The objective of NASA/GEWEX SRB project is to produce and archive a long-term
record of global gridded datasets 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; available here ) 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 link in the adjacent
left hand panel 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 here.