NSA/METTWR/C1 - CMH Data Not Representative

The intake of the CMH was blocked with hoar frost.  The temperatures measured by the 
chilled mirror and the temperature probe were not representative of the ambient conditions as 
a result.  The RH data calculated from these values is incorrect also.

• VPCMH
• SatVPCMH
• CMHDP
• CMHTemp
• CMHRH

NSA/METTWR/C1 - CMH Data missing

CMH dew point and temp data was missing. Since Dew Point and Temp data missing RH% value = 
100% during outage.  Corrosion on power plug was athe problem.

• VPCMH
• SatVPCMH
• CMHDP
• CMHTemp
• CMHRH

NSA/METTWR/C1 - Ultrasonic Wind Sensor Values Incorrect

The values collected from the ultrasonic wind sensor were intermittently incorrect.  Heavy 
wet snow during blizzard condition was interfering with the ultrasonic readings.

• SonicWD_SDU_WVT
• SonicWS_U_WVT
• SonicWS_S_WVT
• SonicS_AVG
• SonicY_AVG
• SonicWD_DU_WVT
• SonicX_AVG

NSA/METTWR/C1 - PWS data missing due to blizzard

PWS was offline and data was missing.  A blizzard consisting of heavy wet snow and strong 
winds caused snow impaction in the optics.  The PWS reported missing data as it was 
unable to measure anything meaningful.

• PcpRate
• InstPwCod
• CumSnow
• Visibility, 10 minute average(AvgVis10m)
• PWSAlarm
• Visibility, 1 minute average(AvgVis1mi)
• PwCod15mi
• PwCod1hr

NSA/METTWR/C1 - 2m Wind Speed Artificially Low

The 2m wind speed values were artificially low due to snow impaction during a heavy 
blizzard.  The cup anemometer heaters could not keep up with the rapid deposition of snow.

• Wind speed, mean, at 2-m height(WS2M_S_WVT)
• Wind speed, vector-averaged, at 2-m height(WS2M_U_WVT)

NSA/METTWR/C1 - CMH temp inaccurate

The CMH Temperature was consistently 4-7 degrees warmer than the 2M, 40M, 20M, and 10M 
temp. Intake fan failure; fan was replaced.

• VPCMH
• SatVPCMH
• CMHDP
• CMHTemp
• CMHRH

NSA/METTWR/C1 - 10m Wind Speed Low

The 10m wind speed values are too low due to ice accumulation on the cup anemometer.

• Wind speed, vector-averaged, at 10-m height(WS10M_U_WVT)
• Wind speed, mean, at 10-m height(WS10M_S_WVT)

NSA/METTWR/C1 - 10m Wind Speed Intermittently Low

The 10m wind speeds are intermittently too low due to ice accumulation on the cup 
anemometer.

• Wind speed, vector-averaged, at 10-m height(WS10M_U_WVT)
• Wind speed, mean, at 10-m height(WS10M_S_WVT)

NSA/METTWR/C1 - 40m Wind Speeds Intermittently Low

The 40m wind speed values were too low due to ice accumulation on the cup anemometer.

• Wind speed, mean, at 40-m height(WS40M_S_WVT)
• Wind speed, vector-averaged, at 40-m height(WS40M_U_WVT)

NSA/METTWR/C1 - 20m Wind Speeds Intermittently Low

The 20m wind speeds were artificially low due to ice accumulation on the cup anemometer.

• Wind speed, vector-averaged, at 20-m height(WS20M_U_WVT)
• Wind speed, mean, at 20-m height(WS20M_S_WVT)

NSA/METTWR/C1 - CMH Data Missing

CMH data was missing due to it being removed for maintenance.

• VPCMH
• SatVPCMH
• CMHDP
• CMHTemp
• CMHRH

NSA/METTWR/C1 - CMH Data Suspect

CMH data was suspect due to incorrect calibration caused by procedural errors.  The 
procedures were corrected and a new calibration completed.

• VPCMH
• SatVPCMH
• CMHDP
• CMHTemp
• CMHRH

NSA/METTWR/C1 - Wind direction measurements suspect

20m wind direction standard deviation was 0 degrees for extended periods of time.  This 
suggests the wind vane was icing up.

• Wind direction, vector-averaged, at 20-m height(WD20M_DU_WVT)
• WD20M_SDU_WVT

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.

• Pressure, atmospheric(AtmPress)

NSA/METTWR/C1 - Present Weather Sensor data missing or incorrect due to calibration.

The Present Weather Sensor data was missing or incorrect due to calibration checks.

• PcpRate
• InstPwCod
• CumSnow
• Visibility, 10 minute average(AvgVis10m)
• PWSAlarm
• Visibility, 1 minute average(AvgVis1mi)
• PwCod15mi
• CumH2O
• PwCod1hr

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.

• Pressure, vapor, at 10-m height(VP10M_AVG)
• RH10M_STD
• T10M_STD
• Wind speed, mean, at 10-m height(WS10M_S_WVT)
• Wind direction, vector-averaged, at 10-m height(WD10M_DU_WVT)
• VP10M_STD
• DP10M_STD
• WD10M_SDU_WVT
• Temperature, dew point, average, at 10-m height(DP10M_AVG)
• Wind speed, vector-averaged, at 10-m height(WS10M_U_WVT)
• RefT10m_AVG
• Relative humidity, average, at 10-m height(RH10M_AVG)
• Temperature, air, average, at 10-m height(T10M_AVG)
• Volt10M_AVG

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.

• VPCMH
• SatVPCMH
• CMHDP
• CMHTemp
• CMHRH

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

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

• Pressure, vapor, at 10-m height(VP10M_AVG)
• RH10M_STD
• T10M_STD
• Wind speed, mean, at 10-m height(WS10M_S_WVT)
• Wind direction, vector-averaged, at 10-m height(WD10M_DU_WVT)
• VP10M_STD
• DP10M_STD
• WD10M_SDU_WVT
• Temperature, dew point, average, at 10-m height(DP10M_AVG)
• Wind speed, vector-averaged, at 10-m height(WS10M_U_WVT)
• RefT10m_AVG
• Relative humidity, average, at 10-m height(RH10M_AVG)
• Temperature, air, average, at 10-m height(T10M_AVG)
• Volt10M_AVG

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.

• Temperature, dew point, average, at 2-m height(DP2M_AVG)
• Temperature, air, average, at 2-m height(T2M_AVG)
• RH2M_STD
• Relative humidity, average, at 2-m height(RH2M_AVG)
• DP2M_STD
• T2M_STD
• VP2M_STD
• Pressure, vapor, at 2-m height(VP2M_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.

• Wind direction, vector-averaged, at 40-m height(WD40M_DU_WVT)
• 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.

• VPCMH
• CMHDP
• CMHTemp
• CMHRH

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.

• Wind direction, vector-averaged, at 40-m height(WD40M_DU_WVT)
• 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.

• Wind direction, vector-averaged, at 40-m height(WD40M_DU_WVT)
• 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.

• PcpRate
• InstPwCod
• CumSnow
• Visibility, 10 minute average(AvgVis10m)
• PWSAlarm
• Visibility, 1 minute average(AvgVis1mi)
• PwCod15mi
• CumH2O
• PwCod1hr

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.

• DP20M_STD
• Temperature, dew point, average, at 20-m height(DP20M_AVG)
• Pressure, vapor, at 20-m height(VP20M_AVG)
• RH20M_STD
• Relative humidity, average, at 20-m height(RH20M_AVG)
• VP20M_STD