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

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

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

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

• Precipitation mean(precip_mean)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Std Dev of Air Temperature(temp_sd)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Precipitation standard deviation(precip_sd)
• Time offset of tweaks from base_time(time_offset)
• Temperature maximum(temp_max)
• Battery Voltage(internal_voltage)
• Wind #2 speed minimum(wind2_spd_min)
• Barometric Pressure(atmos_pressure)
• Vapor pressure standard deviation(vappress_sd)
• Relative humidity minimum(relh_min)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• lat(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)
• Dummy altitude for Zeb(alt)
• Bit data. See details.(bit_data)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Logger panel temperature(logger_temp)
• Wind #1 direction standard deviation(wind1_dir_sd)
• base time(base_time)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Mean Relative Humidity(relh_mean)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Relative humidity maximum(relh_max)
• Wind #1 speed minimum(wind1_spd_min)
• lon(lon)
• Precipitation maximum(precip_max)
• Wind #2 direction standard deviation(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(external_voltage)

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.

• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind speed arithmetic average(up_spd_arith_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 vector average(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.

• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Lower sensor, wind speed maximum(lo_spd_max)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Lower sensor, wind direction standard deviation(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 mean(precip_mean)
• precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(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 mean(precip_mean)
• precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(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.

• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Upper sensor, wind direction standard deviation(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.

• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Upper sensor, wind direction standard deviation(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.

• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Mean Relative Humidity(relh_mean)

TWP/SMET/C2 - Instrument maintenance

Instrument calibration and testing were taking place for brief periods.

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

TWP/SMET/C2 - ORG data incorrect

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

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

TWP/SMET/C2 - Temp/RH probe failure

Temperature/RH probe failed and was replaced.

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

• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Lower sensor, wind speed maximum(lo_spd_max)
• 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/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 arithmetic average(lo_spd_arith_avg)
• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Lower sensor, wind speed maximum(lo_spd_max)
• Lower sensor, wind speed standard deviation(lo_spd_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 mean(precip_mean)
• precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)

TWP/SMET/C2 - Missing data

Data are missing and unrecoverable.

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

• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed maximum(lo_spd_max)
• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Upper sensor, wind speed vector average(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 mean(precip_mean)
• precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)