TWP/MPL/C1 - Poor polarization separation

The MPL was showing signs of laser wear, and was no longer correlating well with either 
the local VCEIL or the local KAZR.  Instrument was not reporting any cloud signatures at 
night, and showes a notable lack of scatter near the surface.  The data began to show signs 
of deterioration around 7/01 and slowly progressed. 

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

• Background signal, cross pol data(background_signal_cross_pol)
• Background signal standard deviation, copol data(background_signal_std_co_pol)
• Attenuated backscatter, cross pol(signal_return_cross_pol)
• Attenuated backscatter, co-pol(signal_return_co_pol)
• Background signal standard deviation, cross-pol(background_signal_std_cross_pol)
• Dead time correction flag(dead_time_corrected)
• Background signal, co-pol(background_signal_co_pol)