The Ground Radiation (GNDRAD) collection of radiometers provides the ENA, TWP, NSA, and AMFs sites with continuous measurements of broadband shortwave (solar, 0.3 to 3.0 µm) and longwave (infrared, 4.0 to 50 µm) irradiances for upwelling components. These 1-minute data are collected to help determine the total radiative energy exchange at each specific research site location.
The GNDRAD datastream contains an IRT just like the stand alone system deployed at SGP. This part of the datastream is a stand alone instrument, and will typically not influence the other measurements (but it has happened in the past). Currently the DQO estimates upwelling longwave using surface IRT measurements for comparison with the PIR. Measurements from the PIR can also be used to calculate the surface radiating temperature for comparison with values from the IRT. This is currently not being done by the DQO and is described in the paper by Jim Liljegren attached at the bottom of this page.
For more information on Radiation Variables, see Radiation Information
For more information see GNDRAD.
The gndrad plot includes
On a completely sunny day, the ULH, USH, and IRT should peak around solar noon.
Radiation
The radiation comparison plot includes data from both the SKYRAD and GNDRAD instruments. The SKYRAD is measuring downwelling radiation while the GNDRAD is measuring upwelling radiation. The values will not compare 1-to-1, but they should generally trend the same.
MET Temperature Comparison
This instrument is located at
Known issues that may not need to be mentioned in DQAs should be documented here:
Problems that do require mention in DQAs and possibly DQPRs:
Calibration of GNDRAD PIR
Once/Twice a year the PIR is rotated 180o to view the sky instead of its normal view of the ground. This is done to check the instrument and perform a calibration. The DQO is not notified of this procedure, and in the past has stumbled up it and entered a DQPR. The first plot shows the instrument being rotated, second showing how the two will not compare well at all and the third plot shows the PIR being returned to normal viewing. The calibration will typically last a few days to 2 weeks. See DQPR 171, DQPR 397, DQPR 606.