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.

• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)

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.

• Upper sensor, wind direction standard deviation(up_dir_sd)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind speed standard deviation(up_spd_sd)

TWP/SMET/C2 - Temp/RH probe failure

Temperature/RH probe failed and was replaced.

• Mean Relative Humidity(relh_mean)
• Mean Air Temperature or Hardware Error(temp_mean)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Std Dev of Air Temperature(temp_sd)
• Vapor pressure standard deviation(vappress_sd)
• Vapor pressure mean(vappress_mean)

TWP/SMET/C3 - Data not representative

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

• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed maximum(lo_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Lower sensor, wind direction standard deviation(lo_dir_sd)
• Upper sensor, wind speed maximum(up_spd_max)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• Upper sensor, wind speed vector average(up_spd_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(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(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(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.

• Precipitation mean(precip_mean)
• Vapor pressure standard deviation(vappress_sd)
• Precipitation maximum(precip_max)
• Mean Relative Humidity(relh_mean)
• Mean Air Temperature or Hardware Error(temp_mean)
• Precipitation standard deviation(precip_sd)
• Vapor pressure mean(vappress_mean)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• precipitation minimum(precip_min)
• Std Dev of Air Temperature(temp_sd)

TWP/SMET/C1 - Upper winds failure

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

• Upper sensor, wind direction standard deviation(up_dir_sd)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind speed standard deviation(up_spd_sd)

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.

• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Lower sensor, wind speed maximum(lo_spd_max)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Lower sensor, wind speed standard deviation(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.

• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Lower sensor, wind direction standard deviation(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.

• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)

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.

• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)

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.

• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Lower sensor, wind speed maximum(lo_spd_max)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Lower sensor, wind speed standard deviation(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.

• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_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.

• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Lower sensor, wind direction standard deviation(lo_dir_sd)

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 maximum(precip_max)
• Precipitation mean(precip_mean)
• precipitation minimum(precip_min)
• Precipitation standard deviation(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 mean(precip_mean)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)

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.

• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)

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.

• Upper sensor, wind speed maximum(up_spd_max)
• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Lower sensor, wind speed maximum(lo_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)