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_sd
• pir1_max
• pir1_min
• pir1_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

• pirs_min
• pirs_mean
• pirs_max
• pirs_sd

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.

• 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_min
• pir1_sd
• pir1_max
• pir1_min
• pirs_mean
• pirs_max
• pirs_sd
• pir1_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_sd
• pir1_max
• pir1_min
• 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%.

• pirs_min
• pirs_mean
• pirs_max
• pirs_sd

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.

• pirs_min
• pir1_sd
• pir1_max
• pir1_min
• pirs_mean
• pirs_max
• pirs_sd
• pir1_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_sd
• pir1_max
• pir1_min
• 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_sd
• pir1_max
• pir1_min
• pir1_mean

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_max
• pir1_sd
• pir1_min
• pir1_mean

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_max
• pir1_sd
• pir1_min
• pir1_mean

NSA/GNDRAD/C1 - Instrument maintenance

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

• pir1_max
• pir1_sd
• 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.

• 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.

• psp1_sd
• psp1_mean
• psp1_min
• psp1_max

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

NSA/GNDRAD/C1 - IRT not connected

The IRT was unplugged from the Zeno data logger on 12/10/1998 for a interference test and 
when it was plugged back in on 12/22, the connector at the data logger was damaged. The 
data logger and connecter were replaced on 1/20/1999.

• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• sfc_ir_temp_std
• Effective Surface (Skin) Temperature(sfc_ir_temp)
• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)

NSA/GNDRAD/C1 - IRT incorrect

The IRT data were very noisy and unrepresentative.

• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• sfc_ir_temp_std
• Effective Surface (Skin) Temperature(sfc_ir_temp)
• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)

NSA/GNDRAD/C1 - IRT scale factor

The IRT scale factors in the data logger were incorrectly set to m = 100 degC/V, b = -60 
degC. They were corrected to 25 degC/V and -50 degC.

• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• sfc_ir_temp_std
• Effective Surface (Skin) Temperature(sfc_ir_temp)
• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)

NSA/SKYRAD/C1 - IRT signal bias

Additional heat tape that was installed around the IRT appears to have produced a negative 
bias of about 10 deg (at a sky temperature of -30C). This was corrected when the heat 
tape was replaced with thermostatically-controlled 75W heaters (that were still 
insufficient in maintaining the IRT above freezing - D990924.2).

• irt1_mean
• irt1_min
• irt1_max

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).

• alt
• irt1_sd
• nip_mean
• time_offset
• pirs_min
• irt1_mean
• pirs_max
• psp1_mean
• uvb_min
• pir1_max
• pir1_min
• irt1_min
• base_time
• nip_min
• lat
• psp1_min
• psp1_max
• irt1_max
• pirs_mean
• external_voltage
• psps_sd
• nip_max
• uvb_mean
• nip_sd
• psp1_sd
• filename
• uvb_max
• bit_data
• psps_max
• lon
• uvb_sd
• pir1_sd
• pirs_sd
• internal_voltage
• pir1_mean
• logger_temp
• psps_mean
• psps_min

• pir2_dome_therm
• time_offset
• pir2_uncorr_irradiance
• base_time
• uvb_temp
• uvb_uncorr_irradiance
• lat
• pir2_case_therm
• pir1_uncorr_irradiance
• pir1_case_therm
• alt
• pir1_dome_therm
• lon
• filename

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.

• Raw data stream - documentation not supported

• irt1_mean
• irt1_min
• irt1_sd
• irt1_max

NSA/SKYRAD/C1 - IRT removed from service

Instrument was removed to check performance.

• Raw data stream - documentation not supported

• irt1_mean
• irt1_min
• irt1_sd
• irt1_max

NSA/GNDRAD/C1 - Reprocess: IRT insufficiently heated

IRT had insufficient heating to maintain an internal reference temperature above 0 degrees 
C.  Measurements of surface 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_up_long_hemisp_dome_temp or inst_up_long_dome_temp)

• irt1_max
• irt1_min
• irt1_sd
• irt1_mean

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)

• irt1_mean
• irt1_min
• irt1_sd
• irt1_max