NSA/METTWR/C1 - Reprocess: Barometric Data Changed from hPa to kPa

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

• Atmospheric Pressure(AtmPress)

NSA/METTWR/C1 - All data from 10m Level Missing

The winch that lowers the tower booms failed.  Manual testing of the motor and winch 
allowed the booms to be lowered briefly and then raised back into position.  A heavy freezing 
rain/icing event added extra weight to the booms.  This extra weight was suspected as the 
cause as to why the 10m boom became disconnected.  After a new motor was installed and 
all booms were lowered and re-raised the 10m level came back on line.

• 10m Average Calculated Dew Point(DP10M_AVG)
• 10m Average QLI Reference Temperature(RefT10m_AVG)
• Standard Deviation of 10m Calculated Vapor Pressure(VP10M_STD)
• 10m Average Relative Humidity(RH10M_AVG)
• 10m Vector Averaged Wind Speed(WS10M_U_WVT)
• 10m Average Calculated Vapor Pressure(VP10M_AVG)
• 10m Average QLI Input Voltage(Volt10M_AVG)
• Standard Deviation of 10m Vector Averaged Wind Direction(WD10M_SDU_WVT)
• 10m Average Temperature(T10M_AVG)
• Standard Deviation of 10m Relative Humidity(RH10M_STD)
• 10m Arithmetic Mean Wind Speed(WS10M_S_WVT)
• 10m Vector Averaged Wind Direction(WD10M_DU_WVT)
• Standard Deviation of 10m Calculated Dew Point(DP10M_STD)
• Standard Deviation of 10m Temperature(T10M_STD)

NSA/METTWR/C1 - Missing CMH data

CMH data are missing.  Corrosion in the serial data line connections caused a loss of 
communication with the CMH.

• Chilled Mirror Calculated Vapor Pressure(VPCMH)
• Chilled Mirror Calculated Relative Humidity(CMHRH)
• Chilled Mirror Dew Point(CMHDP)
• Chilled Mirror Temperature(CMHTemp)
• Chilled Mirror Calculated Saturation Vapor Pressure(SatVPCMH)

NSA/METTWR/C1 - 10m level loss of power

The 10 meter instrument level lost power so all variables from this level are missing.

• 10m Average Calculated Dew Point(DP10M_AVG)
• 10m Average QLI Reference Temperature(RefT10m_AVG)
• Standard Deviation of 10m Calculated Vapor Pressure(VP10M_STD)
• 10m Average Relative Humidity(RH10M_AVG)
• 10m Vector Averaged Wind Speed(WS10M_U_WVT)
• 10m Average Calculated Vapor Pressure(VP10M_AVG)
• 10m Average QLI Input Voltage(Volt10M_AVG)
• Standard Deviation of 10m Vector Averaged Wind Direction(WD10M_SDU_WVT)
• 10m Average Temperature(T10M_AVG)
• Standard Deviation of 10m Relative Humidity(RH10M_STD)
• 10m Arithmetic Mean Wind Speed(WS10M_S_WVT)
• 10m Vector Averaged Wind Direction(WD10M_DU_WVT)
• Standard Deviation of 10m Calculated Dew Point(DP10M_STD)
• Standard Deviation of 10m Temperature(T10M_STD)

NSA/METTWR/C1 - 2m T/RH probe aspirator fan failed

The aspirator fan for the 2m level T/RH probe failed.  This caused higher than normal 
readings for temp and RH and artificially smoothed the data.

• 2m Average Calculated Vapor Pressure(VP2M_AVG)
• Standard Deviation of 2m Calculated Dew Point(DP2M_STD)
• Standard Deviation of 2m Relative Humidity(RH2M_STD)
• 2m Average Relative Humidity(RH2M_AVG)
• Standard Deviation of 2m Calculated Vapor Pressure(VP2M_STD)
• 2m Average Temperature(T2M_AVG)
• Standard Deviation of 2m Temperature(T2M_STD)
• 2m Average Calculated Dew Point(DP2M_AVG)

NSA/METTWR/C1 - Wind direction sensor frozen

After a power outage the 40m wind direction sensor was frozen.  Data from this sensor was 
not representative of the true winds.

• 40m Vector Averaged Wind Direction(WD40M_DU_WVT)
• Standard Deviation of 40m Vector Averaged Wind Direction(WD40M_SDU_WVT)

NSA/METTWR/C1 - CMH Sensor Calibrated Incorrectly

The CMH temp and DP were higher than the co-located T/RH probe at the 2m level.  An 
incorrect calibration along with a failing thermistor caused the readings to be incorrect for 
both measured values Temp and Dew Point.

• Chilled Mirror Calculated Vapor Pressure(VPCMH)
• Chilled Mirror Calculated Relative Humidity(CMHRH)
• Chilled Mirror Dew Point(CMHDP)
• Chilled Mirror Temperature(CMHTemp)

NSA/METTWR/C1 - 40m wind sensor heater failure

The 40m wind direction became frozen at times.  The values from the sensor were flat-lined 
(stdev = 0) much of the time and did not match sensors from other levels.

• 40m Vector Averaged Wind Direction(WD40M_DU_WVT)
• Standard Deviation of 40m Vector Averaged Wind Direction(WD40M_SDU_WVT)

NSA/METTWR/C1 - 40m Wind Direction Data Suspect

The 40m wind direction data was suspect due to icing on the vane or a failing shafter 
heater or a combination of both.  The affected data can be easily seen on comparison plots 
with other levels data or by checking the standard deviation of the 40m wind direction.  
Any standard deviation of less than 0.10 degrees for the 40m level suggest a sluggish/ice 
affected sensor.

• 40m Vector Averaged Wind Direction(WD40M_DU_WVT)
• Standard Deviation of 40m Vector Averaged Wind Direction(WD40M_SDU_WVT)

NSA/METTWR/C1 - PWS Data Questionable

There was a degradation in the PWS lenses.  New lenses were installed on 08/28/2007 but a 
proper calibration was not conducted until 10/10/2007.  Data  during the listed time 
period should be used with caution.

• 15 minute Present Weather Code(PwCod15mi)
• 1 minute Average Visibility(AvgVis1mi)
• Instant Present Weather Code(InstPwCod)
• 1 hour Present Weather Code(PwCod1hr)
• Cumulative Snow Sum(CumSnow)
• 10 minute Average Visibility(AvgVis10m)
• Precipitation Rate(PcpRate)
• Cumulative Water Sum(CumH2O)
• Present Weather Sensor Alarm(PWSAlarm)

NSA/METTWR/C1 - 20m RH Data Questionable

The 20m RH data was questionable at times.  When the data appeared to be poor was when the 
2m and 20m agreed better than the 20m and the 40m and/or 10m.

• Standard Deviation of 20m Calculated Dew Point(DP20M_STD)
• Standard Deviation of 20m Calculated Vapor Pressure(VP20M_STD)
• Standard Deviation of 20m Relative Humidity(RH20M_STD)
• 20m Average Relative Humidity(RH20M_AVG)
• 20m Average Calculated Vapor Pressure(VP20M_AVG)
• 20m Average Calculated Dew Point(DP20M_AVG)

NSA/METTWR/C1 - Intermittent missing data

Intermittent failure of the CMH to communicate with the logging system occurred on a daily 
basis.  This problem occurred anywhere from 4 to 8 hrs.  Problem began after maintenance 
to replace failing aspirator fan on 03/13/2008.

• Chilled Mirror Calculated Vapor Pressure(VPCMH)
• Chilled Mirror Calculated Relative Humidity(CMHRH)
• Chilled Mirror Dew Point(CMHDP)
• Chilled Mirror Temperature(CMHTemp)
• Chilled Mirror Calculated Saturation Vapor Pressure(SatVPCMH)

NSA/METTWR/C1 - 2m Wind Direction Sensor Freezing

The 2m wind direction was failing.  It began to exhibit instances of no movement 
suggesting it was frozen.  After some time it began to make erratic measurements compared to the 
co-located Ultrasonic and compared to the directions at the other levels.

• Standard Deviation of 2m Vector Averaged Wind Direction(WD2M_SDU_WVT)
• 2m Vector Averaged Wind Direction(WD2M_DU_WVT)

NSA/METTWR/C1 - CMH Intake Fan Failure

The CMH intake fan failed causing the dew point and temp data to be incorrect.

If users need only T/RH and derived variables they can use the 2m data collected using the 
HMP-45D probes.  CMH data are unrecoverable.

• Chilled Mirror Calculated Vapor Pressure(VPCMH)
• Chilled Mirror Calculated Relative Humidity(CMHRH)
• Chilled Mirror Dew Point(CMHDP)
• Chilled Mirror Temperature(CMHTemp)
• Chilled Mirror Calculated Saturation Vapor Pressure(SatVPCMH)