TWP/SMET/C3 - Lower wind direction sensor misaligned

The lower wind direction sensor (sensor #2) was misaligned and off by 15 degrees.

• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #2 direction vector average(wind2_dir_vec_avg)

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

TWP/SMET/C3 - Intermittent Pressure Sensor Failure

The Barometric Pressure sensor was intermittently failing at TWP site C3 Darwin.  At times 
there were large pressure fluctuations occurring on the order of 24 mb in a few minutes. 
 Times of large pressure fluctuations are readily apparent in the data.  At these times 
the data should be carefully analyzed before determining it's usefulness.  In between the 
periods of large fluctuations the readings appear to be stable.  It is still suggested 
that independent pressure data be obtained for comparison before use.

• Barometric Pressure(atmos_pressure)

• Barometric Pressure(atmos_pressure)

TWP/SMET/C3 - Data reported at 15sec rather than 60s intervals

Data in these data streams should be reported at 60sec intervals, but
the logger program running during this time had the interval set to
15s.  Users will have to average the 15sec data to get 60sec data.

• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #2 speed maximum(wind2_spd_max)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Precipitation mean(precip_mean)
• Time offset of tweaks from base_time(time_offset)
• Vapor pressure standard deviation(vappress_sd)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #1 direction standard deviation(wind1_dir_sd)
• Temperature maximum(temp_max)
• Logger panel temperature(logger_temp)
• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Battery Voltage(internal_voltage)
• Bit data. See details.(bit_data)
• Wind #2 speed minimum(wind2_spd_min)
• Precipitation maximum(precip_max)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Barometric Pressure(atmos_pressure)
• Relative humidity maximum(relh_max)
• Relative humidity minimum(relh_min)
• Vapor pressure mean(vappress_mean)
• Std Dev of Air Temperature(temp_sd)
• Temperature minimum(temp_min)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• External voltage(external_voltage)
• precipitation minimum(precip_min)
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Mean Relative Humidity(relh_mean)
• Precipitation standard deviation(precip_sd)
• Wind #1 speed maximum(wind1_spd_max)

• Lower sensor, wind direction standard deviation(lo_dir_sd)
• Vapor pressure mean(vappress_mean)
• Logger panel temperature(logger_temp)
• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed minimum(up_spd_min)
• Precipitation standard deviation(precip_sd)
• Lower sensor, wind speed minimum(lo_spd_min)
• Std Dev of Air Temperature(temp_sd)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Precipitation maximum(precip_max)
• precipitation minimum(precip_min)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Tipping bucket raingauge total(tbrg_total)
• Mean Air Temperature or Hardware Error(temp_mean)
• Precipitation mean(precip_mean)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Tipping bucket raingauge count total(tbrg_count_total)
• Time offset of tweaks from base_time(time_offset)
• Mean Relative Humidity(relh_mean)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Barometric Pressure(atmos_pressure)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed maximum(lo_spd_max)
• Vapor pressure standard deviation(vappress_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• time(time)
• Battery Voltage(internal_voltage)

TWP/SMET/C3 - Rain blocked pressure port

Atmospheric pressure values were suspect due to anomolous readings during heavy rain 
events.  Suspect blockage of port due to rainfall.  New logger and enclosure corrected problem.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C3 - Negative rainfall rates

Due to limitations of the Zeno dataloggers all voltage measurements
from the optical rain gauge (ORG) were converted to rainfall rates. 
This resulted in negative values for rain rates.  Any value below
0.10 mm/hr should be considered to be 0 mm/hr.  New dataloggers 
alleviated this problem.

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

TWP/SMET/C3 - Data non-representative

Tower mast was lowered for inspection.  Data during this time is non-representative.

• Lower sensor, wind direction standard deviation(lo_dir_sd)
• Tipping bucket raingauge count total(tbrg_count_total)
• Vapor pressure mean(vappress_mean)
• Mean Relative Humidity(relh_mean)
• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed minimum(up_spd_min)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Precipitation standard deviation(precip_sd)
• Lower sensor, wind speed minimum(lo_spd_min)
• Barometric Pressure(atmos_pressure)
• Std Dev of Air Temperature(temp_sd)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed maximum(lo_spd_max)
• Vapor pressure standard deviation(vappress_sd)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Precipitation maximum(precip_max)
• precipitation minimum(precip_min)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Tipping bucket raingauge total(tbrg_total)
• Mean Air Temperature or Hardware Error(temp_mean)
• Precipitation mean(precip_mean)
• Upper sensor, wind direction vector average(up_dir_vec_avg)

TWP/SMET/C3 - Lower wind direction sensor failure

The lower wind direction sensor failed on 4/14 and disagrees significantly with the upper 
wind direction sensor.  The lower wind sensor reports a constant value around 0-15 
degrees since it failed.  Testing showed that excitation channel two on the logger was the 
problem.  Logger was replaced by spare.

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

TWP/SMET/C3 - Data not representative

Tower was lowered for radiometer change and characterization. Data are not representative 
of local conditions.

• Lower sensor, wind direction standard deviation(lo_dir_sd)
• Tipping bucket raingauge count total(tbrg_count_total)
• Vapor pressure mean(vappress_mean)
• Mean Relative Humidity(relh_mean)
• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed minimum(up_spd_min)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Precipitation standard deviation(precip_sd)
• Lower sensor, wind speed minimum(lo_spd_min)
• Barometric Pressure(atmos_pressure)
• Std Dev of Air Temperature(temp_sd)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed maximum(lo_spd_max)
• Vapor pressure standard deviation(vappress_sd)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Precipitation maximum(precip_max)
• precipitation minimum(precip_min)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Tipping bucket raingauge total(tbrg_total)
• Mean Air Temperature or Hardware Error(temp_mean)
• Precipitation mean(precip_mean)
• Upper sensor, wind direction vector average(up_dir_vec_avg)

TWP/SMET/C3 - Upper wind sensor failure

A lightning strike destroyed the upper wind sensor.

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

TWP/SMET/C3 - RH Values Artificially High

Lightning strike caused RH readings to be higher than reasonable (130%).

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

TWP/SMET/C3 - Instrument failure

A lightning strike caused a failure in the ORG.  Rainfall was being continually recorded.

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

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 standard deviation(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.

• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• 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)

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

TWP/SMET/C3 - Reprocess: Barometric pressure units change

Barometric pressure data during this time period is reported in hPa.  After this time, the 
data have been converted to kPa to standardize the measurement units among ARM sites and 
to conform to accepted standard units determined by the scientific community.

• Barometric Pressure(atmos_pressure)

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/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.

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

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

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

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

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

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

TWP/SMET/C3 - Missing data

Data are missing and unrecoverable.

• Dummy altitude for Zeb(alt)
• Lower sensor, wind direction standard deviation(lo_dir_sd)
• lon(lon)
• base time(base_time)
• Tipping bucket raingauge count total(tbrg_count_total)
• Time offset of tweaks from base_time(time_offset)
• Vapor pressure mean(vappress_mean)
• Mean Relative Humidity(relh_mean)
• Logger panel temperature(logger_temp)
• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed minimum(up_spd_min)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Precipitation standard deviation(precip_sd)
• Lower sensor, wind speed minimum(lo_spd_min)
• Barometric Pressure(atmos_pressure)
• Std Dev of Air Temperature(temp_sd)
• lat(lat)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed maximum(lo_spd_max)
• Vapor pressure standard deviation(vappress_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• time(time)
• Precipitation maximum(precip_max)
• precipitation minimum(precip_min)
• Battery Voltage(internal_voltage)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Tipping bucket raingauge total(tbrg_total)
• Mean Air Temperature or Hardware Error(temp_mean)
• Precipitation mean(precip_mean)
• Upper sensor, wind direction vector average(up_dir_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.

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

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/SMET/C3 - Reprocess: Temperature data biased low

Due to a datalogger problem, the temperature data were biased low by 2.13 degrees C.

The data will be reprocessed.

• Std Dev of Air Temperature(temp_sd)
• Mean Air Temperature or Hardware Error(temp_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

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