Surface Radiation Budget

Project Description
Scientific Objectives:
Surface radiation budget data have the potential for contributing
significantly to improved understanding of the four major components
of the climate system: the oceans, the land surface, the cryosphere,
and the atmosphere. Radiative fluxes into the ocean surface provide
an important boundary forcing for the ocean general circulation.
Furthermore, since the radiative fluxes into the ocean surface are
significantly modulated by boundary layer parameters (e.g., clouds,
atmospheric humidity, and temperature), SRB may be an important factor
in air-sea interactions. With respect to the land surface, the net
radiative balance governs the turbulent fluxes of latent and sensible
heat from the surface into the atmosphere. Surface radiative fluxes
are also needed for studies related to the energy and water balance of
plant canopies. For the cryosphere, the pack ice and its interaction
with surface temperature and solar radiation provides the so-called
ice-albedo feedback which is a vital component governing climate
trends on decadal to longer time scales. Finally, the knowledge of
SRB together with top-of-atmosphere Earth radiation budget data can
yield, for the first time, observational estimates of tropospheric
radiative heating and cloud radiative forcing.
Project Description:
The Surface Radiation Budget (SRB) data sets are derived from a
variety of data sources. The primary data source is the International
Satellite Cloud Climatology Project (ISCCP) C1 data product. Using
the ISCCP C1 parameters as input, SRB results are generated using two
different algorithms. The Pinker algorithm (developed jointly by
Drs. R.T. Pinker and I. Laszlo form the University of Maryland) is a
physical model which uses an iterative procedure based on
delta-Eddington radiative transfer calculations. The Staylor
algorithm (developed by Mr. W.F. Staylor from the NASA Langley
Research Center) is a parameterized physical model in which both cloud
and aerosol transmission characteristics have been separately tuned to
historical data at various locations around the globe. Earth
Radiation Budget Experiment (ERBE) data are also used as input to the
models, as well as for top-of-atmosphere (TOA) irradiance comparisons
with the Pinker Model output. The Swiss Federal Institute of
Technology, Zurich, provides ground-truth fluxes from the Global
Energy Budget Archive (GEBA). These data are used for validation of
the Pinker and Staylor calculated downward shortwave surface
irradiances. SRB uses the same equal area grid system as that used by
ISCCP for its C1 product. The equal-area grid contains 6596 cells
covering the globe; where a cell is approximately 280 km x 280 km at
the equator.
Data Products
The SRB data package consists of daily and monthly shortwave
parameters covering a forty-six month period from March 1985 through
December 1988. The principle parameters in the data sets are Pinker
and Staylor calculated irradiances for the surface and
top-of-atmosphere. The total SRB data package for each month consists
of six files. The first file is the ASCII header file, named
README.MMMYY. The second and third files are ASCII showing Fortran
listings of the Pinker and Staylor algorithms (PINKER.FOR and
STAYLOR.FOR, respectively). The fourth and fifth files are binary
data files in HDF format. The fourth file is the monthly binary file
and presents monthly average gridded values for 52 different items in
each cell (srb_monavgs_yymm). The fifth file is the daily binary file
and presents 24-hr daily average values for 10 key items in each cell
(srb_dayavgs_yymm). The sixth file (b_srb_monavgs_yymm.hdf) is a
graphics file which contains 19 global images in HDF format. The
intent is to allow the user to quickly browse the most important SRB
parameters without the requirement to read the entire data set.
Project Archive Contact: Langley DAAC User Services Office
Mail Stop 157D
NASA Langley Research Center
Hampton, VA 23681-0001
Phone: (757) 864-8656
FAX: (757) 864-8807
WWW Home Page:
Project Manager Contact: Dr. Charles H. Whitlock
NASA Langley Research Center
MS 936
Hampton, VA 23681-0001 USA
Phone: (757) 827-4882
FAX: (757) 864-7996
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