PATHFINDER High Resolution
Surface Radiative Fluxes

Department of Meteorology
University of Maryland, College Park

Department of Meterology


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Specialized Data Sets

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Spcialized data sets

Based on the PATHFINDER  ISCCP observations, several specialized data sets have been developed, to meet a variety of needs in climate research that requires radiative fluxes.

Two examples will be illustrated:

  1. Data for  the Large Scale Biosphere-Atmosphere 
    Experiment in Amazonia (LBA)
  2. To advance the understanding of the water cycle and land-atmosphere interactions in the Amazon region (LBA),  information on surface radiative fluxes  is needed.    It can be used to model and predict the surface hydrological and energy budgets of the LBA region, on time scales from diunal to interannual; to evaluate land surface parameterizations; and test implications for global climate and weather forecasting. 

    Three years (1990-1992) of high-resolution radiative fluxes have been processed, based on the ISSCCP DX satellite observations, over a domain bounded by (20 S, 7 N and 80 W, 50 W).  Since the Amazon region is covered both by GOES and METEOSAT satellites, the satellite observations are merged, using EOF analysis (Zhang and Pinker, 2002). 

    The following parameters are available:

    • Total short-wave radiative fluxes, upwelling and downwelling
    • Photosynthetically Active Radiation (PAR), upwelling and downwelling
    • Near-Infra-Red (NIR) radiation

    The data are available at 3 hourly intervals as instantaneous, hourly averaged, daily and monthly means and distributed via the Global Land Cover Facility (GLCF), Earth Science Information Partnership (ESIP) Federation, at the University of Maryland, at:

    The monthly mean values of surface shortwave downward and upward flux, NIR surface downward and upward flux, and PAR surface downward and upward flux, are provided at :

    These data could be used by the modeling community to synthesize regional hydrological models, and to study teleconnections.  

  3. Photosynthetically Active Radiation (PAR) as Observed from Satellites
  4. In biogeophysical research, of special interest is the solar radiation in the visible part of the spectrum, namely, in the interval of 400-700nm, known as Photosynthetically Active Radiation (PAR). By its control of the evapotranspiration process, information on the spatial and temporal distribution of  PAR and related parameters, such as PAR albedo,  are required for modeling the hydrological cycle and for estimating global oceanic and terrestrial net primary productivity (NPP). The diurnal variation of PAR is also of interest because the response of most environmental systems to the intensity of PAR is non-linear. An activity to derive PAR from satellite observations was undertaken at the University of Maryland. Capabilities were developed to derive PAR on regional and global scale.  These capabilities were applied to the ISCCP PATHFINDER data, to generate climatology of this parameter; to learn about its spatial and temporal variability; to evaluate the satellite estimates against ground truth; to quantify the relationship between PAR and total short-wave radiation; and to make this information available to the scientific community.

Maintained by Banglin Zhang and Chuan Li