State of 3D Convective Vertical Velocity Retrievals at the ARM Sites: Challenges, Uncertainties and Future Recommendations
Poster PDF
Authors
Mariko Oue — Stony Brook University
Pavlos Kollias — Stony Brook University
Aleksandra Tatarevic — McGill University
Kirk North — McGill University
Toshihisa Matsui — Earth System Science Interdisciplinary Center at University of Maryland
Ann M. Fridlind — NASA - Goddard Institute for Space Studies
Die Wang — Brookhaven National Laboratory
Kwang Min Yu — Brookhaven National Laboratory
Category
Convective clouds, including aerosol interactions
Description
The ARM fixed and mobile atmospheric observatories are heavily instrumented with active and passive remote sensors designed to provide 4D observations of clouds and precipitation. During the past 7-8 years, the ARM program has worked towards reliable radar-network based approaches for retrieving the 3D kinematic structure of convective clouds. Dual- or multi-Doppler radar wind retrievals can provide spatial coverage and track storm evolution, but the retrievals still have large uncertainties owing to several sources of errors during radar data post processing (e.g., gridding, smoothing) and selection of the parameters used in the minimization of the cost function (e.g., constraint, weight). These uncertainties can be partially addressed by careful analysis and quality control of the radar observations and proper characterization of the sensitivity of the solution to the parameters used in the cost function. A larger issue and a source of considerable uncertainty is the limited spatiotemporal resolution of our radar networks such as poor coverage of the upper part of convective cloud systems, radar sampling volume increasing with distance from the radar, 6-10 min revisiting time.
Here the impacts of these limitations in multi-Doppler radar-based vertical wind retrievals are investigated using the Cloud Resolving Model Radar SIMulator (CR-SIM) and sub-minute output from the Weather Research Forecasting (WRF) simulation for a mesoscale convective system observed during the MC3E field campaign. In addition, we simulated scanning radar measurements for isolated convective storms developed over the Houston area and examined the impacts of the radar temporal/spatial sampling and sensitivity issues on polarimetric radar measurements. Finally, we will demonstrate how the use of electronically scanning X-band radars that can provide dense coverage in very short time periods (under one min) can substantially improve the capability to retrieve the vertical velocity in deep convective clouds and investigate the interaction of microphysics and dynamics.
