- Data for the Large Scale Biosphere-Atmosphere
Experiment in Amazonia (LBA)
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:
http://glcf.umiacs.umd.edu/data/serf
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 :
http://www.atmos.umd.edu/~srb/lba/cgi-bin/dataavai.cgi
These data could be used by the modeling community to synthesize regional
hydrological models, and to study teleconnections.
- Photosynthetically Active
Radiation (PAR) as Observed
from Satellites
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.
