Start Date | Start Time | End Date | End Time | Data Quality Metric |
---|---|---|---|---|
09/20/2002 | 2347 | 09/20/2003 | 2333 | Suspect |
Subject: | TWP/QCRAD/C2 - Reprocess: Incorrect calibration coefficients |
DataStreams: | twpqcrad1longC2.s2, twpqcrad1longC2.s1, twpqcrad1longC2.c1, twpqcrad1longC2.c2 |
Description: | Incorrect calibration coefficients were used for downwelling shortwave and longwave irradiance. The following calculation method should be applied to correct the data, For the downwelling shortwave(PSPG) (DS) Old Calibration coefficient [W/m2\mV] =119.68 New Calibration Coefficient [W/m2\mV] =125.94 DS(new_value)[W/m2]=( DS(old_value)[W/m2]/ 119.68 [W/m2\mV] )* 125.94 [W/m2/mV] For the longwave irradiance (PIRG): If the .a0 and .b1 data set available the following procedure should be applied for the downwelling LW 1) Obtain the following variables from the 20s datastream for each one minute of the affected time range: inst_down_long_hemisp1_dome_resist (Rd) inst_down_long_ hemisp1_case_resist (Rc) inst_down_long_ hemisp1_tp (tpDIR_mV) 2) Using the 20s tp voltage in mV convert to uV. tpDIR[uV] = inst_down_long_hemisp1_tp [mV]*1000[uV/mV] 3) For each 20s data entry, convert Rd and Rc to temperature Td =1/ (a0 + (a1*LN (Rd*1000) + (a2*LN (Rd*1000)^3))) Tc = 1/ (a0 + (a1*LN (Rc*1000) + (a2*LN (Rc*1000)^3))) Where a0 = 0.0010295 a1 = 0.0002391 a2 = 0.0000001568 4) Apply for each 20s data entry: (correct k1=0.2755) WinDIR(W/m^2)= [0.2755*tpDIR] + Sigma*Tc^4 -4*Sigma*(Td^4 - Tc^4) Where, WinDIR = Corrected down_long_hemisp1 (W/m^2) Sigma = 5.6704E-8 (Stefan-Boltzman Constant) 5) Generate new 1 minute average from the three 20-second measurements For the longwave irradiance (PIRD): If the .a0 and .b1 data set available the following procedure should be applied for the downwelling LW 1) Obtain the following variables from the 20s datastream for each one minute of the affected time range: inst_down_long_hemisp2_dome_resist (Rd) inst_down_long_ hemisp2_case_resist (Rc) inst_down_long_ hemisp2_tp (tpDIR_mV) 2) Using the 20s tp voltage in mV convert to uV. tpDIR[uV] = inst_down_long_hemisp2_tp [mV]*1000[uV/mV] 3) For each 20s data entry, convert Rd and Rc to temperature Td =1/ (a0 + (a1*LN (Rd*1000) + (a2*LN (Rd*1000)^3))) Tc = 1/ (a0 + (a1*LN (Rc*1000) + (a2*LN (Rc*1000)^3))) Where a0 = 0.0010295 a1 = 0.0002391 a2 = 0.0000001568 4) Apply for each 20s data entry: (correct k1=0.2786) WinDIR(W/m^2)= [0.2786*tpDIR] + Sigma*Tc^4 -4*Sigma*(Td^4 - Tc^4) Where, WinDIR = Corrected down_long_hemisp2(W/m^2) Sigma = 5.6704E-8 (Stefan-Boltzman Constant) 5) Generate new 1 minute average from the three 20-second measurements This issue was also described in instrument DQR D031007.3. |
Suggestions: | Correct downwelling SW and LW irradiance with specified recalibration procedures. If "source_BestEstimate_down_short_hemisp" is -1 during this time, apply specified recalibration procedure. |
Measurements: | twpqcrad1longC2.c2: more
twpqcrad1longC2.s2: more twpqcrad1longC2.s1: more twpqcrad1longC2.c1: more |