NSA/SONDE/C1 - Increased precision for alt, dp, pres, rh, tdry

The output precision of the following variables was increased 20060929:

   alt	changed from 1m to 0.1m
   dp	changed from 0.1degC to 0.01degC
   pres changed from 0.1 hPa to 0.01 hPa
   RH	changed from 1%RH to 0.01%RH
   tdry changed from .1degC to 0.01degC

Note that the increase in precision does not necessarily imply an increase
in accuracy.  Users are cautioned to continue to use their best scientific
judgement when using these or any other data.

• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)
• Dummy altitude for Zeb(alt)
• Retrieved pressure profile(pres)
• Surface dew point temperature(dp)

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/SONDE/C1 - Temperature sensor broke at launch

The temperature sensor on this sonde broke at launch.  As a result all the thermodynamic 
data are incorrect.  The wind data are OK, though there will be some uncertainty in the 
altitude values.  This sounding was done at a non-standard time and it isn't clear whether 
it was delayed for some reason or a RHUBC sounding.  In either case, there is no fix.

• Ascent Rate(asc)
• Relative humidity inside the instrument enclosure(rh)
• Dry bulb temperature(tdry)
• Dummy altitude for Zeb(alt)
• Surface dew point temperature(dp)

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)