Quantifying the spatial mismatch and temporal averaging issues. Remote Sensing of Environment 280, 113179. DOI: 10.1016/j.rse.2022.113179.

Notes

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 estimation of the daily exposure of the diffusely transmitted downward surface solar irradiance (SSI) on a pixel (~2 km) level. Here “diffuse” means the solar irradiance was scattered at least once by the atmosphere before reaching the Earth’s surface in downward direction. “Daily exposure”, in MJ/m2, means integral with respect to time from sun rise to sun set, both defined by local solar zenith angle at 90°, and over the wavelength range from 300 nm to 3500 nm.
This product may be used together with the daily exposure of the total downward SSI and the directly transmitted component (HIM_SSI_DE_Total & HIM_SSI_DE_Direct).