NSA/MWR/C1 - Temperature Stabilization of Noise Diode Impaired

On 1/17 we had a big spike in the data and lost temperature stabilization. The instrument 
had problems maintaining the Noise Diode (ND) temperature since. At ambient temperatures 
under about -20 C the ND was not maintaining the set temperature of 30 C. This problem 
was reported in P010122.1.

Fred Solheim recommended on 1/22 that we powercycle the instrument as it looked like the 
instrument CPU had lost the temperature reference.

So we powercycled the instrument on 1/22 @ 20:30 and lost all comumnication to it; after a 
second powercycling the instrument came back on line and the temperature stabilized 
quickly (within a couple of minutes) to the set temperature (30 C)

Fred Solheim reported after the system was restored:
"I've never seen this behavior before. I don't think it was due to the RF deck physically 
hanging temperature, because the recorded temp dropped about 30 C in one observation 
cycle. If this happens again, send the MWR down along with data files for us to look at."

Data collected in the periode 1/17/2001 6:00 to 1/22/2001 21:45 are questionable since it 
is uncertain whether the temperature really was unstable and what really caused the 
problem.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)
• Temperature, brightness, longwave(ir_temp)
• wet_window

NSA/MWR/C1 - negative sky brightness temperatures

The data exhibit occasional negative sky brightness temperatures.
The problem was corrected when the site operator cleaned the cable connectors and coated 
the terminals with dielectric grease.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)

NSA/MWR/C1 - negative sky brightness temperatures

The data exhibit occasional negative sky brightness temperatures.
The problem was corrected when the computer was reconfigured following a virus infection.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)

NSA/MWR/C1 - Reprocess: calibration change

The thicker (1/2-inch) insulation was installed on the RF deck and the reference 
temperature was reduced from 50 C to 30 C to prevent thermal instability in winter. A change in 
the mixer temperature affects the instrument's calibration. A new calibration was 
automatically derived and applied after 1500 valid tip curves were acquired. During the period 
after the temperature was reset and before the calibration was updated, the previous 
calibration was used.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)

NSA/MWR/C1 - incorrect flagging of data

The wet window flag is set high more than expected.

• wet_window

NSA/MWR/C1 - incorrect flagging of data

The wet window flag is set high more frequent than expected.

• wet_window

NSA/MWR/C1 - Reprocess: calibration change

The computer was replaced but not configured correctly for the MWR.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)

NSA/MWR/C1 - Reprocess: wrong calibration

Moisture was found inside the lens of the MWR. Removal of the moisture caused a 
significant change in the calibration, especially in the 23.8 GHz channel. The calibration was 
updated automatically.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)

NSA/MWR/C1 - Contamination or Calibration Effect

A short period of odd data occurs in PWV and the LWP.  Its a sudden offset in the data 
values.  Vic Morris suggests it could be a calibration issue as seen before at SGP.  Data 
make a marked change after the events (suggesting the data were questionable prior to this 
time).  No obvious changes in other instruments occur. Some of these effects may coincide 
with operator's preventive maintenance but others are in the middle of the night local 
time and can not be explained by cleaning.

• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)

NSA/MWR/C1 - Frosting

Spike in PWV and LWP
. Operator reports instrument is frosted. Instrument teflon window was cleaned by 
operator.

• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)

NSA/MWR/C1 - Instrument maintenance

Installed cold weather insulation on radiometer, required time to thermally stabilize.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd23
• tknd
• tnd31
• bb23
• tnd_nom23
• tc23
• sky31
• tnd_nom31
• bb31
• tc31
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• sky23
• tkxc
• Total water vapor along LOS path(vap)
• Temperature, brightness, longwave(ir_temp)
• tkbb
• bbn23
• wet_window
• bbn31
• tkair

NSA/MWR/C1 - MWR moved

The MWR data are unreasonable during this period, because it was shutdown and moved by 
operations at this time.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• East longitude(lon)
• tnd23
• tknd
• tnd_nom23
• bb31
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• tkbb
• time_offset
• wet_window
• bbn23
• base_time
• tkair
• North latitude(lat)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd31
• bb23
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• Temperature, brightness, longwave(ir_temp)
• actaz
• bbn31

NSA/MWR/C1 - negative PWV (bad calibration?)

During this time, the PWV drops to slightly negative values.  This could be related to 
calibration issues.

• Total water vapor along LOS path(vap)

NSA/MWR/C1 - Heater/blower removed

Note that the heater/blower was removed from the MWR during this time.  This may impact 
snow removal from teflon window, thereby affecting the quality of the data between 
cleanings.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd23
• tknd
• tnd31
• tnd_nom23
• tc23
• sky31
• tnd_nom31
• tc31
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• sky23
• tkxc
• Total water vapor along LOS path(vap)
• Temperature, brightness, longwave(ir_temp)
• tkbb
• wet_window
• tkair

NSA/MWR/C1 - Data spikes, possibly due to cleaning events

Unreasonable spikes occurred, which may be due to cleaning of 
the instrument by the operator.  Other cleaning events did
not result in obvious data spikes and have not been included 
in this report.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)

NSA/MWR/C1 - MWR digital board failure

A power failure at the site apparently damaged some of the components of the digital 
board. The MWR was replaced with a spare unit and returned to the manufacturer for repair.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)

SGP/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 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.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)

NSA/MWR/C1  - no air temperature signal

When the new blower was upgraded by Radiometrics and reinstalled on the MWR, the air 
temperature sensor failed to properly report. It was determined that the wires carrying the 
signal to the analog board did not conform to the standard expected by the upgraded blower. 
The problem was corrected by changing the wiring and modifying the MWR software to read 
the signal from the appropriate corresponding channel.

• tkair

NSA/MWR/C1 - 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.

• tkxc
• tknd

NSA/MWR/C1 - damaged window

The MWR dielectric window was damaged by snow from a snow blower and replaced.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd23
• tknd
• tnd31
• tnd_nom23
• bb23
• tc23
• sky31
• tnd_nom31
• bb31
• tc31
• sky23
• tkxc
• Total water vapor along LOS path(vap)
• tkbb
• bbn23
• wet_window
• bbn31
• tkair

NSA/C1 - Site-wide power failure

The Barrow facility experienced a site-wide power failure on 12/13.  Power was restored to 
most instruments between 2250 and 2330 GMT.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• East longitude(lon)
• tnd23
• tknd
• tnd_nom23
• bb31
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• tkbb
• time_offset
• wet_window
• bbn23
• base_time
• tkair
• North latitude(lat)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd31
• bb23
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• Temperature, brightness, longwave(ir_temp)
• actaz
• bbn31

NSA/MWR/C1 - poor air temperature values

After the air temperature sensor was rewired due to a change with the new blower 
(D030515.3), the measurement was initially incorrect. There is no apparent cause for the bad 
signal or its improvement.

• tkair

NSA/MWR/C1 - Reprocess: Revised Calibration 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 NSA.C1 
20020425.1900.  The MONORTM-based retrieval coefficients became active 
at NSA.C1 20050629.0000.

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.

• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)

NSA/MWR/C1 - Possible loss of accuracy due to missing blower

On 7/09 the MWR blower failed. The blower prevents snow and liquid drop from accumulating 
on the window. Accumulation of snow or liquid results in a loss of accuracy of the 
instrument. The loss of accuracy has consequencies on the retrieved liquid water path and 
precipitable water vapor. Usually there will be an overestimation of liquid and vapor. The 
blower was repaired and reinstalled on 7/20. Between 7/9 and 7/20 the tkair variable is 
unavailable as well.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• sky23
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)
• wet_window
• tkair
• sky31

NSA/MWR/C1 - Instrument problem, Heater problem

The heater of the MWR was ON all the time even when the moisture sensor was dry. Jim 
Liljegren suspected a problem with the relay that activates the heater. The suggested action 
was to send the faulty assembly to SGP for repair and get a spare unit from SGP.
The spare unit was sent on 9/15 and was installed on 10/18.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• East longitude(lon)
• tnd23
• tknd
• tnd_nom23
• bb31
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• tkbb
• time_offset
• wet_window
• bbn23
• base_time
• tkair
• North latitude(lat)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd31
• bb23
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• Temperature, brightness, longwave(ir_temp)
• actaz
• bbn31

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

A problem began with the installation of MWR.EXE version 4.12 in September 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 9/15/2005. As a consequence of this 
upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd23
• tknd
• tnd31
• tnd_nom23
• bb23
• tc23
• sky31
• tnd_nom31
• bb31
• tc31
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• sky23
• tkxc
• Total water vapor along LOS path(vap)
• Temperature, brightness, longwave(ir_temp)
• tkbb
• bbn23
• bbn31
• tkair

NSA/MWR/C1 - Reprocessed and Corrected:wrong calibration

DATA REPROCESSED and CORRECTED: 

The calibration had changed as a result of the repairs made by Radiometrics and the RF 
deck temperature had been set to 325K for testing. The temperature was decreased to 307K to 
prevent thermal instability in winter and the calibration was changed in the 
configuration file with the values supplied on the repair report. The calibration coefficients were 
derived automatically after the changes were put into affect. The data were reprocessed 
using the derived calibration coefficients.

ORIGINAL DQR CATEGORY: Red( Incorrect)

REPROCESSED and CORRECTED DATA ARCHIVED:2016-03-29

REPROCESS IDENTIFICATION NUMBER: RID 209
 
---------------------------------------------------
--- ORIGINAL DQR DESCRIPTION ---
---------------------------------------------------
When MWR#20 was returned to service on 9/1/2005, the calibration had changed as a result 
of the repairs made by Radiometrics and the RF deck temperature had been set to 325K for 
testing. On 9/2, the temperature was decreased to 307K to prevent thermal instability in 
winter and the calibration was changed in the configuration file with the values supplied 
on the repair report.  

The data need to be reprocessed with the calibration coefficients that were automatically 
derived after these changes were put into affect. They are: tnd_nom23=185.621, 
tnd_nom31=158.801, tc23=-0.022, tc31=-0.039.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)

NSA/MWR/C1 -  Incorrect time stamp

On Sept 27 the motherboard of the MWR computer was replaced. Following the replacement, 
the date on the computer was not set to the correct time of day, therefore the date and 
time in the files were wrong. The time on the computer was reset on Sept. 30. Time stamps 
between Sept. 27 and Sept. 30 were later corrected based on gathered information, however 
they may have as much as 5 minutes of uncertainty.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• East longitude(lon)
• tnd23
• tknd
• tnd_nom23
• bb31
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• tkbb
• time_offset
• wet_window
• bbn23
• base_time
• tkair
• North latitude(lat)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd31
• bb23
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• Temperature, brightness, longwave(ir_temp)
• actaz
• bbn31

NSA/MWR/C1 - software upgrade (version 3.28)

The MWR operating program was upgraded to version 3.28 on 3 February 1999. This version 
includes a beam width correction as well as providing 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.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)

NSA/MWR/C1 - TKAIR sensor failure

Between 7/14 and 7/28 the tkair variable is missing most of the time and sometimes has 
large negative spikes.  On 7/28, the sensor was cleaned of corrosion and the readings came 
back to normal.

• tkair

NSA/MWR/C1 - Rain sensor always on

The rain sensor was always on between 10/5 and 10/23 2006.
The user should be aware that not all data flagged as rainy are actually rainy. The 
problem was caused by a shift in the sensitivity of the rain sensor and was corrected by 
changing the sensor threshold in the configuration file.

• wet_window

NSA/MWR/C1 - Spikes in air temperature readings

During this month there are occasional negative spikes in the Tkair variable. The problem 
may be corrosion in the temperature sensor or the infiltration of water from melting snow.
The dewblower was replaced and a new sensor installed

• tkair

NSA/MWR/C1 - Missing surface air temperature data

Some wires in the dewblower were not correctly configured.

• tkair

NSA/MWR/C1 - Incorrect brightness temperatures and retrievals

The brightness temperatures and retrieved PWV and LWP show a sudden jump and have values 
that are too high. The suddenly jump back to normal at around 1800 UTC. All other 
parameters seem reasonable so the cause of the jump may just be due to accumulation of either 
snow or melting ice on the radome.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)
• tkair

NSA/MWR/C1 - RFI screening test

The instrument was covered with a shield to test the effect on the RF interference that is 
affecting the measurements since February. The test was performed on 4/15 and 4/16 for a 
few hours.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd23
• tknd
• tnd31
• tnd_nom23
• bb23
• tc23
• sky31
• tnd_nom31
• bb31
• actel
• tc31
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• sky23
• tkxc
• Total water vapor along LOS path(vap)
• Temperature, brightness, longwave(ir_temp)
• tkbb
• actaz
• bbn23
• wet_window
• bbn31
• tkair

NSA/MWR/C1 - High noise in 23.8-GHz channel

Starting approximately on February 13 the MWR experienced high level of noise in the 23.8 
GHz channel. The spikes became more prominent around Feb 17 and increased after that date 
as well. The cause of the interference was identified as the nearby MWRP on Oct 13 and 
the instruments were realigned.

• sky23
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)

NSA/MWR/C1 - Intermittent air temperature readings

Starting on 5/23 the air temperature readings (tkair) were intermittent and had negative 
spikes

• tkair

NSA/MWR/C1 - Air temperature readings missing

The air temperature readings (tkair) dropped on 5/26. The signal was restored on 6/10.

• tkair

NSA/MWR/C1 - Elevated noise

The data have high noise levels.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• sky23
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)
• sky31

NSA/MWR/C1 - Missing data

Data are missing and unrecoverable.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• East longitude(lon)
• tnd23
• tknd
• tnd_nom23
• bb31
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• sky23
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• tkbb
• time_offset
• wet_window
• bbn23
• tkair
• base_time
• North latitude(lat)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd31
• bb23
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• actaz
• Temperature, brightness, longwave(ir_temp)
• bbn31

NSA/MWR/C1 - Temperature sensor failure

The surface temperature readings are incorrect or missing

• tkair

NSA/MWR/C1 - Incorrect brightness temperatures

The radiometer had a problem with the mirror position. Data should be disregarded.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• sky23
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd23
• tnd31
• tnd_nom23
• sky31
• tnd_nom31

NSA/MWR/C1 - Missing data

Data are missing

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• East longitude(lon)
• tnd23
• tknd
• tnd_nom23
• bb31
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• tkbb
• time_offset
• wet_window
• bbn23
• base_time
• tkair
• North latitude(lat)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd31
• bb23
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• Temperature, brightness, longwave(ir_temp)
• actaz
• bbn31

NSA/MWR/C1 - Instrument

Data are missing because the software crashed

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• East longitude(lon)
• tnd23
• tknd
• tnd_nom23
• bb31
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• tkbb
• time_offset
• wet_window
• bbn23
• base_time
• tkair
• North latitude(lat)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd31
• bb23
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• Temperature, brightness, longwave(ir_temp)
• actaz
• bbn31

NSA/MWR/C1 - Instrument

Data are missing because of a software crash

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• East longitude(lon)
• tnd23
• tknd
• tnd_nom23
• bb31
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• tkbb
• time_offset
• wet_window
• bbn23
• base_time
• tkair
• North latitude(lat)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd31
• bb23
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• Temperature, brightness, longwave(ir_temp)
• actaz
• bbn31

NSA/MWR/C1 - Incorrect surface temperature

The surface temperature sensor malfunctioned and was replaced.

• tkair

NSA/MWR/C1 - Missing data

Data are missing

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• qc_bb23
• East longitude(lon)
• qc_liq
• tnd23
• tknd
• tnd_nom23
• bb31
• qc_tkxc
• qc_bbn23
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• qc_tknd
• tkbb
• time_offset
• bbn23
• wet_window
• qc_tbsky23
• tkair
• base_time
• time
• North latitude(lat)
• qc_bb31
• qc_sky31
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• qc_tkair
• tnd31
• qc_tkbb
• bb23
• qc_time
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• qc_tbsky31
• qc_sky23
• qc_bbn31
• actaz
• Temperature, brightness, longwave(ir_temp)
• qc_vap
• bbn31

NSA/IRT/MWR/C1 - Data Missing - Data System Upgrades

Site data systems were being upgraded during this period.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• qc_bb23
• East longitude(lon)
• qc_liq
• tnd23
• tknd
• tnd_nom23
• bb31
• qc_tkxc
• qc_bbn23
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• qc_tknd
• tkbb
• time_offset
• bbn23
• wet_window
• qc_tbsky23
• tkair
• base_time
• time
• North latitude(lat)
• qc_bb31
• qc_sky31
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• qc_tkair
• tnd31
• qc_tkbb
• bb23
• qc_time
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• qc_tbsky31
• qc_sky23
• qc_bbn31
• actaz
• Temperature, brightness, longwave(ir_temp)
• qc_vap
• bbn31

NSA/MWR/C1 Missing data

Data are missing

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• qc_bb23
• East longitude(lon)
• qc_liq
• tnd23
• tknd
• tnd_nom23
• bb31
• qc_tkxc
• qc_bbn23
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• qc_tknd
• tkbb
• time_offset
• wet_window
• bbn23
• qc_tbsky23
• tkair
• base_time
• time
• North latitude(lat)
• qc_bb31
• qc_sky31
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• qc_tkair
• qc_tkbb
• tnd31
• bb23
• qc_time
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• qc_bbn31
• qc_tbsky31
• qc_sky23
• actaz
• Temperature, brightness, longwave(ir_temp)
• qc_vap
• bbn31

NSA/MWR/C1 - Missing data

Data are missing

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• qc_bb23
• East longitude(lon)
• qc_liq
• tnd23
• tknd
• tnd_nom23
• bb31
• qc_tkxc
• qc_bbn23
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• qc_tknd
• tkbb
• time_offset
• wet_window
• bbn23
• qc_tbsky23
• tkair
• base_time
• time
• North latitude(lat)
• qc_bb31
• qc_sky31
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• qc_tkair
• qc_tkbb
• tnd31
• bb23
• qc_time
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• qc_tbsky31
• qc_sky23
• qc_bbn31
• actaz
• Temperature, brightness, longwave(ir_temp)
• qc_vap
• bbn31

NSA/MWR/C1/C2 - Radiometer unstable

The radiometer was unstable due to a sudden change in the temperature set point and 
calibration.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• tc31
• tkxc
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)
• tnd23
• tknd
• tnd31
• tnd_nom23
• tc23
• tnd_nom31

NSA/MWR/C1 - Missing data

Radiometer removed for repairs. Data are missing

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• qc_bb23
• East longitude(lon)
• qc_liq
• tnd23
• tknd
• tnd_nom23
• bb31
• qc_tkxc
• qc_bbn23
• sky23
• Sky/Cloud Infrared Temperature(sky_ir_temp)
• tkxc
• Total water vapor along LOS path(vap)
• Altitude above mean sea level(alt)
• qc_tknd
• tkbb
• time_offset
• bbn23
• wet_window
• qc_tbsky23
• tkair
• base_time
• time
• North latitude(lat)
• qc_bb31
• qc_sky31
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• 23.8 GHz sky brightness temperature(tbsky23)
• qc_tkair
• qc_tkbb
• tnd31
• bb23
• qc_time
• tc23
• sky31
• tnd_nom31
• actel
• tc31
• qc_tbsky31
• qc_sky23
• qc_bbn31
• actaz
• Temperature, brightness, longwave(ir_temp)
• qc_vap
• bbn31

NSA/MWR/C1 - Software Change

The MWR operating software was changed on 16 November 1998 to provide additional 
functionality as described below. This change affects the format of the raw and ingested data. 
   
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.

• tnd23
• tknd
• tnd31
• tkair

NSA/MWR/C1 - Spikes in PWV data

The PWV data began exhibiting a pattern of large (~5 cm) spikes which exponetially degrade 
to normal values. The problem is due to a fault in the serial or fiber optic data 
communication. This pattern began intermittent occurrence on 4/9/98 but it dominates the data 
by 5/1/98.

• Total water vapor along LOS path(vap)

NSA/MWR/C1 - Spikes in PWV data

After reinstallation of repaired MWR #20, PWV data began exhibiting a pattern of large (~5 
cm) spikes which exponetially degrade to normal values. The problem was due to a fault 
in the serial or fiber optic data communication.

This pattern began intermittant ocurrance on 8/15/98 but it dominates the data by 9/6/98.

• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)

NSA/MWR/C1 - Reprocess: incorrect calibrations

MWR #17 was placed in service while MWR #20 was being repaired by the manufacturer.  The 
data need to be reprocessed with calibration coefficients appropriate for this instrument.

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Water, liquid, total along line-of-sight path, mean, 5-min avg(liq)
• Total water vapor along LOS path(vap)
• 23.8 GHz sky brightness temperature(tbsky23)
• East longitude(lon)
• Altitude above mean sea level(alt)
• Temperature, brightness, longwave(ir_temp)
• time_offset
• wet_window
• base_time
• North latitude(lat)