DQR ID | Subject | Data Streams Affected |
---|---|---|
D040421.3 | NSA/SKYRAD/C1 - itermittant IRT bias | nsaskyrad60sC1.b1 |
D051202.1 | NSA/SKYRAD/C1 - Reprocess: Incorrect datalogger program affecting PIR1 and PIR2 downwelling longwave | nsaskyrad20sC1.a0, nsaskyrad60sC1.b1 |
D060630.37 | NSA/SKYRAD/C1 - Reprocess: Longwave Calibration error | nsaskyrad60sC1.b1 |
Start Date | Start Time | End Date | End Time |
---|---|---|---|
03/28/2003 | 0200 | 06/21/2006 | 0215 |
Subject: | NSA/SKYRAD/C1 - itermittant IRT bias |
DataStreams: | nsaskyrad60sC1.b1 |
Description: | A problem with the SKYRAD IRT that itermittantly produced a gradual increase in the sky temperature measurement then a sudden correction, as compared to AERI, appears to have been caused by a combination of a failing IR detector, a poor signal cable, a contaminated (with condensation or frost) mirror or lens, and low ambient temperatures. The positive bias was apparently not consistant in either frequency or duration but on days when the unusual behavior is observed, it usually occurred from about 00:00 to 06:00 local time. The instrument was repaired and recalibrated and the signal cable replaced. |
Measurements: | nsaskyrad60sC1.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
11/04/2004 | 1900 | 09/09/2005 | 2142 |
Subject: | NSA/SKYRAD/C1 - Reprocess: Incorrect datalogger program affecting PIR1 and PIR2 |
DataStreams: | nsaskyrad20sC1.a0, nsaskyrad60sC1.b1 |
Description: | The excitation delays using in measuring the PIR1 case thermistor commonly named "Case1" and the PIR2 dome thermistor called "Dome2" were discovered to have been incorrectly set to 0 in the Skyrad datalogger program when the new CR23X based Skyrad loggers were installed. The result of no delay in these measurements results in an error in the measured resistance of the thermistors, Case1 and Dome2 and thus the calculated PIR1 and PIR2 irradiances. The errors are inversely proportial to temperature. Users can apply the temperature dependent irradiance corrections shown in the table below. Recall that the reported uncertainty of PIRs is typically +-.25% to +-.5% or 1 to 2 W/m2. The error corrections become the same order of magnitude or larger than the instrument uncertainties at or below 260K or 9F. Correction Table for Skyrad (TWP and NSA) DIR1 and DIR2 Irradiance DIR1 DIR1 DIR2 DIR2 T[F] Tcase[K] Correction[W/m2] Tdome[K] Correction[W/m2] 109.4 316.13 0.00 316.13 0.00 100.5 311.20 -0.15 311.20 0.12 93.2 307.14 -0.12 307.14 0.10 87.0 303.70 -0.10 303.70 0.08 81.6 300.70 -0.17 300.70 0.14 77.0 298.15 -0.22 298.15 0.18 59.4 288.35 -0.34 288.35 0.27 47.4 281.72 -0.23 281.72 0.18 38.5 276.74 -0.42 276.74 0.34 31.3 272.77 -0.48 272.77 0.38 25.4 269.48 -0.61 269.48 0.49 20.3 266.67 -0.67 266.67 0.54 16.0 264.25 -0.82 264.25 0.66 12.1 262.11 -0.98 262.11 0.79 8.7 260.19 -0.97 260.19 0.78 5.6 258.46 -1.07 258.46 0.86 2.7 256.89 -1.17 256.89 0.94 0.1 255.44 -1.33 255.44 1.07 -2.3 254.11 -1.41 254.11 1.13 -4.5 252.87 -1.43 252.87 1.15 -6.6 251.71 -1.52 251.71 1.22 -8.5 250.63 -1.63 250.63 1.31 -10.4 249.62 -1.73 249.62 1.39 -12.2 248.58 -1.79 248.58 1.44 -15.4 246.82 -1.93 246.82 1.55 -18.3 245.23 -2.05 245.23 1.65 -20.9 243.78 -2.22 243.78 1.78 -23.3 242.44 -2.36 242.44 1.89 -25.5 241.21 -2.58 241.21 2.07 -27.5 240.07 -2.65 240.07 2.13 -29.5 239.01 -2.75 239.01 2.21 -31.3 238.00 -3.02 238.00 2.42 |
Measurements: | nsaskyrad60sC1.b1:
nsaskyrad20sC1.a0:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
11/04/2004 | 0300 | 12/21/2005 | 1853 |
Subject: | NSA/SKYRAD/C1 - Reprocess: Longwave Calibration error |
DataStreams: | nsaskyrad60sC1.b1 |
Description: | Modified pyrgeometer calibration procedures were implemented beginning in December 2003. These modified procedures introduced a calibration bias in the longwave data. The previous procedures were re-implemented at all sites between December 2005 and February 2006 to restore proper calibrations. The data collected while the incorrect procedures were in place are being reprocessing to remove the calibration bias. Note, this also affected standard deviation, maximum and minimum data fields. |
Measurements: | nsaskyrad60sC1.b1:
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