TWP/SKYRAD/C3 - Tracker inoperative

The tracker at Darwin failed 01/23.  The tracker was power cycled on 01/27 and it returned 
to normal operation.

The affected data streams are short_direct_normal (NIP) and down_short_diffuse_hemisp 
(8-48).  

The down_short_hemisp are not affected.  

The down_long_hemisp1 and 2 (PIR1 and PIR2) should not be affected but direct sun can 
affect individual instrument performance.

• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• down_long_hemisp2_min
• down_long_hemisp2_max
• down_long_hemisp1_max
• down_long_hemisp1_min
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• short_direct_normal_std
• inst_down_long_hemisp1_tp
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• inst_down_long_hemisp2_case_temp
• down_long_hemisp2_std
• inst_down_long_hemisp2_dome_temp
• inst_down_long_hemisp1_case_temp
• down_long_hemisp1_std
• inst_down_long_hemisp2_tp
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• inst_down_long_hemisp1_dome_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)

• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp2_case_resist
• inst_down_long_hemisp1_dome_resist
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp2_tp
• inst_direct_normal
• inst_diffuse
• inst_down_long_hemisp2_dome_resist

TWP/SKYRAD/C2 - Tracker inoperative

The tracker failed in park position.  Tracker was replaced 5/14 but did not resume fully 
normal operation until 5/18.

The down_short_diffuse and short_direct_normal data are directly affected by this failure. 
 These data are not recoverable.

• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• short_direct_normal_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)

• inst_direct_normal
• inst_diffuse

GRW/SKYRAD/M1 - Tracker inoperative

The solar tracker arms were caught and pulled way out of alignment. Problem corrected by 
OPs at 0815Z May 11th.  All bolts tightened and alignment and tracking checked. 

Down_short_hemisp_diffuse (8-48 instrument)is incorrect and not recoverable. 
short_direct_normal (NIP instrument) is suspect during this time as well.  down_short_hemisp (PSP 
instrument) was unaffected.

• inst_direct_normal
• inst_diffuse

• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_short_diffuse_hemisp_std
• short_direct_normal_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)

TWP/SKYRAD/C2 - Instrument grounding problem

During this time period the IRT analog output line appears to have adversely affected the 
skyrad datalogger grounding.  This resulted in intermittent anomalous readings across all 
skyrad datalogger channels including logger voltage.

• inst_down_long_hemisp2_case_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• IR Brightness Temperature(sky_ir_temp)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• sky_ir_temp_std
• down_long_hemisp1_min
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• inst_down_long_hemisp2_tp
• down_long_hemisp1_max
• inst_down_long_hemisp1_tp
• down_long_hemisp2_std
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• sky_ir_temp_min
• down_short_hemisp_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• down_long_hemisp1_std
• inst_down_long_hemisp1_dome_temp
• short_direct_normal_std
• down_long_hemisp2_max
• down_long_hemisp2_min
• inst_down_long_hemisp2_dome_temp
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• sky_ir_temp_max
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• inst_down_long_hemisp1_case_temp
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)

• inst_diffuse
• inst_down_long_hemisp2_tp
• inst_direct_normal
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp2_case_resist
• inst_sky_ir_signal
• inst_down_long_hemisp2_dome_resist
• inst_global
• inst_down_long_hemisp1_dome_resist

TWP/SKYRAD/C2 - IRT Missing

After a significant rain event on 5/25, the IRT was found to be the cause of grounding 
problems with the SKYRAD datalogger that was affecting the measurements from other 
instruments. This problem was solved by removing the IRT signal from the datalogger. The problem 
was suspected to be with either the power/signal cable or the internal grounding of the 
IRT. The problem was corrected when both the IRT and analog cable were replaced on 6/23.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std
• sky_ir_temp_max
• sky_ir_temp_min

• inst_sky_ir_signal

GRW/SKYRAD/M1 - Reprocessed: IRT configuration

The SKYRAD IRT was used in testing a revised serial communication program. During the 
testing, the analog output configuration was to changed to default values (used at TWP and 
NSA sites) that are different than those used at AMF. So, the IRT's analog output was set 
to a scale of 25K/V and an offset of 213.2K but the logger converted the signal using a 
scale of 26K/V and an offset of 173.2K. 

The sky temperature measurements were corrected using the following equation

        Tnew = (25/26)(Told-173.2K)+213.2K

and the data were reprocessed.  The reprocessed data were archived in April 2011.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_min
• sky_ir_temp_max

TWP/SKYRAD/C2 - Reprocess: IRT configuration

When the IRT was replaced, it was not initially configured correctly.  The data will be 
reprocessed.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_max
• sky_ir_temp_min

GRW/SKYRAD/M1 - Possible dirty dome

The difference between downwelling shortwave hemispheric irradiance and derived 
downwelling shortwave hemispheric irradiance was larger than normal (>50W/m2) and was most 
noticeable at lower zenith angles.  The problem spontaneously resolved itself on 7/16 without any 
specific callouts by the GRW cleaning personnel on their reports.  Short_direct_normal 
datastream is suspected to be low due to potentially dirty NIP instrument window during 
this time period.  The commencement of this problem corresponds with a rain event early 
7/12. The possibility of other radiometers affected by dirty domes is also possible. 
Longwave instruments are typically immune to this level of contamination.

• inst_global
• inst_diffuse
• inst_direct_normal

• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_short_hemisp_std
• down_short_diffuse_hemisp_std
• short_direct_normal_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)

GRW/SKYRAD/M1 - Daily brief instrument shading

Due to the persistent cloudy conditions at this site this shading of the NIP and PSP is 
rarely evident in the data. But from approximately 1745 to 1810 GMT from 8/26 to 10/23 and 
from 3/01 to 4/18 during the AMF deployment years 2009 and 2010, the NIP and PSP are 
shaded by the 10m met tower to the SE of the Skystand. 

Data review indicates that the NIP (short_direct_normal) and PSP (down_short_hemisp) are 
shaded by a single tower pole and possibly other tower mounted objects.  The data are not 
correctable but the azimuth and zenith windows to avoid are:
short_direct_normal (NIP instrument)
	     Zenith angle > 62 deg
  254 deg < Azimuth angle < 262 deg
primary obstruction at 255 deg Az

down_short_diffuse(PSP instrument)
	     Zenith angle > 59 deg
  246 deg < Azimuth angle < 257 deg
primary obstruction at 251.5 deg Az


Date ranges this problem will exist for are:
20090301-20090418 (pre-official deployment, data exist)
20090826-20091023
20100301-20100418
20100826-20101023

The QCrad VAP should flag bad data points via its QC logic.  Users should either exclude 
the data within the windows above or review data for outliers in these zenith, azimuth 
angles.

• inst_direct_normal
• inst_global

• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_short_hemisp_std
• short_direct_normal_std
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)

GRW/SKYRAD/M1 - IRT grounding

The IRT analog output line appears to have adversely affected the
SKYRAD datalogger grounding.  This resulted in intermittent anomalous readings across all 
SKYRAD datalogger channels including logger voltage.

The problem was corrected by regrounding the analog cable.

• inst_down_long_hemisp2_case_resist
• inst_down_long_hemisp1_dome_resist
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp2_dome_resist
• inst_global
• inst_diffuse
• inst_down_long_hemisp2_tp
• inst_sky_ir_signal
• inst_down_long_hemisp1_case_resist
• inst_direct_normal

• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• inst_down_long_hemisp1_case_temp
• short_direct_normal_std
• sky_ir_temp_max
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• down_long_hemisp2_min
• down_long_hemisp2_max
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• IR Brightness Temperature(sky_ir_temp)
• inst_down_long_hemisp2_tp
• logger_temp
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_short_hemisp_std
• down_short_diffuse_hemisp_std
• sky_ir_temp_std
• sky_ir_temp_min
• inst_down_long_hemisp2_case_temp
• inst_down_long_hemisp1_dome_temp
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• inst_down_long_hemisp1_tp
• vBatt
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_long_hemisp2_std
• inst_down_long_hemisp2_dome_temp
• down_long_hemisp1_std
• down_long_hemisp1_max
• down_long_hemisp1_min

TWP/SKYRAD/C3 - IRT power supply

The IRT external DC power supply had shut down for an unknown reason. The problem was 
corrected by restarting the power supply.

• sky_ir_temp_min
• sky_ir_temp_max
• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std

GRW/SKYRAD/M1 - AOS tower Obstruction

Due to the persistent cloudy conditions at this site the shading is rarely evident in the 
data. But at approximately 1010GMT everyday during from approximately 12/2/2009 to 
1/11/2010 the NIP is shaded by the AOS tower.  Data review indicates that only the NIP 
(short_direct_normal) is obstructed when the sun is at 130 to 132 deg azimuth during the time 
period specified.

NIP data are not recoverable.  However, short_direct_normal can be reconstructed by 
applying 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)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• short_direct_normal_std

NSA/SKYRAD/C1 - Frosting/Condensation

The down_long_hemisp1 varied up to 40 W/m^2 higher than down_long_hemisp2 during the 
affected time periods. Cold temperatures reported by the IRT suggest the issue is with PIR1.  
Icing or frost on PIR1 or within the ventilator may be to blame but ops reports can't 
substantiate this. Data from PIR1 should be avoided during these suspect time periods.

• down_long_hemisp1_min
• down_long_hemisp1_std
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• down_long_hemisp1_max

• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp1_dome_resist

NSA/SKYRAD/C2 - NIP Frost or Ice

Frost or ice likely obstructed the NIP as short_direct_normal values were near zero for 
the affected time periods. These times correspond to mornings before OPS has the 
opportunity to clean the instruments. Clear days at Atqusuk are rare and the NIP instrument can 
very well be ice covered and it won't be apparent in the data.  In this case the clear days 
and overnight icing made the icing issue very apparent.

• inst_direct_normal

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

GRW/SKYRAD/M1 - Short direct normal questionable

Starting on 05/08/2010 values of short_direct_normal from the NIP instrument were reading 
low (up to 50W/m2).  This was most apparent during sunny/partly sunny periods.  The 
values spontaneously returned to normal on 5/14 with no Ops intervention.  Data system checks 
after that date revealed no apparent problems with instruments or datalogger. The problem 
has not recurred.

Only the short_direct_normal values during this time period are suspect.  If direct normal 
values are needed they can be re-constructed using the following relationship for each 
minute of data:
down_short_hemisp = short_direct_normal * cos(zenith angle) + down_short_diffuse_hemisp

• inst_direct_normal

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

TWP/SKYRAD/C3 - IRT power supply

The IRT power supply failed and was replaced.

• sky_ir_temp_min
• sky_ir_temp_max
• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std

NSA/SKYRAD/C2 - Instrument grounding problem

The down_long_hemisp1 was often 50 W/m^2 greater than down_long_hemisp2 during the suspect 
times.  Data logger grounding issues were addressed by site ops and have corrected the 
problem.

• inst_down_long_hemisp1_dome_resist
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_case_resist

• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• down_long_hemisp1_min
• down_long_hemisp1_max
• down_long_hemisp1_std

TWP/SKYRAD/C2 - Suspect PIR1 data

PIR1 was exhibiting unusual data excursions during the specified time ranges and data are 
suspect.  The problem spontaneously resolved on October 11th without site ops action.  
The problem has not returned.

• down_long_hemisp1_max
• down_long_hemisp1_std
• down_long_hemisp1_min
• inst_down_long_hemisp1_dome_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• inst_down_long_hemisp1_case_temp

• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp1_dome_resist
• inst_down_long_hemisp1_tp

NSA/SKYRAD/C2 - Suspect PIR1

PIR1 (down_long_hemisp) data are suspect during these time ranges due to the large 
differences between PIR1 and PIR2 (i.e. greater than 10W/m2).  Maintenance on 12/26 indicated a 
failed ventilator heater connector on PIR1.  After 12/26 PIR1 and PIR2 returned to 
tracking each other within 10W/m2 as typical.

• inst_down_long_hemisp1_dome_resist
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_case_resist

• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• inst_down_long_hemisp1_case_temp
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_dome_temp
• down_long_hemisp1_min
• down_long_hemisp1_max
• down_long_hemisp1_std

NSA/SKYRAD/C1 - Reprocessed: Incorrect calibration coefficients

On 7/20/2011 starting 2229GMT ops replaced the Skyrad shortwave instruments (PSP/8-48/NIP) 
corresponding to the datastreams (down_short_hemisp, down_short_diffuse_hemisp, 
short_direct_normal) but the calibration coefficients weren't changed until 07/25/2011 1842GMT.  

Data were reprocessed and archived in September 2011.

• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• down_short_hemisp_std
• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)

• inst_global
• inst_diffuse
• inst_direct_normal

TWP/SKYRAD/C2 - Tracker failure

Tracker failed on 6/16/2011. Ops replaced with a spare tracker. The affected instruments 
are the 8-48 (down_short_diffuse) and NIP (direct_normal) shortwave instruments.

The down_long_hemisp1 and 2 (PIR1 and PIR2) performance may have been affected by exposure 
to direct sun.

• inst_down_long_hemisp2_case_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• down_long_hemisp1_min
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• inst_down_long_hemisp2_tp
• down_long_hemisp1_max
• inst_down_long_hemisp1_tp
• down_long_hemisp2_std
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• down_long_hemisp1_std
• inst_down_long_hemisp1_dome_temp
• short_direct_normal_std
• down_long_hemisp2_max
• down_long_hemisp2_min
• inst_down_long_hemisp2_dome_temp
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• inst_down_long_hemisp1_case_temp

• inst_diffuse
• inst_down_long_hemisp2_tp
• inst_direct_normal
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp2_case_resist
• inst_down_long_hemisp2_dome_resist
• inst_down_long_hemisp1_dome_resist

NSA/SKYRAD/C1 - Incorrect data during power outage

During a power outage the downwelling diffuse 8-48 and the downwelling shortwave direct 
were incorrect. The IRT was also affected during this time period.

• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• sky_ir_temp_min
• sky_ir_temp_max
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_short_diffuse_hemisp_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• sky_ir_temp_std
• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• IR Brightness Temperature(sky_ir_temp)

• inst_diffuse
• inst_sky_ir_signal
• inst_direct_normal

NSA/SKYRAD/C1 - Noisy data due to grounding issue

Improper grounding of the IRT serial cable connection caused significant noise in the 
signals of the other SKYRAD instruments. It was corrected by disconnecting the serial cable 
from the RocketPort.

• inst_down_long_hemisp2_tp
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• down_short_hemisp_std
• down_long_hemisp1_min
• inst_down_long_hemisp1_tp
• short_direct_normal_std
• inst_down_long_hemisp2_dome_temp
• down_long_hemisp1_max
• inst_down_long_hemisp2_case_temp
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• inst_down_long_hemisp1_dome_temp
• down_long_hemisp2_min
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_short_diffuse_hemisp_std
• down_long_hemisp2_std
• down_long_hemisp2_max
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• inst_down_long_hemisp1_case_temp
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• down_long_hemisp1_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)

• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Irradiance, longwave, downwelling, hemispheric(down_long_hemisp)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)

TWP/SKYRAD/C2 - IRT power failure

The IRT measurements were incorrect due to a drop in the logger battery voltage.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std
• sky_ir_temp_max
• sky_ir_temp_min

• inst_sky_ir_signal

GAN/SKYRAD/M1 - Degraded IRT mirror

The gold mirror was worn and needed to be replaced. Degradation of the mirror occurs 
gradually and it is difficult to determine when it begins to affect the measurement. To 
estimate the beginning of the problem, I used the time when the difference in IR sky 
temperature from the MWR3C was consistantly greater that 2.4K (2 times the resolution of the IRT 
measurement).

The problem was corrected when the mirror was replaced.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std
• sky_ir_temp_min
• sky_ir_temp_max

GAN/SKYRAD/M1 - PIR2 failure

Increasing difference between PIR1 and PIR2 beginning December 12.  Suspected problem with 
PIR2 thermistor bridge or instrument thermistor.  OPS replaced PIR2 unit with a spare. 
The data from PIR2 after replacement appears to be normal.

• down_long_hemisp2_max
• down_long_hemisp2_min
• inst_down_long_hemisp2_case_temp
• down_long_hemisp2_std
• inst_down_long_hemisp2_tp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• inst_down_long_hemisp2_dome_temp

• inst_down_long_hemisp2_case_resist
• inst_down_long_hemisp2_tp
• inst_down_long_hemisp2_dome_resist

SBS/SKYRAD/M1 - Noise in downwelling SW hemispheric

Downwelling Shortwave Hemispheric signal varies wildly between missing (-9999) and large 
positive values over this period.

• inst_global

• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• down_short_hemisp_std
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)

GAN/SKYRAD/M1 - PIR1 failure

PIR1 irradiance data are incorrect beginning Feb 4th and questionable as far back as Jan 
31st around 0400 UTC.  Site operations ceased Feb 9 before repairs were made.

• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_case_temp
• down_long_hemisp1_std
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• inst_down_long_hemisp1_dome_temp
• down_long_hemisp1_min
• down_long_hemisp1_max

• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp1_dome_resist

TWP/SKYRAD/C1 - IRT failure

The IRT failed and was replaced.

• inst_sky_ir_signal

• sky_ir_temp_max
• sky_ir_temp_std
• sky_ir_temp_min
• IR Brightness Temperature(sky_ir_temp)

TWP/SKYRAD/C2 - Downwelling LW #1 questionable

Hemispheric downwelling measurements on the hemisp1 were suspect due to the large 
differences between PIR1 and PIR2 (i.e. greater than 10W/m2). Maintenance on 3/14/2012 indicated 
problem with the connector and ops re-seated the connector on PIR 1. After the 
maintenance, PIR1 and PIR2 returned to tracking each other within 10W/m2 as typical.

• down_long_hemisp1_max
• inst_down_long_hemisp1_tp
• down_long_hemisp1_std
• down_long_hemisp1_min
• inst_down_long_hemisp1_dome_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• inst_down_long_hemisp1_case_temp

• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp1_dome_resist
• inst_down_long_hemisp1_tp

PVC/SKYRAD/M1 - Intake Fan Failure

PSP (down_short_hemisp) ventilator fan failed from start of PVC deployment.  Site ops 
repaired/replaced on 8/28. Instrument data are not recoverable.

The down_short_hemisp data are not recoverable but can be re-constructed using the 
short_direct_normal and down_short_diffuse_hemispheric measurements and the following formula: 

Global = Direct * cos(zenith angle) + Diffuse

• inst_global

• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• down_short_hemisp_std

PVC/SKYRAD/M1 - Reprocessed: Incorrect calibration coefficients

Incorrect programs were used in Skyrad since PVC deployment period began.  The Skyrad 
program was corrected 09/05/2012 approx 20:00GMT. Reprocessing will be required of all 
instruments at this station except the IRT. This will require applying the following 
corrections for the time range specified. 
Serial numbers(incorrectly applied): 
PIR1-DIR: 34306
PIR2-DIR: 34303
Diffuse PSP: 34284
NIP: 34097
PSP-DS: 34293

Serial numbers(correct): 
PIR1-DIR: 34303
PIR2-DIR: 34306
Diffuse PSP: 35751
NIP: 37285
PSP-DS: 37302
    
Data: 
Longwave requires reprocessing using the 20second datastream and applying the following k1 
coefficients (note: the longwave instruments were swapped according to datalogger).
down_long_hemisp1 (old cal) = 0.23041
down_long_hemisp1 (corr cal) = 0.24750
down_long_hemisp2 (old cal) = 0.24750
down_long_hemisp2 (corr cal) = 0.23041

Shortwave only requires application of the following corrections to 1min and 20 second 
data.
down_short_diffuse_hemisp(corr) = down_short_diffuse_hemisp(old value)*(104.45(corr 
cal)/120.91(incorr cal))
short_direct_normal(corr) = short_direct_normal(old value)*(117.25(new cal)/124.97(incorr 
cal))
up_short_hemip(corr) = up_short_hemip(old value)*(119.21(new cal)/108.48(incorr cal))

Contact radiometer mentor with any comments/questions

Reprocessing completed 20121217

• inst_down_long_hemisp1_case_resist
• inst_global
• inst_diffuse
• inst_direct_normal
• inst_down_long_hemisp2_case_resist
• inst_down_long_hemisp2_dome_resist
• inst_down_long_hemisp1_dome_resist
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp2_tp

• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_long_hemisp2_std
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• inst_down_long_hemisp2_case_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• inst_down_long_hemisp2_tp
• down_long_hemisp1_max
• down_long_hemisp2_min
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_long_hemisp1_std
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• down_short_diffuse_hemisp_std
• short_direct_normal_std
• down_long_hemisp2_max
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• down_short_hemisp_std
• inst_down_long_hemisp2_dome_temp
• inst_down_long_hemisp1_case_temp
• inst_down_long_hemisp1_dome_temp
• down_long_hemisp1_min
• inst_down_long_hemisp1_tp

PVC/SKYRAD/M1 - Reprocess: Incorrect IRT Configuration

The SKYRAD IRT was installed temporarily (waiting for the new enclosure) in
a vertical orientation, without the use of the gold mirror. When irt_comm
was started, the emissivity parameter in the startup file was not changed to 1.000 
compensate for the absence of the mirror, resulting in a positive bias of about 5 K.

These data may be corrected by adjusting the radiance values for the difference in 
emmissivity.

• sky_ir_temp_min
• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_max

PVC/SKYRAD/M1 - IRT failure

The IRT failed because of water intrusion.

• inst_sky_ir_signal

• sky_ir_temp_std
• sky_ir_temp_min
• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_max

PVC/SKYRAD/M1 - IRT scale factor

The IRT was replaced with a unit with the wrong analog output configuration, such that the 
sky temperature was below the measurable range, resulting in a constant output of 0 
volts or 173.2 K.

• inst_sky_ir_signal

• sky_ir_temp_std
• sky_ir_temp_min
• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_max

PGH/SKYRAD/M1 - Reprocess: Incorrect calibrations

During the entire India deployment the Skyrad system was configured with incorrect 
calibration coefficients for the shortwave instruments. The program hadn't been updated since 
the previous deployment in the Azores.

The instrument mentor, site personal and OSS support have attempted to best determine the 
serial numbers of instruments installed at PGH during the deployment period.  The 
following instrument data will need to be reprocessed with the following correction multipliers:

PIR1-DIR(down_long_hemisp1): OK, no correction required
PIR2-DIR(down_long_hemisp2): OK, no correction required
Diffuse 8-48 (down_short_diffuse): 116.95(correct)/120.91(incorrect) = .96725
NIP (short_direct_normal): 127.03(correct)/124.97(incorrect) = 1.01648
PSP-DS (down_short_hemsip): 111.29(correct)/108.48(incorrect) = 1.02590
IRT: calibration should be validated by instrument mentor (Vic Morris): mult=26, 
offset=173.2

Correct serial numbers:   
Diffuse 8-48 (down_short_diffuse): 34066
NIP (short_direct_normal): 34135E6
PSP-DS (down_short_hemsip): 33942F3

• inst_global
• inst_diffuse
• inst_sky_ir_signal
• inst_direct_normal

• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• down_short_hemisp_std
• IR Brightness Temperature(sky_ir_temp)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• sky_ir_temp_min
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• sky_ir_temp_max
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• sky_ir_temp_std
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• down_short_diffuse_hemisp_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• short_direct_normal_std

TWP/SKYRAD/C2 - Tracker Failure

The solar tracker failed resulting in incorrect short_direct_normal and 
down_short_diffuse_hemisp data.  Data are not recoverable.

• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• short_direct_normal_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)

• inst_direct_normal
• inst_diffuse

TWP/SKYRAD/C2 - Tracker problem

The tracker has a problem in tracking the sun continuously in the southern hemisphere and 
close to the equator. This happened between the March equinox and September equinox 
around solar noon. Affected hours are between 00:00 to 1:00 each day for the specified time 
range.

Note: This will likely occur again in 2013 between March equinox and September equinox 
around solar noon.

Note2: The tracker tracking being off only affects data when there is direct sun, i.e. 
when the sun is not blocked by cloud. Thus in the tropics much of this data are not 
inherently "bad" plus only the direct and diffuse are "bad" when there's direct sun present. The 
QCRad has a test for "tracker off" that detects the tracker not shading the diffuse 
instrument and the NIP not being aimed at the sun when the sun is not blocked by cloud. Thus 
the ARM recommended measure QCRad data set will catch most of these "bad" data and set the 
values to "-9999.9" when the sun is not blocked by cloud, and leave the data that is OK 
when the sun is blocked by cloud (unless that data fails some other testing of course).

• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• short_direct_normal_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)

• inst_direct_normal
• inst_diffuse

PVC/SKYRAD/M1 - Instrument noise

All instruments on Skyrad exhibit intermittant erratic behavior from 10/05 through 10/23. 
Appears to have been an grounding issue with the IRT installed on Skyrad and replaced 
10/17. After the last problem period on 10/23 the problem resolved itself without operator 
involvement.

All data on Skyrad during these erratic behaviour periods are not recoverable. Bad data 
can generally be identified by screening vBatt for values outside normal operation range of 
13.3-13.6V.

• inst_down_long_hemisp1_case_resist
• inst_global
• inst_diffuse
• inst_sky_ir_signal
• inst_direct_normal
• inst_down_long_hemisp2_case_resist
• inst_down_long_hemisp1_dome_resist
• inst_down_long_hemisp2_dome_resist
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp2_tp

• sky_ir_temp_std
• sky_ir_temp_min
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_long_hemisp2_std
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• inst_down_long_hemisp2_case_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• inst_down_long_hemisp2_tp
• down_long_hemisp1_max
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_long_hemisp2_min
• down_long_hemisp1_std
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• down_short_diffuse_hemisp_std
• down_long_hemisp2_max
• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• down_short_hemisp_std
• inst_down_long_hemisp2_dome_temp
• inst_down_long_hemisp1_case_temp
• inst_down_long_hemisp1_dome_temp
• IR Brightness Temperature(sky_ir_temp)
• down_long_hemisp1_min
• sky_ir_temp_max
• inst_down_long_hemisp1_tp

PVC/SKYRAD/M1 - IRT disconnected

The IRT was disconnected to diagnose PIR signal noise.

• sky_ir_temp_std
• sky_ir_temp_min
• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_max

PVC/SKYRAD/M1 - Tracker removed for storm

Site preparation for a pending storm in Cape Cod Area included stowing the tracker for the 
affected period.  During this time the only SKYRAD instruments with accurate 
measurements were down_short_hemisp (global horizontal shortwave pyranometer instrument), 
down_long_hemisp1 and down_long_hemisp2 (pyrgeometer instruments).

The short_direct_normal (pyrheliometer DNI instrument) and down_short_diffuse_hemisp (8-48 
shaded diffuse instrument) data are not recoverable.

Additionally, there may have been undocumented periods of missing data during this time.

• inst_diffuse
• inst_direct_normal

• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_short_diffuse_hemisp_std
• short_direct_normal_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)