SGP/SIRS/C1 - SW direct normal data drop out

NIP cable had failed during this time period.

Short_direct_normal data are not recoverable during this time period. However, it can be 
reconstructed using the following formula for each one minute data:
   short_direct_normal = (down_short_hemisp-down_short_diffuse_hemisp)/cos(zenith angle)

• inst_direct_normal

• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)

SGP/SIRS/C1 - Reprocessed: Upwelling shortwave

The upwelling shortwave hemispheric data were bad 20090914-20091009 due to a broken 
instrument cable.  The cable was replaced on 10/09 at 1711 GMT but the leads were reversed. The 
leads were corrected 10/19 at 2001 GMT.

The data for 20090914-20091019 have been reprocessed. The bad data from 20090914-20091009 
were set to missing in the newly available reprocessed data set. The 20091009-20091019 
data were corrected by applying a (-1) multiplier.

• inst_up_short_hemisp

• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)
• up_short_hemisp_std
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Minima(up_short_hemisp_min)
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Maxima(up_short_hemisp_max)

SGP/SIRS/C1 - Failed Upwelling SW cable

The upwelling shortwave hemispheric (up_short_hemisp) data were missing or incorrect due 
to a bad cable.  Cable was replaced on 6/30 and the problem was resolved.

• inst_up_short_hemisp

• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)
• up_short_hemisp_std
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Minima(up_short_hemisp_min)
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Maxima(up_short_hemisp_max)

SGP/SIRS/C1 - NIP failure

The short_direct_normal (NIP instrument) cable failed during this time period.	Data are 
not recoverable.

Users can derive an estimate of direct normal values using the following formula:
short_direct_normal = (down_short_hemisp - down_short_diffuse_hemisp)/cos(zenith angle)

• inst_direct_normal

• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)

SGP/SIRS/C1 - NIP Failure

The short_direct_normal (NIP instrument) cable failed (broken wire in NIP connector) 
during this time period. Data are not recoverable.


An estimate of direct normal values can be derived using the following formula:

short_direct_normal = (down_short_hemisp - down_short_diffuse_hemisp)/cos(zenith angle)

• inst_direct_normal

• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)

SGP/SIRS/C1 - Reprocess: Incorrect downwelling longwave calibration coefficient

Calibration coefficient for downwelling longwave was incorrect for the specified period.

To correct the one minute data b1 datastream follow the procedure below:
1) Obtain the following variables from the 20s datastream for each one minute of the 
affected time range:
  inst_down_long_shaded_dome_resist (Rd)
  inst_down_long_shaded_case_resist (Rc)
  inst_down_long_hemisp_shaded_tp (tpDIR_mV)
                                         
2) using the 20s tp voltage in mV convert to uV.
  tpDIR[uV] = inst_down_long_hemisp_shaded_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=0.2762)
  WinDIR(W/m2)= [0.2762*tpDIR] + Sigma*Tc^4 -4*Sigma*(Td^4 - Tc^4)
  where, Sigma = 5.6704E-8 (Stefan-Boltzman Const)
                                      
5) Generate new 1 minute average from the 3 20-second measurements

• inst_down_long_shaded_dome_resist
• inst_down_long_shaded_case_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded_tp)

• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• down_long_hemisp_shaded_std
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• Downwelling Longwave Hemispheric Net Infrared(down_long_netir)
• inst_down_long_shaded_case_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• inst_down_long_shaded_dome_temp

SGP/SIRS/C1 - Reprocess: Incorrect downwelling longwave calibration coefficient

The calibration coeff and serial number for the down_long_hemisp_shaded was incorrect 
during the period specified. 

Correct Instrument serial number = 30010F3 
                              K1 = 0.3125
Incorrect Instrument serial number = 30690F3 
                                K1 = 0.2762
 
Data will be reprocessed.

To correct the one minute data b1 datastream follow the procedure below:
1) Obtain the following variables from the 20s datastream for each one minute of the 
affected
time range:
  inst_down_long_shaded_dome_resist (Rd)
  inst_down_long_shaded_case_resist (Rc)
  inst_down_long_hemisp_shaded_tp (tpDIR_mV)
					 
2) using the 20s tp voltage in mV convert to uV.
  tpDIR[uV] = inst_down_long_hemisp_shaded_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=0.3125)
  WinDIR(W/m^2)= [0.3125*tpDIR] + Sigma*Tc^4 -4*Sigma*(Td^4 - Tc^4)
  where, 
        WinDIR = Corrected down_long_hemisp_shaded (W/m^2)
        Sigma =	5.6704E-8 (Stefan-Boltzman Constant)

				      
5) Generate new 1 minute average from the three 20-second measurements

• inst_down_long_shaded_dome_resist
• inst_down_long_shaded_case_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded_tp)

• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• down_long_hemisp_shaded_std
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• Downwelling Longwave Hemispheric Net Infrared(down_long_netir)
• inst_down_long_shaded_case_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• inst_down_long_shaded_dome_temp