TWP/SONDE/C2  - Broken temperature sensor

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

• Humidity, relative(rh)
• Dewpoint 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.

• Humidity, relative(rh)
• Dewpoint 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.

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

TWP/SMET/C3 - ORG data noisy due to degraded ground

SMET Rain Data began to be noisy during December 2005 and the problem slowly became worse 
over time so that in February 2006 the ORG was reporting with a constant background value 
of around 0.10 mm/hr rain rate.  ORG voltage showed a near constant value above the 85mV 
threshold.  The ground for the ORG had become degraded and was lost due to corrosion.

• precip_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)

TWP/SMET/C3 - Reprocessed: Lower windspeed sensor calibration error

The lower anemometer was replaced but the calibration coefficients were not changed during 
this period.  The data were reprocessed to apply the correct calibrations and the 
reprocessed data were archived in August 2008.

• lo_spd_vec_avg
• lo_spd_sd
• lo_spd_min
• lo_spd_arith_avg
• lo_spd_max

TWP/SMET/C1 - Upper wind sensor failure

The upper wind speed sensor was binding at low wind speeds.  Comparison to the lower wind 
sensor showed that the upper sensor flat-lines for long periods of time.  The upper 
anemometer was replaced.

• up_dir_sd
• up_spd_max
• up_spd_sd
• up_dir_vec_avg
• up_spd_vec_avg
• up_spd_arith_avg
• up_spd_min

TWP/SMET/C2 - Temp/RH probe failure

Temperature/RH probe failed and was replaced.

• vappress_sd
• relh_sd
• temp_sd
• Vapor pressure mean(vappress_mean)
• Relative humidity mean(relh_mean)
• Mean Air Temperature or Hardware Error(temp_mean)

TWP/SMET/C3 - Data not representative

The Anemometer readings were incorrect due to the tower being lowered for maintenance.

• lo_spd_sd
• lo_spd_vec_avg
• lo_spd_min
• lo_dir_sd
• up_spd_arith_avg
• lo_spd_max
• up_spd_vec_avg
• up_dir_sd
• up_spd_max
• lo_dir_vec_avg
• up_spd_min
• up_spd_sd
• lo_spd_arith_avg
• up_dir_vec_avg

TWP/SMET/C1 - Reprocess: Tipping bucket rain gauge added

A tipping bucket rain gauge was added to the TWP.C1 SMET suite of instruments on 20061017. 
 Effective 20060926, two new variables (count and rain amount) were added to the end of 
the twpsmet60sC1.b1 datastream.  Between 9/26 and 10/17, the data for these two variables 
are filled with zeros.  Users should not use the data during this period as the zeros 
are not representative of the rain fall at the site.  When reprocessing of this datastream 
occurs these variables will be added for the 19961009-20060926 and data from 
19961009-20061017 will be filled with -9999 (missing).

• base_time

TWP/SMET/C2 - Reprocess: Tipping bucket rain gauge added

A tipping bucket rain gauge was added to the TWP.C2 SMET suite of instruments on 20061129. 
Effective 20060926, two new variables (count and rain amount) were added to the end of 
the twpsmet60sC2.b1 datastream.  Between 9/26 and 11/29, the data for these two variables 
are filled with zeros.  Users should not use the data during this period as the zeros are 
not representative of the rain fall at the site.  When reprocessing of this datastream 
occurs these variables will be added for the 19981021-20060926 and data from 
19981021-20061129 will be filled with -9999 (missing).

• base_time

TWP/SMET/C3 - Reprocess: Tipping bucket rain gauge added

A tipping bucket rain gauge was added to the SMET suite of instruments effective 20060926. 
 Two new variables (count and rain amount) were added at the end of the twpsmet60sC1.b1 
datastream.  When reprocessing of this datastream occurs these variables will be added 
with -9999 (missing) as the value for dates prior to gauge installation.

• base_time

TWP/SMET/C2 - Barometer failure

The barometer began experiencing problems with noise resulting in incorrect data.  The 
problem becames worse over time; after 12/19/2006 @0151 GMT the barometer data is completely 
missing.  The barometer was replaced.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C3 - Barometer Data Incorrect

The barometer data was incorrect or missing due to water intrusion.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C3 - Water in enclosure

Data became erratic and unreasonable after water intrusion into the enclosure.

• relh_sd
• precip_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• temp_sd
• Vapor pressure mean(vappress_mean)
• Mean Air Temperature or Hardware Error(temp_mean)
• Precipitation mean(precip_mean)
• vappress_sd
• Relative humidity mean(relh_mean)

TWP/SONDE/C2 - Surface Temperature Incorrect

The first two temperature values in the datafile are incorrect.  It appears that the 
observer mis-typed the surface temperature as -27 instead of +27.  The next value was 8 which 
is also incorrect and was caused by the system interpolating from the incorrect surface 
value and what the sonde temperature sensor was reading.

• Dry Bulb Temperature(tdry)

TWP/SONDE/C2 - Surface RH value incorrect

The surface RH value was incorrect.  It appears the observer mis-typed 70 instead of 80.  
This error also caused the dew point temperature to be incorrect.

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

TWP/SONDE/C2 - Surface RH value incorrect

The surface RH was reproted as 78%.  The value should have been in the low 50's.  It 
appears the observer did not allow the sonde to equilibrate to ambient conditions before 
taking the reading.  This error also caused an incorrect dew point.

• Humidity, relative(rh)
• Dewpoint 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.

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

TWP/SONDE/C2 - Surface RH Value incorrect

The surface value entered by the observers for RH (96%) is incorrect.  At the ascent time 
listed in the .ptu file the readings by the Sonde were around 65%.  This low RH value is 
supported by the nearby SMET tower RH reading of 71.8%.  This also caused the surface dew 
point to be incorrect.

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

TWP/SONDE/C2 - Surface RH too high

The surface Rh was entered as 94%.  The ascent time has 72% and this value is supported by 
RH values from the nearby SMET system.  This error also will affect the dew point.

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

TWP/SMET/C1 - Upper winds failure

The upper wind instrument was inoperative resulting in constant wind direction and speed.  
A failed cable was replaced.

• up_dir_sd
• up_spd_max
• up_spd_sd
• up_dir_vec_avg
• up_spd_vec_avg
• up_spd_arith_avg
• up_spd_min

TWP/SONDE/C2 - Broken temperature sensor at launch

Temperature sensor broken at launch.  All thermodynamic values are incorrect.

• Wind Direction(deg)
• Humidity, relative(rh)
• Dewpoint Temperature(dp)

TWP/SONDE/C2 - Broken temperature sensor at launch

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

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

TWP/SMET/C2 - Lower windspeed sensor questionable

Lower wind speed sensor had degraded bearings.  This sensor was reporting as much as 0.4 
m/s lower values than the upper sensors when the winds were 2 m/s or below.  The sensor 
was replaced.

• lo_spd_arith_avg
• lo_spd_min
• lo_spd_vec_avg
• lo_spd_max
• lo_spd_sd

TWP/SMET/C2 - Lower Wind Sensor Direction Incorrect

Wind directions between lower and upper anemometers were displaced by approximately 45 
degrees when a new sensor was installed to replace the failing lower winde sensor.  The new 
sensor direction data incorrect.

• lo_dir_vec_avg
• lo_dir_sd

TWP/SMET/C3 - Upper wind speed artificially slow

The upper wind measurement was consistently slower by around 0.5 - 1 m/s than the lower 
wind measurement.  The bearings on the upper wind measurement were binding.

• up_spd_vec_avg
• up_spd_max
• up_spd_sd
• up_spd_min
• up_spd_arith_avg

TWP/SMET/C3 - ORG overestimated rainfall

Optical rain gauge (ORG) measured approximately 10mm higher than two co-located tipping 
bucket rain gauges and a co-located disdrometer.  The ORG is typically higher but usually 
not by an order of magnitude.

• precip_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)

TWP/SMET/C2 - Lower Wind Speed Data Suspect

The lower wind speed bearings appeared to be binding at speeds below 2 m/s as it did not 
compare well with the upper wind sensor.

• lo_spd_arith_avg
• lo_spd_min
• lo_spd_vec_avg
• lo_spd_max
• lo_spd_sd

TWP/SMET/C3 - Upper Wind Sensor Data Questionable

The wind_up vs. wind_low wind directions diverged, with the differences between the two 
eventually reached 45 degrees. The Upper sensor was found to be mis-aligned and loose.

• up_spd_vec_avg
• up_spd_max
• up_spd_sd
• up_spd_min
• up_spd_arith_avg

TWP/SMET/C1 - Reprocess: ORG Data has very small rainrate values

The ORG data is collected via analog signal and not digital.  Therefore, we continuously 
collect data even when no rain is occurring.  We also capture small events such as leaves, 
large bugs, dust, etc blowing through the measurement path.  Because this discrete event 
occurs quickly the value is usually captured for 1 or 2 seconds.  This value is then 
averaged to the minute producing rainrate on the order of .009 mm/hr or less.  These values 
are not indicative of rain and should be removed from the record or summing over long 
periods can bias the climate record.  We are reprocessing the data to remove these small 
values and are adjusting the collection program to remove them before ingest.

• Precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• precip_sd
• Precipitation mean(precip_mean)

TWP/SMET/C3 - Reprocess: ORG Data has very small rainrate values

The ORG data is collected via analog signal and not digital.  Therefore, we
continuously collect data even when no rain is occurring.  We also capture small events 
such as leaves, large bugs, dust, etc blowing through the measurement path.  Because this 
discrete event occurs quickly the value is usually captured for 1 or 2 seconds.  This 
value is then averaged to the minute producing rainrate on the order of .009 mm/hr or less.  

These values are not indicative of rain and should be removed from the record or summing 
over long periods can bias the climate record.  We will reprocess the data to remove these 
small values.

• precip_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)

TWP/SMET/C2 - Reprocess: ORG Data has very small rainrate values

The ORG data is collected via analog signal and not digital.  Therefore, we continuously 
collect data even when no rain is occurring.  We also capture small events such as leaves, 
large bugs, dust, etc blowing through the measurement path.  Because this discrete event 
occurs quickly the value is usually captured for 1 or 2 seconds.  This value is then 
averaged to the minute producing rainrate on the order of .009 mm/hr or less.  

These values are not indicative of rain and should be removed from the record or summing 
over long periods can bias the climate record.  We will reprocess the data to remove these 
small values.

• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• precip_sd

TWP/SMET/C3 - Lower Wind Direction Intermittently Wrong

The lower wind sensor cabling had a problem causing an intermittent connection for the 
wind direction data.

• lo_dir_sd
• lo_dir_vec_avg

TWP/SMET/C2 - ORG rainfall measurements too large

The ORG was collecting large amounts of rainfall compared to the co-located tipping bucket 
raingauge.  The cable was chewed by mice causing the wires to make contact 
intermittently mimicking rainfall.

• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• precip_sd

TWP/SMET/C1 - ORG Precip Data Incorrect

Moisture intrusion into the sensor body allowed condensation on the lens of the ORG.  
Continual and long-term precipitation was reported during this time.

• Precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• precip_sd
• Precipitation mean(precip_mean)

TWP/SMET/C3 - Upper wind speed data incorrect

Beginning on 07/08, the upper wind sensor started reporting significantly lower wind 
speeds than the lower wind sensor.  The cable connections weather proofing failed allowing 
corrosion to occur and increasing he resistance of the cables.  This in turn lowered the 
wind speeds artificially.

• up_spd_vec_avg
• up_spd_max
• up_spd_sd
• up_spd_min
• up_spd_arith_avg

TWP/SMET/C3 - Missing data

Data are missing and unrecoverable.

• alt
• lo_dir_sd
• lon
• base_time
• tbrg_count_total
• time_offset
• Vapor pressure mean(vappress_mean)
• Relative humidity mean(relh_mean)
• logger_temp
• up_spd_max
• up_spd_min
• lo_spd_vec_avg
• lo_spd_sd
• precip_sd
• lo_spd_min
• Barometric Pressure(atmos_pressure)
• temp_sd
• lat
• up_spd_arith_avg
• lo_spd_max
• vappress_sd
• up_spd_vec_avg
• relh_sd
• up_dir_sd
• time
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• up_spd_sd
• lo_dir_vec_avg
• internal_voltage
• lo_spd_arith_avg
• tbrg_total
• Precipitation mean(precip_mean)
• Mean Air Temperature or Hardware Error(temp_mean)
• up_dir_vec_avg

TWP/SONDE/C2 - Bad RH values throughout sounding

RH values fluctuate largely in a stepping function throughout the sounding.  Suspect bad 
RH sensors.

• Humidity, relative(rh)

TWP/SMET/C1 - Wind Speed data contain offset due to induced voltage

The marine model of the RM Young wind sensor needs twisted pair shielded cable.  The 
manufacturer did not originally supply the pigtail with twisted pair shielded cable.  Use of 
twisted pair shielded cable for the rest of the cable run to the logger was also not 
specified.  This caused an induced voltage in the wind speed line from the wind direction 
excitation.  The induced voltage varied from sensor to sensor and probably changed anytime 
the cable was replaced or parts of the wind sensor were repaired or replaced. The induced 
voltage has been seen to vary from 0.15 m/s to as much as 1.08 m/s.

• lo_spd_max
• up_spd_max
• lo_spd_vec_avg
• lo_spd_min
• lo_spd_arith_avg
• up_spd_sd
• up_spd_vec_avg
• up_spd_arith_avg
• up_spd_min
• lo_spd_sd

TWP/SMET/C2 - Wind Speed data contain offset due to induced voltage

The marine model of the RM Young wind sensor needs twisted pair shielded cable.  The 
manufacturer did not originally supply the pigtail with twisted pair shielded cable.  Use of 
twisted pair shielded cable for the rest of the cable run to the logger was also not 
specified.  This caused an induced voltage in the wind speed line from the wind direction 
excitation.  The induced voltage varied from sensor to sensor and probably changed anytime 
the cable was replaced or parts of the wind sensor were repaired or replaced. The induced 
voltage has been seen to vary from 0.15 m/s to as much as 1.08 m/s.

• lo_spd_arith_avg
• lo_spd_min
• lo_spd_vec_avg
• up_spd_min
• up_spd_arith_avg
• lo_spd_max
• up_spd_sd
• up_spd_max
• lo_spd_sd
• up_spd_vec_avg

TWP/SMET/C3 - Wind Speed data contain offset due to induced voltage

The marine model of the RM Young wind sensor needs twisted pair shielded cable.  The 
manufacturer did not originally supply the pigtail with twisted pair shielded cable.  Use of 
twisted pair shielded cable for the rest of the cable run to the logger was also not 
specified.  This caused an induced voltage in the wind speed line from the wind direction 
excitation.  The induced voltage varied from sensor to sensor and probably changed anytime 
the cable was replaced or parts of the wind sensor were repaired or replaced. The induced 
voltage has been seen to vary from 0.15 m/s to as much as 1.08 m/s.

• up_spd_vec_avg
• lo_spd_vec_avg
• lo_spd_sd
• lo_spd_min
• up_spd_max
• up_spd_sd
• up_spd_min
• lo_spd_arith_avg
• up_spd_arith_avg
• lo_spd_max

TWP/SMET/C2 - ORG rainrate high due to calibration.

The rainrate from the ORG was high due to calibration.  This data is not real.

• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• precip_sd

TWP/SONDE/C2 - Defective Temperature Sensor

Temperature sensor shows a +30C offset for duration of flight.

• Dry Bulb Temperature(tdry)

TWP/SMET/C3 - Reprocess: Station Pressure values reported in hPa instead of kPa.

An incorrect program was entered into the datalogger.  This program did not convert the 
station pressure from hPa to kPa.  This made the values larger by a factor of 10 and caused 
the QC bit to be tripped.

• Barometric Pressure(atmos_pressure)

TWP/SONDE/C2 - Suspect RH values

RH values only are suspect for the duration of this radiosonde flight, exhibiting a 
"sawtooth" pattern.

• Humidity, relative(rh)

TWP/SMET/C1 - Optical Rain Gage Inoperative

Beginning on 02/07/2009, the trending between the TBRG and ORG began to look poor, one 
recording precip when the other was not and vice versa.  After a while the ORG quit 
registering any precip at all.  ORG was replaced.

• Precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• precip_sd
• Precipitation mean(precip_mean)

TWP/SMET/C3 - Reprocess: Temperature Biased low by 1.06 Degrees

The temperature of the SMET system was biased low by 1.06 Deg C due to a non-precision 
resistor being used int he measurement circuit.  The data will be reprocessed.  Saturation 
Vapor pressure and Vapor pressure will have to be reprocessed also.

Add 1.06 degrees to the temperature data.  

Correct Sat Vap Press using the Buck approximation:
   Es = 6.1121exp((17.502*T)/(240.97 + T) 
where T is the temperature in C.  

Correct Vapor pressure using: E = (RH*Es)/100

• temp_sd
• Mean Air Temperature or Hardware Error(temp_mean)
• Vapor pressure mean(vappress_mean)
• vappress_sd

TWP/SMET/C2 - Barometer data incorrect

Beginning 05/20, atmos_pressure exceeded MAX between ~21:00 and 01:00 UTC on most days.  
The inlet tube was accidentally pinched in the door of the logger enclosure artificially 
increasing the atmospheric pressure during the listed times.  Only a few hours exceeded 
max limits.

• Barometric Pressure(atmos_pressure)

TWP/SONDE/C1 - Wind data missing

A GPS problem associated with Vaisala BBSS ground station software issues caused the 
ground stations to enter into an error state when using GPS wind finding. In some instances, 
the flight was aborted due to the error state and not data was collected.  A workaround 
was developed to allow sondes to be launched without collecting wind data.

• wstat
• Northward Wind Component(v_wind)
• Eastward Wind Component(u_wind)
• Mean Wind Speed(wspd)

TWP/SONDE/C2 - Wind data missing

A GPS problem associated with Vaisala BBSS ground station software issues caused the 
ground stations to enter into an error state when using GPS wind finding. In some instances, 
the flight was aborted due to the error state and not data was collected.  A workaround 
was developed to allow sondes to be launched without collecting wind data.

• wstat
• Eastward Wind Component(u_wind)
• Northward Wind Component(v_wind)
• Mean Wind Speed(wspd)

TWP/SMET/C1 - Reprocess: Barometric pressure data scaled incorrectly

The barometer data was scaled incorrectly when a new program was loaded into the 
datalogger.  The pressure data was reported as mb (hPa) instead of the standard kPa.  So, in 
essence the value was a factor of ten to large.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C2 - Induced wind speed when calm

The upper and lower wind sensors were not trending well at wind speed below 1 m/s.  Both 
sensors were showing values above 0m/s when calm.  The lightning protector was at fault 
resulting in an induced wind voltage during calm conditions.

Users should subtract any offset found (for example 0.19 m/s for upper wind speed) when 
the wind speeds are flat-lined.  The offset value was not consistent.

• lo_spd_arith_avg
• lo_spd_min
• lo_spd_vec_avg
• up_spd_min
• up_spd_arith_avg
• lo_spd_max
• up_spd_max
• up_spd_vec_avg

TWP/SMET/C3 - Tower Lowered for Maintenance

The tower was lowered for annual anemometer changes.  The wind data is suspect.

• lo_spd_sd
• lo_spd_vec_avg
• lo_spd_min
• lo_dir_sd
• up_spd_arith_avg
• lo_spd_max
• up_spd_vec_avg
• up_dir_sd
• up_spd_max
• lo_dir_vec_avg
• up_spd_min
• up_spd_sd
• lo_spd_arith_avg
• up_dir_vec_avg

TWP/SMET/C2 - Tower Lowered for Maintenance

Data is suspect due to the tower being lowered.

• vappress_sd
• lo_spd_arith_avg
• relh_sd
• lo_spd_min
• lo_dir_vec_avg
• temp_sd
• up_dir_vec_avg
• lo_spd_vec_avg
• Vapor pressure mean(vappress_mean)
• up_spd_min
• up_dir_sd
• up_spd_max
• Mean Air Temperature or Hardware Error(temp_mean)
• up_spd_vec_avg
• lo_dir_sd
• Relative humidity mean(relh_mean)
• up_spd_arith_avg
• lo_spd_max
• up_spd_sd
• lo_spd_sd

TWP/SMET/C2 - Barometer failure

The atmos_pressure values were spiking high (up to 110 kPa) from 06:00 UTC on 02/04 until 
the data went missing at 10:44 UTC on 02/06 when the barometer failed completely.

Barometer replaced 2/23.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C1 - Missing RH, Barometer, and ORG data

Atmos_pressure data suddenly went missing on 03/02 at 07:34 UTC and consequently, the 
relative humidity data flatlined. 

Furthermore, after a sudden precipitation event when the max precip rate flag was tripped 
the TBRG total has not agreed with the comparison ORG or the precip rate plot. 

A loose wire connection was fixed 3/22 restoring RH and barometer data.  A damaged cable 
was repaired 5/11 restoring ORG data.

• Relative humidity mean(relh_mean)
• Precipitation minimum(precip_min)
• relh_sd
• Barometric Pressure(atmos_pressure)
• Precipitation maximum(precip_max)
• precip_sd
• Precipitation mean(precip_mean)

TWP/SMET/C1 - Aux (lower) wind sensor failed

The lower wind direction sensor on the C1 site was flatlining at 270 degrees throughout 
most of the daylight hours of the day. During the night the sensor appeared to be working 
fine.

• lo_spd_max
• lo_spd_vec_avg
• lo_spd_min
• lo_spd_arith_avg
• lo_dir_vec_avg
• lo_dir_sd
• lo_spd_sd