Multiparameter Radar Estimation of Raindrop Size Distribution
Abstract
The error structure of multiparameter radar and surface disdrometer measurements of rainfall has been studied in detail. The radar observables studied were reflectivity, differential reflectivity and X-band specific attenuation. These radar observables were simulated from fundamental considerations which incorporated statistical fluctuations due to the Doppler spectrum and the cross-correlation between H and V-polarized signals at zero time lag. Surface disdrometer measurements were also simulated accounting for the Poisson and Gamma distributed nature of the drop samples. Sampling fluctuation as well as physical variabilities of the drop size distribution were incorporated into the radar and disdrometer simulations. An intercomparison of these simulated variables revealed the nature and reason for certain inconsistencies. The use of differential reflectivity does indeed improve the characterization of the median drop size, and that its use in rainfall rate estimation will increase the accuracy by approximately a factor of 2 over conventional reflectivity based methods. The axis ratio of raindrops is analyzed as functions of their size using 2D-PMS probe images of drops in convective rainshafts. Axis ratios were estimated for about 3500 drops using the Fourier descriptor technique.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 07, 1989
- Accession Number
- ADA212410
Entities
People
- V. Chandrasekar
- V. N. Bringi
Organizations
- Colorado State University