NSA/SKYRAD/C1 - reprocess: PIR identified as unshaded is really shaded

On 5/15/02 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.

• inst_down_long_unshaded_case_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer2)(inst_down_long_hemisp_unshaded_tp)
• inst_down_long_unshaded_dome_resist

NSA/SKYRAD/C1 - Reprocess: PIR identified as unshaded is really shaded

On 5/15/02 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, Shaded Pyrgeometer2(down_long_hemisp2)
• inst_down_long_hemisp2_tp
• inst_down_long_hemisp2_case_temp
• down_long_hemisp2_min
• inst_down_long_hemisp2_dome_temp
• down_long_hemisp2_std
• down_long_hemisp2_max

NSA/SKYRAD/C1 - PIR data suspect

PIR shaded and PIR unshaded show unusual differences during this time period, frosting or 
icing is the most probable explanation but we don't know for sure.

• pir1_mean
• pir1_max
• pir1_sd
• pir1_min

• pir1_sd
• pir1_max
• pir1_min
• pir1_mean

NSA/SKYRAD/C1 - Shaded PIR data unreasonable

Scientificly unreasonable data values, the problem disappeared after the datalogger was 
exchanged with the spare. The data logger was exchanged on 11/7 at 20:10 GMT.

• pirs_sd
• pirs_min
• pirs_mean
• pirs_max

• pirs_min
• pirs_mean
• pirs_max
• pirs_sd

NSA/SKYRAD/C1 - PIR data suspect

PIR shaded and PIR unshaded show unusual differences during this time period, frosting or 
icing is one possible explanation but we don't know.

• pirs_mean
• pir1_min
• pir1_mean
• pir1_max
• pirs_sd
• pir1_sd
• pirs_min
• pirs_max

• pir1_max
• pir1_min
• pirs_mean
• pir1_sd
• pirs_min
• pirs_sd
• pirs_max
• pir1_mean

NSA/SKYRAD/C1 - Unshaded PIR maintenance

Unreasonable data from 3/15 23:45 until 3/16 0:45 due to exchange of PIR instrument to the 
PIR spare (32054F3). This was done so the PIR could go to NOAA/CMDL in Boulder for 
calibration as part of the IPARSC II IOP and be included in this work.

• pir1_mean
• pir1_max
• pir1_sd
• pir1_min

• pir1_sd
• pir1_max
• pir1_min
• pir1_mean

NSA/SKYRAD/C1 - Miscalibrated Unshaded PIR data

Calibration coefficient for PIR spare (32054F3) was updated on 3/25 2:35 GMT. The old PIR 
cal coefficient was used during this period. The PIR spare (32054F3) was calibrated by 
NOAA/CMDL in Boulder prior to the IOP and replacement on 3/16 when the original station PIR 
was shipped to Boulder for a post IOP calibration.

• pir1_mean
• pir1_max
• pir1_sd
• pir1_min

• pir1_sd
• pir1_max
• pir1_min
• pir1_mean

NSA/SKYRAD/C1 - Noise in Unshaded PIR data

Noise increased and an offset from shaded PIR became apparent during this period.

• pir1_mean
• pir1_max
• pir1_sd
• pir1_min

• pir1_sd
• pir1_max
• pir1_min
• pir1_mean

NSA/SKYRAD/C1 - NIP shaded by skyrad stand around local midnight

Around local midnight 9:30-10:30 GMT during summer clear sky the normal incidence 
pyranometer is shaded by the instrument stand.This causes the reading to be 0 W/m2. If cosine 
correction is applied for irradiance calulations this effect is negligible due to the low 
solar angle.

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

• nip_max
• nip_sd
• nip_min
• nip_mean

NSA/SKYRAD/C1 - PSP shaded by MFRSR after local midnight

Just past local midnight (11:00-11:40 GMT during summer clear sky) the global 
hemispherical pyranometer is shaded by the MFRSR instrument for about 40 minutes. This causes the 
reading to be 0 W/m2. This effect would be negligible in a daily average due to the low 
solar angle.

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

• psp1_sd
• psp1_mean
• psp1_min
• psp1_max

NSA/SKYRAD/C1: Noisy PIR data at Barrow

PIR1 data is noisy throughout the entire period, though there is still a definite signal 
through the noise.

• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• down_long_hemisp_shaded_std
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)

• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• down_long_hemisp_shaded_std
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)

NSA/SKYRAD/C1 - IRT failed

• sky_ir_temp_min
• sky_ir_temp_std
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)

• sky_ir_temp_max
• sky_ir_temp_std
• sky_ir_temp_min
• Temperature, Sky Infra-Red(sky_ir_temp)

NSA/SKYRAD/C1 - IRT incorrectly configured

The IRT was removed for repair and replaced with a
spare that was not configured properly.  Data are incorrect.

• sky_ir_temp_min
• sky_ir_temp_std
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)

• sky_ir_temp_max
• sky_ir_temp_std
• sky_ir_temp_min
• Temperature, Sky Infra-Red(sky_ir_temp)

NSA/SKYRAD/C1 - IRT incorrect min/max value

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_ir_temp_min
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)

NSA/SKYRAD/C1 - 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_ir_temp_min
• sky_ir_temp_std
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)

NSA/SKYRAD/C1 - NSA B&W nighttime offset in Barrow too large

This problem only became apparent as NSA C1 nights became long enough for full darkness. 
The shaded global diffuse instrument (Eppley 8-48) showed a negative nighttime offset 
larger than the expected 0 to -4 W/m2. Typically -5 to -8 W/m2. This size of offset is not 
uncommon with Eppley PSPs but not observed with Eppley 8-48s.  The problem was corrected 
with replacement of mounting screws which were creating a ground loop.

• Raw data stream - documentation not supported

• psps_sd
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• psps_mean
• psps_min
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• psps_max

• psps_max
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• 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)
• psps_sd
• psps_mean
• psps_min

NSA/SKYRAD/C1 - Noisy PIR data at Barrow

PIR1 data is noisy throughout the entire period, though there is still a definite signal 
through the noise.

• down_long_hemisp_shaded1_max
• down_long_hemisp_shaded1_std
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• down_long_hemisp_shaded1_min

• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• down_long_hemisp_shaded1_max
• down_long_hemisp_shaded1_min
• down_long_hemisp_shaded1_std

NSA/SKYRAD/C1 - Downwelling IRT bias

The downwelling IRT was measuring higher sky/cloud temperatures than the AERI. The problem 
was corrected when the mirror was replaced.

• sky_ir_temp_min
• sky_ir_temp_std
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)

NSA/SKYRAD/C1 - direct normal pyhrheliometer (NIP)shaded by WWRp

Direct normal radiation values drop nearly to zero from about 1515 GMT - 1525 GMT from 
4/05 to 4/16 2004.  Field observation reveals the WWRp is shading the NIP instrument during 
this time.  This shading event was expected to occur several months after the soltice as 
well but archive data showed no shading on or around 8/30/2004.  The direct normal 
instrument was apparently only shaded during the time period noted.

• Raw data stream - documentation not supported

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

NSA/SKYRAD/C1 - Tracker Inoperative

A blown fuse resulted in the tracker not shading the PIR and B&W
and the NIP not following the sun.

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

NSA/SKYRAD/C1 - itermittant IRT bias

A problem with the SKYRAD IRT that itermittantly produced a gradual increase in the sky 
temperature measurement then a sudden correction, as compared to AERI, appears to have been 
caused by a combination of a failing IR detector, a poor signal cable, a contaminated 
(with condensation or frost) mirror or lens, and low ambient temperatures. The positive 
bias was apparently not consistant in either frequency or duration but on days when the 
unusual behavior is observed, it usually occurred from about 00:00 to 06:00 local time. 

The instrument was repaired and recalibrated and the signal cable replaced.

• sky_ir_temp_min
• sky_ir_temp_std
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)

NSA/SKYRAD/C1 - Frosting and Condensation

The operators in both Barrow and Atqasuk reported significant ice buildup during nights 
for the period specified, with the ice melting during the days. This condition is reported 
in preventative maintenance reports as continuing until on or near 5/18/2004. However, 
review of data shows no discernable radiometer icing.

• Raw data stream - documentation not supported

• down_long_hemisp_shaded2_std
• down_long_hemisp_unshaded_std
• sky_ir_temp_min
• psps_mean
• sky_ir_temp_max
• psps_min
• down_long_hemisp_shaded2_max
• pirs_mean
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• uvb_mean
• nip_min
• down_long_hemisp_shaded1_max
• pirs_min
• pir1_sd
• short_direct_normal_std
• pirs_max
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• psps_sd
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer, Minima(down_long_hemisp_unshaded_min)
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer, Maxima(down_long_hemisp_unshaded_max)
• psp1_min
• psp1_max
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_short_diffuse_hemisp_std
• pir1_mean
• nip_max
• psp1_mean
• sky_ir_temp_std
• Downwelling Ultra-Violet Irradiance, UV Biometer(down_uvb)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• irt1_mean
• uvb_min
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• down_uvb_std
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• nip_mean
• Downwelling Ultra-Violet Irradiance, UV Biometer, Maxima(down_uvb_max)
• uvb_sd
• down_short_hemisp_std
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• uvb_max
• pirs_sd
• irt1_min
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)
• Temperature, Sky Infra-Red(sky_ir_temp)
• psp1_sd
• irt1_max
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• down_long_hemisp_shaded2_min
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer(down_long_hemisp_unshaded)
• nip_sd
• pir1_min
• Downwelling Ultra-Violet Irradiance, UV Biometer, Minima(down_uvb_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• down_long_hemisp_shaded_std
• psps_max
• irt1_sd
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• pir1_max
• down_long_hemisp_shaded1_std
• down_long_hemisp_shaded1_min

• pir2_dome_therm
• inst_down_long_unshaded_case_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded_tp)
• Irradiance, ultraviolet, downwelling (UV Biometer)(inst_down_uvb_irradiance)
• inst_down_long_shaded_dome_resist
• pir2_uncorr_irradiance
• inst_down_uvb_temp
• inst_down_long_shaded2_dome_resist
• inst_down_long_shaded1_case_resist
• inst_down_long_shaded_case_resist
• uvb_temp
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer2)(inst_down_long_hemisp_unshaded_tp)
• inst_down_long_shaded1_dome_resist
• uvb_uncorr_irradiance
• inst_down_long_shaded2_case_resist
• pir2_case_therm
• pir1_uncorr_irradiance
• pir1_case_therm
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer2)(inst_down_long_hemisp_shaded2_tp)
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded1_tp)
• pir1_dome_therm
• inst_down_long_unshaded_dome_resist

NSA/SKYRAD/C1 - Datalogger grounding problem

Both PIRs reported unreasonable high readings with coincident low reading from the IRT. 
Since both PIR instruments exhibited exactly the same behaviour and the IRT an opposite 
response during large suspect data excursions this indicates that the false signal maybe the 
result of poor grounding. 

The PIR1,2 data and the IRT data are most adversely affected.  During the problem periods 
PIR irradiance increased (typ pos 200-300W/m2) while the IRT response was negative (typ 
neg 20-30W/m2) but followed the response of the PIR.  The Skyrad shortwave instruments 
were also affected but to much less extent (within their uncertainties).  Data quality flags 
are typically not triggered during these problem periods.

Data logger grounding was improved on 6/10 2005.  The problem hasn't re-occurred since 
that time.

• Raw data stream - documentation not supported

• down_long_hemisp_shaded2_std
• psps_mean
• alt
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• uvb_mean
• nip_min
• down_long_hemisp_shaded1_max
• short_direct_normal_std
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer, Minima(down_long_hemisp_unshaded_min)
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer, Maxima(down_long_hemisp_unshaded_max)
• psp1_min
• psp1_max
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• nip_max
• sky_ir_temp_std
• base_time
• uvb_min
• down_uvb_std
• external_voltage
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• nip_mean
• Downwelling Ultra-Violet Irradiance, UV Biometer, Maxima(down_uvb_max)
• uvb_sd
• uvb_max
• pirs_sd
• Temperature, Sky Infra-Red(sky_ir_temp)
• psp1_sd
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer(down_long_hemisp_unshaded)
• nip_sd
• lon
• Downwelling Ultra-Violet Irradiance, UV Biometer, Minima(down_uvb_min)
• internal_voltage
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• down_long_hemisp_shaded_std
• irt1_sd
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• pir1_max
• down_long_hemisp_shaded1_min
• down_long_hemisp_unshaded_std
• sky_ir_temp_min
• sky_ir_temp_max
• psps_min
• down_long_hemisp_shaded2_max
• pirs_mean
• logger_temp
• pirs_min
• pir1_sd
• pirs_max
• psps_sd
• down_short_diffuse_hemisp_std
• pir1_mean
• psp1_mean
• Downwelling Ultra-Violet Irradiance, UV Biometer(down_uvb)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• irt1_mean
• lat
• 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)
• down_short_hemisp_std
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• irt1_min
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)
• bit_data
• time_offset
• irt1_max
• filename
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• down_long_hemisp_shaded2_min
• pir1_min
• psps_max
• down_long_hemisp_shaded1_std

• inst_down_long_unshaded_case_resist
• pir2_uncorr_irradiance
• base_time
• inst_down_uvb_temp
• inst_down_long_shaded2_dome_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer2)(inst_down_long_hemisp_unshaded_tp)
• inst_down_long_shaded2_case_resist
• lat
• pir1_uncorr_irradiance
• pir1_case_therm
• alt
• lon
• inst_down_long_unshaded_dome_resist
• filename
• pir2_dome_therm
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded_tp)
• Irradiance, ultraviolet, downwelling (UV Biometer)(inst_down_uvb_irradiance)
• time_offset
• inst_down_long_shaded_dome_resist
• inst_down_long_shaded1_case_resist
• inst_down_long_shaded_case_resist
• uvb_temp
• inst_down_long_shaded1_dome_resist
• uvb_uncorr_irradiance
• pir2_case_therm
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer2)(inst_down_long_hemisp_shaded2_tp)
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded1_tp)
• pir1_dome_therm

• inst_sky_ir_signal
• inst_down_long_shaded2_case_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded1_tp)
• inst_global
• alt
• time_offset
• inst_down_long_shaded1_case_resist
• inst_down_long_shaded1_dome_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer2)(inst_down_long_hemisp_shaded2_tp)
• inst_down_long_shaded2_dome_resist
• inst_diffuse
• lat
• base_time
• inst_direct_normal
• time
• lon

NSA/SKYRAD/C1 - IRT failure

The IRT failed and was replaced with a spare.

• sky_ir_temp_min
• sky_ir_temp_std
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)

NSA/SKYRAD/C1 - Instrument logger, possible gounding problem

Possible Skyrad datalogger grounding issues have re-appeared at NSA/C1 for only this short 
time period.  Anomalous data readings during the time range specified are similar to 
problem which occurred in early summer 2005.

• Raw data stream - documentation not supported

• down_long_hemisp_shaded2_std
• down_long_hemisp_unshaded_std
• sky_ir_temp_min
• sky_ir_temp_max
• psps_mean
• psps_min
• down_long_hemisp_shaded2_max
• pirs_mean
• alt
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• logger_temp
• nip_min
• uvb_mean
• down_long_hemisp_shaded1_max
• pir1_sd
• pirs_min
• short_direct_normal_std
• pirs_max
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• psps_sd
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer, Minima(down_long_hemisp_unshaded_min)
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer, Maxima(down_long_hemisp_unshaded_max)
• psp1_min
• psp1_max
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_short_diffuse_hemisp_std
• pir1_mean
• nip_max
• psp1_mean
• sky_ir_temp_std
• Downwelling Ultra-Violet Irradiance, UV Biometer(down_uvb)
• base_time
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• irt1_mean
• uvb_min
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• lat
• down_uvb_std
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• external_voltage
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• nip_mean
• Downwelling Ultra-Violet Irradiance, UV Biometer, Maxima(down_uvb_max)
• uvb_sd
• down_short_hemisp_std
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• uvb_max
• pirs_sd
• irt1_min
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)
• bit_data
• Temperature, Sky Infra-Red(sky_ir_temp)
• time_offset
• psp1_sd
• irt1_max
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• filename
• down_long_hemisp_shaded2_min
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer(down_long_hemisp_unshaded)
• lon
• nip_sd
• pir1_min
• Downwelling Ultra-Violet Irradiance, UV Biometer, Minima(down_uvb_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• internal_voltage
• down_long_hemisp_shaded_std
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• irt1_sd
• psps_max
• pir1_max
• down_long_hemisp_shaded1_std
• down_long_hemisp_shaded1_min

• inst_down_long_shaded1_case_resist
• inst_down_long_shaded1_dome_resist
• inst_sky_ir_signal
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer2)(inst_down_long_hemisp_shaded2_tp)
• inst_down_long_shaded2_dome_resist
• inst_down_long_shaded2_case_resist
• inst_diffuse
• lat
• base_time
• inst_direct_normal
• time
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded1_tp)
• inst_global
• lon
• alt
• time_offset

NSA/SKYRAD/C1 - Reprocess: Incorrect datalogger program affecting PIR1 and PIR2 
downwelling longwave

The excitation delays using in measuring the PIR1 case thermistor commonly named "Case1" 
and the PIR2 dome thermistor called "Dome2" were discovered to have been incorrectly set 
to 0 in the Skyrad datalogger program when the new CR23X based Skyrad loggers were 
installed.  The result of no delay in these measurements results in an error in the measured 
resistance of the thermistors, Case1 and Dome2 and thus the calculated PIR1 and PIR2 
irradiances.  The errors are inversely proportial to temperature.

Users can apply the temperature dependent irradiance corrections shown in the table below. 
 Recall that the reported uncertainty of PIRs is typically +-.25% to +-.5% or 1 to 2 
W/m2.  The error corrections become the same order of magnitude or larger than the 
instrument uncertainties at or below 260K or 9F. 

Correction Table for Skyrad (TWP and NSA) DIR1 and DIR2 Irradiance				
	DIR1	DIR1	DIR2	DIR2
T[F]	Tcase[K]	Correction[W/m2]	Tdome[K]	Correction[W/m2]
109.4	316.13	0.00	316.13	0.00
100.5	311.20	-0.15	311.20	0.12
93.2	307.14	-0.12	307.14	0.10
87.0	303.70	-0.10	303.70	0.08
81.6	300.70	-0.17	300.70	0.14
77.0	298.15	-0.22	298.15	0.18
59.4	288.35	-0.34	288.35	0.27
47.4	281.72	-0.23	281.72	0.18
38.5	276.74	-0.42	276.74	0.34
31.3	272.77	-0.48	272.77	0.38
25.4	269.48	-0.61	269.48	0.49
20.3	266.67	-0.67	266.67	0.54
16.0	264.25	-0.82	264.25	0.66
12.1	262.11	-0.98	262.11	0.79
8.7	260.19	-0.97	260.19	0.78
5.6	258.46	-1.07	258.46	0.86
2.7	256.89	-1.17	256.89	0.94
0.1	255.44	-1.33	255.44	1.07
-2.3	254.11	-1.41	254.11	1.13
-4.5	252.87	-1.43	252.87	1.15
-6.6	251.71	-1.52	251.71	1.22
-8.5	250.63	-1.63	250.63	1.31
-10.4	249.62	-1.73	249.62	1.39
-12.2	248.58	-1.79	248.58	1.44
-15.4	246.82	-1.93	246.82	1.55
-18.3	245.23	-2.05	245.23	1.65
-20.9	243.78	-2.22	243.78	1.78
-23.3	242.44	-2.36	242.44	1.89
-25.5	241.21	-2.58	241.21	2.07
-27.5	240.07	-2.65	240.07	2.13
-29.5	239.01	-2.75	239.01	2.21
-31.3	238.00	-3.02	238.00	2.42

• down_long_hemisp_shaded2_std
• down_long_hemisp_shaded2_min
• down_long_hemisp_shaded2_max
• down_long_hemisp_shaded1_max
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• down_long_hemisp_shaded1_std
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)
• down_long_hemisp_shaded1_min

• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded1_tp)
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer2)(inst_down_long_hemisp_shaded2_tp)
• inst_down_long_shaded1_case_resist
• inst_down_long_shaded2_dome_resist
• inst_down_long_shaded2_case_resist
• inst_down_long_shaded1_dome_resist

NSA/SKYRAD/C1 - Power outage affecting some SKYRAD instruments

During the power outage the downwelling global measurement from the PSP instrument and 
downwelling diffuse 8-48 instrument shows a slight increase from -5 to +0 W/m2.  This is due 
to removal of thermal offsets induced by the AC heater during the power outage.  This 
heater is installed within the PSP ventilator - it is necessary for the NSA/C1 climate.
The downwelling longwave PIR instrument is unaffected due to case and dome temperature 
corrections.
The IRT is AC powered and was not operational during this time period.

• Raw data stream - documentation not supported

• 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)
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• down_short_hemisp_std
• Temperature, Sky Infra-Red(sky_ir_temp)

• inst_global
• inst_diffuse
• inst_sky_ir_signal

NSA/SKYRAD/C1 - Instrument noise

Skyrad data appears affected by noise creating bias in analog voltage readings on 
02/15/2006 from 1300-1800GMT and again on 02/16/2006 from 1300-1500GMT.  The second night the 
noise is attenuated significantly.  By 02/17 no bias/noise is detectable. The thermistor 
measurements in PIR1 and PIR2 were unaffected during these excursions and showed no 
deviation from normal during the problem period.  In addition, the onboard logger temperature and 
battery voltage read normal throughout.  The problem has not reappeared as of 4/25/2006.

• down_long_hemisp_shaded2_std
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• sky_ir_temp_min
• sky_ir_temp_max
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• down_long_hemisp_shaded2_max
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• down_long_hemisp_shaded1_max
• down_short_hemisp_std
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)
• short_direct_normal_std
• Temperature, Sky Infra-Red(sky_ir_temp)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• down_long_hemisp_shaded2_min
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_short_diffuse_hemisp_std
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• sky_ir_temp_std
• down_long_hemisp_shaded1_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_long_hemisp_shaded1_min

• inst_down_long_shaded1_case_resist
• inst_down_long_shaded1_dome_resist
• inst_sky_ir_signal
• inst_direct_normal
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded1_tp)
• inst_global
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer2)(inst_down_long_hemisp_shaded2_tp)
• inst_down_long_shaded2_dome_resist
• inst_down_long_shaded2_case_resist
• inst_diffuse

NSA/SKYRAD/C1 - 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.

• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)

NSA/SKYRAD/C1 - Summer solstice shading of radiometers

On and around the summer solstice, the NIP (Direct Normal shortwave measurement) and PSP 
(global hemispheic shortwave measurement) radiometers are shaded by other instruments or 
support structures.  Shading azimuths have been determined for this site.  The radiometer 
mentor suggests not using the data from the NIP and PSP radiometers when the sun is 
within the following azimuth bounds (typically from May 8th to August 5th of each year):
Instrmt Obstruction     AzStart     AzEnd     
NIP     rad table       346         358
NIP     met tower       13          15
PSP     mfrsr           6           16

• psps_sd
• psp1_sd
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• psps_mean
• psps_min
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• nip_sd
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• psp1_min
• psp1_max
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• nip_mean
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• nip_min
• psps_max
• nip_max
• psp1_mean
• down_short_hemisp_std
• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)

NSA/TSI/C1 - camera lens covered

The shadowband was not properly masking the sun so the camera lens was covered on 4/13 to 
prevent damage to the CCD. On 4/20, the mirror was blown off by a snow storm and the 
instrument was brought inside for repair. The mirror was replaced, the lens uncovered, and 
the instrument reinstalled.

• region.zenith.count.opaque
• count.sub.proczen
• count.sub.horz
• count.opaque
• Cloud amount, thin (percent)(percent.thin)
• count.thin
• region.horizon.count.opaque
• region.sun.count
• region.horizon.count.thin
• count.unknown
• region.horizon.count
• region.sun.count.thin
• region.zenith.count
• region.zenith.count.thin
• Sunshine Meter(sunny)
• sun.strength
• region.sun.count.opaque
• count.box
• count.sky
• count.mask
• Cloud amount, opaque (percent)(percent.opaque)

• Cloud decision images, Total Sky Imager, PNG format(png)

• JPEG data stream - documentation not yet available

NSA/TSI/C1 - shadowband misaligned

At several times during this period the shadowband did not mask the sun because the mirror 
was not properly secured. Attempts were made to align the mirror on 4/2, 4/3, and 4/10.

• region.zenith.count.opaque
• count.sub.horz
• count.sub.proczen
• count.opaque
• Cloud amount, thin (percent)(percent.thin)
• count.thin
• region.horizon.count.opaque
• region.sun.count
• region.horizon.count.thin
• count.unknown
• region.horizon.count
• region.sun.count.thin
• region.zenith.count
• region.zenith.count.thin
• sun.strength
• region.sun.count.opaque
• count.box
• count.sky
• count.mask
• Cloud amount, opaque (percent)(percent.opaque)

• Cloud decision images, Total Sky Imager, PNG format(png)

• JPEG data stream - documentation not yet available

NSA/SKYRAD/C1 - Preventive maintenance

Preventive maintenance to rebuild ventilator fan and exchange instruments during this time 
removed Skyrad instruments from operation.  Most data collected are not scientifically 
relevant.

• down_long_hemisp_shaded2_std
• down_long_hemisp_unshaded_std
• psps_mean
• psps_min
• down_long_hemisp_shaded2_max
• pirs_mean
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• uvb_mean
• nip_min
• down_long_hemisp_shaded1_max
• pirs_min
• pir1_sd
• short_direct_normal_std
• pirs_max
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• psps_sd
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer, Minima(down_long_hemisp_unshaded_min)
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer, Maxima(down_long_hemisp_unshaded_max)
• psp1_min
• psp1_max
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_short_diffuse_hemisp_std
• pir1_mean
• psp1_mean
• nip_max
• Downwelling Ultra-Violet Irradiance, UV Biometer(down_uvb)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• uvb_min
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• down_uvb_std
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• external_voltage
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• nip_mean
• Downwelling Ultra-Violet Irradiance, UV Biometer, Maxima(down_uvb_max)
• uvb_sd
• down_short_hemisp_std
• uvb_max
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• pirs_sd
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)
• psp1_sd
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• filename
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• down_long_hemisp_shaded2_min
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer(down_long_hemisp_unshaded)
• nip_sd
• pir1_min
• Downwelling Ultra-Violet Irradiance, UV Biometer, Minima(down_uvb_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• down_long_hemisp_shaded_std
• psps_max
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• pir1_max
• down_long_hemisp_shaded1_std
• down_long_hemisp_shaded1_min

• inst_down_long_shaded1_case_resist
• inst_down_long_shaded1_dome_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer2)(inst_down_long_hemisp_shaded2_tp)
• inst_down_long_shaded2_dome_resist
• inst_down_long_shaded2_case_resist
• inst_diffuse
• inst_direct_normal
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded1_tp)
• inst_global

NSA/SKYRAD/C1 - Missing data

Data are missing and unrecoverable.

• vBatt
• inst_down_long_hemisp2_tp
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• lat
• sky_ir_temp_min
• sky_ir_temp_max
• 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)
• alt
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• logger_temp
• down_short_hemisp_std
• down_long_hemisp1_min
• inst_down_long_hemisp1_tp
• short_direct_normal_std
• inst_down_long_hemisp2_dome_temp
• time_offset
• Temperature, Sky Infra-Red(sky_ir_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
• time
• lon
• 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_max
• down_long_hemisp2_std
• inst_down_long_hemisp1_case_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• sky_ir_temp_std
• base_time
• down_long_hemisp1_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)

NSA/SKYRAD/C1 - Reprocessed: Incorrect calibration coefficient

Installed Skyrad PSP (downwelling shortwave hemispheric irradiance) had calibration 
coefficient Rs applied when it should have used Rsc.  ARM is using IR corrected Rsc and CFc 
coefficients for PSPs deployed at all facilities.  

PSP #32026 should use RSc@45=8.7578 ?V/W/m? and not Rs@45=8.6335.

Reprocessed to correct downwelling shortwave hemispheric irradiance (DS) by:
DS(new) = (DS(old) / 115.83 ) * 114.18

Reprocessing completed March 2008.

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

• inst_global

NSA/SKYRAD/C1 - Instrument cleaning effects

Starting Dec 16th the Skyrad PIR1 and PIR2 (down_long_hemispheric)started differing by 
greater than 30W/m2 at times.  This is much greater than expected  for these instruments 
(typical is <10-15 W/m2).  NSA OMIS reports and observer comments reveal that PM 
periodically clean the snow from the IRT and ventilator fans on Skyrad and Gndrad.  In the case of 
the Skyrad PIRs, one lies in the wind shadow of the other and builds up more snow which is 
periodically cleaned out and then builds up again causing the PIR1 PIR2 discrepancies.

Disregard down_long_hemispheric during this time period. However, data suggests PIR2 is 
most likely at fault - potentially use PIR1 data during this time period.

• inst_down_long_hemisp2_tp
• inst_down_long_hemisp2_case_temp
• inst_down_long_hemisp1_dome_temp
• down_long_hemisp2_min
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• down_long_hemisp2_max
• down_long_hemisp2_std
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• inst_down_long_hemisp1_case_temp
• down_long_hemisp1_min
• inst_down_long_hemisp1_tp
• down_long_hemisp1_std
• inst_down_long_hemisp2_dome_temp
• down_long_hemisp1_max

• inst_down_long_hemisp1_dome_resist
• inst_down_long_hemisp2_tp
• inst_down_long_hemisp2_case_resist
• inst_down_long_hemisp2_dome_resist
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_case_resist

NSA/SKYRAD/C1 - IRT mirror heater failure

The heater of the IRT gold mirror failed due to a broken wire (that probably occurred on 
12/13 during maintenance of the solar tracker) allowing snow and frost to accumulate on 
the mirror until it was cleared during daily preventative maintenance. The problem was 
corrected when the heater wires were replaced.

• sky_ir_temp_min
• sky_ir_temp_std
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)

• inst_sky_ir_signal

NSA/TSI/C1 - frost/condensation in lens

The sky image appeared hazy and was corrected by cleaning the neutral-density filter and 
lens of the camera. The determination of cloud fraction may be affected.

• Cloud amount, thin (percent)(percent.thin)
• Cloud amount, opaque (percent)(percent.opaque)

• JPEG data stream - documentation not yet available

NSA/SKYRAD/C1 - Direct and Diffuse incorrect

The short_direct_normal (NIP) instrument and cable were damaged by tracker rewind 
malfunction. Tracker and NIP replaced on 4/22 2200GMT but tracker not operational until 4/23 
1815GMT.  Thus, down_short_diffuse_hemisp (8-48) was not shaded 4/22 to 4/23.

Do not use 8-48 data from 4/22 to 4/23. NIP data is not recoverable during entire time but 
can be estimated using component sum for each 1 minute data: Direct = (global - 
diffuse)/cos(zenith angle)

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

• inst_diffuse
• inst_direct_normal

NSA/SKYRAD/C1 - Tracker inoperative

Tracker stopped working at this site during the time range specified. Reason for failure 
is unknown.  Tracker power cycled and restarted by maintenance 06/30 2008 1740 GMT.

The short_direct_normal (NIP) and down_short_diffuse_hemisp (8-48) data are bad during 
this time.  Data are not recoverable.

• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)

• inst_diffuse
• inst_direct_normal

NSA/SKYRAD/C1 - Reprocess: IRT insufficiently heated

IRT had insufficient heating to maintain an internal reference temperature above 0 degrees 
C. Measurements of sky temperature were over-estimated when instrument was below 
freezing.

Data will be reprocessed, but users can correct data using the following correction 
factor:

If T_reference < -5?C, then

  IRT_corrected = (IRT_original - 32.993K)/0.87238

where T_reference can be estimated with the ambient temperature (e.g.
inst_down_long_hemisp_dome_temp or inst_down_long_dome_temp)

• sky_ir_temp_min
• sky_ir_temp_std
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)

NSA/TSI/C1 - Mirror frozen

The mirror was not rotating so the shadowband was not masking the sun. This appears to 
have been caused by snow that was melted by the mirror heater and then re-frozen by high, 
cold winds.

• region.zenith.count.opaque
• count.opaque
• Cloud amount, thin (percent)(percent.thin)
• count.thin
• region.horizon.count.opaque
• region.sun.count
• region.horizon.count.thin
• region.horizon.count
• region.zenith.count
• region.sun.count.thin
• region.zenith.count.thin
• region.sun.count.opaque
• count.sky
• Cloud amount, opaque (percent)(percent.opaque)

• Cloud decision images, Total Sky Imager, PNG format(png)

• JPEG data stream - documentation not yet available

NSA/SKYRAD/C1 - IRT covered with snow

The IRT mirror was buried with snow by the dew-line snow-blower.

• sky_ir_temp_min
• sky_ir_temp_std
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)

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