SGP/IRT/E13 - Missing data

Data are missing and unrecoverable.

• time
• time_offset
• Sky infrared temperature(sky_ir_temp)
• ref_ir_temp
• Altitude above mean sea level(alt)
• ref_ir_temp_std
• sky_ir_temp_max
• samples_in_average
• base_time
• East longitude(lon)
• sky_ir_temp_std
• North latitude(lat)
• sky_ir_temp_min

SGP/IRT/E13 - Reprocess: Sky temperature bias

Measurements of sky temperature, especially those <250K,, were positively biased compared 
with AERI because there was no compensation for the effect of the emissivity and 
temperature of the gold mirror. The problem was corrected by changing the IRT emissivity from 
1.000 to 0.987, adding an RTD and transmitter electronics to measure the temperature of the 
mirror, and changing the ambient temperature measurement for internal reference to 
external mirror temperature.

Use sky temperature measurements less than 230K with caution. Biases as large as 30K have 
been observed when the actual temperature, as measured by AERI, is less than 210 K.

• Sky infrared temperature(sky_ir_temp)
• sky_ir_temp_max
• sky_ir_temp_min

SGP/IRT/E13 - Reprocess: Sensor Calibration

The measurements are greater than AERI, especially when sky temperature is less than -40C. 
The lens and mirror was cleaned on 11/21/2008 and the mirror was replaced on 1/28/2009 
but these actions did not correct the problem. It was learned that the internal 
calibration factor was not changed by the manufacturer after the unit was repaired and recalibrated 
on 9/6/2007. The calibration factor was corrected from 1.2172 to 1.4100 on 2/12/2009.

• Sky infrared temperature(sky_ir_temp)
• sky_ir_temp_max
• sky_ir_temp_std
• sky_ir_temp_min

SGP/IRT/E13 - Reprocessing Notice (RID 545)

See below for details of reprocessing that was completed on 20150113.  Original 
DQR category: 4 (Red, Incorrect).

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While diagnosing serial communication problems, the IRT configuration was reset to factory 
defaults so the temperature unit parameter was set to C instead of K.

• Sky infrared temperature(sky_ir_temp)
• ref_ir_temp
• sky_ir_temp_max
• sky_ir_temp_min

SGP/IRT/E13 - Response time

The time response of the temperature measurement was changed from 1.0 to 0.1 sec to 
accommodate the 5Hz sample rate. This caused a 370% decrease in the resolution (to 1.85C at a 
sky temperature of -50C) and a significant decrease in the signal-to-noise ratio.

• ref_ir_temp_std
• sky_ir_temp_std

SGP/IRT/E13 - Instrument output invalid

The signal was missing for 25 min and then changed to a constant values of 
sky_ir_temp=262.22K and ref_ir_temp=313.10K. The problem was corrected when the intrument was 
power-cycled.

• Sky infrared temperature(sky_ir_temp)
• ref_ir_temp
• ref_ir_temp_std
• sky_ir_temp_max
• sky_ir_temp_std
• sky_ir_temp_min

SGP/IRT/E13 - Bird intrusion

A bird entered and nested inside the enclosure. The measurement of sky temperature was 
interrupted everytime the bird was in the field-of-view. The nest was removed on 5/10 and 
5/24 in attempts to discourage the bird  but it persisted on rebuilding the nest until 6/6 
when the nest was replaced with bird deterrent spikes.

• Sky infrared temperature(sky_ir_temp)
• sky_ir_temp_max
• sky_ir_temp_std
• sky_ir_temp_min

SGP/IRT/E13 - Mirror contamination

The sky temperature was abnormally high compared to all other sites and the AERI. The gold 
mirror was found to be worn (mostly by birds nesting inside the enclosure) and was 
replaced.

• Sky infrared temperature(sky_ir_temp)
• sky_ir_temp_max
• sky_ir_temp_std
• sky_ir_temp_min

SGP/IRT/E13 - Sky temperature too warm

The sky temperature exhibited a "stepped feature" and was ~10K larger than that measured 
by AERI and MWR3C, increasing to ~50K on 10/26. The IRT was replaced.

• Sky infrared temperature(sky_ir_temp)
• sky_ir_temp_max
• sky_ir_temp_std
• sky_ir_temp_min

SGP ALL INSTRUMENTS - Icing Event

An icing event (winter storm Cara) passed slowly through the area during this time frame.  
Instruments at the SGP may have been affected by ice accumulation.

• Sky infrared temperature(sky_ir_temp)
• ref_ir_temp
• sky_ir_temp_max
• samples_in_average
• sky_ir_temp_std
• sky_ir_temp_min

SGP Site Power Outage Due to Winter Storm

On Saturday and Sunday, December 26 and 27th a powerful winter storm (Goliath) brought 
sleet and freezing rain to much of Oklahoma with wind gusts of 45 MPH at times. The result 
was very very slick roads and mass power outages.
 
The SGP central facility lost power at 8:55 PM CDT on Sunday, December 27th.  
The power was restored on 7:56 PM CDT on Wednesday, December 30th
 
Site Emergency procedures were activated and Technicians drained water out of instrument 
reservoirs and other measures as needed, early Monday morning.
 
On Wednesdays as roads and power started was restored to much of the areas east of I-35 , 
Site Technicians performed maintenance on several Extended Facilities.

During this period, data are potentially missing, incorrect, or suspect.  Carefully 
inspect the data before use.

• time_offset
• time
• Sky infrared temperature(sky_ir_temp)
• ref_ir_temp
• Altitude above mean sea level(alt)
• sky_ir_temp_max
• samples_in_average
• East longitude(lon)
• base_time
• sky_ir_temp_std
• North latitude(lat)
• sky_ir_temp_min

SGP/IRT/E13 - Data system Upgrades: Data Missing

The site data system was upgraded.  Data were not collected during this period.

• qc_ref_ir_temp
• Sky infrared temperature(sky_ir_temp)
• Altitude above mean sea level(alt)
• sky_ir_temp_max
• samples_in_average
• base_time
• East longitude(lon)
• sky_ir_temp_std
• North latitude(lat)
• qc_sky_ir_temp
• qc_sky_ir_temp_min
• qc_sky_ir_temp_max
• sky_ir_temp_min
• time_offset
• time
• ref_ir_temp