SGP/SONDE/C1 - Surface pressure incorrect

I think the operator inadvdertently mistyped a digit when entering the surface pressure 
value.  The value entered is 975.6 hPa but the value shown in the raw data file at launch 
is 972.6.  As a result, the absolute altitudes in this sounding will be slightly incorrect 
as will be the ascent rate during the first 30 seconds of flight.

• Ascent Rate(asc)
• Dummy altitude for Zeb(alt)

SGP/VCEIL/C1 - poor signal

When parameters were changed (set noise_h2_compensation to "ON" and units to "METERS") to 
correct a low amplitude problem, the backscatter plots began displaying horizontal 
stripes indicating detector "ringing". However, the cloud base heights are not affected. The 
problem was corrected when the instrument was replaced.

• Detection status. See details(detection_status)
• Aerosol backscatter coefficient at 355 nm(backscatter)

SGP/VCEIL/C1 - low amplitude

When the instrument was replaced with a spare, the backscatter plots began displaying a 
suspiciously low amount of amplitude (noise) but the cloud base heights were not affected. 

Discovered that when the vendor repaired this unit in August 2004, noise compensation was 
set to "OFF". Changed the parameters to "ON".

Also noted that the measurement units was set to "FEET".  This was changed to "METERS.  
The heights are not affected because the ingest recognizes the raw data units and 
automatically converts to meters.

• Aerosol backscatter coefficient at 355 nm(backscatter)

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

The output precision of the following variables was increased 20060928

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.

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