TWP/GNDRAD/C1 - Incorrect dome calibration factor

The Manus GNDRAD PIR had an incorrect dome factor since installation.  The following is an 
estimate by Chris Cornwall of the magnitude of the effect of this calibration error. The 
magnitude of this error is smaller than the calibration accuracy.

"Processed the instantaneous data from ARCS2 (10, 30 and 50 seconds after the minute) 
using 4.32 as the dome factor, and also using 4.00 as the dome factor, as it should have 
been. The difference between the calculated irradiance results was negligible, as was 
expected with an instrument operating in the downward-facing direction.

Over the three days from 11/06/98 to 11/08/98, the error between the two signals averaged 
0.09%.  Overnight values were much lower than this, daytime values peaked at 0.42%. The 
statistics for these error signals were as follows:
  average error 0.000895
  standard dev  0.001119
  max error     0.004242
  min error    -0.00064

We should change ARCS1 so it is using the correct value for the groundrad pir dome 
coefficient (4.0 instead of 4.32), and we may want to include a DQR stating these findings, 
although they are much smaller than the overall uncertainty of the PIR itself."

• up_long_hemisp_std
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Minima(up_long_hemisp_min)
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Maxima(up_long_hemisp_max)

• pir1_sd
• pir1_max
• pir1_mean
• pir1_min

• pir1_voltage
• pir1_dome_therm
• pir1_case_therm

NSA/SKYRAD/C1 - IRT removed for repair

The instrument was damaged by internal water condensation caused by the 
exterior foam insulation used to keep the IRT above freezing. It was returned 
in July 1998 to the manufacturer for repair.

• Raw data stream - documentation not supported

• irt1_mean
• irt1_min
• irt1_sd
• irt1_max

NSA/GNDRAD/C1 - Reprocess: IRT insufficiently heated

IRT had insufficient heating to maintain an internal reference temperature above 0 degrees 
C.  Measurements of surface temperature were over-estimated when instrument was below 
freezing.

Data will be reprocessed, but users can correct data using the following correction 
factor:

If T_reference < -5?C, then

  IRT_corrected = (IRT_original - 32.993K)/0.87238

where T_reference can be estimated with the ambient temperature (e.g. 
inst_up_long_hemisp_dome_temp or inst_up_long_dome_temp)

• irt1_max
• irt1_min
• irt1_sd
• irt1_mean