Stephen J. Cox

An assessment of satellite surface radiation products for highlands with Tibet instrumental data

[1] This study presents results of comparisons between instrumental radiation data in Tibet and two satellite products: the Global Energy and Water cycle Experiment Surface Radiation Budget (GEWEX-SRB) and International Satellite Cloud Climatology Project - Flux Data (ISCCP-FD). Severe and systematic errors were found in monthly-mean SRB shortwave radiation (SW) and FD longwave radiation (LW). Errors in diurnal variations are even larger than the monthly mean errors. Though the LW errors can be reduced nearly 10 W m 2 after an altitudinal correction, the remaining errors are still higher than that for other regions. The large errors in SRB SW were caused by neglecting elevation effects, but the errors in FD LW were mainly due to significant errors in input data. We suggest reanalyzing all ancillary data and reprocessing these satellite surface radiation data, at least for highland areas like Tibet. Citation: Yang, K., T. Koike, P. Stackhouse, C. Mikovitz, and S. J. Cox (2006), An assessment of satellite surface radiation products for highlands with Tibet instrumental data, Geophys. Res. Lett., 33, L22403, doi:10.1029/2006GL027640.

The NASA GEWEX surface radiation budget project: Dataset validation and climatic signal identification

The NASA GEWEX-SRB (Global Energy and Water cycle Experiment - Surface Radiation Budget) project has produced and archived shortwave and longwave radiative fluxes at the top of atmosphere (TOA) and the Earths surface at a 1° × 1° resolution continuously for a time span of 24.5 years from July 1983 to December 2007. The latest version of the data in archive is Release 3.0 and is available as 3-hourly, daily and monthly means. Through August, 2011, the Baseline Surface Radiation Network (BSRN) archive has 5969 site-months of ground-measured data from 52 sites around the globe. We first performed quality-check on the original BSRN data and, then processed the data to produce 3-hourly, 3-hourly-monthly, daily and monthly means. The SRB-BSRN comparisons show generally good agreement for both the shortwave and longwave downward fluxes at the Earths surface. It is found that signals of large-scale climatic variation, such as El Nino Southern Oscillation, can be identified through EOF analysis. Polynomial fitting of order 3 for Southern and Northern Hemispheric and global mean downward shortwave fluxes from 1984 to 2007 shows variability consistent with global dimming through 1980s and brightening thereafter.The NASA GEWEX-SRB (Global Energy and Water cycle Experiment - Surface Radiation Budget) project has produced and archived shortwave and longwave radiative fluxes at the top of atmosphere (TOA) and the Earths surface at a 1° × 1° resolution continuously for a time span of 24.5 years from July 1983 to December 2007. The latest version of the data in archive is Release 3.0 and is available as 3-hourly, daily and monthly means. Through August, 2011, the Baseline Surface Radiation Network (BSRN) archive has 5969 site-months of ground-measured data from 52 sites around the globe. We first performed quality-check on the original BSRN data and, then processed the data to produce 3-hourly, 3-hourly-monthly, daily and monthly means. The SRB-BSRN comparisons show generally good agreement for both the shortwave and longwave downward fluxes at the Earths surface. It is found that signals of large-scale climatic variation, such as El Nino Southern Oscillation, can be identified through EOF analysis. Polynomial fitti...

Validating the new results from the next generation of the NASA GEWEX SRB against the BSRN, GEBA, WRDC as well as the PMEL data

The NASA GEWEX SRB project is moving toward the next generation, or Release 4, of its products as its algorithms are updated and new inputs from the ISCCP become available. This paper compares its early shortwave/longwave results with the surface-based BSRN, GEBA, WRDC as well as the PMEL data. The comparison statistics show that the new algorithms along with the new inputs appreciably improve the quality of the products.

NASA/GEWEX Surface Radiation Budget: Integrated Data Product With Reprocessed Radiance, Cloud, and Meteorology Inputs, and New Surface Albedo Treatment

The NASA/GEWEX Surface Radiation Budget (SRB) project produces shortwave and longwave surface and top of atmosphere radiative fluxes for the 1983-near present time period. Spatial resolution is 1 degree. The current Release 3.0 (available at gewex-srb.larc.nasa.gov) uses the International Satellite Cloud Climatology Project (ISCCP) DX product for pixel level radiance and cloud information. This product is subsampled to 30 km. ISCCP is currently recalibrating and recomputing their entire data series, to be released as the H product, at 10km resolution. The ninefold increase in pixel number will allow SRB a higher resolution gridded product (e.g. 0.5 degree), as well as the production of pixel-level fluxes. Other key input improvements include a detailed aerosol history using the Max Planck Institute Aerosol Climatology (MAC), and temperature and moisture profiles from nnHIRS.The NASA/GEWEX Surface Radiation Budget (SRB) project produces shortwave and longwave surface and top of atmosphere radiative fluxes for the 1983-near present time period. Spatial resolution is 1 degree. The current Release 3.0 (available at gewex-srb.larc.nasa.gov) uses the International Satellite Cloud Climatology Project (ISCCP) DX product for pixel level radiance and cloud information. This product is subsampled to 30 km. ISCCP is currently recalibrating and recomputing their entire data series, to be released as the H product, at 10km resolution. The ninefold increase in pixel number will allow SRB a higher resolution gridded product (e.g. 0.5 degree), as well as the production of pixel-level fluxes. Other key input improvements include a detailed aerosol history using the Max Planck Institute Aerosol Climatology (MAC), and temperature and moisture profiles from nnHIRS.