| Subject: | SGP/BRS/C1 - Downwelling SW below empirical limit |
| DataStreams: | sgpbrsC1.b1, sgpbrs20sC1.a0
|
| Description: | Downwelling shortwave values appear to drop below the empirical limit (-10 W/m^2) at
night, and during the day the values are less than the calculated downwelling shortwave by
about 20-30 W/m^2 (at times close to 50 W/m^2 difference). Field techs performed maintenance
but could not find obvious instrument problems.
The data exhibit the three component failure with global being flagged too low. The
difference is likely due to the artifact of the cosine response of the particular installed PSP
coupled with typical uncertainties of this set of installed radiometers. Also the unique
variation of pyranometer responsivity (calibration factor) as a function of solar zenith
angle could play a factor in the discrepancy. |
| Suggestions: | null |
| Measurements: | sgpbrs20sC1.a0: - Instantaneous Downwelling Hemispheric Shortwave, Pyranometer Thermopile Voltage(inst_global)
more
sgpbrsC1.b1: - Downwelling Shortwave Hemispheric Irradiance, Pyranometer, Minima(down_short_hemisp_min)
- Downwelling shortwave hemispheric irradiance, pyranometer, maxima(down_short_hemisp_max)
- Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer, Standard
Deviation(down_short_hemisp_std) - Down-welling unshaded pyranometer voltage(down_short_hemisp)
more
|