A Disdrometer Best Estimate Product for Precipitation Properties
Authors
Aifang Zhou — Brookhaven National Laboratory
Joseph Clinton Hardin — Pacific Northwest National Laboratory
Mary Jane Bartholomew — Brookhaven National Laboratory
Scott Giangrande — Brookhaven National Laboratory
Die Wang — Brookhaven National Laboratory
Tami Fairless — Pacific Northwest National Laboratory
Category
ARM infrastructure
Description
Disdrometers are a useful instrument that measures the distribution of raindrop sizes (DSD) as these droplets fall from the clouds and reach the surface. These DSDs and their evolution are of fundamental importance to cloud and precipitation process studies, with various parameters or radar quantities of interest associated with DSDs also of great interest to the ARM climate modeling and observational communities. Although disdrometer datasets have been collected by ARM for several years at a variety of sites, the proper usage of these data requires careful considerations for quality control, processing and assumptions therein to ensure proper application by ARM users. This newly proposed ARM value added product (VAP) uses standard methods to reject drops with unrealistic fall speeds and estimate the DSD parameters (exponential or gamma-type fitting) similar to those predicted in cloud resolving and global climate models. Disdrometers have traditionally also been used as anchor for other instrumentation efforts, including rain gauge and radar studies/calibration. To support radar and other hydrological product comparisons, this new VAP also calculates radar equivalent parameters, including dual polarization quantities of interest for the variety of ARM radar wavelengths, using T-Matrix scattering.
