Sensitivity of a Bowing Mesoscale Convective System to Horizontal Grid Spacing in a Convection-Allowing Ensemble

Thumbnail Image
Date
2020-04-14
Authors
Lawson, John
Gallus, William
Potvin, Corey
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Authors
Person
Gallus, William
Professor
Research Projects
Organizational Units
Journal Issue
Is Version Of
Versions
Series
Department
Geological and Atmospheric SciencesEnvironmental ScienceHuman Computer Interaction
Abstract

The bow echo, a mesoscale convective system (MCS) responsible for much hail and wind damage across the United States, is associated with poor skill in convection-allowing numerical model forecasts. Given the decrease in convection-allowing grid spacings within many operational forecasting systems, we investigate the effect of finer resolution on the character of bowing-MCS development in a real-data numerical simulation. Two ensembles were generated: one with a single domain of 3-km horizontal grid spacing, and another nesting a 1-km domain with two-way feedback. Ensemble members were generated from their control member with a stochastic kinetic-energy backscatter scheme, with identical initial and lateral-boundary conditions. Results suggest that resolution reduces hindcast skill of this MCS, as measured with an adaptation of the object-based Structure–Amplitude–Location method. The nested 1-km ensemble produces a faster system than in both the 3-km ensemble and observations. The nested 1-km simulation also produced stronger cold pools, which could be enhanced by the increased (fractal) cloud surface area with higher resolution, allowing more entrainment of dry air and hence increased evaporative cooling.

Comments

This article is published as Lawson, John R., William A. Gallus, and Corey K. Potvin. "Sensitivity of a Bowing Mesoscale Convective System to Horizontal Grid Spacing in a Convection-Allowing Ensemble." Atmosphere 11, no. 4 (2020): 384. DOI: 10.3390/atmos11040384. Posted with permission.

Description
Keywords
Citation
DOI
Copyright
Wed Jan 01 00:00:00 UTC 2020
Collections