HFE/MWR/M1 - Insufficient calibration stability

The noise diode temperature suddenly jumped to > 60 C after a power outage. Following 
additional power problems the noise diode injection temperature drifted fast and the 
radiometer was not able to calibrate properly.

Data during the indicated time periods are poorly calibrated and sometimes erratic. Users 
should be aware that the accuracy of the measurements is dramatically degraded. 

Users can use the microwave profiler (MWRP) data to supplement the MWR data.

• Sky brightness temperature at 31.4 GHz(tbsky31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• MWR column precipitable water vapor(vap)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Averaged total liquid water along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• (tknd)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)

• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• 23.8 GHz sky brightness temperature derived from tip curve(tbsky23tip)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Mixer kinetic (physical) temperature(tkxc)
• Temperature correction coefficient at 31.4 GHz(tc31)
• 31.4 GHz sky brightness temperature derived from tip curve(tbsky31tip)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• (tknd)

HFE/MWRHF/M1 - 150-GHz data drop out

The sky brightness temperature at 150 GHz (tbsky150) dropped to zero at 12:29 GMT on 
20080804 and stayed flat lined until 23:40 GMT on 20081002.

• Sky brightness temperature (150 GHz)(tbsky150)

HFE/MWRHF/M1 - Frosting/Condensation

The heater module was installed on 6/4/2008. Before this time there is condensation on the 
window during night time and early morning. On 8/18 the heater appears to have failed 
and nighttime condensation re-occurred on the radome during conditions of high humidity.

Users can identify the segments affected by observing a smooth steady increase in the 
brightness temperature (BT). BT values can increase to more than 250 K and then smoothly 
decrease. The RH during these events is usually above 70%. Users should disregard data 
affected by condensation.

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

HFE/MWRHF/M1 - Calibration updates

The MWRHF calibration algorithm updates the calibration parameters every time a new 
successful tip curve is acquired. 

This results in small jumps (1-2 K) in the brightness temperatures each time calibration 
is updated. During times of frequent calibrations the data appear discontinuous with short 
data segments interrupted by small jumps.

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

HFE/MWRHF/M1 - Rain sensor failure

The rain sensor failed and the rain flag was always on.  When the rain flag is on the 
radiometer does not perform tip curves. The rain sensor was replaced 8/4.

• Rain flag(rain_flag)

HFE/MWRHF/M1 - Elevated noise in 150 GHz data

The noise level of the 150 GHz channel was about 4 times higher than expected, likely due 
to failure of the noise diode.  Disregard the 150 GHz data.

• Sky brightness temperature (150 GHz)(tbsky150)

HFE/MWR/M1 - Missing data

Data are missing and unrecoverable.

• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz blackbody(bb31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Time offset of tweaks from base_time(time_offset)
• Averaged total liquid water along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• (tknd)
• time(time)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• lon(lon)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• MWR column precipitable water vapor(vap)
• lat(lat)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Blackbody kinetic temperature(tkbb)
• 31.4 GHz sky signal(sky31)
• Sky Infra-Red Temperature(sky_ir_temp)
• Ambient temperature(tkair)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 23.8 GHz Blackbody signal(bb23)
• Dummy altitude for Zeb(alt)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 23.8 GHz sky signal(sky23)
• base time(base_time)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)

• 31.4 GHz goodness-of-fit coefficient(r31)
• 31.4 GHz sky signal(tipsky31)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Mixer kinetic (physical) temperature(tkxc)
• 31.4 GHz sky brightness temperature derived from tip curve(tbsky31tip)
• Ambient temperature(tkair)
• Time offset of tweaks from base_time(time_offset)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Actual Azimuth(actaz)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• time(time)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• 23.8 GHz sky brightness temperature derived from tip curve(tbsky23tip)
• base time(base_time)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• lon(lon)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• 31.4 GHz blackbody(bb31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Dummy altitude for Zeb(alt)
• (tknd)
• Actual elevation angle(actel)
• 23.8 GHz Blackbody signal(bb23)
• lat(lat)
• 23.8 GHz sky signal(tipsky23)