NSA/SKYRAD/C2 - Reprocess: PIR identified as unshaded is really shaded

On 5/24/02 the Global PIR was moved from the unshaded position on the Skyrad stand to a 
shaded spot on the tracker.  It is still using the same Logger channel as it did as an 
unshaded PIR even though it is now shaded.

• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer2, Minima(down_long_hemisp2_min)
• Instantaneous Downwelling Pyrgeometer Thermopile, Pyrgeometer2(inst_down_long_hemisp2_tp)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer2, Maxima(down_long_hemisp2_max)
• Instantaneous Downwelling Pyrgeometer Case Thermistor Temperature, Pyrgeometer2(inst_down_long_hemisp2_case_temp)
• Instantaneous Downwelling Pyrgeometer Dome Thermistor Temperature, Pyrgeometer2(inst_down_long_hemisp2_dome_temp)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer2, Standard Deviation(down_long_hemisp2_std)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer2(down_long_hemisp2)

NSA/SKYRAD/C2  - Solar tracker problem.

Beginning on 6/13, there was a problem with the solar 
tracker/shading at Atqasuk.  The observed downwelling shortwave
was not in good agreement with the theoretical value calculated 
from the direct, diffuse, and solar zenith angle, which usually 
indicates a tracking problem. The direct (NIP) data occasionally 
exhibited a stair-step pattern of dropping off slightly for a few 
minutes, then rising, then dropping off again, rather than the 
smooth increase during the hours of greater sunlight that is 
normally observed in clear sky conditions.

This problem was resolved on the morning of 6/20.

• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer,
  Minima(down_short_diffuse_hemisp_min)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Minima(short_direct_normal_min)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer(down_short_diffuse_hemisp)
• Downwelling Shortwave Hemispheric Irradiance, Pyranometer, Standard Deviation(down_short_diffuse_hemisp_std)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer,
  Maxima(down_short_diffuse_hemisp_max)
• Shortwave Direct Normal Irradiance, Pyrgeometer(short_direct_normal)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Standard Deviation(short_direct_normal_std)

NSA/SKYRAD/C2  - IRT incorrect min/max values

The values of valid_min and valid_max for field sky_ir_temp were incorrectly assigned to 
-49.7 and +50.0 C, respectively. The actual values should be -60 and +40 C.

• Sky Infra Red Temperature Maxima(sky_ir_temp_max)
• Sky Infra Red Temperature Minima(sky_ir_temp_min)
• Sky Infra-Red Temperature(sky_ir_temp)

NSA/SKYRAD/C2 - IRT measurements during precipitation events

The IRT measurement of sky/cloud temperature was in question during
precipitation events because rain or snow could accumulate in the 
upward-pointed lens barrel. This was corrected by reorienting the
IRT to measure the sky temperature as reflected by a gold mirror.

• Sky Infra Red Temperature Maxima(sky_ir_temp_max)
• Sky Infra Red Temperature Minima(sky_ir_temp_min)
• Standard Deviation of Sky Infra Red Temperature(sky_ir_temp_std)
• Sky Infra-Red Temperature(sky_ir_temp)

NSA/GNDRAD/C2 - Reprocess: Longwave Calibration error

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.

• Upwelling (10 meter) Longwave Hemispheric Irradiance, Pyrgeometer(up_long_hemisp)

NSA/SKYRAD/C2 - Station noise problem

From 8/18 through 8/20 the logger battery voltage (vBatt) periodically jumps in voltage 
with noise on all differential measurements.  The qc fields caught most of the 
down_long_hemisp MAX failures but the bad short_direct_normal, down_short_hemisp and 
down_short_diffuse_hemisp values were not flagged.

Noise returned on 8/22, 8/25-26 and 8/27-28.

Site Ops checked and re-routed the Sky stand grounds on 8/21 and performed additional 
ground re-work on 8/28.  After that date, noise has not returned to the Skystand logger 
instruments.

• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer,
  Minima(down_short_diffuse_hemisp_min)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer1(down_long_hemisp1)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer2, Maxima(down_long_hemisp2_max)
• Down-welling unshaded pyranometer voltage(down_short_hemisp)
• Standard Deviation of Sky Infra Red Temperature(sky_ir_temp_std)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer1, Maxima(down_long_hemisp1_max)
• Instantaneous Downwelling Pyrgeometer Dome Thermistor Temperature, Pyrgeometer1(inst_down_long_hemisp1_dome_temp)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Standard Deviation(short_direct_normal_std)
• Battery Voltage(vBatt)
• Sky Infra-Red Temperature(sky_ir_temp)
• Instantaneous Downwelling Pyrgeometer Thermopile, Pyrgeometer1(inst_down_long_hemisp1_tp)
• Sky Infra Red Temperature Maxima(sky_ir_temp_max)
• Downwelling Shortwave Hemispheric Irradiance, Pyranometer, Standard Deviation(down_short_diffuse_hemisp_std)
• Sky Infra Red Temperature Minima(sky_ir_temp_min)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer2(down_long_hemisp2)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Minima(short_direct_normal_min)
• Instantaneous Downwelling Pyrgeometer Case Thermistor Temperature, Pyrgeometer2(inst_down_long_hemisp2_case_temp)
• Instantaneous Downwelling Pyrgeometer Dome Thermistor Temperature, Pyrgeometer2(inst_down_long_hemisp2_dome_temp)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer1, Standard Deviation(down_long_hemisp1_std)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer,
  Maxima(down_short_diffuse_hemisp_max)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer1, Minima(down_long_hemisp1_min)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Maxima(short_direct_normal_max)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Standard
  Deviation(down_short_hemisp_std)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer(down_short_diffuse_hemisp)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer2, Minima(down_long_hemisp2_min)
• Instantaneous Downwelling Pyrgeometer Thermopile, Pyrgeometer2(inst_down_long_hemisp2_tp)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer2, Standard Deviation(down_long_hemisp2_std)
• Shortwave Direct Normal Irradiance, Pyrgeometer(short_direct_normal)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Instantaneous Downwelling Pyrgeometer Case Thermistor Temperature, Pyrgeometer1(inst_down_long_hemisp1_case_temp)

• Instantaneous Downwelling Pyrgeometer Thermopile, Pyrgeometer2(inst_down_long_hemisp2_tp)
• Instantaneous Downwelling Hemispheric Shortwave, Unshaded Pyranometer Thermopile
  Voltage(inst_global)
• Instantaneous Downwelling Pyrgeometer Dome Thermistor Resistance, Pyrgeometer1(inst_down_long_hemisp1_dome_resist)
• Instantaneous Downwelling Pyrgeometer Case Thermistor Resistance, Pyrgeometer1(inst_down_long_hemisp1_case_resist)
• Instantaneous Uncorrected Downwelling Shortwave Diffuse, Shaded Pyranometer
  Thermopile Voltage(inst_diffuse)
• Instantaneous Downwelling Pyrgeometer Thermopile, Pyrgeometer1(inst_down_long_hemisp1_tp)
• Instantaneous Downwelling Pyrgeometer Dome Thermistor Resistance, Pyrgeometer2(inst_down_long_hemisp2_dome_resist)
• Instantaneous Downwelling Pyrgeometer Case Thermistor Resistance, Pyrgeometer2(inst_down_long_hemisp2_case_resist)
• Instantaneous Sky/Cloud Infrared(inst_sky_ir_signal)
• Instantaneous Direct Normal Shortwave Irradiance, Pyheliometer Thermopile
  Voltage(inst_direct_normal)