TWP/MWR/C1 - Rain on window

The data is subject to contamination due to rain on the sensor window
and should be used with caution because the heater/blower assembly that
prevents water from accumulating on the sensor's teflon window was out
of commission.

• 23.8 GHz goodness-of-fit coefficient(r23)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 31.4 GHz blackbody(bb31)
• 31.4 GHz sky signal(tipsky31)
• 23.8 GHz Blackbody signal(bb23)
• 23.8 GHz sky signal(tipsky23)
• Tip configuration number(tipn)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• IR Brightness Temperature(ir_temp)

• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• IR Brightness Temperature(ir_temp)
• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 23.8 GHz(tbsky23)

TWP/MWR/C1 - Intermittent Negative Sky Brightness Temperatures

Several related and recurring problems with the MWRs have been reported dating back to 
1999.  These problems were due to the occurrence of blackbody signals (in counts) that were 
half of those expected. The symptoms included noisy data, spikes in the data, negative 
brightness temperatures, and apparent loss of serial communication between the computer and 
the radiometer, which results in a self-termination of the MWR program.

Because these all initially appeared to be hardware-related problems, the instrument 
mentor and SGP site operations personnel (1) repeatedly cleaned and replaced the fiber optic 
comm. components, (2) swapped radiometers, (3) sent radiometers back to Radiometrics for 
evaluation (which did not revealed any instrument problems), and (4) reconfigured the 
computer's operating system.  Despite several attempts to isolate and correct it, the problem 
persisted.

It became apparent that some component of the Windows98 configuration conflicted with the 
DOS-based MWR program or affected the serial port or the contents of the serial port 
buffer. This problem was finally corrected by upgrading the MWR software with a new 
Windows-compatible program.

• Sky brightness temperature at 31.4 GHz(tbsky31)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• MWR column precipitable water vapor(vap)

TWP/MWR/C1 - wrong azimuth

The MWR was initially installed at an azimuth angle defined as 180 degrees but the value 
in the configuration file was not changed from the default of 0 degrees. In examining 
photos taken during the installation of the AWS tower, I noticed that the MWR was rotated 
opposite the normal orientation. The value in the configuration file was changed to reflect 
the actual azimuth of the instrument.

• Actual Azimuth(actaz)

TWP/MWR/C1 - Reprocessed: Revised Retrieval Coefficients

IN THE BEGINNING (June 1992), the retrieval coefficients used to derive 
the precipitable water vapor (PWV) and liquid water path (LWP) from the 
MWR brightness temperatures were based on the Liebe and Layton (1987) 
water vapor and oxygen absorption model and the Grant (1957) liquid 
water absorption model.

Following the SHEBA experience, revised retrievals based on the more 
recent Rosenkranz (1998) water vapor and oxygen absorption models and 
the Liebe (1991) liquid waer absorption model were developed.  The 
Rosenkranz water vapor absorption model resulted a 2 percent increase 
in PWV relative to the earlier Liebe and Layton model.  The Liebe 
liquid water absorption model decreased the LWP by 10% relative to the 
Grant model.  However, the increased oxygen absorption caused a 
0.02-0.03 mm (20-30 g/m2) reduction in LWP, which was particularly 
significant for low LWP conditions (i.e. thin clouds encountered at 
SHEBA).

Recently, it has been shown (Liljegren, Boukabara, Cady-Pereira, and 
Clough, TGARS v. 43, pp 1102-1108, 2005) that the half-width of the 
22 GHz water vapor line from the HITRAN compilation, which is 5 percent 
smaller than the Liebe and Dillon (1969) half-width used in Rosenkranz 
(1998), provided a better fit to the microwave brightness temperature 
measurements at 5 frequencies in the range 22-30 GHz, and yielded more 
accurate retrievals. Accordingly, revised MWR retrieval coefficients 
have been developed using MONORTM, which utilizes the HITRAN compilation 
for its spectroscopic parameters.  These new retrievals provide 3 
percent less PWV and 2.6 percent greater LWP than the previous 
retrievals based on Rosenkranz (1998).

The Rosenkranz-based retrieval coefficients became active at TWP.C1 
20020504.0200.  The MONORTM-based retrieval coefficients became active 
at TWP.C1 20050630.2100.

Note: The TWP.C1 data for 19961011-20050630 have been reprocessed to apply the

• Averaged total liquid water along LOS path(liq)
• MWR column precipitable water vapor(vap)

• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)

• Averaged total liquid water along LOS path(liq)
• MWR column precipitable water vapor(vap)

TWP/MWR/C1 - New software version (4.15) installed

A problem began with the installation of MWR.EXE version 4.12 in October 2002. The 
software had been upgraded from a "DOS" to a "Windows"-compiled program to address an earlier 
problem.  The software upgrade corrected the earlier problem but introduced a new one that 
caused line-of-sight observing cycles to be skipped, a 15% reduction in the number of tip 
curves, and saturation of CPU usage.  Software versions 4.13 and 4.14 also produced 
these problems.

The new MWR software version (4.15) was installed on 9/13/2005. As a consequence of this 
upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s.

• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 31.4 GHz sky signal(tipsky31)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• IR Brightness Temperature(ir_temp)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• (tknd)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Blackbody temperature 1(tkbb1)
• Blackbody temperature 2(tkbb2)
• 31.4 GHz goodness-of-fit coefficient(r31)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• 31.4 GHz blackbody(bb31)
• Mixer kinetic (physical) temperature(tkxc)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Tip configuration number(tipn)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Ambient temperature(tkair)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 23.8 GHz Blackbody signal(bb23)
• 23.8 GHz sky signal(tipsky23)

• Ambient temperature(tkair)
• Sky Infra-Red Temperature(sky_ir_temp)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• IR Brightness Temperature(ir_temp)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Averaged total liquid water along LOS path(liq)
• Temperature correction coefficient at 31.4 GHz(tc31)
• (tknd)
• 31.4 GHz blackbody(bb31)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 23.8 GHz sky signal(sky23)
• Mixer kinetic (physical) temperature(tkxc)
• 31.4 GHz sky signal(sky31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Blackbody kinetic temperature(tkbb)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 23.8 GHz Blackbody signal(bb23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• MWR column precipitable water vapor(vap)

TWP/MWR/C1 - Software Change

The MWR operating software was changed on 27 February 1999 to provide additional
functionality as described below.
   
NEW FEATURES
1. Faster sampling rate
   
Standard line-of-sight (LOS) observations can now be acquired at 15-second intervals vs. 
20-second intervals previously. (The standard LOS cycle is comprised of one sky sample per 
blackbody sample and gain update.)
   
2. More flexible sampling strategy
   
Multiple sky observations can be acquired during a LOS cycle, up to 1024 per gain update. 
This permits sky samples to be acquired at intervals of 2.67 seconds for improved 
temporal resolution of cloud liquid water variations and better coordination with the millimeter 
cloud radar during IOPs.
   
3. Separation of zenith LOS observations from TIP data
   
When the radiometer is in TIP mode, the zenith LOS observations are now extracted, the PWV 
and LWP computed and reported separately in the output file. This eliminates the periods 
of missing LOS data during calibration checks/updates.
   
4. Automatic self-calibration
   
The software now permits the calibration to be updated at specified intervals or 
continuously. In the first case, LOS mode is automatically changed to TIP mode at user-specified 
intervals or whenever clear sky conditions occur, the tip data reduced, the calibration 
updated, and the radiometer returned to LOS mode without operator intervention. In the 
second case, the radiometer is continuously is TIP mode until changed by the operator.
   
5. Graphical user display
   
The graphical display is comprised of a status display, a message display, a temperature 
plot, a plot of the retrieved PWV and LWP, and (in TIP mode) a plot of the latest tip 
curves.

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

TWP/MWR/C1 - software upgrade (version 3.29)

The MWR operating program was upgraded to version 3.29 on 15 March 1999. This version 
included a beam width correction as well as provided the capability to automatically level 
the elevation mirror (that is, to automatically detect and correct offsets in the elevation 
angle stepper motor position.)
   
The improvement in the quality of the tip curves resulting from the auto-leveling has been 
dramatic: differences in the brightness temperatures at 3 airmasses (19.5 and 160.5 
degrees) have been reduced from +/- 5 K to +/- 0.5 K. In order to take full advantage of this 
improvement to detect and reject cloudy tip curves, the minimum value of the 
goodness-of-fit coefficient for a valid tip curve has been increased from 0.995 to 0.998.

• Sky brightness temperature at 31.4 GHz(tbsky31)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• MWR column precipitable water vapor(vap)

TWP/MWR/C1 - Radiometer failure

The instrument stopped responding and had to be powered off. Suspect cause of failure is a 
faulty digital board.

• null(Raw data stream - documentation not supported)

• 31.4 GHz blackbody(31bb)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Dummy altitude for Zeb(alt)
• 31.4 GHz noise diode calib adjusted to tknd_nom and low_pass filltered(31expave)
• 31.4 GHz sky signal(tipsky31)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• 23.8 GHz noise diode calib adjusted to tknd_nom and low_pass filltered(23expave)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 23.8 GHz noise diode calib (injection temp) at Tkxc(23ndiode)
• IR Brightness Temperature(ir_temp)
• 31.4 GHz sky signal(31tipsky)
• base time(base_time)
• 23.8 GHz sky signal+noise injection signal(23tipskynd)
• Airmass value(airm)
• Actual elevation angle(actel)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz calibration curve slope(31gain)
• Actual Azimuth(actaz)
• 23.8 GHz goodness-of-fit coefficient(r23)
• 31.4 GHz blackbody signal(31tipbb)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 23.8 GHz calibration curve offset(23tbzenith)
• 23.8 GHz blackbody+noise injection signal(23bbn)
• 31.4 GHz blackbody+noise injection signal(31bbn)
• 31.4 GHz sky signal+noise injection signal(31tipskynd)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• 31.4 GHz goodness-of-fit coefficient(31r)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 23.8 GHz blackbody signal(23tipbb)
• (tknd)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 23.8 GHz Blackbody signal(23bb)
• Blackbody temperature 1(tkbb1)
• Blackbody temperature 2(tkbb2)
• 23.8 GHz sky signal(23tipsky)
• 23.8 GHz calibration curve slope(23gain)
• 31.4 GHz goodness-of-fit coefficient(r31)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• 31.4 GHz blackbody(bb31)
• Mixer kinetic (physical) temperature(tkxc)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Blackbody kinetic temperature(tkbb)
• Tip configuration number(tipn)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• lon(lon)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Time offset of tweaks from base_time(time_offset)
• Ambient temperature(tkair)
• 31.4 GHz noise diode calib (injection temp) at Tkxc(31ndiode)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• lat(lat)
• 23.8 GHz Blackbody signal(bb23)
• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz calibration curve offset(31tbzenith)
• 23.8 GHz goodness-of-fit coefficient(23r)

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

TWP/MWR/C1 - Missing data

Data are missing and unrecoverable.

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

TWP/MWR/C1/C2 - Sun in the field of view

Every day between around noon local time (usually between 1 and 2 AM UTC time) there is an 
increase in the brightness temperatures due to the sun in the field of view of the 
radiometer.

• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz sky signal(tipsky31)

• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)

• Averaged total liquid water along LOS path(liq)
• 23.8 GHz sky signal(sky23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• 31.4 GHz sky signal(sky31)
• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 23.8 GHz(tbsky23)

• Sky brightness temperature at 31.4 GHz(tbsky31)
• 31.4 GHz sky signal(sky31)
• 23.8 GHz sky signal(sky23)
• Averaged total liquid water along LOS path(liq)
• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 23.8 GHz(tbsky23)

TWP/MWR/C1 - Intermittent data

After a computer change the MWR program did not restart properly.  Data are intermittent 
between 6/12 and 6/17.

• 31.4 GHz blackbody(31bb)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Dummy altitude for Zeb(alt)
• 31.4 GHz noise diode calib adjusted to tknd_nom and low_pass filltered(31expave)
• 31.4 GHz sky signal(tipsky31)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• 23.8 GHz noise diode calib adjusted to tknd_nom and low_pass filltered(23expave)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 23.8 GHz noise diode calib (injection temp) at Tkxc(23ndiode)
• IR Brightness Temperature(ir_temp)
• 31.4 GHz sky signal(31tipsky)
• base time(base_time)
• 23.8 GHz sky signal+noise injection signal(23tipskynd)
• Airmass value(airm)
• Actual elevation angle(actel)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz calibration curve slope(31gain)
• Actual Azimuth(actaz)
• 23.8 GHz goodness-of-fit coefficient(r23)
• 31.4 GHz blackbody signal(31tipbb)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 23.8 GHz calibration curve offset(23tbzenith)
• 23.8 GHz blackbody+noise injection signal(23bbn)
• 31.4 GHz blackbody+noise injection signal(31bbn)
• 31.4 GHz sky signal+noise injection signal(31tipskynd)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• 31.4 GHz goodness-of-fit coefficient(31r)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 23.8 GHz blackbody signal(23tipbb)
• (tknd)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 23.8 GHz Blackbody signal(23bb)
• Blackbody temperature 1(tkbb1)
• Blackbody temperature 2(tkbb2)
• 23.8 GHz sky signal(23tipsky)
• 23.8 GHz calibration curve slope(23gain)
• 31.4 GHz goodness-of-fit coefficient(r31)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• 31.4 GHz blackbody(bb31)
• Mixer kinetic (physical) temperature(tkxc)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Blackbody kinetic temperature(tkbb)
• Tip configuration number(tipn)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• lon(lon)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Time offset of tweaks from base_time(time_offset)
• Ambient temperature(tkair)
• 31.4 GHz noise diode calib (injection temp) at Tkxc(31ndiode)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• lat(lat)
• 23.8 GHz Blackbody signal(bb23)
• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz calibration curve offset(31tbzenith)
• 23.8 GHz goodness-of-fit coefficient(23r)

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

TWP/MWR/C1 - Incorrect ambient temperature readings

Starting on 11/21 the ambient temperature readings are intermittent and have spikes.
Site operators replaced the dew-blower on 12/11 and readings came back to normal

• Ambient temperature(tkair)

• Ambient temperature(tkair)

TWP/MWR/C1 - Short periods of wrong ambient temperature

During this month there are a few intermittent instances of bad ambient temperature 
readings. I will summarize here these short time ranges:
20080909 between 02:00 and 03:00 UTC
20080909 between 09:00 and 14:00 UTC

Additionally the ambient temperature has short but frequent data gaps.  The data gaps are 
very short (less than one hour). Users could interpolate missing data or use alternative 
sensors such as the surface meteorological data available for the site.

• Ambient temperature(tkair)

• Ambient temperature(tkair)

TWP/MWR/C1 - Ambient temperature data missing

The ambient temperature readings (tkair) suddenly failed. The sensor was replaced on Feb 
6.

• Ambient temperature(tkair)

• Ambient temperature(tkair)