TWP/C2/SMET Wind Speeds

Beginning on December 24, Anemometer #1 (there are two anemometers on
the SMET stand) occasionally reported wind speed values that were low
relative to the other sensor.  It is clear from the data that the low
reading here is the anomalous one.

• Wind #1 speed minimum(wind1_spd_min)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• wind1_dir_sd
• wind1_spd_sd
• Wind #1 speed maximum(wind1_spd_max)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Wind #1 direction vector average(wind1_dir_vec_avg)

• Raw data stream - documentation not supported

• wind1_spd_sd
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• wind1_dir_sd
• Wind #1 speed maximum(wind1_spd_max)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #1 speed maximum gust(wind1_spd_max_gust)

TWP/C2/SMET Wind Speeds

Beginning on December 24, Anemometer #1 (there are two anemometers on
the SMET stand) occasionally reported wind speed values that were low
relative to the other sensor.  It is clear from the data that the low
reading here is the anomalous one.

• Wind #1 speed minimum(wind1_spd_min)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• wind1_dir_sd
• wind1_spd_sd
• Wind #1 speed maximum(wind1_spd_max)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Wind #1 direction vector average(wind1_dir_vec_avg)

• Raw data stream - documentation not supported

• wind1_spd_sd
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• wind1_dir_sd
• Wind #1 speed maximum(wind1_spd_max)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #1 speed maximum gust(wind1_spd_max_gust)

TWP/C2/SMET Winds Speeds

Beginning on December 24, Anemometer #1 (there are two anemometers on
the SMET stand) occasionally reported wind speed values that were low
relative to the other sensor.  It is clear from the data that the low
reading here is the anomalous one.

• Wind #1 speed minimum(wind1_spd_min)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• wind1_dir_sd
• wind1_spd_sd
• Wind #1 speed maximum(wind1_spd_max)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Wind #1 direction vector average(wind1_dir_vec_avg)

• Raw data stream - documentation not supported

• wind1_spd_sd
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• wind1_dir_sd
• Wind #1 speed maximum(wind1_spd_max)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #1 speed maximum gust(wind1_spd_max_gust)

TWP/C2/SMET Temperature spike

There was a brief -4 C spike in the temperature at approximately
21.5 Z on December 3.  This spike also showed up in the vapor pressure
which is calculated from the temperature and relative humidity.

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

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

TWP/C2/SMET - Pressure sensitivity to rain

The pressure behaves anomalously during rain events - even very mild
ones.  Normally, the pressure undergoes a smooth semi-diurnal
oscillation with little higher frequency variability.  However, during
and shortly after rain events, the pressure signal exhibits abrupt
changes - this sort of behavior has occasionally been observed at
Manus but not with the regularity seen here.  Examples of this
behaviour occur on (date in the form YYYYMMDD):

19981212
19981215
19981216
19981217
19981223
19981224
19981225
19981230
19981231

• vappress_sd
• Vapor pressure mean(vappress_mean)
• Barometric Pressure(atmos_pressure)

• Barometric Pressure(atmos_pressure)
• Vapor pressure mean(vappress_mean)
• vappress_sd

TWP/SMET/C2 - RH Sensor bad at Nauru

RH sensor bad from 16 Dec 2001 03 GMT to 3 Jan 2002

• relh_sd
• Relative humidity mean(relh_mean)
• Relative humidity maximum(relh_max)
• Relative humidity minimum(relh_min)

• relh_sd
• Relative humidity minimum(relh_min)
• Relative humidity mean(relh_mean)
• Relative humidity maximum(relh_max)

TWP/SMET/C1/C2 - Switch to new Data Header Formats not timely

On April 1, 2001 at 00:00:00 new data header with consistent variable naming conventions, 
etc were to be used for all sites, all data streams.  At the TWP sites the time of the 
movement to the new convention did not occur precisely at 00:00:00.  The following data 
files contain between 40 seconds and 20 minutes of data from 4/1/02 in the old format.  The 
delayed format change did not affect data quality in any way.

twpsmet60sC1.a1.20010401.000001.cdf
twpsmet60sC1.b1.20010401.000001.cdf
twpsmet60sC2.a1.20010401.000000.cdf
twpsmet60sC2.b1.20010401.000000.cdf

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

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

• Mean Air Temperature or Hardware Error(temp_mean)
• lat
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• vappress_sd
• relh_sd
• time_offset
• Vapor pressure mean(vappress_mean)
• bit_data
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• temp_sd
• Wind #2 speed maximum(wind2_spd_max)
• internal_voltage
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• alt
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• external_voltage
• wind1_spd_sd
• Wind #1 speed minimum(wind1_spd_min)
• wind2_dir_sd
• Temperature maximum(temp_max)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Barometric Pressure(atmos_pressure)
• Temperature minimum(temp_min)
• Wind #2 speed minimum(wind2_spd_min)
• lon
• Precipitation maximum(precip_max)
• Wind #1 speed maximum(wind1_spd_max)
• Precipitation mean(precip_mean)
• precip_sd
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Precipitation minimum(precip_min)
• logger_temp
• Relative humidity mean(relh_mean)
• Relative humidity maximum(relh_max)
• wind2_spd_sd
• Wind #2 direction vector average(wind2_dir_vec_avg)
• base_time
• Relative humidity minimum(relh_min)
• wind1_dir_sd

• Precipitation mean(precip_mean)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• wind2_spd_sd
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• temp_sd
• Wind #1 direction vector average(wind1_dir_vec_avg)
• precip_sd
• time_offset
• Temperature maximum(temp_max)
• internal_voltage
• Wind #2 speed minimum(wind2_spd_min)
• Barometric Pressure(atmos_pressure)
• vappress_sd
• Relative humidity minimum(relh_min)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• lat
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Precipitation minimum(precip_min)
• Temperature minimum(temp_min)
• Wind #2 speed maximum(wind2_spd_max)
• alt
• bit_data
• wind1_spd_sd
• logger_temp
• wind1_dir_sd
• base_time
• relh_sd
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Relative humidity mean(relh_mean)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Relative humidity maximum(relh_max)
• Wind #1 speed minimum(wind1_spd_min)
• lon
• Precipitation maximum(precip_max)
• wind2_dir_sd
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #1 speed maximum(wind1_spd_max)
• Vapor pressure mean(vappress_mean)
• external_voltage

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.

• vappress_sd
• Wind #1 speed minimum(wind1_spd_min)
• wind1_dir_sd
• Vapor pressure mean(vappress_mean)
• wind1_spd_sd
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• time_offset
• lat
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• relh_sd
• temp_sd
• bit_data
• Temperature minimum(temp_min)
• internal_voltage
• Wind #2 speed minimum(wind2_spd_min)
• filename
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Barometric Pressure(atmos_pressure)
• Precipitation mean(precip_mean)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• wind2_dir_sd
• Relative humidity maximum(relh_max)
• Relative humidity minimum(relh_min)
• Temperature maximum(temp_max)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• base_time
• logger_temp
• Precipitation maximum(precip_max)
• lon
• Wind #2 speed maximum(wind2_spd_max)
• alt
• precip_sd
• Wind #1 speed maximum(wind1_spd_max)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• external_voltage
• Precipitation minimum(precip_min)
• wind2_spd_sd
• Relative humidity mean(relh_mean)
• Wind #2 speed maximum gust(wind2_spd_max_gust)

• Raw data stream - documentation not supported

• Precipitation mean(precip_mean)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Precipitation minimum(precip_min)
• Temperature minimum(temp_min)
• Wind #2 speed maximum(wind2_spd_max)
• wind2_spd_sd
• filename
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• alt
• bit_data
• wind1_spd_sd
• logger_temp
• wind1_dir_sd
• Wind #2 speed vector average(wind2_spd_vec_avg)
• base_time
• temp_sd
• relh_sd
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Relative humidity mean(relh_mean)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Relative humidity maximum(relh_max)
• time_offset
• precip_sd
• Temperature maximum(temp_max)
• internal_voltage
• Wind #2 speed minimum(wind2_spd_min)
• Barometric Pressure(atmos_pressure)
• Wind #1 speed minimum(wind1_spd_min)
• vappress_sd
• lon
• Precipitation maximum(precip_max)
• Relative humidity minimum(relh_min)
• wind2_dir_sd
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #1 speed maximum(wind1_spd_max)
• Vapor pressure mean(vappress_mean)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• lat
• external_voltage

TWP/SMET/C2 - Temperature Sensor Failed, Data Missing

The T/RH sensor on Nauru failed and was replaced (only the temperature sensor failed).

• Temperature maximum(temp_max)
• temp_sd
• Temperature minimum(temp_min)
• Mean Air Temperature or Hardware Error(temp_mean)

• Mean Air Temperature or Hardware Error(temp_mean)
• temp_sd
• Temperature maximum(temp_max)
• Temperature minimum(temp_min)

TWP/SMET/C2 - Upper wind sensor failed

The upper wind speed sensor failed.  Wind speeds were reported as 0 m/s and wind direction 
data was not in agreement with the lower wind sensor. Anemometer was replaced.

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

TWP/SMET/C2 - Lower wind sensor failure

The lower wind sensor failed.  Wind direction showed little or no variation, unlike the 
co-located/upper sensor.  This caused depressed wind speed values as the sensor was not 
rotating properly to orient itself parallel to the wind stream.  The sensor was replaced.

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

TWP/SMET/C2 - connection and timing issues with new logger

Atmospheric pressure data are intermittent during this time period due to connection 
problems and program timing issues with new logger installation.  Data resumed normal 
operations after this time period.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C2 - 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 minimum(precip_min)
• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• precip_sd

TWP/SMET/C2 - Incorrect rainrate equation used.

There are two different Optical Raingages in use at the TWP sites.  The incorrect equation 
was used at this site.  The incorrect equation is (25*(V^1.87)) - 0.15.
The correct equation is (20*(V^2)) - 0.05.  The correct equation was installed.

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

TWP/SMET/C2 - Upper wind direction sensor failure

The upper wind direction sensor failed. Wind direction was reported at a near constant 
value of 69 degrees and was significantly different than the lower wind sensor's direction 
values. Sensor replaced.

• up_dir_vec_avg
• up_dir_sd

TWP/SMET/C2 - Upper wind direction sensor failure

After replacement on 03/03/2005 the upper wind direction sensor began reporting erroneous 
values again on 03/09/2005 becoming very apparent after 03/17/2005.  Wind speed data 
appears reasonable but the wind direction data do not agree well with the lower wind sensor.

• up_dir_vec_avg
• up_dir_sd

TWP/SMET/C2 - RH sensor failure

Relative humidity values were frequently over MAX value of 104% starting on 7/10/2005 
through end of period.  Sensor was replaced.

• relh_sd
• Relative humidity mean(relh_mean)

TWP/SMET/C2 - Instrument maintenance

Instrument calibration and testing were taking place for brief periods.

• vappress_sd
• lo_spd_arith_avg
• lo_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)
• tbrg_count_total
• Precipitation maximum(precip_max)
• up_spd_arith_avg
• lo_spd_sd
• relh_sd
• lo_spd_min
• temp_sd
• up_dir_vec_avg
• precip_sd
• Barometric Pressure(atmos_pressure)
• lo_dir_sd
• up_spd_vec_avg
• Precipitation mean(precip_mean)
• Precipitation minimum(precip_min)
• tbrg_total
• Relative humidity mean(relh_mean)
• lo_spd_max
• up_spd_sd

TWP/SMET/C2 - ORG data incorrect

Data from the ORG was incorrect due to heavy condensation on the lens.

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

TWP/SMET/C2 - Tower down for calibration activities

Tower lowered, wind vanes spun at different frequencies, and ORG tested with electronic 
rain.

• vappress_sd
• Temperature maximum(temp_max)
• Wind #1 speed minimum(wind1_spd_min)
• wind1_dir_sd
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Vapor pressure mean(vappress_mean)
• wind1_spd_sd
• Mean Air Temperature or Hardware Error(temp_mean)
• Precipitation maximum(precip_max)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #2 speed maximum(wind2_spd_max)
• relh_sd
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• temp_sd
• Temperature minimum(temp_min)
• precip_sd
• Wind #2 speed minimum(wind2_spd_min)
• Wind #1 speed maximum(wind1_spd_max)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)
• wind2_spd_sd
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Relative humidity mean(relh_mean)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• wind2_dir_sd
• Relative humidity maximum(relh_max)
• Relative humidity minimum(relh_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/C2 - 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/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/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/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/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/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/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/C2 - Missing data

Data are missing and unrecoverable.

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