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

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

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

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

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

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

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

TWP/SMET/C3 - Intermittent Pressure Sensor Failure

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

• Barometric Pressure(atmos_pressure)

• Barometric Pressure(atmos_pressure)

TWP/SMET/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 maximum(lo_spd_max)
• 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)

• Wind #2 speed arithmetic average(wind2_spd_arith_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)
• Wind #2 speed minimum(wind2_spd_min)
• Wind #2 speed vector average(wind2_spd_vec_avg)

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

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

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

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

TWP/SMET/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/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 minimum(precip_min)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• Precipitation mean(precip_mean)

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

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

TWP/SMET/C3 - Data non-representative

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

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

TWP/SMET/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 standard deviation(lo_dir_sd)
• Lower sensor, wind direction vector average(lo_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 minimum(precip_min)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• Precipitation mean(precip_mean)

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/C3 - Data not representative

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

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

TWP/SMET/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/C3 - Upper wind sensor failure

A lightning strike destroyed the upper wind sensor.

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

TWP/SMET/C3 - RH Values Artificially High

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

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

TWP/SMET/C3 - Instrument failure

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

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

TWP/SMET/C3 - ORG data noisy due to degraded ground

SMET Rain Data began to be noisy during December 2005 and the problem slowly became worse 
over time so that in February 2006 the ORG was reporting with a constant background value 
of around 0.10 mm/hr rain rate.  ORG voltage showed a near constant value above the 85mV 
threshold.  The ground for the ORG had become degraded and was lost due to corrosion.

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

TWP/SMET/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/C1 - 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 are reprocessing the data to remove these small 
values and are adjusting the collection program to remove them before ingest.

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

TWP/SMET/C3 - 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 standard deviation(precip_sd)
• Precipitation maximum(precip_max)
• precipitation minimum(precip_min)
• Precipitation mean(precip_mean)

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

TWP/SMET/C1 - Missing data

Data are missing and unrecoverable.

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

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/C3 - Missing data

Data are missing and unrecoverable.

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

TWP/SMET/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 maximum(lo_spd_max)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind speed maximum(up_spd_max)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Lower sensor, wind speed minimum(lo_spd_min)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• 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)
• Lower sensor, wind speed standard deviation(lo_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/C3 - Wind Speed data contain offset due to induced voltage

The marine model of the RM Young wind sensor needs twisted pair shielded cable.  The 
manufacturer did not originally supply the pigtail with twisted pair shielded cable.  Use of 
twisted pair shielded cable for the rest of the cable run to the logger was also not 
specified.  This caused an induced voltage in the wind speed line from the wind direction 
excitation.  The induced voltage varied from sensor to sensor and probably changed anytime 
the cable was replaced or parts of the wind sensor were repaired or replaced. The induced 
voltage has been seen to vary from 0.15 m/s to as much as 1.08 m/s.

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

TWP/SMET/C3 - Reprocess: Temperature data biased low

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

The data will be reprocessed.

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

TWP/SMET/C3 - Reprocess: Temperature Biased low by 1.06 Degrees

The temperature of the SMET system was biased low by 1.06 Deg C due to a non-precision 
resistor being used int he measurement circuit.  The data will be reprocessed.  Saturation 
Vapor pressure and Vapor pressure will have to be reprocessed also.

Add 1.06 degrees to the temperature data.  

Correct Sat Vap Press using the Buck approximation:
   Es = 6.1121exp((17.502*T)/(240.97 + T) 
where T is the temperature in C.  

Correct Vapor pressure using: E = (RH*Es)/100

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