TWP/MPL/C1 - Poor polarization separation

The MPL is showing signs of laser wear, and is no longer correlating well with either the 
local VCEIL or the local KAZR.  Instrument is not reporting any cloud signatures at 
night, and shows a notable lack of scatter near the surface.  The data seems to have begun to 
show signs of deterioration around 7/01 and has slowly progressed until current date. 

Upper level cloud detection algorithms are likely ok but ice descrimination is likely 
inaccurate.

• Attenuated backscatter, cross pol(signal_return_cross_pol)
• Preliminary cloud base height above ground level(preliminary_cbh)
• deadtime_correction
• background_signal_co_pol
• overlap_correction
• background_signal_cross_pol
• Attenuated backscatter, copol(signal_return_co_pol)