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/C2 - Wind speed values artificially low

Wind speed values were artificially low due to snow/ice accumulation on the anemometer 
cups during blizzard conditions.  The heaters on the cups were not able to keep up with 
conditions.

• Wind speed, vector-averaged(WinSpeed_U_WVT)
• Wind speed, mean(WinSpeed_S_WVT)

NSA/METTWR/C2 - CMH Data incorrect

CMH data was incorrect due to blockage of intake by heavy, wet snow during blizzard 
conditions.

• VPCMH
• CMHDP
• SatVPCMH
• CMHRH
• CMHTemp

NSA/METTWR/C2 - PWS data incorrect

The Present Weather Sensor measurement optics were blocked by heavy, wet snow during 
blizzard conditions.

• PWCod1hr
• CumSnow
• PWSAlarm
• CumH2O
• PWcod15mi
• InstPWCod
• Visibility, 1 minute average(AvgVis1mi)
• Precipitation Rate(PCPRate)
• Visibility, 10 minute average(AvgVis10m)

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/C2 - CMH Intake Fan Failure

Intake fan failing causing poor readings from the CMH.

• VPCMH
• CMHDP
• SatVPCMH
• CMHRH
• CMHTemp

NSA/METTWR/C2 - CMH Data Suspect

CMH data was suspect due to incorrect intake fan installed.  Proper spares were not on 
hand.

• VPCMH
• CMHDP
• SatVPCMH
• CMHRH
• CMHTemp

NSA/METTWR/C2 - CMH Data Suspect

CMH data was suspect due to blockage of intake by snow.

• VPCMH
• CMHDP
• SatVPCMH
• CMHRH
• CMHTemp

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

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

• Pressure, atmospheric(AtmPress)

NSA/METTWR/C2 - CMH data missing and/or incorrect during maintenance.

CMH measured data was missing and the derived variables were incorrect due to routine 
maintenance.

• VPCMH
• CMHDP
• SatVPCMH
• CMHRH
• CMHTemp

NSA/METTWR/C2 - PWS data missing/incorrect due to maintenance.

Present Weather Sensor data was missing or incorrect due to maintenance activities 
repeated approximately daily as we were trying to correct another problem.

• PWCod1hr
• CumSnow
• PWSAlarm
• CumH2O
• PWcod15mi
• InstPWCod
• Visibility, 1 minute average(AvgVis1mi)
• Precipitation Rate(PCPRate)
• Visibility, 10 minute average(AvgVis10m)
• CMHTemp

NSA/METTWR/C2 - Met data incorrect due to tower being lowered for maintenance.

Data from the tower is not representative of local conditions due to the tower being 
lowered for radiometer change.  Sensors not attached to the tower such as the Present Weather 
Sensor, the Chilled Mirror Hygrometer and the Barometer were not affected.

• RH2m_STD
• Wind speed, vector-averaged(WinSpeed_U_WVT)
• DP5m_STD
• Relative humidity, average, at 2-m height(RH5m_AVG)
• WinDir_SDU_WVT
• VP5m_STD
• Temperature, air, average, at 2-m height(T2m_AVG)
• T2m_STD
• Wind speed, mean(WinSpeed_S_WVT)
• Temperature, dew point, average, at 5-m height(DP5m_AVG)
• VP2m_STD
• T5m_STD
• Pressure, vapor, at 2-m height(VP2m_AVG)
• RH5m_STD
• Relative humidity, average, at 2-m height(RH2m_AVG)
• Pressure, vapor, at 5-m height(VP5m_AVG)
• DP2m_STD
• Temperature, dew point, average, at 2-m height(DP2m_AVG)
• Wind direction, vector-averaged(WinDir_DU_WVT)
• Temperature, air, average, at 5-m height(T5m_AVG)

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/C2 - 2m Temp/RH sensor blocked with snow

The 2m RH, Dew Point and Vapor Pressure values are incorrect due to the intake of the 
aspirated shield being blocked with snow and ice.  The RH% values are artificially larger 
than the 5m and Chilled Mirror values.

• RH2m_STD
• Pressure, vapor, at 2-m height(VP2m_AVG)
• Relative humidity, average, at 2-m height(RH2m_AVG)
• DP2m_STD
• Temperature, dew point, average, at 2-m height(DP2m_AVG)
• VP2m_STD

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

NSA/TSI/C1 - camera lens covered

The shadowband was not properly masking the sun so the camera lens was covered on 4/13 to 
prevent damage to the CCD. On 4/20, the mirror was blown off by a snow storm and the 
instrument was brought inside for repair. The mirror was replaced, the lens uncovered, and 
the instrument reinstalled.

• region.zenith.count.opaque
• count.sub.proczen
• count.sub.horz
• count.opaque
• Cloud amount, thin (percent)(percent.thin)
• count.thin
• region.horizon.count.opaque
• region.sun.count
• region.horizon.count.thin
• count.unknown
• region.horizon.count
• region.sun.count.thin
• region.zenith.count
• region.zenith.count.thin
• Sunshine Meter(sunny)
• sun.strength
• region.sun.count.opaque
• count.box
• count.sky
• count.mask
• Cloud amount, opaque (percent)(percent.opaque)

• Cloud decision images, Total Sky Imager, PNG format(png)

• JPEG data stream - documentation not yet available

NSA/TSI/C1 - shadowband misaligned

At several times during this period the shadowband did not mask the sun because the mirror 
was not properly secured. Attempts were made to align the mirror on 4/2, 4/3, and 4/10.

• region.zenith.count.opaque
• count.sub.horz
• count.sub.proczen
• count.opaque
• Cloud amount, thin (percent)(percent.thin)
• count.thin
• region.horizon.count.opaque
• region.sun.count
• region.horizon.count.thin
• count.unknown
• region.horizon.count
• region.sun.count.thin
• region.zenith.count
• region.zenith.count.thin
• sun.strength
• region.sun.count.opaque
• count.box
• count.sky
• count.mask
• Cloud amount, opaque (percent)(percent.opaque)

• Cloud decision images, Total Sky Imager, PNG format(png)

• JPEG data stream - documentation not yet available

NSA/RWP/C1 - Instrument problem

When data returned to ingest the windcon wind direction and wind speeds are not comparing 
well with the co-located sondes.  Wind direction values are constant, with no changes.  
Problem is that the phase shifter wiring was bad when it was reinstalled.

• range_gate
• prf
• sitime
• bins
• Backscatter, doppler spectrum, 915 MHz RWP(spc_amp)
• alt
• ncoh
• elevation
• ipp
• dly
• lon
• vband
• tditime
• bswitch
• beam
• lat
• plen
• nheight
• sampr
• rgs
• time_offset
• oband
• pcbits
• rgl
• nspc
• rgf
• base_time
• vsr
• spcavetim
• height_t

• Eastward Wind Component(u_wind)
• lon
• nspc
• Wind speed, horizontal, at altitude, 915 MHz RWP(spd)
• vvsr
• power
• base_time
• ovsr
• nheight
• plen
• azimuth1
• azimuth0
• azimuth3
• azimuth2
• Beam 2 radial wind speed(vel2)
• azimuth4
• Beam 1 radial wind speed(vel1)
• Wind direction, horizontal, at altitude, 915 MHz RWP(dir)
• Beam 4 radial wind speed(vel4)
• Beam 3 radial wind speed(vel3)
• time_offset
• avgint
• nrec0
• tditime
• nrec1
• oband
• nrec2
• height_p
• nrec3
• nrec4
• sampr
• vband
• rgl
• pcbits
• rgf
• Beam 0 radial wind speed(vel0)
• bswitch
• spcavetim
• ipp
• range_gate
• lat
• rgs
• nrcns4
• nrcns3
• nrcns2
• nrcns1
• nrcns0
• ncns1
• ncns0
• ncns3
• ncns2
• ncns4
• elevation0
• ncoh
• Northward Wind Component(v_wind)
• elevation2
• elevation1
• elevation4
• elevation3
• snr3
• snr4
• snr0
• snr1
• snr2
• prf
• alt
• dly
• sitime

• rgl
• rgs
• tditime
• snr
• oband
• range_gate
• rgf
• nspc
• spcavetime
• Spectral Width(specw)
• prf
• nheight
• noise
• height_t
• pcbits
• base_time
• lat
• alt
• ipp
• dly
• vband
• mdf
• sitime
• plen
• ncoh
• bswitch
• time_offset
• sampr
• lon
• vsr
• elevation
• beam

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.

• VPCMH
• SatVPCMH
• CMHDP
• CMHTemp
• CMHRH

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.

• WD2M_SDU_WVT
• Wind direction, vector-averaged, at 2-m height(WD2M_DU_WVT)

NSA/TSI/C1 - frost/condensation in lens

The sky image appeared hazy and was corrected by cleaning the neutral-density filter and 
lens of the camera. The determination of cloud fraction may be affected.

• Cloud amount, thin (percent)(percent.thin)
• Cloud amount, opaque (percent)(percent.opaque)

• JPEG data stream - documentation not yet available

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.

• VPCMH
• SatVPCMH
• CMHDP
• CMHTemp
• CMHRH

NSA/METTWR/C1 - 2m Datalogger Failed

The 2m temperature, wind speed, wind direction, and relative humidity were reporting the 
missing value (-9999).

• WD2M_SDU_WVT
• Relative humidity, average, at 2-m height(RH2M_AVG)
• Wind speed, mean, at 2-m height(WS2M_S_WVT)
• T2M_STD
• DP2M_STD
• Temperature, air, average, at 2-m height(T2M_AVG)
• Temperature, dew point, average, at 2-m height(DP2M_AVG)
• RH2M_STD
• Wind speed, vector-averaged, at 2-m height(WS2M_U_WVT)
• RefT2M_AVG
• VP2M_STD
• Volt2M_AVG
• Pressure, vapor, at 2-m height(VP2M_AVG)
• Wind direction, vector-averaged, at 2-m height(WD2M_DU_WVT)

NSA/METTWR/C1 - CMH required Calibration

The Chilled Mirror was showing some signs of being out of calibration.  Temperatures were 
at times higher than co-located temp probes and the dew point temperature values at times 
were not consistent with co-located RH sensors.

• VPCMH
• SatVPCMH
• CMHDP
• CMHTemp
• CMHRH

NSA/METTWR/C1 - 2m level data incorrect

The 2m data for temp, RH, dew point, wind speed wind direction & vapor pressure were 
incorrect.  The voltage values for the datalogger at that level were reporting as 60V with 
excursions to 100V.  These values should have damaged the logger at that level.  After an 
extended power outage on 08/04 the data all became reasonable. There is no explanation as 
to the cause of this failure.

• WD2M_SDU_WVT
• Relative humidity, average, at 2-m height(RH2M_AVG)
• Wind speed, mean, at 2-m height(WS2M_S_WVT)
• T2M_STD
• DP2M_STD
• Temperature, air, average, at 2-m height(T2M_AVG)
• Temperature, dew point, average, at 2-m height(DP2M_AVG)
• RH2M_STD
• Wind speed, vector-averaged, at 2-m height(WS2M_U_WVT)
• RefT2M_AVG
• VP2M_STD
• Volt2M_AVG
• Pressure, vapor, at 2-m height(VP2M_AVG)
• Wind direction, vector-averaged, at 2-m height(WD2M_DU_WVT)