TWP/VDIS/C1 - Lightbulb failures

VDIS was not comparing well to the local MET TBRG at C1. Most weeks had mulitple days that 
were above/below the allowable +/-50% difference between the VDIS and the MET. Several 
days had no data recorded as well.

Sample July/August differences:
-7/1 VDIS recording 163% of MET TBRG
-7/2 VDIS recording 2% of MET TBRG
-7/5 no data found 
-7/6 VDIS recording 191% of MET TBRG
-7/10 VDIS recording 2% of MET TBRG
-7/11 no data found
-7/12 VDIS recording 6% of MET TBRG
-7/17 VDIS recording 37% of MET TBRG 
-7/26 no data found
-7/27 VDIS recording 0% of MET TBRG
-7/28 VDIS recording 0.16% of MET TBRG
-8/2 no data found 
-8/12 VDIS recording 33% of MET TBRG
-8/13 VDIS recording 0% of MET TBRG
-8/16 VDIS recording 13% of MET TBRG 
-8/17-8/18, 8/22-8/23 no data found
-8/19 VDIS recording 1% of MET TBRG
-8/21 VDIS recording 45% of MET TBRG 
-8/24-8/25 no data found

The instrument was having light bulb problems.  Repaired and calibrationed in October 
2013.

• fall_speed
• drop_volume
• oblateness
• drop_width_b
• drop_width_a
• area
• equivolumetric_sphere_diameter
• drop_height_a
• drop_height_b

• rain_rate
• liquid_water_content
• radar_reflectivity
• diameter_max
• drop_diameter
• slope_parameter
• num_density
• liquid_water_distribution_mean
• moment1
• intercept_parameter
• median_volume_diameter
• moment6
• moment5
• moment4
• moment3
• moment2
• num_drops
• rain_amount
• diameter_min