Start Date | Start Time | End Date | End Time | Data Quality Metric |
---|---|---|---|---|
08/02/2004 | 0200 | 09/09/2005 | 2022 | Incorrect |
Subject: | TWP/QCRAD/C1 - Reprocess: Incorrect datalogger program affecting PIR1 and PIR2 downwelling |
DataStreams: | twpqcrad1longC1.c2, twpqcrad1longC1.s1, twpqcrad1longC1.c1, twpqcrad1longC1.s2 |
Description: | Downwelling longwave calibration incorrect. Needs to be reprocessed. Described in instrument DQR D051202.5: 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 absolute value of the errors are inversely proportial to temperature. Users can apply 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. Irradiance Correction Table for Skyrad (TWP and NSA) DIR1 and DIR2 Irradiance DIR1 DIR1 DIR2 DIR2 T[F] Tc[K] [W/m2] Td[K] [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 |
Suggestions: | Apply suggested corrections. |
Measurements: | twpqcrad1longC1.c1: more
twpqcrad1longC1.s1: more twpqcrad1longC1.c2: more twpqcrad1longC1.s2: more |