TWP/C1 - Incorrect elevation reported in Manus Data

(From Bill Clements) We have been using 6m MSL as the station
elevation of Momote (Manus).  This was based on information
posted near the station barometer in the Momote Weather Service
Office.  It turns out that the official WMO station elevation
for Momote is 4m MSL and the upper air elevation is 5m MSL.

All Manus instruments except the sonde station are at 4m MSL.
The sonde launching station is at 5m MSL.

• Dummy altitude for Zeb(alt)

TWP/C1/Balloon Soundings Maximum Altitude

Only surface data included in this data file.

• Mean Wind Speed(wspd)
• Dummy altitude for Zeb(alt)
• Dry bulb temperature(tdry)
• Retrieved pressure profile(pres)
• Ascent Rate(asc)
• lat(lat)
• base time(base_time)
• Wind Status(wstat)
• Relative humidity inside the instrument enclosure(rh)
• lon(lon)
• Surface dew point temperature(dp)
• Time offset of tweaks from base_time(time_offset)
• Wind Direction(deg)

• Time offset of tweaks from base_time(time_offset)
• Surface dew point temperature(dp)
• lon(lon)
• lat(lat)
• Retrieved pressure profile(pres)
• Relative humidity inside the instrument enclosure(rh)
• Wind Status(wstat)
• Ascent Rate(asc)
• V-component(v_wind)
• Dummy altitude for Zeb(alt)
• base time(base_time)
• U-component(u_wind)
• Mean Wind Speed(wspd)
• Dry bulb temperature(tdry)
• Wind Direction(deg)

TWP/C1/Balloon Soundings Maximum Altitude

Only surface data included in this data file.

• Mean Wind Speed(wspd)
• Dummy altitude for Zeb(alt)
• Dry bulb temperature(tdry)
• Retrieved pressure profile(pres)
• Ascent Rate(asc)
• lat(lat)
• base time(base_time)
• Wind Status(wstat)
• Relative humidity inside the instrument enclosure(rh)
• lon(lon)
• Surface dew point temperature(dp)
• Time offset of tweaks from base_time(time_offset)
• Wind Direction(deg)

• Time offset of tweaks from base_time(time_offset)
• Surface dew point temperature(dp)
• lon(lon)
• lat(lat)
• Retrieved pressure profile(pres)
• Relative humidity inside the instrument enclosure(rh)
• Wind Status(wstat)
• Ascent Rate(asc)
• V-component(v_wind)
• Dummy altitude for Zeb(alt)
• base time(base_time)
• U-component(u_wind)
• Mean Wind Speed(wspd)
• Dry bulb temperature(tdry)
• Wind Direction(deg)

TWP/C1/Balloon Soundings Maximum Altitude

Only surface data included in this data file.

• Mean Wind Speed(wspd)
• Dummy altitude for Zeb(alt)
• Dry bulb temperature(tdry)
• Retrieved pressure profile(pres)
• Ascent Rate(asc)
• lat(lat)
• base time(base_time)
• Wind Status(wstat)
• Relative humidity inside the instrument enclosure(rh)
• lon(lon)
• Surface dew point temperature(dp)
• Time offset of tweaks from base_time(time_offset)
• Wind Direction(deg)

• Time offset of tweaks from base_time(time_offset)
• Surface dew point temperature(dp)
• lon(lon)
• lat(lat)
• Retrieved pressure profile(pres)
• Relative humidity inside the instrument enclosure(rh)
• Wind Status(wstat)
• Ascent Rate(asc)
• V-component(v_wind)
• Dummy altitude for Zeb(alt)
• base time(base_time)
• U-component(u_wind)
• Mean Wind Speed(wspd)
• Dry bulb temperature(tdry)
• Wind Direction(deg)

TWP/C1/Balloon Soundings Maximum Altitude

Only surface data included in this data file.

• Mean Wind Speed(wspd)
• Dummy altitude for Zeb(alt)
• Dry bulb temperature(tdry)
• Retrieved pressure profile(pres)
• Ascent Rate(asc)
• lat(lat)
• base time(base_time)
• Wind Status(wstat)
• Relative humidity inside the instrument enclosure(rh)
• lon(lon)
• Surface dew point temperature(dp)
• Time offset of tweaks from base_time(time_offset)
• Wind Direction(deg)

• Time offset of tweaks from base_time(time_offset)
• Surface dew point temperature(dp)
• lon(lon)
• lat(lat)
• Retrieved pressure profile(pres)
• Relative humidity inside the instrument enclosure(rh)
• Wind Status(wstat)
• Ascent Rate(asc)
• V-component(v_wind)
• Dummy altitude for Zeb(alt)
• base time(base_time)
• U-component(u_wind)
• Mean Wind Speed(wspd)
• Dry bulb temperature(tdry)
• Wind Direction(deg)

TWP/C1/Balloon Soundings Maximum Altitude

This sonde only reached a height of 0.3 km.

• Mean Wind Speed(wspd)
• Dummy altitude for Zeb(alt)
• Dry bulb temperature(tdry)
• Retrieved pressure profile(pres)
• Ascent Rate(asc)
• lat(lat)
• base time(base_time)
• Wind Status(wstat)
• Relative humidity inside the instrument enclosure(rh)
• lon(lon)
• Surface dew point temperature(dp)
• Time offset of tweaks from base_time(time_offset)
• Wind Direction(deg)

• Time offset of tweaks from base_time(time_offset)
• Surface dew point temperature(dp)
• lon(lon)
• lat(lat)
• Retrieved pressure profile(pres)
• Relative humidity inside the instrument enclosure(rh)
• Wind Status(wstat)
• Ascent Rate(asc)
• V-component(v_wind)
• Dummy altitude for Zeb(alt)
• base time(base_time)
• U-component(u_wind)
• Mean Wind Speed(wspd)
• Dry bulb temperature(tdry)
• Wind Direction(deg)

SGP/SONDE/C1 - Bad temp (other?) data in 12/3/01:2328 sounding

It looks as though the temperature sensor was damaged on launch.  The
recorded temp goes from 16.4 at the surface to -42.6 at 2 seconds into the
flight.  The temperature never exceeds -42 though the RH and pressure look
reasonable, but probably should be considered questionable.

• null(Raw data stream - documentation not supported)

• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)

• null(Raw data stream - documentation not supported)

SGP/SONDE/C1 - Bad temperature in CF sounding 12/22/01:0527

The temperature data in this sounding look bad after the first value.  The
temperature series is 11.4, 2.6, -14.3, -32.4 in the first 6 seconds of
flight.  I don't know why this occurred, but it obviously is incorrect.
The pressure and RH data look reasonable.

• Dry bulb temperature(tdry)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)

SGP/SONDE/C1 - Bad temperature data CF sounding 12/28/01:2326

The temperature data in this sounding are bad from approximately 16 seconds
into the flight.  The temperature series is 9.9, 10.8, 11.3, 1.5, 11.6, 11.6,
11.6, -32.2 and remains below -30 degC.  I don't know why this occurred, but
it clearly is incorrect.  The pressure data looks OK as does the RH, though
the RH data are missing (probably sensor failure) above roughly 3.5 km.

• Dry bulb temperature(tdry)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)

SGP/SONDE/C1 - Bad temperature in SGP/CF sounding 20020108:0528

Temperature values in this sounding went from 3.5 degC at the surface to
-33.3 degC at the next sample.  It appears that all the remaining
temperature values have an approximate -35 degC offset.  The pressure
and RH values appear reasonable.

• Dry bulb temperature(tdry)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)

SGP/SONDE/C1 - CF sounding 20020522:1130 bad temperature/RH

It appears that the sonde sensor boom was damaged upon launch.  The result
is that no RH data are reported and the reported temperature is something on
the order of 60 degC too low.

• Dry bulb temperature(tdry)
• Dummy altitude for Zeb(alt)
• Relative humidity inside the instrument enclosure(rh)
• Ascent Rate(asc)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)
• Ascent Rate(asc)
• Dummy altitude for Zeb(alt)

SGP/SONDE/C1 - Bad T/RH data in CF sounding 20020523:1129

It appears that the sensor boom was damaged shortly after launch.  The
temperature reading jumps -60 degC and the RH goes to 0.

• Dry bulb temperature(tdry)
• Dummy altitude for Zeb(alt)
• Relative humidity inside the instrument enclosure(rh)
• Ascent Rate(asc)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)
• Ascent Rate(asc)
• Dummy altitude for Zeb(alt)

SGP/SONDE/C1 - CF sounding 20020609:0229 bad temp/rh/etc

The temperature and RH for this sounding look bad, either because of
interference from another sonde or because the temperature sensor was
broken on launch.  The sounding terminated early in any event.

• Dry bulb temperature(tdry)
• Dummy altitude for Zeb(alt)
• Relative humidity inside the instrument enclosure(rh)
• Ascent Rate(asc)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)
• Ascent Rate(asc)
• Dummy altitude for Zeb(alt)

TWP/C1 - Incorrect elevation reported in Manus Data

(From Bill Clements) We have been using 6m MSL as the station
elevation of Momote (Manus).  This was based on information
posted near the station barometer in the Momote Weather Service
Office.  It turns out that the official WMO station elevation
for Momote is 4m MSL and the upper air elevation is 5m MSL.

All Manus instruments except the sonde station are at 4m MSL.
The sonde launching station is at 5m MSL.

• Dummy altitude for Zeb(alt)

SGP/SONDE/C1 - Incorrect Surface Pressure

It appears that the operator made a typographical error when entering the
surface pressure.  The file has 987.0 hPa and it probably should be 978.0
which would be consistent with the first sample provided by the radiosonde
(977.3 hPa), the surface pressures recorded for the adjacent soundings, and
the THWAPS pressure.

Because the sounding altitude is calculated assuming the surface pressure
is correct, the altitude values for the entire flight and the ascent rate 
values for the first 30 seconds of the sounding will be incorrect.

• Dummy altitude for Zeb(alt)
• Ascent Rate(asc)

• Ascent Rate(asc)
• Dummy altitude for Zeb(alt)

SGP/SONDE/C1 - Bad Temperature Sensor

It appears that the temperature sensor broke shortly after launch.  As a
result, the temperature and dewpoint values are incorrect.

• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)

SGP/SONDE/C1 - Temperature sensor failure

Temperature sensor broke at launch.  All temperature-related variables
are incorrect.

• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)

• Integrated vapor column from sonde using MWR Instrument Performance Model (IPM)(integ_vap_sonde)
• Integrated vapor column from sonde using a direct calculation (external from the
  IPM)(integ_vap_sonde_direct)

SGP/SONDE/C1 - Bad Temperature Sensor

It appears that the temperature sensor broke upon launch and therefore the reported 
temperature is approximately 40 degC too low.

• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)

• Integrated vapor column from sonde using MWR Instrument Performance Model (IPM)(integ_vap_sonde)

• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)

SGP/SONDE/C1 - Bad Temperature Sensor

It appears that the temperature sensor broke shortly after launch. Temperatures are offset 
by approxmiately (but not constantly) 40 degC.

• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)

• Integrated vapor column from sonde using MWR Instrument Performance Model (IPM)(integ_vap_sonde)

• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)

Bad temperature sensor

It appears that the temperture sensor broke a few seconds into flight.  This results in an 
unreasonably low temperature for the rest of the flight.  For some reason, the rh values 
also go missing shortly after launch.  Only the wind and pressure data are reliable.

• Dummy altitude for Zeb(alt)
• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)
• Ascent Rate(asc)

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)
• Ascent Rate(asc)
• Dry bulb temperature(tdry)
• Dummy altitude for Zeb(alt)

• Dummy altitude for Zeb(alt)
• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)

SGP/SONDE/C1 - Questionable RH: CF sounding 11/13/2002:2044

The RH data in this sounding is erratic between 2km and 10 km, oscillating between 
reasonable values (~40%RH) and zero.  I certainly doubt that this is a real, heretofore 
unreported, atmospheric phenomenon so I have to conclude that something is probably wrong with 
the sensor.  I have not seen this behavior before.  One would have to look at the 
absolutely raw RH data to explore further.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

SGP/SONDE/C1 - Contaminated by interference

These three soundings are contaminated by interference from another radiosonde.  It is not 
clear why; this doesn't usually happen at the CF where the operators are very 
experienced and frequency separation is not usually a problem.

• Mean Wind Speed(wspd)
• Dummy altitude for Zeb(alt)
• V-component(v_wind)
• base time(base_time)
• Relative humidity inside the instrument enclosure(rh)
• Ascent Rate(asc)
• Wind Direction(deg)
• Wind Status(wstat)
• U-component(u_wind)
• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Time offset of tweaks from base_time(time_offset)
• lat(lat)
• lon(lon)
• Retrieved pressure profile(pres)

• Mean Wind Speed(wspd)
• U-component(u_wind)
• lat(lat)
• Ascent Rate(asc)
• lon(lon)
• Time offset of tweaks from base_time(time_offset)
• V-component(v_wind)
• Dummy altitude for Zeb(alt)
• Surface dew point temperature(dp)
• base time(base_time)
• Relative humidity inside the instrument enclosure(rh)
• Retrieved pressure profile(pres)
• Wind Direction(deg)
• Wind Status(wstat)
• Dry bulb temperature(tdry)

• null(Raw data stream - documentation not supported)

SGP/SONDE/C1 - Interference CF sounding 20021120:0225

Like several soundings on 11/19, this sounding was affected by interference from another 
radiosonde.

• Mean Wind Speed(wspd)
• Dummy altitude for Zeb(alt)
• V-component(v_wind)
• base time(base_time)
• Relative humidity inside the instrument enclosure(rh)
• Ascent Rate(asc)
• Wind Direction(deg)
• Wind Status(wstat)
• U-component(u_wind)
• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Time offset of tweaks from base_time(time_offset)
• lat(lat)
• lon(lon)
• Retrieved pressure profile(pres)

• Mean Wind Speed(wspd)
• U-component(u_wind)
• lat(lat)
• Ascent Rate(asc)
• lon(lon)
• Time offset of tweaks from base_time(time_offset)
• V-component(v_wind)
• Dummy altitude for Zeb(alt)
• Surface dew point temperature(dp)
• base time(base_time)
• Relative humidity inside the instrument enclosure(rh)
• Retrieved pressure profile(pres)
• Wind Direction(deg)
• Wind Status(wstat)
• Dry bulb temperature(tdry)

• null(Raw data stream - documentation not supported)

SGP/SONDE/C1 - Questionable RH CF sounding 0211211:1130

The RH samples in this sounding oscillate between reasonable values (60-80%) and zero.  
This may be a problem with the RH sensor or the software that alternates between the heated 
and non-heated RH elements.  In either case, the reported values are questionable.  More 
investigation of the raw binary data would be required to diagnose further.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

TWP/SONDE/C1  - Broken Temperature Sensor

The temperature sensor on these radiosondes broke after launch.
All the temperature related data are incorrect.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)

• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)
• Surface dew point temperature(dp)

TWP/Sonde/C1 - Bad RH Values

The RH values from the surface to approximately 11.5 km oscillate between reasonable 
values and zero.  This is apparently caused by a failure in the RH sensor heating process.  
Although the oscillation stops when the heating stops (at temperatures below ~ -45degC) I 
think the values must be viewed as suspect.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

SGP/SONDE/C1 - Bad RH Data

The RH values during the first 15 minutes 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.  I have informed Vaisala of the problem and provided 
raw data files to them for analysis.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

TWP/SONDE/C1 - Questionable RH

It appears that the RH sensor heating circuit failed during this portion of the sounding 
(approximately between 5km and 10km).  The RH oscillates rapidly between low (~5 %RH) and 
not so low (~50 %RH) and the oscillation seems to stop when the temperature is below ~35 
degC.  According to Vaisala these are symptoms of failure in the ASIC (application 
specific integrated circuit) that controls the heating.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

TWP/SONDE/C1 - Bad RH

The RH sensor heating circuit failed on this radiosonde.  The RH-related values obtained 
between 0 and 10000 meters oscillate between near-zero and reasonable ambient values.  
Above 10000 the RH values are likely correct.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

NSA/SONDE/C1 - Broken temperature sensor

It appears that the temperature sensor on this radiosonde broke after launch.  There is a 
sudden drop of 12 degC in 2 seconds and the remaining tdry values seem to be about 30 
degC low.

• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)
• Surface dew point temperature(dp)

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)

TWP/SONDE/C1 - Broken temperature sensor

The temperature sensor on this radiosonde broke after launch.  All the temperature-related 
data are incorrect.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)

• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)
• Surface dew point temperature(dp)

TWP/SONDE/C1 - Broken temperature sensor

The temperature sensor on these radiosondes broke after launch
All the temperature-related data are incorrect.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)

TWP/SONDE/C1 - Bad RH sensors

It appears that the RH sensor heating circuit failed during this portion of the sounding 
(approximately between 0km and 12km).  The RH oscillates rapidly in a 20% range and the 
oscillation seems to stop when the temperature is below ~45 degC.  These are symptoms of 
failure in the ASIC (application specific integrated circuit) that controls the heating.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

TWP/SONDE/C1 - Bad RH sensor

It appears that the RH sensor heating circuit failed during this portion of the sounding 
(approximately between the surface and 11km).  The RH oscillates rapidly between low (~0 
%RH) and high (~80 %RH) and the oscillation seems to stop when the temperature is below 
~40 degC.  According to Vaisala these are symptoms of failure in the ASIC (application 
specific integrated circuit) that controls the heating.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

TWP/SONDE/C1 - Bad RH at beginning of sounding

It appears that the RH sensor heating circuit failed during this portion of the sounding 
(approximately between 0km and 11km).  The RH oscillates rapidly between low (~15 %RH) and 
not so low (~50 %RH) and the oscillation seems to stop when the temperature is below ~40 
degC.  According to Vaisala these are symptoms of failure in the ASIC (application 
specific integrated circuit) that controls the heating.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

TWP/SONDE/C1 - Bad RH at beginning of sounding

It appears that the RH sensor heating circuit failed during this portion of the sounding 
(approximately between 0km and 11km).  The RH oscillates rapidly between low (~0 %RH) and 
not so low (~80 %RH) and the oscillation seems to stop when the temperature is below ~40 
degC.  According to Vaisala these are symptoms of failure in the ASIC (application 
specific integrated circuit) that controls the heating.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

TWP/SONDE/C1  - Bad RH in short interval aloft

It appears that the RH sensor heating circuit on this sonde failed about 31 minutes into 
the flight.  The RH values look reasonable from the surface to approximately 8.25 km at 
which point they begin to oscillate between 0 and 40%.  This behavior stops when the sonde 
reaches approximately 11.0km when the air temperature drops below -40 degC.  The 
oscillation stops at that point, though the RH remains higher than might be expected even under 
supersaturated conditions.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

TWP/SONDE/C1 - Bad RH at beginning of sounding

It appears that the RH sensor heating circuit failed during this portion of the sounding 
(approximately between 0km and 11km).  The RH oscillates rapidly between low (~2 %RH) and 
not so low (~90 %RH) and the oscillation seems to stop when the temperature is below ~40 
degC.  According to Vaisala these are symptoms of failure in the ASIC (application 
specific integrated circuit) that controls the heating.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

NSA/SONDE/C1 - This is a test sounding done using an RS80H radiosonde

This was a sounding done using an RS80H radiosonde to test a special operational 
procedure.  There is nothing wrong with the data, though users should be aware that the sounding 
was not done using the current ARM standard RS90 radiosonde.

• Mean Wind Speed(wspd)
• Wind Direction(deg)
• Ascent Rate(asc)
• Dry bulb temperature(tdry)
• V-component(v_wind)
• base time(base_time)
• Retrieved pressure profile(pres)
• lat(lat)
• U-component(u_wind)
• lon(lon)
• Surface dew point temperature(dp)
• Wind Status(wstat)
• Time offset of tweaks from base_time(time_offset)
• Relative humidity inside the instrument enclosure(rh)
• Dummy altitude for Zeb(alt)

TWP/SONDE/C1 - Bad RH at beginning of sounding

It appears that the RH sensor heating circuit failed during this portion of the sounding 
(approximately between 0km and 11km).  The RH oscillates rapidly between low (~1 %RH) and 
high (~80 %RH).  According to Vaisala these are symptoms of failure in the ASIC 
(application specific integrated circuit) that controls the heating.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

NSA/SONDE/C1 - Test sounding using RS80H

This is a test sounding done using an old RS80H radiosonde rather than the production RS90 
version.  Although the sonde functioned normally, the RH data may be subject to a dry 
bias caused by the age of the sensor and possible contamination.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

NSA/SONDE/C1 - Incorrect surface altitude

The value of the station altitude (relative to mean sea level) is
incorrect in all NSA radiosonde files prior to 2/14/2004.  The correct
value is 8 m.  The incorrect value can be different.  Prior to 4/24/2002
(in platform nsaisssonde...) it was given as 12 m.  From 4/24/2002 to
2/13/2004 (in platform nsasondewnpn...) it is almost always given as
27 m (sometimes [rarely] 17 m).

• Dummy altitude for Zeb(alt)

• null(Raw data stream - documentation not supported)

TWP/SONDE/C1 - Bad RH at beginning of sounding

It appears that the RH sensor heating circuit failed during this portion of the sounding 
(approximately between 0km and 11km).  The RH oscillates rapidly between low (~5 %RH) and 
not so low (~70 %RH) and the oscillation seems to stop when the temperature is below ~40 
degC.  According to Vaisala these are symptoms of failure in the ASIC (application 
specific integrated circuit) that controls the heating.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

TWP/SONDE/C1 - Bad RH at beginning of sounding

It appears that the RH sensor heating circuit failed during this portion of the sounding 
(approximately between 0km and 12km).  The RH oscillates rapidly between low (~2 %RH) and 
not so low (~80 %RH) and the oscillation seems to stop when the temperature is below ~40 
degC.  According to Vaisala these are symptoms of failure in the ASIC (application 
specific integrated circuit) that controls the heating.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

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.

• Mean Wind Speed(wspd)
• Wind Direction(deg)
• Ascent Rate(asc)
• Dry bulb temperature(tdry)
• V-component(v_wind)
• base time(base_time)
• Retrieved pressure profile(pres)
• lat(lat)
• U-component(u_wind)
• lon(lon)
• Surface dew point temperature(dp)
• Wind Status(wstat)
• Time offset of tweaks from base_time(time_offset)
• Relative humidity inside the instrument enclosure(rh)
• Dummy altitude for Zeb(alt)

PYE/SONDE/M1 - Broken RH sensor

One of the RH sensors on this radiosonde was bad.  The RH oscillates rapidly between near 
0 and ambient up to approximately 11 km.  The near-zero values are incorrect.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

PYE/SONDE/M1 - Bad temperature and RH

The temperature appears to be approximately 10 degC too high during the entire sounding.  
This also causes the RH to be too low.  Most likely the problem was a bad temperature 
sensor.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)

PYE/SONDE/M1 - Bad RH sensor

The RH sensor heating circuit failed on this sounding.  RH values during the first part of 
the sounding oscillate between a reasonable value and a very low value.  It appears that 
(a) the heating was out of phase, and (b) incorrect values were being reported during 
the first 10 minutes or so of flight.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

PYE/SONDE/M1 - Bad RH sensor

Two problems here - failure of the RH sensor heating circuit and a bad RH sensor.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

NIM/SONDE/M1 - RH data incorrect.

RH% values oscillate between ambient values and 0%.  The 0% RH values are incorrect.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

NSA/SONDE/C1 - Noisy/Unstable RH and dew point data

The RH readings during the first 8 minutes of this sounding include three apparently 
incorrect oscillations to near-zero values.  After checking the absolutely raw data, it seems 
as though this period was excessively noisy, resulting in many missing values.  The noise 
abatted and the remaining sounding values are valid.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

NSA/SONDE/C1 - Bad surface RH and temperature values

This is a subtle problem that might escape notice.  For the identified sonde launches, the 
ground station lost its signal between the time it was removed from the ground check set 
and the time it was launched.  As a result, the software, which automatically determines 
the launch time and surface conditions at time of launch mistakenly used values of 
temperature and RH representative of the ground check set and the GW rather than of the 
ambient conditions before launch.  The bad values influenced only the first few samples and the 
remainder of the sounding values are correct.  

A procedural problem was identified and corrected.

• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)
• Surface dew point temperature(dp)

NSA/SONDE/C1 - RH values offset due to error in ground check

Background: After installation of the latest software update , we began performing formal 
ground checks on RS92 radiosondes.  By comparing the radiosonde readings with reference 
values in a controlled environment, the ground check is intended to ensure that the 
radiosonde sensors are in calibration before launch.  The radisonde values during the ground 
check process are recorded automatically; the reference values are entered by the operator. 
 If the radiosonde readings vary from the reference values, the system 'corrects' the 
radiosonde values.  In the case of RH, the correction is applied as an offset (true RH = 
indicated RH + correction).

Problem: Some operators misunderstood the ground-check procedure and entered the 
radiosonde values of RH rather than the reference value (assumed 0%RH), thus, some soundings done 
during this period have RH values that are different from what they would be if the 
ground check procedure had been done correctly.

Consequence:  Because the RH corrections generally are small (averaging about 0.5% RH) and 
the precision of the reported RH data during this time period is 1% RH, some values will 
not be affected at all; others will be off by about 1% RH (still within the stated 
accuracy of the sensor).  Furthermore, because entering the radiosonde value as the reference 
value results in a near zero 'correction,' one may view these soundings as being done 
without the ground check correction.  Also note that the dew point value will be suspect as well.

I am attaching below a listing of the soundings that were affected during the indicated 
time period.  Users can see the magnitude of the problem and choose whether or not to apply 
an offset in RH.  Note that application of the offset to the processed RH data (in the 
netCDF file) will not have the same effect of applying the correction to the absolutely 
raw data (before processing), but the differences should be insignificant.  Also note that 
the corrections for each sounding are included in the netCDF header information.  These 
attributes are named 'humidity_correction' and 'humidity_correction_2'.  The values of RH 
indicated by the radiosonde while it is in the ground check set are in attributes 
'humidity_gc_sonde' and 'humidity_gc_sonde_2.'  There is an RH reading for each of the two RH 
sensors used in the RS92 radiosonde.

Here is the list - RH1 and RH2 are the radiosonde readings in the ground check set.  Ref 
is the reference value entered by the operator.  The correcte reference value should be 
0%.  To obtain an approximation to the RH value that would have been recorded if the ground 
check had been done properly, subtract the Ref value from the indicated RH.

 YYYYMMDD  HHMM  SerialNo     RH1     RH2     Ref
 20060713  0532  B1924431    0.30    0.20    0.30
 20060713  1751  B1854963    0.20    0.30    0.30
 20060714  0521  B1924425    0.40    0.40    0.40
 20060714  1739  B1854206    0.30    0.30    0.30
 20060715  0522  B1715127    1.20    1.20    1.20
 20060715  1737  B1854966    0.60    0.60    0.60
 20060716  0508  B1715126    0.40    0.40    0.40
 20060716  1732  B1844098    0.50    0.50    0.50
 20060717  0517  B1914170    0.40    0.40    0.40
 20060718  0516  B1914173    0.70    0.70    0.70
 20060720  0523  B1854149    0.40    0.40    0.40
 20060721  0517  B1914153    0.40    0.40    0.40
 20060722  0521  B1844097    1.00    1.10    1.10
 20060722  1730  B1914174    0.60    0.70    0.70
 20060723  0537  B1714439    0.40    0.40    0.40
 20060723  1734  B1734155    0.50    0.50    0.50
 20060724  0529  B1134336    0.50    0.50    0.50
 20060725  0525  B1754099    0.60    0.70    0.70
 20060726  0541  B1844108    1.80    1.80    1.80
 20060727  0520  B1714382    0.70    0.80    0.70
 20060728  0531  B1854116    0.80    0.80    0.80
 20060729  0527  B1724027    1.00    1.00    1.00
 20060729  1726  B1714392    0.70    0.80    0.80
 20060730  0522  B1854100    0.70    0.80    0.80
 20060730  1724  B1854764    0.90    1.00    1.00
 20060731  0515  B1664086    0.90    0.80    0.90
 20060801  0520  B1724758    1.50    1.50    1.50
 20060801  1729  B1754116    1.10    1.10    1.10
 20060802  0518  B1724516    0.80    0.80    0.80
 20060803  0523  B1674148    0.80    0.80    0.80
 20060804  0532  B1754092    0.90    0.90    0.90
 20060804  1727  B1844117    3.50    3.50    3.50
 20060805  0531  B1714741    0.30    0.30    0.30
 20060805  1728  B1754098    0.30    0.30    0.30
 20060806  0528  B1844115    0.40    0.40    0.40
 20060806  1728  B1914161    0.20    0.20    0.20
 20060807  0530  B1714549    0.30    0.30    0.30
 20060808  0517  B1844107    0.50    0.50    0.50
 20060808  1744  B1914166    0.20    0.20    0.20
 20060809  0527  B1914164    0.30    0.40    0.40
 20060809  1736  B1914163    0.30    0.30    0.30
 20060810  0521  B1914160    0.40    0.50    0.50
 20060810  1745  B1744671    0.40    0.40    0.40
 20060811  0525  B1854965    0.50    0.50    0.50
 20060811  1753  B1724131    0.10    0.10    0.10
 20060812  0527  B1754104    0.50    0.50    0.50
 20060812  1740  B1854256    0.30    0.40    0.40
 20060813  0522  B1854240    0.30    0.40    0.40
 20060814  0525  B1714106    0.20    0.20    0.20
 20060814  1742  B1854106    0.40    0.40    0.40
 20060815  0534  B1914169    0.50    0.60    0.60
 20060815  1734  B1854233    0.60    0.70    0.70
 20060816  0539  B1724791    0.20    0.20    0.20
 20060816  1732  B1914171    0.10    0.20    0.20
 20060817  0535  B1354283    0.10    0.10    0.10
 20060817  1740  B1354574    0.40    0.40    0.40
 20060818  0516  B1354633    0.50    0.40    0.50
 20060818  1744  B1364673    0.20    0.20    0.20
 20060819  0538  B1364126    0.20    0.30    0.30
 20060819  1745  B1354598    0.50    0.60    0.60
 20060820  0532  B1354290    1.10    1.10    1.10
 20060820  1729  B1354317    0.40    0.40    0.40
 20060821  0530  B1354545    0.60    0.70    0.70
 20060821  1728  B1354516    0.70    0.70    0.70
 20060822  0524  B1354619    0.50    0.60    0.60
 20060822  1728  B1364377    0.40    0.40    0.40
 20060823  0533  B1354309    0.30    0.30    0.30
 20060823  1730  B1354527    0.70    0.70    0.70
 20060824  0533  B1354230    0.60    0.60    0.60
 20060824  1812  B1354587    0.70    0.70    0.70
 20060825  0517  B1354614    0.70    0.70    0.70
 20060825  1730  B1354630    0.60    0.60    0.60
 20060826  0537  B1334114    0.90    0.90    0.90
 20060826  1734  B1354246    0.70    0.70    0.70
 20060827  0508  B1354534    0.70    0.70    0.70
 20060827  1729  B1354618    0.60    0.60    0.60
 20060828  0517  B1354115    0.40    0.40    0.40
 20060828  1738  B1354206    0.50    0.60    0.60
 20060829  0516  B1354617    0.50    0.60    0.60
 20060829  1717  B1354622    0.50    0.60    0.60
 20060830  0511  B1354314    0.40    0.50    0.50
 20060830  1732  B1354537    0.60    0.70    0.70
 20060831  1802  B1354239    0.60    0.80    0.80
 20060905  1724  B1354626    0.60    0.60    0.60
 20060906  0522  B1354525    0.60    0.80    0.80
 20060906  1734  B1354107    0.50    0.50    0.50
 20060907  0537  B1354543    0.70    0.70    0.70
 20060907  1803  B1354586    0.80    0.80    0.80
 20060908  0531  B1354519    0.60    0.60    0.60
 20060908  1728  B1354224    0.60    0.60    0.60
 20060909  0534  B1354532    0.70    0.80    0.80
 20060909  1732  B1354513    0.80    0.90    0.90
 20060910  0516  B1354125    0.60    0.70    0.60
 20060910  1727  B1354110    0.40    0.50    0.50
 20060911  0528  B1354235    0.90    0.90    0.90
 20060911  1849  B1354514    0.70    0.70    0.70
 20060912  0525  B1354124    0.60    0.70    0.70
 20060913  0534  B1344478    0.50    0.50    0.50
 20060914  0520  B1354226    0.70    0.70    0.70
 20060915  0529  B1344459    0.40    0.50    0.50
 20060916  0532  B1344469    0.50    0.40    0.50
 20060916  1732  B1354106    0.50    0.60    0.60
 20060917  0527  B1354210    0.70    0.70    0.70
 20060918  0533  B1354087    0.60    0.60    0.60
 20060919  0526  B1354097    0.70    0.50    0.60
 20060920  0516  B1344462    0.50    0.40    0.50
 20060920  1810  B1354536    0.70    0.70    0.70
 20060921  0534  B1354112    0.50    0.60    0.60
 20060921  1800  B1344502    0.40    0.40    0.40
 20060922  0525  B1354531    0.70    0.80    0.80
 20060922  1736  B1354541    0.70    0.70    0.70
 20060923  0519  B1354101    0.50    0.60    0.60
 20060923  1738  B1354576    0.70    0.50    0.70
 20060924  0536  B1354095    0.60    0.60    0.60
 20060925  0536  B1354098    0.60    0.60    0.60
 20060925  1755  B1354100    0.50    0.50    0.50
 20060926  0531  B1334691    0.70    0.70    0.70
 20060926  1742  B1354108    0.40    0.50    0.50

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

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.

• Surface dew point temperature(dp)
• Dry bulb temperature(tdry)
• Relative humidity inside the instrument enclosure(rh)
• Retrieved pressure profile(pres)
• Dummy altitude for Zeb(alt)

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 inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)
• Dummy altitude for Zeb(alt)
• Retrieved pressure profile(pres)
• Surface dew point temperature(dp)

NSA/SONDE/C1 - Incorrect surface values of T and RH

The radiosonde was launched too quickly after being removed from the ground check set.  As 
a result, the system did not equilibrate with the local ground conditions and the 
automatically entered surface values are incorrect.

• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)
• Surface dew point temperature(dp)

NSA/SONDE/C1 - RH sensor failure

It appears that one of the two RH sensors on this radiosonde was affected by ice after 
emerging from a low cold cloud.  As a result the reported RH values oscillate by about 10 
percent until the alternate heating cycle stops.  I suspect the lower value is more close 
to correct, but can't be absolutely sure.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

NSA/SONDE/C1 - Incorrect surface RH value

For an unknown reason the surface RH was reported a 0%.  Becuase these values are entered 
automatically by the system, this is NOT likely an operator error.  Examination of the 
raw data shows that the surface RH at launch time was approximately 81.2 %RH.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)

NSA/SONDE/C1 - Temperature sensor broke at launch

The temperature sensor on this sonde broke at launch.  As a result all the thermodynamic 
data are incorrect.  The wind data are OK, though there will be some uncertainty in the 
altitude values.  This sounding was done at a non-standard time and it isn't clear whether 
it was delayed for some reason or a RHUBC sounding.  In either case, there is no fix.

• Ascent Rate(asc)
• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)
• Dummy altitude for Zeb(alt)
• Surface dew point temperature(dp)

TWP/SONDE/C1 - Surface RH value incorrect

The surface RH value of 77% when the value should have been in the low 60's.  It appears 
the observers did not allow the sonde to equilibrate to ambient conditions before 
collecting the surface data.  This error also caused the dew point to be incorrect.

• Surface dew point temperature(dp)
• Relative humidity inside the instrument enclosure(rh)

FKB/SONDE/M1 - RH values may be slightly overcorrected.

The desiccant in the GC25 ground check set began to lose efficiency at the beginning of 
this time period.  Prior to 9/11/2007 the radiosonde RH readings while in the GC25 (assumed 
RH=0%) were below 1%RH.  The RH readings began to exceed 1%RH on 9/11/2007 and increased 
more or less exponentially to 2.3% RH by the end of 9/18/2007.  The desiccant was 
changed on 9/19/2007 and the radiosonde RH values while in the GC25 again dropped within the 
acceptable limit (< 0.5%RH, in fact).

Because the value obtained from the radiosonde while in the GC25 is subtracted from the 
subsequent RH values as part of the ground check procedure, it is likely that soundings 
done late in this period may be biased low by no more than 2%RH.  The exact amount of the 
correction applied is included in the netCDF header of each file.

• Relative humidity inside the instrument enclosure(rh)
• Surface dew point temperature(dp)