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)

SGP/RL/C1 - Invalid liquid water channel data

On 20060906, the liquid water channel (LWC) was disabled due to the removal of its 
photomultiplier tube (PMT).  Consequently, the signals recorded for the LWC contain either zero 
or pure noise after that date.

Also, starting on 20070522, the LWC was populated with data from the T2 channel as a 
result of a slight reconfiguration of the data acquisition system.

On 4 March 2008 The LW channel photomultiplier tube was reinstalled in the Raman lidar. 
Effective 0000 UTC on 5 March 2008 the LW channel began producing valid liquid water data 
once again.

• Number of photons counted in the liquid water channel(liquid_counts_high)
• Summed analog signal in the liquid water channel(liquid_analog_high)