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

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

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

TWP/SMET/C1 - Wind speed calibration errors

Wind speed calibration factors were reversed between wind speed sensors 1 (upper) and 2 
(lower). Results in less than 1% error, but correction factors may be used.

To correct wind speed #1 (upper) add 0.03 m/s.
To correct wind speed #2 (lower) subtract 0.03 m/s.

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

• Wind #2 speed minimum(wind2_spd_min)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Wind #1 speed maximum(wind1_spd_max)
• Wind #2 speed maximum(wind2_spd_max)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)

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

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

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

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

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

TWP/C1 - Incorrect elevation reported in Manus Data

(From Bill Clements) We have been using 6m MSL as the station
elevation of Momote (Manus).  This was based on information
posted near the station barometer in the Momote Weather Service
Office.  It turns out that the official WMO station elevation
for Momote is 4m MSL and the upper air elevation is 5m MSL.

All Manus instruments except the sonde station are at 4m MSL.
The sonde launching station is at 5m MSL.

• Dummy altitude for Zeb(alt)

• Dummy altitude for Zeb(alt)

• Dummy altitude for Zeb(alt)

• Dummy altitude for Zeb(alt)

• Dummy altitude for Zeb(alt)

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

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

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/C1 - Reprocess: Lower Wind Speed incorrect

The lower wind speed sensor (sensor #2) was reporting values 10 times above the actual 
value.  During an update to the logger configuration file the calibration multiplier was 
incorrectly entered.  The multiplier inserted was .97630 when it should have been .09763.  
This caused the readings from this sensor to be incorrect.

• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• 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)

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

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

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.

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

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

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

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.

• Barometric Pressure(atmos_pressure)

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 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.

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

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

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 sensor failure

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

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

TWP/SMET/C3 - Data not representative

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

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

TWP/SMET/C2 - Instrument maintenance

Instrument calibration and testing were taking place for brief periods.

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

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/C3 - Upper wind sensor failure

A lightning strike destroyed the upper wind sensor.

• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_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)
• Mean Relative Humidity(relh_mean)
• Vapor pressure mean(vappress_mean)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)

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

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: 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: 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: 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/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/C1 - Missing data

Data are missing and unrecoverable.

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

TWP/SMET/C2 - Missing data

Data are missing and unrecoverable.

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

TWP/SMET/C3 - Missing data

Data are missing and unrecoverable.

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

TWP/SMET/C1 - 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 vector average(lo_spd_vec_avg)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• 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)
• Lower sensor, wind speed maximum(lo_spd_max)

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.

• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Lower sensor, wind speed minimum(lo_spd_min)
• Upper sensor, wind speed maximum(up_spd_max)
• 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)
• Upper sensor, wind speed arithmetic average(up_spd_arith_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)

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

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.

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

TWP/SMET/C1 - Optical Rain Gage Inoperative

Beginning on 02/07/2009, the trending between the TBRG and ORG began to look poor, one 
recording precip when the other was not and vice versa.  After a while the ORG quit 
registering any precip at all.  ORG was replaced.

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

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

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

TWP/SMET/C1 - Surface pressure spike

A spike occured in the surface pressure.  The reported pressure rose as
high as 1300 hPa but returned to normal levels after 15 minutes.

• Barometric Pressure(atmos_pressure)