TWP/C2/Sonde Missing Data

There were no sondes launced during this period because there was
no helium on site and the hydrogen generator was not working.  The
hydrogen generator was repaired and launches resumed.

• null(Raw data stream - documentation not supported)

• null(Raw data stream - documentation not supported)

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

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

TWP/SONDE/C2 - Missing Winds

About half of the soundings in November-December exhibited drop-outs
in the winds.  These dropouts were typically over a depth of 1-2 km.
Sometimes the dropout occurred at the surface, sometimes at the top of
the sounding and sometimes in the middle.  These gaps occurred on:

19981126
19981129
19981206
19981209
19981210
19981211
19981212
19981221
19981222

• Mean Wind Speed(wspd)
• U-component(u_wind)
• V-component(v_wind)

• Mean Wind Speed(wspd)

TWP/C2/Balloon Soundings: Missing Flights

No sondes were launched during this period for reasons unknown.

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

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

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.

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

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

TWP/C1/Balloon Soundings Maximum Altitude

This sonde only reached a height of 0.3 km.

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

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

TWP/C2  Installation

The Nauru ARCS was installed during the period September-November
1998.  Data were being collected by the end of October, but for the
first several weeks of November, the site was undergoing considerable
change, so data from that period should be used with caution.  The
official site dedication occured on November 20.  Most on-site
activity ended following the dedication so we will consider November
20 to be the beginning of the Nauru operations.  The last members of
the installation team left Nauru on November 24.

• null(Raw data stream - documentation not supported)

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

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

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/SONDE/C2  - Broken Temperature Sensor

The temperature sensors on these radiosondes broke at launch.  All
the temperature-related data are incorrect.

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

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

TWP/SONDE/C1  - Broken Temperature Sensor

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

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

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

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.

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

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

TWP/SONDE/C2 - Bad RH Data (AIRS Validation Sonde)

The RH sensor heating circuit failed on this sonde.  This results in
oscillation of reported RH between reasonable values and values near zero.
This was an AIRS validation sounding.

• 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 - 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.

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

• 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.

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

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

TWP/SONDE/C1 - Broken temperature sensor

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

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

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

TWP/SONDE/C2  - Failure of RH sensor

It appears that the RH sensor heating circuit failed during this sounding.  The RH 
oscillates rapidly between low (~0 %RH) and not so low (ambient %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/C2 - Strange problem with data -

This is very strange.  The data has what appears to be a pressure jump at launch (from 
1007.2 to 956.5 hPa) but the sounding temperature and RH data clearly look to be 
interpolated between the surface and tropopause.  By examining the absolutely raw data, I found that 
the system assigned an elapsed time of 408 seconds (since system start up) to the launch 
point, but there is no raw data between 410 and 532 seconds.  The raw pressure value at 
410 seconds is 1007.6 hPa and that at 532 seconds is 40.9 hPa!  Unless this sounding was 
done by using a rocket-powered balloon (maybe even then), it would be impossible for the 
sonde to get to 40.9 hPa in 2 minutes.  Because the apparent gap is only two minutes, the 
system was able to interpolate but is not sophisticated enough to understand that the 
limits of the interpolation are unreasonable.

I can't imagine what went wrong - I've not seen anything like this before.

• null(Raw data stream - documentation not supported)

• null(Raw data stream - documentation not supported)

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

TWP/SONDE/C2 - RH sensor bad

It appears that the RH sensor heating circuits failed during these
soundings.  The RH oscillates rapidly between low (~0 %RH) and not
so low (ambient %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.

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

TWP/SONDE/C2 - Broken temperature sensors

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

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

TWP/SONDE/C2  - Questionable rH data

It appears that the RH sensor heating circuit failed during this sounding.  The RH 
oscillates rapidly between low (~0 %RH) and not so low (ambient %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.

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

TWP/SONDE/C2  - Bad RH sensor

It appears that the RH sensor heating circuit failed during this sounding.  The RH 
oscillates rapidly between low (~0 %RH) and not so low (ambient %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.

• Relative humidity inside the instrument enclosure(rh)
• 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.

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

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

TWP/SONDE/C2 - Bad RH values aloft

It appears that the RH sensor heating circuit on this sonde failed about 24 minutes into 
the flight.  The RH values look reasonable, though somewhat noisy, from the surface to 
approximately 6.9 km (439 hPa) at which point they begin to oscillate between 0 and 100 %.  
This behavior stops when the sonde reaches approximately 11.5km (232 hPa) 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.

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

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.

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

• 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.

• 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 (~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.

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

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.

• 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 (~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.

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

TWP/SONDE/C2  - RH sensor failure near surface

It appears that the RH sensor heating circuit failed during this sounding.  The RH 
oscillates rapidly between low (~0 %RH) and not so low (ambient %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.

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

TWP/SONDE/C2 - Operator used wrong calibration tape

It appears as though the opperator used the wrong calibration tape for this sounding.  The 
primary symptom is a jump in temperature from a surface value of 30.1 degC to the first 
value aloft of 61.0 degC.  Secondly, the recorded serial number for this sounding is 
Z1430179 which is the same serial number recorded for the previous sounding.

This problem points to three failures of procedure (I have notified TWP site ops by 
e-mail).  The first failure is using the wrong tape. The second failure is not checking the 
radiosonde values before launch which relates to the third failure of not entering the 
radiosonde values as the surface values of the sounding.

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

TWP/SONDE/C2  - RH sensor failure below 9km

It appears that the RH sensor heating circuit failed during this sounding.  The RH 
oscillates rapidly between low (~0 %RH) and not so low (ambient %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.

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

TWP/SONDE/C2 - Bad RH values aloft

It appears that the RH sensor heating circuit on these sondes failed after launch but 
resume proper operation when the ambient temperature dropped below ~40 degC.

• 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 (~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.

• 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 (~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.

• 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 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.

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

TWP/SONDE/C2 - Bad RH sensor

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

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

TWP/SONDE/C2 - Broken temperature sensor

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

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

TWP/SONDE/C2  - Broken temperature sensor

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

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

TWP/SONDE/C2  - Broken temperature sensor

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

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

TWP/SONDE/C2  - Broken temperature sensor

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

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

TWP/SONDE/C2  - Bad RH in lower 8km

It appears that the RH sensor heating circuit failed during this sounding.  The RH 
oscillates rapidly between low (~0 %RH) and not so low (ambient %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.

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

TWP/SONDE/C2 - Failure of RH sensor

The RH sensor ASIC that controls the sensor heating failed.  As a result the RH at the 
beginning of the sounding oscillates between near-zero and ambient values.  The RH heating 
cycle stops when the ambient temperature reaches below -30 degC; above this level RH 
values should be valid.

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