TWP/SMET/C2 - Wind Sensor failure

Wind sensor #2 (lower one) failed.  Wind direction showed little or
no variation, unlike the colocated sensor #1.  This caused lower
wind speed values as the sensor was not rotating properly to orient
itself parallel to the wind stream.  The sensor was replaced.

• Wind #2 speed maximum(wind2_spd_max)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Wind #2 speed minimum(wind2_spd_min)

TWP/SMET/C1 - Poor Performing Sensor

On 4/23/2004 condensation was found inside the target area of the ORG lens. A spare was 
sent and installed but did not solve the problem of high background voltage values causing 
rainrate values to be recorded during no rainfall.  Values range anywhere from 0.06 to 
0.12 mm/hr.  

A new Optical Rain Gage was installed on 01/19/2005 @ 13:30 GMT alleviating the high 
background voltage values that lead to consistent rainfall rates of around 0.11 to 0.15 mm/hr 
on a consistent basis.  

The formula used to calculate rainfall rates from the new Optical Rain Gage is:  RR 
(mm/hr) = 25(V^1.87) - 0.15.

Older model formula = 20(V^2) - 0.05

The two formulas result in comparable data.

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

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.

• Atmospheric pressure(atmos_pressure)

TWP/SMET/C3 - Data missing due to Logger Change

All Data from this site are missing during this time period due to a change of the 
collection system, logger and enclosure.  Data resumed after change.

• External voltage(external_voltage)
• north latitude for all the input platforms.(lat)
• Time offset of tweaks from base_time(time_offset)
• Precipitation maximum(precip_max)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Internal voltage(internal_voltage)
• Wind #1 speed minimum(wind1_spd_min)
• Internal Logger Temperature(logger_temp)
• Wind #2 speed maximum(wind2_spd_max)
• precipitation minimum(precip_min)
• Wind #1 direction standard deviation(wind1_dir_sd)
• Wind #2 speed minimum(wind2_spd_min)
• Wind #1 speed maximum(wind1_spd_max)
• Mean Air Temperature or Hardware Error(temp_mean)
• Max Temperature at lowest Model Level- 1 hr(temp_max)
• Vapor pressure mean(vappress_mean)
• Atmospheric pressure(atmos_pressure)
• Vapor pressure standard deviation(vappress_sd)
• Relative humidity mean(relh_mean)
• Relative humidity maximum(relh_max)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Relative humidity minimum(relh_min)
• Bit data. See details.(bit_data)
• Precipitation mean(precip_mean)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Time offset from base_time(base_time)
• Min Temperature at lowest Model Level- 1 hr(temp_min)
• altitude above sea levelaltunits(alt)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Precipitation standard deviation(precip_sd)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• east longitude for all the input platforms.(lon)
• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Temperature standard deviation(temp_sd)

TWP/SMET/C2 - All data missing due to logger change

All data are missing at this site during this time period due to collection system, logger 
and enclosure change.  Data resumed after change.

• Relative humidity mean(relh_mean)
• Wind #1 direction standard deviation(wind1_dir_sd)
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #1 speed maximum(wind1_spd_max)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Time offset from base_time(base_time)
• Max Temperature at lowest Model Level- 1 hr(temp_max)
• east longitude for all the input platforms.(lon)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Internal Logger Temperature(logger_temp)
• Bit data. See details.(bit_data)
• Time offset of tweaks from base_time(time_offset)
• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• precipitation minimum(precip_min)
• Wind #2 speed minimum(wind2_spd_min)
• Vapor pressure mean(vappress_mean)
• Internal voltage(internal_voltage)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Wind #2 speed maximum(wind2_spd_max)
• Wind #1 speed minimum(wind1_spd_min)
• GPS raw data filename(filename)
• Temperature standard deviation(temp_sd)
• Min Temperature at lowest Model Level- 1 hr(temp_min)
• Atmospheric pressure(atmos_pressure)
• altitude above sea levelaltunits(alt)
• Relative humidity minimum(relh_min)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Vapor pressure standard deviation(vappress_sd)
• north latitude for all the input platforms.(lat)
• Relative humidity maximum(relh_max)
• Precipitation maximum(precip_max)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• External voltage(external_voltage)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Precipitation mean(precip_mean)
• Precipitation standard deviation(precip_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.

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

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

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

TWP/SMET/C1 - 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 maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)

TWP/SMET/C3 - Data non-representative

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

• Precipitation maximum(precip_max)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #2 speed maximum(wind2_spd_max)
• precipitation minimum(precip_min)
• Wind #1 direction standard deviation(wind1_dir_sd)
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #1 speed maximum(wind1_spd_max)
• Wind #2 speed minimum(wind2_spd_min)
• Max Temperature at lowest Model Level- 1 hr(temp_max)
• Vapor pressure mean(vappress_mean)
• Atmospheric pressure(atmos_pressure)
• Vapor pressure standard deviation(vappress_sd)
• Relative humidity mean(relh_mean)
• Relative humidity maximum(relh_max)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Relative humidity minimum(relh_min)
• Precipitation mean(precip_mean)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Min Temperature at lowest Model Level- 1 hr(temp_min)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Precipitation standard deviation(precip_sd)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Temperature standard deviation(temp_sd)

TWP/SMET/C2 - Instrument failure

Upper wind 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.

• Wind #1 direction standard deviation(wind1_dir_sd)
• Wind #1 direction vector average(wind1_dir_vec_avg)

TWP/SMET/C2 - Upper wind sensor failure

After replacement on 03/03/2005 the upper wind 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.

• Wind #1 direction standard deviation(wind1_dir_sd)
• Wind #1 direction vector average(wind1_dir_vec_avg)

TWP/SMET/C3 - Instrument logger problem, Sensor failure

The wind_lower direction sensor failed on 4/14 and disagrees significantly with the 
wind_upper direction.  The wind_lower 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.

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

TWP/SMET/C1 - 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.  New loggers were installed 03/09/2004 @ 2243 GMT.

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

TWP/SMET/C2 - RH failure

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

• Relative humidity mean(relh_mean)
• Relative humidity maximum(relh_max)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Relative humidity minimum(relh_min)

TWP/SMET/C3 - Data not representative

Tower was lowered for radiometer change and characterization.  Wind, temp and RH data not 
representative of local conditions.

• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #2 speed maximum(wind2_spd_max)
• Wind #1 direction standard deviation(wind1_dir_sd)
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #1 speed maximum(wind1_spd_max)
• Wind #2 speed minimum(wind2_spd_min)
• Max Temperature at lowest Model Level- 1 hr(temp_max)
• Vapor pressure mean(vappress_mean)
• Vapor pressure standard deviation(vappress_sd)
• Relative humidity mean(relh_mean)
• Relative humidity maximum(relh_max)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Relative humidity minimum(relh_min)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Min Temperature at lowest Model Level- 1 hr(temp_min)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Temperature standard deviation(temp_sd)

TWP/SMET/C3 - Towrr lowered for sensor comparisons, data not representative

The tower was lowered for radiometer change and comparisons.  During the time period the 
data listed was not representative.

• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #2 speed maximum(wind2_spd_max)
• Wind #1 direction standard deviation(wind1_dir_sd)
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #1 speed maximum(wind1_spd_max)
• Wind #2 speed minimum(wind2_spd_min)
• Max Temperature at lowest Model Level- 1 hr(temp_max)
• Vapor pressure mean(vappress_mean)
• Vapor pressure standard deviation(vappress_sd)
• Relative humidity mean(relh_mean)
• Relative humidity maximum(relh_max)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Relative humidity minimum(relh_min)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Min Temperature at lowest Model Level- 1 hr(temp_min)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Temperature standard deviation(temp_sd)

TWP/SMET/C2 - Instrument maintenance

Instrument calibration and testing were taking place for brief periods.

• Relative humidity mean(relh_mean)
• Wind #1 direction standard deviation(wind1_dir_sd)
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #1 speed maximum(wind1_spd_max)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Max Temperature at lowest Model Level- 1 hr(temp_max)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Vapor pressure mean(vappress_mean)
• Wind #2 speed minimum(wind2_spd_min)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #2 speed maximum(wind2_spd_max)
• Temperature standard deviation(temp_sd)
• Min Temperature at lowest Model Level- 1 hr(temp_min)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Relative humidity minimum(relh_min)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Vapor pressure standard deviation(vappress_sd)
• Relative humidity maximum(relh_max)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #1 speed maximum gust(wind1_spd_max_gust)

TWP/SMET/C2 - ORG data incorrect

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

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

TWP/SMET/C2 - Tower down for calibration activities

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

• Relative humidity mean(relh_mean)
• Wind #1 direction standard deviation(wind1_dir_sd)
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #1 speed maximum(wind1_spd_max)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Max Temperature at lowest Model Level- 1 hr(temp_max)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• precipitation minimum(precip_min)
• Vapor pressure mean(vappress_mean)
• Wind #2 speed minimum(wind2_spd_min)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #2 speed maximum(wind2_spd_max)
• Temperature standard deviation(temp_sd)
• Min Temperature at lowest Model Level- 1 hr(temp_min)
• Relative humidity minimum(relh_min)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Vapor pressure standard deviation(vappress_sd)
• Precipitation maximum(precip_max)
• Relative humidity maximum(relh_max)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Precipitation mean(precip_mean)
• Precipitation standard deviation(precip_sd)

TWP/SMET/C3 - Upper wind sensor failure

A lightning strike destroyed the upper (#1) wind sensor.

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

TWP/SMET/C3 - RH Values Artificially High

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

• Vapor pressure standard deviation(vappress_sd)
• Relative humidity mean(relh_mean)
• Relative humidity maximum(relh_max)
• Vapor pressure mean(vappress_mean)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Relative humidity minimum(relh_min)

TWP/SMET/C3 - Instrument failure

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

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

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 - Reprocess: Barometric Data Changed from hPa to kPa

Barometric pressure data was converted from hPa to kPa in order to standardize the 
measurement units among ARM sites and to conform to accepted standard units determined by the 
scientific community.

• Atmospheric pressure(atmos_pressure)

TWP/SMET/C2 - Reprocess: Barometric Data Changed from hPa to kPa

Barometric pressure data was converted from hPa to kPa in order to standardize the 
measurement units among ARM sites and to conform to accepted standard units determined by the 
scientific community.

• Atmospheric pressure(atmos_pressure)

TWP/SMET/C3 - Reprocess: Barometric Data Changed from hPa to kPa

Barometric pressure data was converted from hPa to kPa in order to standardize the 
measurement units among ARM sites and to conform to accepted standard units determined by the 
scientific community.

• Atmospheric pressure(atmos_pressure)

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).

• Time offset from 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).

• Time offset from 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.

• Time offset from base_time(base_time)