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Validation
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Validation
Satellite based estimates of PAR were evaluated against long term time series of ground observations, as made at the Meteorological Observatory, Moscow State University (Dr. O. A. Shilovtzeva, private communication), who provided daily aver
aged PAR observations for 1987-88 from the Moscow State University and Karabag (44.90N; 35.20E), Russia; daily averaged PAR observations from the 1990 Monsoon Experiment, Walnut Gulch, Arizona (W. Kustas, private communication); daily averaged PAR
observations for several months for Nevada (M. Wetzel, private communication); three minute averaged PAR observations and total shortwave radiation as we observed at the NOAA/NWS Testing and Evaluation Facility, Sterling, VA, for 10/1992-11/1993 and at
the University of Ilorin, Nigeria, sub-Sahel Africa for 8/1992-9/1994. The following examples are illustrated:
- In Fig. 5, the time series of the conversion factor (CF) as measured for a two year period at Ilorin, Nigeria (8.32N; 4.34E) in sub-Sahel Africa, at 3 minute averaging intervals, is illustrated.
In the upper panel of Figure 6, a comparison was made between monthly mean PAR as observed during 1992-93 at the NOAA/NWS Testing and Evaluation Facility, Sterling Va, and a five year average (19
83-1988) of satellite inferred values, as obtained from ISCCP C1. The lower panel of Figure 6 is similar to the upper one, but for the sub-Sahel site. Note: at the time the ground observations were made, the corresponding satel
lite data were not yet available. Therefore, the two data sets are not for the same time period.
In Figure 7, a comparison was made between monthly mean observations of PAR, as taken at the NOAA/NWS Testing and Evaluation Facility, Sterling, VA, and satellite estimates, based on a specialize
d "target" satallite observation made over the Sterling, VA, by NOAA/NESDIS (J. D. Tarpley, private communication).
In Figure 8, a comparison is made between daily values of PAR, as observed at the Moscow State University, and satellite estimates, based on ISCCP C1 data.
In Figure 9, the monthly mean PAR albedos, as measured at the NOAA/NWS Testing and Evaluation Facility, Sterling, VA, are illustrated.
Since June 7, 2001, real time validation of PAR at six
stations in the United States, at hourly time scale, is presented at:
http://meto.umd.edu/~srb/gcip/cgi-bin/di-urnal.cgi
Maintained by Banglin Zhang
zhang@atmos.umd.edu
and Chuan Li cli@atmos.umd.edu
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