Last Update: 8/29/2003

INTRODUCTION

This research project is focused on studying the behavior of updraft regeneration within multicell convection using analytical, numerical, and observational methods. The goal is to further our understanding of the role mesoscale forcing plays on the thunderstorm updraft. The project team consists of two scientists (Chuck Doswell and Dan Weber) and a graduate student at the OU School of Meteorology (Adrian Loftus). The initial idea was put forth by Chuck Doswell (for a theoretical perspective see Chuck's " bubbles " document) and later expanded by Dan Weber to include a parameter range study to characterize the parameter space associated with the convective environment. " document. The project team submitted a proposal to the National Science Foundation seeking support for the numerical study. The main thrust of our proposed work is focused on performing numerous numerical simulations to characterize the environmental conditions favorable for producing either discrete bubble or plume-like updraft behavior or a superposition of the two types of updraft behavior.

RECENT PUBLICATIONS

Bubble Paper #1 Multicell Thunderstorm Initiating Mechanism

NWP Optimization Paper

Student Conference Papers

In the process of developing and submitting the proposal to NSF, we have performed several simulations using idealized conditions and reviewed observations of thunderstorms. This web site includes time lapse movies and animated gif's of the numerical experiments.

OBSERVATIONS

Time lapse video of convection

video #1 mpeg (2mb)

video #2 mpeg (2mb)

video #3 mpeg (2mb)

video #4 mov (53mb) uncompressor required

NUMERICAL EXPERIMENTS

Using a three-dimensional numerical model (ARPI3D ) several simulations were performed and the results studied in order to facilitate the development of the NSF proposal and to initiate the project team to conducting numerical experiments of convective updrafts. The current list of experiments includes both 2 and 3-dimensional simulations forced by a near surface heat source. The numerical simulations contained simple warm rain precipitation physics described by Kessler (1972). In addition, a switch to turn off the generation of rain was added to the model and simulations performed with only condensation and evaporative process enabled. In general, the model was initialized with a background profile obtained from the May 20, 1977 Del City thunderstorm case, but with modified wind profiles and near surface stability. The results are characterized according to dimensionality and rain/no-rain processes as well as vertical wind profiles and near surface stability. The following table provides a summary of the model run name, atmospheric profile, model input file, and results including animated gif's displaying liquid cloud water content from several numerical experiments. Note that the experiments associated with the NSF proposal are denoted with an asterisk.

Numerical Experiments Results TABLE