Surface Radiation Budget (SRB)
The objective of NASA/GEWEX SRB project is to produce and archive a long-term record of global gridded data sets for shortwave (SW) and longwave (LW) surface and TOA parameters starting no later than July 1983 and currently extending to December 2007. To accomplish this objective, SW and LW SRB data sets are derived on a 1° x 1° global grid with two sets of algorithms, known as primary and Langley parameterized algorithms, and from a variety of input data sources. The primary SW algorithm is adapted from Pinker and Laszlo (Modeling Surface Solar Irradiance for Satellite Applications on a Global Scale, J. Appl. Met., 31, 194-211, 1992) and the primary LW algorithm is an adaptation of Fu et al., (JAS, Vol. 54, 2799-2812, 1997). The Langley Parameterized SW algorithm (LPSA; Gupta et al. – NASA/TP-2001-211272, Dec. 2001) was developed at the Langley Research Center by W. F. Staylor, and the Langley Parameterized LW algorithm is by Gupta et al. (J. Appl. Meteor., 31, 1361-1367, 1992).
These datasets are produced using cloud parameters derived from International Satellite Cloud Climatology Project (ISCCP) products and meteorological inputs from GMAO reanalysis datasets with radiative transfer algorithms. The start date of July 1983 is dictated by the availability of ISCCP data. A key long-term goal is that these satellite-derived parameters have a monthly uncertainty of less than 10 Wm-2 or 5 percent, which ever is smaller. The Parameter Accuracy/Validation provides a synopsis of the accuracy for the parameters currently available in SRB release version 3.0 from the NASA Langley Research Center’s Atmospheric Science Data Center (ASDC).
Column ozone values for most of the duration of this dataset (July 1983 to December 2004) were obtained primarily from the Total Ozone Mapping Spectrometer (TOMS) archive. For the early period (July 1983-November 1994), TOMS data came from NIMBUS-7 and Meteor-3 satellites. There was an interruption of about 20 months (December 1994-July 1996) after which TOMS data from EP-TOMS became available in August 1996 and continued until December 2004. All gaps in TOMS data, including those over the polar night areas every year, were filled with column ozone values from TIROS Operational Vertical Sounder (TOVS) data. Column ozone data continued to be available beyond December 2004 from OMI instrument aboard Aura satellite but TOVS data, which is essential for filling the gaps in OMI data, developed some unexplained gaps of its own and became unusable. Beginning in January 2005, GEWEX/SRB started using a daily analysis ozone product from NOAA Climate Predictions Center (CPC), known as the Stratospheric Monitoring-group Ozone Blended Analysis (SMOBA).
Temperature and moisture profiles were obtained from the 4-D data assimilation Goddard EOS Data Assimilation System, level-4 (GEOS-4) obtained from the Global Modeling and Assimilation Office (GMAO) at NASA Goddard Space Flight Center (GSFC) (Bloom et al., 2005) Surface emissivities were taken from a map developed at NASA LaRC (Wilber et al. 1999).
ERBE TOA measurements are used for comparisons with the Pinker model output. Ground-based measurements for the validation of model products are obtained from the Baseline Surface Radiation Network (BSRN), the Global Energy Balance Archive (GEBA), and other national and international networks.
Known data issues are explained on the “Known Data Irregularities” page.