NSA/SKYRAD/C1 - Unshaded PIR data unreasonable

Periods of very large negative values. 
Negative readings of thermistors caused concurrent calculation 
in logger of temperature to fail.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)

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 unshaded standard deviation(pir1_sd)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)

NSA/SKYRAD/C1 - Shaded PIR data unreasonable

Periods of very large negative values. 
Negative readings of thermistors causes concurrent calculation 
in logger of temperature to fail.

• PIR shaded maximum(pirs_max)
• PIR shaded standard deviation(pirs_sd)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

NSA/SKYRAD/C1 - Corrupted Shaded PIR data

Erroneous data due to file truncation problem during logger download and corresponding 
ingest problems when the truncated lines were read. Problem was identified in a PIF 
submitted by Rune Storvold

• PIR shaded maximum(pirs_max)
• PIR shaded standard deviation(pirs_sd)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

NSA/SKYRAD/C1 - Shaded PIR data unreasonable

There was  a 10-25 W/m2 spike in data probably due to operator working around instrument 
or cleaning it.

• PIR shaded maximum(pirs_max)
• PIR shaded standard deviation(pirs_sd)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

NSA/SKYRAD/C1 - Unshaded and Shaded PIR data bad

Large unreasonable spikes and some missing data points. Cause of problem unknown.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR shaded maximum(pirs_max)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR shaded standard deviation(pirs_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

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.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR shaded maximum(pirs_max)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR shaded standard deviation(pirs_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

NSA/SKYRAD/C1 - Corrupted Unshaded PIR data

Erroneous data due to file truncation problem during logger download and corresponding 
ingest problems when the truncated lines were read. Problem was identified in a PIF 
submitted by Rune Storvold

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)

NSA/SKYRAD/C1 - Shaded PIR data suspect

The instrument had incorrect calibration settings on two accounts: 1. From 12/09 to 12/12, 
the calibration was set incorrectly. 2. The dome correction coefficients were not 
properly set until the early morning of 12/14. The erroneous settings caused an error probably 
less than 4%.

• PIR shaded maximum(pirs_max)
• PIR shaded standard deviation(pirs_sd)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

NSA/SKYRAD/C1 - PIR data suspect

The PIR unshaded and the PIR shaded have a persistent offset between them, ranging from 0 
to 10 W/m2. It is particularly apparent during clear sky. The line of sight of the PIRd 
is obstructed making it difficult to assess the problem. The instrument was moved to its 
proper location in early February. The problem seems to have resolved itself with the move.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR shaded maximum(pirs_max)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR shaded standard deviation(pirs_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

NSA/SKYRAD/C1 - Shaded PIR data incorrect

There were two sudden increases (about 50-100 W/m2) at 23:00 and 24:00.

• PIR shaded maximum(pirs_max)
• PIR shaded standard deviation(pirs_sd)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

NSA/SKYRAD/C1 - Spikes in Unshaded PIR data

There was  a 10-25 W/m2 spike in data probably due to operator working around instrument 
or cleaning it.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)

NSA/SKYRAD/C1 - Discontinuity in Unshaded PIR data

There was a sudden increase in irradiance (from 140 to 190 W/m2) at 02/03/99 23:00.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)

NSA/SKYRAD/C1 - Unshaded PIR data incorrect

Data from this time period is incorrect because instrument was swapped out for 
calibration and correct calibrations were not entered for replacement.  Some 
missing data during this time interval as well

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)

NSA/GNDRAD/C1 - Unreasonable/missing PIR data due to maintenance

During this period, there are data gaps and the data that were
collected are unreasonable.  Instrument maintenance was being
performed

• PSP1 unshaded maximum(psp1_max)
• NET mean(net_mean)
• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)
• Net Radiation, Minima(net_min)
• PIR1 unshaded minimum(pir1_min)
• Net Radiation(net)
• NET standard deviation(net_sd)
• Net Radiation, Standard Deviation(net_std)
• PSP1 unshaded mean(psp1_mean)
• PSP1 unshaded minimum(psp1_min)
• Net Radiation, Maxima(net_max)
• PSP1 unshaded standard deviation(psp1_sd)

NSA/GNDRAD/C1 - Noisy PIR Data

During the period referenced, the ground PIR was noisy in comparison to the sky PIR data.  
At the end of November, the noise increased to roughly 10 W/m2 from peak to peak.  After 
12/23/98, the noise decreased in amplitude but still had noisy patterns.  

On 01/17-18/99, there was an increase again in the noise level (4 GMT 01/17 - 5 GMT 
01/18). During this period the gndrad IRT data also exhibited noise patterns (the IRT was not 
operational).

In February, the instrument exhibited large noise variations again.  On 02/16, a wiring 
problem was corrected and the noise dropped back to 1-5 W/m2.  However, the noise levels 
began to increase again.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded minimum(pir1_min)

NSA/GNDRAD/C1 - Noisy PIR Data

During the period referenced, the ground PIR was noisy in  
              comparison to the the sky PIR data.  (Note U021211.1 documents
              same problem for 9/1/98-2/28/99)

              The noise problem continued after the GNDRAD data logger was 
              replaced in late September. Particularly strong examples of the 
              noise can be seen in data from 11/10 - 11/19/99. The peak to 
              peak noise reaches 12 W/m2.

• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)
• PIR1 unshaded standard deviation(pir1_sd)

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded minimum(pir1_min)

NSA/GNDRAD/C1 - PIR1 Calibration problems resulted in small error

The dome correction coefficients were not properly reset in calibration file until the 
early morning of 12/15. These errors probably account for less than 4% in error.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded minimum(pir1_min)

NSA/GNDRAD/C1 - PIR offline

The PIR was taken off line during this period; data recorded 
              during this period are garbage.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded minimum(pir1_min)

NSA/GNDRAD/C1 - Instrument maintenance

Instrument replaced. Data affected by the work done during this time.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded minimum(pir1_min)

NSA/GNDRAD/C1 - Unreasonable PSP Data

During the darkness in the middle of this night, the PSP had a
              signal of 15 W/m2 over a three hour long period.  Cause unknown.

• PSP1 unshaded standard deviation(psp1_sd)
• PSP1 unshaded minimum(psp1_min)
• PSP1 unshaded mean(psp1_mean)
• PSP1 unshaded maximum(psp1_max)

• PSP1 unshaded maximum(psp1_max)
• PSP1 unshaded mean(psp1_mean)
• PSP1 unshaded minimum(psp1_min)
• PSP1 unshaded standard deviation(psp1_sd)

NSA/GNDRAD/C1 - Bad PSP calibrations applied

The ground radiation data are bad during this period due to 
              erroneous calibration factors in the logger configuration file.

• PSP1 unshaded maximum(psp1_max)
• NET mean(net_mean)
• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)
• Net Radiation, Minima(net_min)
• PIR1 unshaded minimum(pir1_min)
• Net Radiation(net)
• NET standard deviation(net_sd)
• Net Radiation, Standard Deviation(net_std)
• PSP1 unshaded mean(psp1_mean)
• PSP1 unshaded minimum(psp1_min)
• Net Radiation, Maxima(net_max)
• PSP1 unshaded standard deviation(psp1_sd)

NSA/GNDRAD/C1 - Data corrupted by brief spike

There is a unreasonable spike at this time. Simultaneous spikes on the NET, the PSP, and 
the PIR. Cause unknown, but most likely related to data logger.

• Net Radiation(net)
• PSP1 unshaded mean(psp1_mean)
• Net Radiation, Standard Deviation(net_std)
• Net Radiation, Maxima(net_max)
• PSP1 unshaded maximum(psp1_max)
• NET mean(net_mean)
• PSP1 unshaded standard deviation(psp1_sd)
• NET standard deviation(net_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded minimum(pir1_min)
• Net Radiation, Minima(net_min)
• PIR1 unshaded maximum(pir1_max)
• PSP1 unshaded minimum(psp1_min)

• PSP1 unshaded maximum(psp1_max)
• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded maximum(pir1_max)
• Net Radiation, Minima(net_min)
• PIR1 unshaded minimum(pir1_min)
• NET standard deviation(net_sd)
• Net Radiation, Maxima(net_max)
• NET mean(net_mean)
• PIR1 unshaded mean(pir1_mean)
• Net Radiation(net)
• Net Radiation, Standard Deviation(net_std)
• PSP1 unshaded mean(psp1_mean)
• PSP1 unshaded minimum(psp1_min)
• PSP1 unshaded standard deviation(psp1_sd)

NSA/GNDRAD/C1 - Rad instruments shaded by shelter

Each day around 02:00 - 03:30 GMT there is a unexpected decrease 
              for the PSP irradiance measurement due to a shading problem 
              associated with the swing set location relative to the instrument 
              shelter.  The GNDRAD NET and MFR instrument data also reflects 
              this problem.  Problem was resolved when the GNDRAD instruments 
              were moved to the 10 meter tip tower.

• Net Radiation(net)
• PSP1 unshaded mean(psp1_mean)
• Net Radiation, Standard Deviation(net_std)
• Net Radiation, Maxima(net_max)
• PSP1 unshaded maximum(psp1_max)
• NET mean(net_mean)
• PSP1 unshaded standard deviation(psp1_sd)
• NET standard deviation(net_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded minimum(pir1_min)
• Net Radiation, Minima(net_min)
• PIR1 unshaded maximum(pir1_max)
• PSP1 unshaded minimum(psp1_min)

• PSP1 unshaded maximum(psp1_max)
• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded maximum(pir1_max)
• Net Radiation, Minima(net_min)
• PIR1 unshaded minimum(pir1_min)
• NET standard deviation(net_sd)
• Net Radiation, Maxima(net_max)
• NET mean(net_mean)
• PIR1 unshaded mean(pir1_mean)
• Net Radiation(net)
• Net Radiation, Standard Deviation(net_std)
• PSP1 unshaded mean(psp1_mean)
• PSP1 unshaded minimum(psp1_min)
• PSP1 unshaded standard deviation(psp1_sd)

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.

• NIP maximum(nip_max)
• NIP standard deviation(nip_sd)
• NIP minimum(nip_min)
• NIP mean(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.

• PSP1 unshaded mean(psp1_mean)
• PSP1 unshaded minimum(psp1_min)
• PSP1 unshaded maximum(psp1_max)
• PSP1 unshaded standard deviation(psp1_sd)

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

NSA/SKYRAD - Barrow SKYRAD PIRD Misconfiguration 12/9 - 12/12/98

The PIRD was incorrectly set from 12/9/98 to 12/12/98 that resulted in an 
error of approximately 3.7% (was set to 243902 instead of 235294).

• east longitude for all the input platforms.(lon)
• Instantaneous UVB temperature(uvb_temp)
• Instantaneous UVB uncorrected irradiance(uvb_uncorr_irradiance)
• north latitude for all the input platforms.(lat)
• altitude above sea levelaltunits(alt)
• Instantaneous PIR2 uncorrected irradiance(pir2_uncorr_irradiance)
• Instantaneous PIR1 uncorrected irradiance(pir1_uncorr_irradiance)
• Instantaneous PIR2 case thermistor(pir2_case_therm)
• Instantaneous PIR1 dome thermistor(pir1_dome_therm)
• Instantaneous PIR2 dome thermistor(pir2_dome_therm)
• Time offset of tweaks from base_time(time_offset)
• Time offset from base_time(base_time)
• GPS raw data filename(filename)
• Instantaneous PIR1 case thermistor(pir1_case_therm)

• PSP shaded minimum(psps_min)
• PIR1 unshaded maximum(pir1_max)
• IRT1 minimum(irt1_min)
• PSP shaded standard deviation(psps_sd)
• NIP mean(nip_mean)
• PIR1 unshaded standard deviation(pir1_sd)
• NIP maximum(nip_max)
• Time offset of tweaks from base_time(time_offset)
• UVB minimum(uvb_min)
• PSP shaded maximum(psps_max)
• PIR shaded standard deviation(pirs_sd)
• PSP shaded mean(psps_mean)
• Bit data. See details.(bit_data)
• PIR shaded minimum(pirs_min)
• IRT1 mean(irt1_mean)
• Time offset from base_time(base_time)
• PSP1 unshaded mean(psp1_mean)
• altitude above sea levelaltunits(alt)
• PSP1 unshaded minimum(psp1_min)
• PIR1 unshaded minimum(pir1_min)
• NIP standard deviation(nip_sd)
• Internal Logger Temperature(logger_temp)
• PSP1 unshaded standard deviation(psp1_sd)
• IRT1 maximum(irt1_max)
• UVB mean(uvb_mean)
• PSP1 unshaded maximum(psp1_max)
• UVB maximum(uvb_max)
• PIR shaded maximum(pirs_max)
• PIR1 unshaded mean(pir1_mean)
• External voltage(external_voltage)
• IRT1 standard deviation(irt1_sd)
• Internal voltage(internal_voltage)
• GPS raw data filename(filename)
• NIP minimum(nip_min)
• north latitude for all the input platforms.(lat)
• PIR shaded mean(pirs_mean)
• east longitude for all the input platforms.(lon)
• UVB standard deviation(uvb_sd)

NSA/SKYRAD/C1 - IRT removed for repair

The instrument was damaged by internal water condensation caused by the 
exterior foam insulation used to keep the IRT above freezing. It was returned 
in July 1998 to the manufacturer for repair.

• IRT1 maximum(irt1_max)
• IRT1 standard deviation(irt1_sd)
• IRT1 minimum(irt1_min)
• IRT1 mean(irt1_mean)

• Raw data stream - documentation not supported(Raw data stream - documentation not supported)

NSA/SKYRAD/C1 - IRT insufficiently insulated

IRT was reinstalled with insufficient insulation to maintain an
internal reference temperature above 0 degrees C.

• IRT1 maximum(irt1_max)
• IRT1 standard deviation(irt1_sd)
• IRT1 minimum(irt1_min)
• IRT1 mean(irt1_mean)

• Raw data stream - documentation not supported(Raw data stream - documentation not supported)

NSA/SKYRAD/C1 - IRT insufficiently insulated

IRT was reinstalled with insufficient insulation to maintain an
internal reference temperature above 0 degrees C.

• IRT1 maximum(irt1_max)
• IRT1 standard deviation(irt1_sd)
• IRT1 minimum(irt1_min)
• IRT1 mean(irt1_mean)

• Raw data stream - documentation not supported(Raw data stream - documentation not supported)

NSA/SKYRAD/C1 - IRT removed from service

Instrument was removed to check performance.

• IRT1 maximum(irt1_max)
• IRT1 standard deviation(irt1_sd)
• IRT1 minimum(irt1_min)
• IRT1 mean(irt1_mean)

• Raw data stream - documentation not supported(Raw data stream - documentation not supported)

NSA/GNDRAD/C1 - 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.

• IRT1 standard deviation(irt1_sd)
• IRT1 mean(irt1_mean)
• IRT1 maximum(irt1_max)
• IRT1 minimum(irt1_min)

NSA/SKYRAD/C1 - 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.

• IRT1 maximum(irt1_max)
• IRT1 standard deviation(irt1_sd)
• IRT1 minimum(irt1_min)
• IRT1 mean(irt1_mean)