SGP/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.

• tkair

• tkair

SGP/SONDE/C1 - Bad RH Data

The RH values during the first half of this sounding oscillate between reasonable values 
and near-zero values.  The oscillation is irregular and seems to be related to failure of 
the RH sensor heating process.

• Dewpoint Temperature(dp)
• Humidity, relative(rh)

SGP/SONDE/C1 - Bad RH Data

The RH values during the first part of this sounding oscillate between reasonable values 
and near-zero values.  The oscillation seems to be related to failure of the RH sensor 
heating process.

• Dewpoint Temperature(dp)
• Humidity, relative(rh)

SGP/SONDE/C1 - Surface pressure incorrect

I think the operator inadvdertently transposed to digits when entering the surface 
pressure value.  The value entered is 987.0 hPa but the value shown in the raw data file at 
launch is 978.0.  As a result, the absolute altitudes in this sounding will be slightly 
incorrect as will be the ascent rate during the first 30 seconds of flight.

• alt
• asc

SGP/SONDE/C1 - Broken temperature sensor

The temperature sensor broke at launch on this sounding.  All of the temperature-related 
data (tdry, rh, dp) are incorrect.

• Dry Bulb Temperature(tdry)
• Dewpoint Temperature(dp)
• Humidity, relative(rh)

SGP/SONDE/C1 - Broken temperature sensor

The temperature sensor broke shortly after launch on this sounding.  All of the 
temperature-related data (tdry, rh, dp) are incorrect.

• Dry Bulb Temperature(tdry)
• Dewpoint Temperature(dp)
• Humidity, relative(rh)

SGP/SONDE/C1 - Temperature sensor broke high into the sounding

The temperature sensor on this radiosonde appeared to break 56 minutes and 22 seconds into 
the sounding at an altitude of 16570 m.  All the data below this point are good; only 
the data above this point to the end of the sounding (88 minutes and 14 seconds) are bad.

• Dry Bulb Temperature(tdry)
• Dewpoint Temperature(dp)
• Humidity, relative(rh)

SGP/MWR/C1 - Instrument problem

The MWR mixer temperature, blackbody temperature, and moisture flag are incorrect. This 
began when the instrument was returned to service after the analog board was temporarily 
removed to check the presence and absence of certain resistors. The board must have been 
accidently damaged during this process.

• tc23
• tnd23I
• tknd
• tkbb
• tkxc
• wet_window
• tnd31I
• tnd_nom23
• tkair
• tnd31
• tc31
• tnd_nom31
• tnd23

• tknd
• tnd_nom31
• tc23
• tnd31
• tkbb
• tc31
• wet_window
• tkxc
• tnd23
• tkair
• tnd_nom23

• tkxc
• wet_window
• tnd_nom31
• tc31
• tkbb
• tc23
• tkair
• tnd_nom23
• tnd23
• tnd31
• tknd

SGP/SONDE/C1 - Incorrect surface temperature

The operator entered a the surface temperature incorrectly on this sounding.  The sonde 
data file shows the temperature as 33.5 degC but the operations log shows it as 3.5 degC.  
The first temperature recorded by the sonde after launch is 3.7 degC, consistent with the 
typical early morning inversion.

• Dry Bulb Temperature(tdry)
• Dewpoint Temperature(dp)
• Humidity, relative(rh)

SGP/SONDE/C1 - Scheduled Soundings Missed

The following scheduled sonde launches were missed due to computer 
system failures:

20040116.2330
20040117.0530
20040117.1130
20040117.1730
20040118.0530
20040121.0530

• Raw data stream - documentation not supported

• Dewpoint Temperature(dp)
• Dry Bulb Temperature(tdry)
• lon
• Mean Wind Speed(wspd)
• base_time
• asc
• Pressure, atmospheric, constant value of model level, RUC model output(pres)
• Wind Direction(deg)
• Northward Wind Component(v_wind)
• time_offset
• lat
• alt
• wstat
• Humidity, relative(rh)
• Eastward Wind Component(u_wind)

SGP/MWR/C1 - thermal instability

The analog board was replaced with a spare (D041001.3) with a reference temperature that 
was set too low (306 K) so that during periods of high ambient temperature, the instrument 
became thermally unstable. The problem was corrected when the temperature setting was 
increased (to 311 K).

• liqtip
• vaptip
• tbsky23tip
• tbsky31tip

• Total water vapor along LOS path(vap)
• Total liquid water along LOS path(liq)
• 31.4 GHz sky brightness temperature(tbsky31)
• Radiation, longwave, brightness temperature, 23.8 GHz(tbsky23)

• 31.4 GHz sky brightness temperature(tbsky31)
• Radiation, longwave, brightness temperature, 23.8 GHz(tbsky23)
• Total water vapor along LOS path(vap)
• Total liquid water along LOS path(liq)

SGP/MWR/C1 - Reprocess: wrong retrievals

When the computer and core configuration were upgraded, retrieval coefficients for BF1 
were accidently included in the configuration file.
The correct coefficients for CF1 were applied when the configuration file was updated.

• liqtip
• vaptip

• mean_liq_mwr
• mean_vap_mwr

• Total water vapor along LOS path(vap)
• Total liquid water along LOS path(liq)

• Total water vapor along LOS path(vap)
• Total liquid water along LOS path(liq)

SGP/SONDE/C1 - Possibly bad pressure sensor or operator data entry error

There is a discrepency between the surface pressure and temperature data entered by the 
operator and that recorded by the THWAPS.  Review of the raw data from the radiosonde shows 
that the pressure was periodically varying by as much as 12 hPa (~988 to 1000)in the 
time period before launch.  The operator entry of 998.2 is at the high end of this range - 
the concurrent THWAPS reading was about 988.4 at the low end.  The operator entered 
temperature 6.2 degC is considerably higher than the THWAPS value of 1.8.  The pre-flight log 
entry for this sounding is missing from the OMIS database.  If not for the extremely 
unstable pressure reading I would have assumed this was an operator error.  It will take some 
more research to figure out what is going on.

• Dewpoint Temperature(dp)
• Dry Bulb Temperature(tdry)
• lon
• Mean Wind Speed(wspd)
• base_time
• asc
• Pressure, atmospheric, constant value of model level, RUC model output(pres)
• Wind Direction(deg)
• Northward Wind Component(v_wind)
• time_offset
• lat
• alt
• wstat
• Humidity, relative(rh)
• Eastward Wind Component(u_wind)

SGP/SONDE/C1 - Surface pressure incorrect

I think the operator inadvdertently entered an incorrect surface pressure value.  The 
value entered is 988.8 hPa but the value shown in the raw data file at launch is 968.8.  As a 
result, the absolute altitudes in this sounding will be slightly incorrect as will be 
the ascent rate during the first 30 seconds of flight.

• alt
• asc

SGP/SONDE/C1 - Surface pressure bad and other data noisy

I was checking this sounding because the surface pressure entered by the operator was 
considerably higher than that recorded by the TWHAPS and SMOS.  I'm not sure why, but the 
pressure data are very noisy while the sonde is on the ground (which accounts for the 
incorrect surface pressure) and the RH data aloft do not look terrible but do not look great 
either.

• Dewpoint Temperature(dp)
• Dry Bulb Temperature(tdry)
• lon
• Mean Wind Speed(wspd)
• base_time
• asc
• Pressure, atmospheric, constant value of model level, RUC model output(pres)
• Wind Direction(deg)
• Northward Wind Component(v_wind)
• time_offset
• lat
• alt
• wstat
• Humidity, relative(rh)
• Eastward Wind Component(u_wind)

SGP/SONDE/C1 - Surface pressure incorrect

I think the operator inadvdertently typed an 89 instead of a 78 when entering the surface 
pressure value.  The value entered is 989.9 hPa but the value shown in the raw data file 
at launch is 978.9.  As a result, the absolute altitudes in this sounding will be 
slightly incorrect as will be the ascent rate during the first 30 seconds of flight.

• alt
• asc

SGP/SONDE/C1 - Surface pressure incorrect

I think the operator inadvdertently mistyped a digit when entering the surface pressure 
value.  The value entered is 975.6 hPa but the value shown in the raw data file at launch 
is 972.6.  As a result, the absolute altitudes in this sounding will be slightly incorrect 
as will be the ascent rate during the first 30 seconds of flight.

• alt
• asc

SGP/MWR/C1 - 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 as follows (BCR 456):
SGP/C1 (Lamont)     4/16/2002, 2000
SGP/B1 (Hillsboro)  4/12/2002, 1600
SGP/B4 (Vici)       4/15/2002, 2300
SGP/B5 (Morris)     4/15/2002, 2300
SGP/B6 (Purcell)    4/16/2002, 2200
SGP/E14(Lamont)     4/16/2002, 0000
NSA/C1 (Barrow)     4/25/2002, 1900 
NSA/C2 (Atqasuk)    4/18/2002, 1700
TWP/C1 (Manus)      5/04/2002, 0200
TWP/C2 (Nauru)      4/27/2002, 0600
TWP/C3 (Darwin)     inception

The MONORTM-based retrieval coefficients became active as follows (BCR 984):

SGP/C1 (Lamont)     6/28/2005, 2300
SGP/B1 (Hillsboro)  6/24/2005, 2100
SGP/B4 (Vici)       6/24/2005, 2100
SGP/B5 (Morris)     6/24/2005, 2100
SGP/B6 (Purcell)    6/24/2005, 1942
SGP/E14(Lamont)     6/28/2005, 2300
NSA/C1 (Barrow)     6/29/2005, 0000 
NSA/C2 (Atqasuk)    6/29/2005, 0000
TWP/C1 (Manus)      6/30/2005, 2100
TWP/C2 (Nauru)      6/30/2005, 2100
TWP/C3 (Darwin)     6/30/2005, 2100
PYE/M1 (Pt. Reyes)  4/08/2005, 1900**

** At Pt. Reyes, the original retrieval coefficients implemented in March 2005 were based 
on a version of the Rosenkranz model that had been modified to use the HITRAN half-width 
at 22 GHz and to be consistent with the water vapor continuum in MONORTM.  These 
retrievals yield nearly identical results to the MONORTM retrievals.  Therefore the Pt. Reyes 
data prior to 4/08/2005 may not require reprocessing.

• Total liquid water along LOS path(liq)
• Total water vapor along LOS path(vap)

• liqtip
• vaptip

• mean_liq_mwr
• mean_vap_mwr

• Total water vapor along LOS path(vap)
• Total liquid water along LOS path(liq)

• Total water vapor along LOS path(vap)
• Total liquid water along LOS path(liq)

• Total water vapor along LOS path(vap)
• Total liquid water along LOS path(liq)

SGP/SONDE/C1 - Bad RH Data

The RH values below 6 km are incorrect.  The problem relates to a failure of the GC25 
ground check set used before this particular sounding.  The failure seems to have affected 
the sensor calibration with the effect that one of the two sensors was reading artificially 
high.  Because the internal processing software uses the highest of the two sensor 
readings, the bad sensor value is chosen whenever it is not heated.

• Dewpoint Temperature(dp)
• Humidity, relative(rh)

SGP/SONDE/C1 - Bad T/RH and surface P.

Apparently multiple failures.  The radiosonde temperature sensor broke on launch causing 
an approximate 35 degC negative offset and as a result, the RH is incorrect.  Furthermore, 
it appears that the pressure sensor was off by approximately 4 hPa, though this would 
not affect the altitude calculation, the absolute pressure is wrong.

• Dry Bulb Temperature(tdry)
• Humidity, relative(rh)
• Pressure, atmospheric, constant value of model level, RUC model output(pres)

SGP/SONDE/C1 - Temperature/RH incorrect

The temperature throughout this sounding is too high and as a result the RH values will be 
incorrect as well.  I'm not sure what is wrong here but the operators noted reasonable 
values (18.1 degC, 87%) in the log before launch.  Review of the raw data, however, shows 
the sonde reporting temperatures nearly 20 degC higher.  I suppose it is possible that 
the operator entered into the log the reference temperature from the GC25 ground check set 
rather than the temperature reported by the sonde - I can't think of any other 
explanation - there is no doubt that the temperature sensor on this sonde was bad.

• Humidity, relative(rh)
• Dry Bulb Temperature(tdry)

• Dry Bulb Temperature(tdry)
• Dewpoint Temperature(dp)
• Humidity, relative(rh)

SGP/MWR/C1 - Instrument noise problem

Various variables including the mixer temperatures were very noisy. After several attempts 
to fix the problem, the instrument was taken off line and returned to the manufacturer 
for repair.

• vap_sdev
• Temperature, brightness, longwave(ir_temp)
• number_obs_averaged
• 23tbsky
• liq_sdev
• prob_slope_change
• tbsky23_sdev
• ir_temp_sdev
• water_flag_fraction
• tbsky31_sdev
• Total water vapor along LOS path(vap)
• prob_outlier
• 31tbsky
• water_flag
• prob_level_change
• Radiation, longwave, brightness temperature, 23.8 GHz(tbsky23)
• Total liquid water along LOS path(liq)
• 31.4 GHz sky brightness temperature(tbsky31)

• tipsky23
• tipsky31
• tnd31I
• r23
• bbn31
• tnd_nom23
• tkair
• tbsky31tip
• tnd23
• tc23
• liqtip
• tnd23I
• tbsky23tip
• tkxc
• tknd
• tkbb
• wet_window
• bb23
• tnd31
• tc31
• vaptip
• bbn23
• r31
• tnd_nom31
• bb31

• 31.4 GHz sky brightness temperature(tbsky31)
• 31tbsky
• dlm_flag_fraction
• Radiation, longwave, brightness temperature, 23.8 GHz(tbsky23)
• water_flag_periods
• vap_sdev
• Total water vapor along LOS path(vap)
• tbsky31_sdev
• 23tbsky
• Total liquid water along LOS path(liq)
• ir_temp_sdev
• liq_sdev
• tbsky23_sdev
• water_flag_fraction
• Temperature, brightness, longwave(ir_temp)
• dlm_flag_periods

• wet_window
• bbn31
• tkair
• sky23
• tnd23
• tnd31
• tknd
• bbn23
• tkxc
• tnd_nom31
• tc31
• Radiation, longwave, brightness temperature, 23.8 GHz(tbsky23)
• Total liquid water along LOS path(liq)
• tkbb
• sky31
• tc23
• bb31
• Total water vapor along LOS path(vap)
• bb23
• tnd_nom23
• 31.4 GHz sky brightness temperature(tbsky31)
• IR Brightness Temperature(sky_ir_temp)

SGP/MWR/C1 - 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 08/04/2005. As a consequence of this 
upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to 
~50s.

• tc23
• liqtip
• tnd23I
• tbsky23tip
• tipsky23
• tipsky31
• tkbb
• tknd
• tkxc
• tnd31I
• r23
• bbn31
• tnd_nom23
• bb23
• tkair
• tnd31
• tc31
• vaptip
• tbsky31tip
• bbn23
• r31
• tnd_nom31
• bb31
• tnd23

• bbn23
• tkxc
• tnd_nom31
• Radiation, longwave, brightness temperature, 23.8 GHz(tbsky23)
• tc31
• Total liquid water along LOS path(liq)
• tkbb
• sky31
• tc23
• bb31
• Total water vapor along LOS path(vap)
• bbn31
• tkair
• bb23
• tnd_nom23
• sky23
• 31.4 GHz sky brightness temperature(tbsky31)
• tnd23
• IR Brightness Temperature(sky_ir_temp)
• tnd31
• tknd

SGP/SONDE/C1 - Bad RH Data

The RH values during this sounding oscillate between reasonable values and near-zero 
values.  The oscillation is due to failure of the RH sensor heating process.

• Dewpoint Temperature(dp)
• Humidity, relative(rh)

SGP/SONDE/C1 - Sonde RH values incorrect

RH values for all sondes launched during this time were incorrect due to a faulty Ground 
Check set which damaged or conditioned the RH sensor improperly.

• Dewpoint Temperature(dp)
• Humidity, relative(rh)

SGP/SONDE/C1 - DigiCORAIII failed, replaced with S01/S02 launches

The digiCORA-III failed on Saturday 2004-01-17.  The operators reported that they were 
unable to load the software and conduct normal soundings.	Following procedure, they 
conducted the regular soundings by using the S01/S02 systems as allowed by the AIRS IOP schedule.
The netCDF header fields "input_source" and "facility_id" will mention which of the 
S01/S02 systems was used in these launches.

• Raw data stream - documentation not supported

• alt
• lon
• lat

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

The output precision of the following variables was increased 20060928

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.

• alt
• Dry Bulb Temperature(tdry)
• Dewpoint Temperature(dp)
• Humidity, relative(rh)
• Pressure, atmospheric, constant value of model level, RUC model output(pres)

SGP/MWR/C1 - Missing data

Data are missing and unrecoverable.

• bbn23
• tkxc
• wet_window
• lon
• tnd_nom31
• tc31
• Radiation, longwave, brightness temperature, 23.8 GHz(tbsky23)
• Total liquid water along LOS path(liq)
• tkbb
• lat
• sky31
• tc23
• time_offset
• bb31
• Total water vapor along LOS path(vap)
• bbn31
• tkair
• bb23
• tnd_nom23
• sky23
• 31.4 GHz sky brightness temperature(tbsky31)
• tnd23
• IR Brightness Temperature(sky_ir_temp)
• base_time
• tnd31
• tknd
• alt