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.

• Raw data stream - documentation not supported(Raw data stream - documentation not supported)

• Ambient temperature(tkair)

• Ambient temperature(tkair)

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.

• Ambient temperature(tkair)

• Ambient temperature(tkair)

NSA/SONDE/C1 - Bad temperature

Because of strong winds, the radiosonde hit the ground after launch and the temperature 
sensor broke.  The RH and pressure data also should be considered suspect.

• surface wind speed(wspd)
• Wind Direction(deg)
• Ascent Rate(asc)
• Dry-Bulb Temperature(tdry)
• model meridional wind velocity(v_wind)
• Time offset from base_time(base_time)
• pressure at constant pressure surface(pres)
• north latitude for all the input platforms.(lat)
• model zonal wind velocity(u_wind)
• east longitude for all the input platforms.(lon)
• Surface dew point temperature(dp)
• Wind Status(wstat)
• Time offset of tweaks from base_time(time_offset)
• Relative humidity scaled, by total column amount from MWR(rh)
• altitude above sea levelaltunits(alt)

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.

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

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

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

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

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.

• 23.8 GHz sky signal(tipsky23)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• Ambient temperature(tkair)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• 31.4 GHz sky signal(tipsky31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)

• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Mean total liquid water amount along LOS path(liq)
• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• 23.8 GHz sky signal(sky23)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• 31.4 GHz sky signal(sky31)
• Ambient temperature(tkair)

NSA/MWR/C1 - Missing Data

Instrument was removed for repair.

• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Fraction of data in averaging interval with water on the Teflon window(water_flag_fraction)
• Time offset of tweaks from base_time(time_offset)
• Standard deviation about the mean for the total liquid water amount(liq_sdev)
• east longitude for all the input platforms.(lon)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Standard deviation about the mean for the IR brightness temperature(ir_temp_sdev)
• Number of points included in the ir_temp ensemble(num_obs_irt)
• Standard deviation about the mean for the 23.8 GHz sky brightness temperature(tbsky23_sdev)
• north latitude for all the input platforms.(lat)
• Mean IR brightness temperature(ir_temp)
• Standard deviation about the mean for the 31.4 GHz sky brightness temperature(tbsky31_sdev)
• Number of points included in the ensemble of all the fields except the ir_temp
  fields(num_obs)
• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)
• altitude above sea levelaltunits(alt)
• Time offset from base_time(base_time)
• Standard deviation about the mean for the total water vapor amount(vap_sdev)

• Raw data stream - documentation not supported(Raw data stream - documentation not supported)

• Actual elevation angle(actel)
• Actual Azimuth(actaz)
• 31.4 GHz Blackbody signal(bb31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• north latitude for all the input platforms.(lat)
• Sky/Cloud Infra-Red Temperature(sky_ir_temp)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Noise diode mount temperature(tknd)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Mean IR brightness temperature(ir_temp)
• Ambient temperature(tkair)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Time offset from base_time(base_time)
• Blackbody kinetic temperature(tkbb)
• Mean total water vapor amount along LOS path(vap)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 23.8 GHz Blackbody signal(bb23)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• Time offset of tweaks from base_time(time_offset)
• 31.4 GHz sky signal(sky31)
• east longitude for all the input platforms.(lon)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Mean total liquid water amount along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• altitude above sea levelaltunits(alt)
• 23.8 GHz sky signal(sky23)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Temperature correction coefficient at 23.8 GHz(tc23)

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

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.

• Raw data stream - documentation not supported(Raw data stream - documentation not supported)

• Actual elevation angle(actel)
• Blackbody kinetic temperature(tkbb)
• Actual Azimuth(actaz)
• 31.4 GHz Blackbody signal(bb31)
• Mean total water vapor amount along LOS path(vap)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 23.8 GHz Blackbody signal(bb23)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• Time offset of tweaks from base_time(time_offset)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz sky signal(sky31)
• north latitude for all the input platforms.(lat)
• Sky/Cloud Infra-Red Temperature(sky_ir_temp)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• east longitude for all the input platforms.(lon)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Mean total liquid water amount along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise diode mount temperature(tknd)
• altitude above sea levelaltunits(alt)
• 23.8 GHz sky signal(sky23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Mean IR brightness temperature(ir_temp)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Ambient temperature(tkair)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Time offset from base_time(base_time)
• Temperature correction coefficient at 23.8 GHz(tc23)

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.

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

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

NSA/MWR/C1 - Reprocess: wrong calibration

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 total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean total liquid water amount along LOS path(liq)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)
• Mean 31.4 GHz sky brightness temperature(tbsky31)

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

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.

• Raw data stream - documentation not supported(Raw data stream - documentation not supported)

• Actual elevation angle(actel)
• Blackbody kinetic temperature(tkbb)
• Actual Azimuth(actaz)
• 31.4 GHz Blackbody signal(bb31)
• Mean total water vapor amount along LOS path(vap)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 23.8 GHz Blackbody signal(bb23)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• Time offset of tweaks from base_time(time_offset)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz sky signal(sky31)
• north latitude for all the input platforms.(lat)
• Sky/Cloud Infra-Red Temperature(sky_ir_temp)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• east longitude for all the input platforms.(lon)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Mean total liquid water amount along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise diode mount temperature(tknd)
• altitude above sea levelaltunits(alt)
• 23.8 GHz sky signal(sky23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Mean IR brightness temperature(ir_temp)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Ambient temperature(tkair)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Time offset from base_time(base_time)
• Temperature correction coefficient at 23.8 GHz(tc23)

NSA/SONDE/C1 - Increased precision for alt, dp, pres, rh, tdry

The output precision of the following variables was increased 20060929:

   alt	changed from 1m to 0.1m
   dp	changed from 0.1degC to 0.01degC
   pres changed from 0.1 hPa to 0.01 hPa
   RH	changed from 1%RH to 0.01%RH
   tdry changed from .1degC to 0.01degC

Note that the increase in precision does not necessarily imply an increase
in accuracy.  Users are cautioned to continue to use their best scientific
judgement when using these or any other data.

• Relative humidity scaled, by total column amount from MWR(rh)
• Dry-Bulb Temperature(tdry)
• altitude above sea levelaltunits(alt)
• pressure at constant pressure surface(pres)
• Surface dew point temperature(dp)