Measurement accuracy can be affected by

• Variations in drop size distribution (Z-R relationship)
• Earth curvature
• Atmospheric refraction
• Beam filling
• Terrain blocking
• Attenuation
• System losses/Hardware calibration
• Radome losses
• Below beam effects

Measurement accuracy can also be affected by

• Drop-Size Distribution
  
  • Inherent variability, difficult to correct
    
• Earth curvature
  
  • Can be corrected
    
• Atmospheric refraction
  
  • Can be allow for “standard” refraction, but non-standard refraction often occurs.

Reminder: what you see is not clouds!