The NASA/GEWEX SRB Release 4: Long-Term Surface Radiation Budget Using Newly Reprocessed Data Inputs from NOAA and NASA

The NASA Global Energy and Water Exchanges (GEWEX) Surface Radiation Budget (SRB) project produces longwave and shortwave radiative fluxes for the surface and top-of-atmosphere (TOA). Along with improvements in the algorithms, the primary inputs of cloud and meteorology data have been undergoing improvements in quality and spatial and temporal resolution. Many of these inputs are being developed in collaboration with other GEWEX projects to ensure consistency between GEWEX radiation and other GEWEX data products (i.e., ISCCP, SeaFlux, LandFlux, GPCP, etc.). As part of this effort, the NOAA NCEI has completed processing the first version of ISCCP “H” series data set that features recalibrated radiances and improved cloud retrievals at nearly a nine-fold increase in number of available pixels. These improvements will allow for more varied cloud fractions on the current 1-degree grid system and also allow for finer horizontal resolutions in the future. Additionally, ISCCP is processing an atmospheric temperature and humidity data set called nnHIRS that will be used for a GEWEX Integrated Product run leveraging inputs from other GEWEX global data sets.

Here, we present an analysis of at least a 10-year period of surface longwave (LW) and shortwave (SW) fluxes computed with these cloud properties and meteorology. The Langley Research Center Fu-Liou radiative transfer code (Rose et al. 2006) is used to compute the longwave fluxes. The SW algorithm includes recalculated atmospheric transmissivities and reflectivities yielding a less transmissive atmosphere. Ocean albedo and snow/ice albedo are also improved from Release 3. Total solar irradiance is now variable, averaging 1361 Wm^-2 consistent with the results from SORCE. The calculations also include variable aerosol composition, allowing for the use of a detailed aerosol history from the Max Planck Institute Aerosol Climatology (MAC) in the SW and LW fluxes.

We explore the temporal variability of the Rel. 4 fluxes as it relates to the input data, Rel. 3.1 SRB fluxes. We also compare these to a 10-year run using NASA’s MERRA-2 for the temperature and moisture profiles and compare to newly released CERES TOA and surface radiation data sets. Finally, we present the surface validation of the various surface LW and SW flux data products with site measurements from BSRN and PMEL ocean buoys.