DQRID : D031007.3
Start DateStart TimeEnd DateEnd Time Data Quality Metric
09/20/2002234709/20/20032333Suspect
more
Subject:
TWP/SKYRAD/C2 - Incorrect Calibration Coefficients Applied
DataStreams:twpskyrad20sC2.a0, twpskyrad60sC2.b1
Description:
Incorrect calibration coefficients were entered for three instruments (PSPG, PIRD and 
PIRG) at the RESET period.

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
Suggestions: 
Measurements:twpskyrad60sC2.b1:
  • inst_down_long_hemisp1_dome_temp
  • inst_down_long_hemisp2_tp
  • inst_down_long_hemisp1_case_temp
  • down_long_hemisp1_std
  • down_long_hemisp1_max
  • inst_down_long_hemisp2_dome_temp
  • inst_down_long_hemisp1_tp
  • down_long_hemisp1
  • down_short_hemisp_min
  • down_long_hemisp2_std
  • inst_down_long_hemisp2_case_temp
  • down_long_hemisp2_max
  • down_long_hemisp1_min
  • down_long_hemisp2
  • down_short_hemisp
  • down_long_hemisp2_min
  • down_short_hemisp_std
  • down_short_hemisp_max
more
twpskyrad20sC2.a0:
  • inst_global
  • inst_down_long_hemisp2_tp
  • inst_down_long_hemisp1_tp
  • inst_down_long_hemisp1_case_resist
  • inst_down_long_hemisp2_case_resist
  • inst_down_long_hemisp1_dome_resist
  • inst_down_long_hemisp2_dome_resist
more

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