Development and Evaluation of a Shallow Convection Parameterization for Mesoscale Models

EPA Grant Number: R825254
Title: Development and Evaluation of a Shallow Convection Parameterization for Mesoscale Models
Investigators: Seaman, Nelson
Current Investigators: Seaman, Nelson , Kain, John S.
Institution: Pennsylvania State University
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1996 through September 30, 1999
Project Amount: $449,000
RFA: Air Quality (1996) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Air


The purpose of this project is to develop and evaluate a shallow-convection parameterization for describing the specific characteristics of subgrid-scale clouds required by air-quality models. A prototype shallow-convection model has already been constructed, which will serve as the basis for development of a consistent methodology that covers boundary-layer turbulent mixing and both shallow and deep convection. The hybrid closure used for the parameterization is based on the concept that shallow-cloud updraft characteristics are dominated mostly by large boundary-layer eddies, while deep convective updrafts are controlled primarily by convective available potential energy in the atmospheric column. The goal is to provide a unified approach to shallow-deep-convective parameterization that provides smooth transitions from dry boundary-layer convection to shallow (non-precipitating) convection to deep (precipitating) convection. Performance evaluation and parameter estimation will be based on comparisons with numerous data sources, including several field programs and extensive data collected by scientists at Penn State using a 94-GHz cloud radar and instrumented aircraft. Evaluation will also include the application in an air-quality model of the predicted cloud variables (cloud-base mass flux, entrainment/detrainment profiles, liquid water content, cloud depth, areal coverage, parcel residence times). It is intended that the unified convection concept will be applicable for model resolutions of about 10 - 60 km, while the shallow convection component may be applicable at scales as small as 4 km. The key benefit will be improved predictions of the evolution and transport of ozone, particulates and other pollutants in regional air quality models by providing with explicit and self-consistent mesoscale meteorology related to shallow and deep convection.

Publications and Presentations:

Publications have been submitted on this project: View all 17 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 2 journal articles for this project

Supplemental Keywords:

particulates, modeling, Northeast, Pennsylvania, PA, Region 3., RFA, Scientific Discipline, Air, Geographic Area, particulate matter, State, tropospheric ozone, Atmospheric Sciences, EPA Region, particulates, mesoscale models, shallow convection parameterization, Pennsylvania, Region 3, air sampling, boundary layer turbulence, cloud-based mass flux, air pollution models, atmospheric transport, Acute health effects, acute toxicity, cloud radar, modeling studies, subgrid scale clouds, particle transport, acid particles

Progress and Final Reports:

  • 1997
  • 1998
  • Final Report