PATHFINDER High Resolution
Surface Radiative Fluxes

Department of Meteorology
University of Maryland, College Park

Department of Meterology


Project Description

Available Data


Known Problems

Data Access





Specialized Data Sets

Back to Front Page

Project Description

The objective is to provide information on surface and Top of the Atmosphere radiative fluxes for large areas, and for sufficient time length, to be of interest in climate research. The inference techniques developed at the University of Maryland (Pinker and Laszlo, 1992) have been used to estimate the surface short-wave (SW) fluxes  using the ISCCP  satellite observations.  The method is based on radiative transfer theory, and produces direct and diffuse fluxes in five spectral intervals in the range of 200-4000 nm. The radiative transfer model accounts for the absorption and scattering processes occurring in the atmosphere and for the interaction of the radiation with the surface. The interaction with the surface is modeled spectrally, and as such, it is ready to incorporate spectral observations, as anticipated from  such observation  as the EOS   MODerate resolution Imaging Spectrometer (MODIS) (King et al., 1992) and the GLI sesor, on ADEOS-II. The radiative fluxes at the boundaries of the atmosphere are computed by determining the atmospheric transmission and reflection (optical functions) and the surface albedo, pertaining to a particular satellite observation. The retrieved optical functions, along with the surface albedos are then used to compute the fluxes for clear and cloudy conditions, independently. The all-sky flux is obtained by using information on cloud cover. The results presented at this Web site were produced with Version 2.1 of the Global Energy and Water cycle EXperiment/Surface Radiation Budget (GEWEX/SRB) model (Whitlock et al., 1995; Pinker et al., 1995), which includes improved parametrization of water vapor absorption, as well as improved techniques for replacing missing observations. Version 1.1 of this algorithm has been implemented in the past, at the Surface Radiation Budget/Satellite Data Analysis center (SDAC) at NASA Langley Research Center with ISCCP C1 data, at 2.5 degree resolution for July 1983 - December 1988, and results are available from the Langley DAAC, at:


This work was initiated under grant NAGW4740 from the Earth Science Data and Information System Branch, and continued under grant NAG56667 from the Mission to Planet Earth (MTPE) Program, Science Division. The ISCCP data were obtained from the NASA Langley Research Center EOSDIS Distributed Active Archive Center.

Maintained by Chuan Li