SGP/MWRHF/C1 - 90-GHz questionable calibration

Between 20061103 and 20070301 one of the parameters thresholds used to select good tip 
curves used in the calibratio process was not optimal. This resulted in data that have a 
high standard deviation and a unsatisfactory agreement with model computations.
After collecting enough points needed to conduct a model comparison the threshold was 
changed on March 1.
From a limited data analysis for the month pf March it appears that the change in 
threshold has improved the agreement between measurements and the model.

• Sky brightness temperature (90 GHz)(tbsky90)

SGP/MWRHF/C1 - 150-Ghz channel not working

Starting on 2/23 the 150-Ghz channel is showing a temperature of 310 K. The suspected 
cause of the problem is a hardware failure. The instrument was removed and sent for repair on 
4/2

• Sky brightness temperature (150 GHz)(tbsky150)

SGP/MWRHF/C1 - Instrument removed

Due to a hardware failure the instrument was removed and sent for repairs

• Raw data stream - documentation not supported

• Rain flag(rain_flag)
• Sky brightness temperature (90 GHz)(tbsky90)
• Barometric pressure(pressure)
• Sky brightness temperature (150 GHz)(tbsky150)
• base_time
• Humidity, relative(rh)
• time_offset
• alt
• lat
• time
• lon
• elevation
• Temperature, air(temp)

SGP/MWRHF/C1 - Dew formation on window

During night time, when the humidity is very high (RH ~ 100%) data are strongly affected 
by
dew formation on the window. 
This results in a smooth and large (80-150 K) increase of the brightness temperature from
early night to sunrise. Data are affected mostly at night.

• Sky brightness temperature (90 GHz)(tbsky90)
• Sky brightness temperature (150 GHz)(tbsky150)

SGP/MWRHF/C1 - Reprocessed: Rapid drift in 90 GHz noise diode

The noise diode of the 90 GHz channel was showing rapid drifts that affected the accuracy 
of the calibration. Although the algorithm is designed to follow slow drifts in the noise 
diode, in this case (because the variation was fast) the computed brightness temperature 
was probably about 4-5 K colder than it should be.

Ingest was modified and data were reprocessed and archived in September 2011

• Sky brightness temperature (90 GHz)(tbsky90)

SGP/MWRHF/C1 - Dew formation on window

During the indicated time there was moisture or dew on the radiometer window and the 
brightness temperatures are too high. The presence of dew can be recognized by a smooth 
increase in the brightness temperature followed by a smooth decrease over several hours.

• Sky brightness temperature (90 GHz)(tbsky90)
• Sky brightness temperature (150 GHz)(tbsky150)