SGP/MWR/B1 - occasional negative brightness temperatures

Occasional spikes in the MWR data were observed. Inspection of
the data indicates that these are due to spikes in the gain that result from
either unrealistically low values of the blackbody target temperature (~150 K) or
unrealistically low values of the microwave signal counts when viewing the
blackbody target. Unrealistically low values of the mixer temperature have also been
observed.

• null(Raw data stream - documentation not supported)

• 23.8 GHz sky brightness temperature(23tbsky)
• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)
• 31.4 GHz sky brightness temperature(31tbsky)

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

• null(Raw data stream - documentation not supported)

• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz sky signal(tipsky31)
• Mixer kinetic (physical) temperature(tkxc)

SGP/MWR/B1 - Spikes in sky temperature data

There are negative spikes in the sky temperature data, per Victor Morris.

• 23.8 GHz sky brightness temperature(23tbsky)
• 31.4 GHz sky brightness temperature(31tbsky)

• Sky brightness temperature at 31.4 GHz(tbsky31)
• Sky brightness temperature at 23.8 GHz(tbsky23)

SGP/MWR/B1 - noisy data

The MWR exhibited occasional negative sky brightness temperatures that were resolved, 
after eliminating the instrument and communication lines as the source of the problem, by 
reformatting and reconfiguring the laptop computer.

• 23.8 GHz sky brightness temperature(23tbsky)
• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)
• 31.4 GHz sky brightness temperature(31tbsky)

• Mixer kinetic (physical) temperature(tkxc)

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

SGP/MWR/B1 - Intermittent Negative Sky Brightness Temperatures

Several related and recurring problems with the SGP 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 (especially at Purcell),
spikes in the data (especially at Vici), 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 (especially at the CF).

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

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

SGP/MWR/B1  - min/max/delta values incorrect

The values of valid_min, valid_max, and valid_delta for fields tkxc and tknd were 
incorrect. They should be 303, 333, and 0.5 K, respectively.

• (tknd)
• Mixer kinetic (physical) temperature(tkxc)

SGP/MWR/B1 - thermal instability

During periods of high ambient temperature, the instrument may have been thermally 
unstable.

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

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

SGP/MWR/B1 - Reprocess: 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).

Although the MWR data will be reprocessed to apply the new monortm-based retrievals, for 
most purposes it will be sufficient to correct the data using the following factors:

PWV_MONORTM = 0.9695 * PWV_ROSENKRANZ
LWP_MONORTM = 1.026  * LWP_ROSENKRANZ

The Rosenkranz-based retrieval coefficients became active at SGP.B1 20020412.1600.  The 
MONORTM-based retrieval coefficients became active at SGP.B1 20050624.2100.

Note: a reprocessing effort is already underway to apply the Rosenkranz-based retrieval 
coefficients to all MWR prior to April 2002.  An additional reprocessing task will be 
undertaken to apply the MONORTM retrieval to all MWR data when the first is completed.  Read 
reprocessing comments in the netcdf file header carefully to ensure you are aware which 
retrieval is in play.

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

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

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

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

• Ensemble average for MWR liquid in window centered about balloon release(mean_liq_mwr)
• Ensemble average for MWR vapor in window centered about balloon release(mean_vap_mwr)

SGP/MWR/B1 - thermal instability

During periods of high ambient temperature, the instrument may have been thermally 
unstable. The problem was corrected by increasing the RF deck temperature from 50 to 52 C.

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

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

SGP/MWR/B1 - Reprocess: mixer temp adjustment

The RF deck temperature was increased from 50 to 52 C to prevent thermal instability in 
summer.  This resulted in a change in the calibration.  The data need to be reprocessed 
with the calibration coefficients that were automatically derived after the reference 
temperature, tkmx, was adjusted.

• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)

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

SGP/MWR/B1 - New software version (4.15) installed

A problem began with the installation of MWR.EXE version 4.12 in July 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 at 21:25. As a consequence 
of this upgrade, the tip curve frequency increased. The tip cycle time decreased from 
~60s to ~50s.

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

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

SGP/MWR/B1 - missing data

The instrument software was accidentally left in "EXIT" mode after troubleshooting so it 
would not restart. The problem was corrected by returning the mode to "LOS".

• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Mixer kinetic (physical) temperature(tkxc)
• 31.4 GHz blackbody(bb31)
• 23.8 GHz sky signal(sky23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• MWR column precipitable water vapor(vap)
• 31.4 GHz sky signal(sky31)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Sky Infra-Red Temperature(sky_ir_temp)
• Actual Azimuth(actaz)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• (tknd)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz sky brightness temperature(31tbsky)
• 23.8 GHz Blackbody signal(bb23)
• 23.8 GHz sky brightness temperature(23tbsky)
• Actual elevation angle(actel)
• Dummy altitude for Zeb(alt)
• Ambient temperature(tkair)
• lat(lat)
• Averaged total liquid water along LOS path(liq)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• lon(lon)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• base time(base_time)
• Blackbody kinetic temperature(tkbb)
• IR Brightness Temperature(ir_temp)
• Time offset of tweaks from base_time(time_offset)

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

SGP/MWR/B1 - Reprocessed: Corrected calibration

The radiometer was thermally unstable. Calibration coefficients for the time interval were 
re-derived after screening for bad values of TKxc and the data were reprocessed.  
Reprocessed MWRLOS data were archived January 2007.  MWRTIP data will not be reprocessed.

• 23.8 GHz sky signal(tipsky23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Mixer kinetic (physical) temperature(tkxc)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• (tknd)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz sky signal(tipsky31)
• 31.4 GHz goodness-of-fit coefficient(r31)

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

• null(Raw data stream - documentation not supported)

SGP/MWR/B1 - Missing data

Data are missing in this time period.

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

• Blackbody kinetic temperature(tkbb)
• Actual elevation angle(actel)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 23.8 GHz Blackbody signal(bb23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz blackbody(bb31)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Mixer kinetic (physical) temperature(tkxc)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Actual Azimuth(actaz)
• 23.8 GHz sky signal(tipsky23)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• lat(lat)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• Time offset of tweaks from base_time(time_offset)
• (tknd)
• Ambient temperature(tkair)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• lon(lon)
• Dummy altitude for Zeb(alt)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz sky signal(tipsky31)
• base time(base_time)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 31.4 GHz blac2body+noise injection signal(bbn31)

SGP/MWR/B1 - Radiometer removed for IOP

On 9/20 the radiometer was removed and shipped to the SGP Central Facility for the 
MWR-intercomparison IOP. Datastream from this radiometer will be available as IOP data under the 
facility name S01.

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

• Blackbody kinetic temperature(tkbb)
• Actual elevation angle(actel)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 23.8 GHz Blackbody signal(bb23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz blackbody(bb31)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Mixer kinetic (physical) temperature(tkxc)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Actual Azimuth(actaz)
• 23.8 GHz sky signal(tipsky23)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• lat(lat)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• Time offset of tweaks from base_time(time_offset)
• (tknd)
• Ambient temperature(tkair)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• lon(lon)
• Dummy altitude for Zeb(alt)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz sky signal(tipsky31)
• base time(base_time)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 31.4 GHz blac2body+noise injection signal(bbn31)

• null(Raw data stream - documentation not supported)

SGP/MWR/B1 - Calibration failure

The radiometer suddenly stopped performing successful tip curve calibrations. Brightness 
temperatures are inaccurate during this time. The instrument was removed from service 
20071126.  Reprocessing is not possible.

• 23.8 GHz sky signal(tipsky23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz sky signal(tipsky31)
• 31.4 GHz goodness-of-fit coefficient(r31)

• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 23.8 GHz sky signal(sky23)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 31.4 GHz sky signal(sky31)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• MWR column precipitable water vapor(vap)

SGP/MWR/B1 - Radiometer out of service

Following a malfunction the radiometer was taken out of service for diagnosis and repairs

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

• MWR column precipitable water vapor(vap)
• Number of points included in the ir_temp ensemble(num_obs_irt)
• Number of contiguous periods in averaging interval with water on Teflon window(water_flag_periods)
• Standard deviation about the mean for the 23.8 GHz sky brightness temperature(tbsky23_sdev)
• Fraction of data in averaging interval flagged by Dynamic Linear Model as poten(dlm_flag_fraction)
• Standard deviation about the mean for the total water vapor amount(vap_sdev)
• Time offset of tweaks from base_time(time_offset)
• Number of contiguous periods in averaging interval flagged by Dynamic Linear Mo(dlm_flag_periods)
• Standard deviation about the mean for the IR brightness temperature(ir_temp_sdev)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• 31.4 GHz sky brightness temperature(31tbsky)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• lat(lat)
• lon(lon)
• Dummy altitude for Zeb(alt)
• base time(base_time)
• 23.8 GHz sky brightness temperature(23tbsky)
• Fraction of data in averaging interval with water on Teflon window(water_flag_fraction)
• Number of data points averaged for 23tbsky, 31tbsky, vap & liq(num_obs)
• IR Brightness Temperature(ir_temp)
• Averaged total liquid water along LOS path(liq)
• Number of data points averaged for ir_temp(num_obs_ir)
• Standard deviation about the mean for the total liquid water amount(liq_sdev)
• Standard deviation about the mean for the 31.4 GHz sky brightness temperature(tbsky31_sdev)

• Blackbody kinetic temperature(tkbb)
• Actual elevation angle(actel)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 23.8 GHz Blackbody signal(bb23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz blackbody(bb31)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Mixer kinetic (physical) temperature(tkxc)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Actual Azimuth(actaz)
• 23.8 GHz sky signal(tipsky23)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• lat(lat)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• Time offset of tweaks from base_time(time_offset)
• (tknd)
• Ambient temperature(tkair)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• lon(lon)
• Dummy altitude for Zeb(alt)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz sky signal(tipsky31)
• base time(base_time)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 31.4 GHz blac2body+noise injection signal(bbn31)

• null(Raw data stream - documentation not supported)

SGP/MWR/B1/B4/B5/B6 - data file split at 23:59

A problem with the MWR operating software has been corrected.  However, several files were 
generated that contain one record of data collected at midnight but labeled with the 
previous day's date.

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

• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• (tknd)
• Averaged total liquid water along LOS path(liq)
• Blackbody kinetic temperature(tkbb)
• Time offset of tweaks from base_time(time_offset)
• 31.4 GHz blackbody(bb31)
• 23.8 GHz sky signal(sky23)
• Ambient temperature(tkair)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Mixer kinetic (physical) temperature(tkxc)
• 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)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Temperature correction coefficient at 23.8 GHz(tc23)
• base time(base_time)
• IR Brightness Temperature(ir_temp)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 31.4 GHz sky signal(sky31)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 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)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 31.4 GHz sky signal(tipsky31)
• Blackbody kinetic temperature(tkbb)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Actual Azimuth(actaz)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Temperature correction coefficient at 31.4 GHz(tc31)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Time offset of tweaks from base_time(time_offset)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• (tknd)
• 23.8 GHz Blackbody signal(bb23)
• Mixer kinetic (physical) temperature(tkxc)
• Ambient temperature(tkair)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• base time(base_time)
• 23.8 GHz goodness-of-fit coefficient(r23)
• 23.8 GHz sky signal(tipsky23)
• Actual elevation angle(actel)
• 31.4 GHz blackbody(bb31)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)

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

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

• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz sky signal(tipsky31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Time offset of tweaks from base_time(time_offset)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Actual elevation angle(actel)
• 31.4 GHz blackbody(bb31)
• base time(base_time)
• Mixer kinetic (physical) temperature(tkxc)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• (tknd)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Actual Azimuth(actaz)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 23.8 GHz Blackbody signal(bb23)
• Ambient temperature(tkair)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)

• 23.8 GHz Blackbody signal(bb23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Ambient temperature(tkair)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz blackbody(bb31)
• Time offset of tweaks from base_time(time_offset)
• Actual Azimuth(actaz)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 31.4 GHz sky signal(tipsky31)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Mixer kinetic (physical) temperature(tkxc)
• Actual elevation angle(actel)
• Blackbody kinetic temperature(tkbb)
• 23.8 GHz sky signal(tipsky23)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• base time(base_time)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• (tknd)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• 31.4 GHz blac2body+noise injection signal(bbn31)

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

• Actual elevation angle(actel)
• 31.4 GHz blackbody(bb31)
• Actual Azimuth(actaz)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Blackbody kinetic temperature(tkbb)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 23.8 GHz Blackbody signal(bb23)
• Mixer kinetic (physical) temperature(tkxc)
• 23.8 GHz sky signal(tipsky23)
• Time offset of tweaks from base_time(time_offset)
• (tknd)
• 31.4 GHz sky signal(tipsky31)
• 31.4 GHz goodness-of-fit coefficient(r31)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Ambient temperature(tkair)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• base time(base_time)

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

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

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