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."

• Instantaneous PIR1 dome thermistor(pir1_dome_therm)
• Instantaneous PIR1 uncorrected irradiance(pir1_voltage)
• Instantaneous PIR1 case thermistor(pir1_case_therm)

• Upwelling (10 meter) Longwave Hemispheric Irradiance, Pyrgeometer, Standard
  Deviation(up_long_hemisp_std)
• Upwelling (10 meter) Longwave Hemispheric Irradiance, Pyrgeometer, Maxima(up_long_hemisp_max)
• Upwelling (10 meter) Longwave Hemispheric Irradiance, Pyrgeometer(up_long_hemisp)
• Upwelling (10 meter) Longwave Hemispheric Irradiance, Pyrgeometer, Minima(up_long_hemisp_min)

• PIR1 unshaded mean(pir1_mean)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded maximum(pir1_max)