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(fall_speed)
• Drop volume(drop_volume)
• Oblateness(oblateness)
• Individual drop width as measured by camera B(drop_width_b)
• Individual drop width as measured by camera A(drop_width_a)
• Instrument effective measurement area(area)
• Equivolumetric sphere diameter(equivolumetric_sphere_diameter)
• Individual drop height as measured by camera A(drop_height_a)
• Individual drop height as measured by camera B(drop_height_b)

• Rainfall rate(rain_rate)
• Retrieved Liquid Water Content(liquid_water_content)
• Radar reflectivity(radar_reflectivity)
• Diameter of largest drop observed(diameter_max)
• Center diameter of drop size bin(drop_diameter)
• Slope parameter, assuming an ideal Marshall-Palmer type distribution(slope_parameter)
• Number density(num_density)
• Liquid water distribution mean, assuming an ideal Marshall-Palmer type
  distribution(liquid_water_distribution_mean)
• Moment 1 from the observed distribution(moment1)
• Intercept parameter, assuming an ideal Marshall-Palmer type distribution(intercept_parameter)
• Median volume diameter, assuming an ideal Marshall-Palmer type distribution(median_volume_diameter)
• Moment 6 from the observed distribution(moment6)
• Moment 5 from the observed distribution(moment5)
• Moment 4 from the observed distribution(moment4)
• Moment 3 from the observed distribution(moment3)
• Moment 2 from the observed distribution(moment2)
• Number of drops per bin(num_drops)
• Rain amount(rain_amount)
• Diameter of smallest drop observed(diameter_min)