The Dynamical Coupling of Convective Updrafts, Downdrafts, and Cold Pools in Simulated Supercell Thunderstorms

G. R. Marion, Robert Trapp

Research output: Contribution to journalArticle

Abstract

The initiation of second-generation convective storms by the cold pools of first-generation storms is known to depend on cold pool characteristics such as depth and speed. It is not clear, however, how these characteristics relate back to the convective storm components and, in turn, to the environment. Here we investigate the hypothesis that wider updraft cores result in wider downdraft cores, which subsequently lead to the development of deeper cold pools that are more likely to initiate new convection. This hypothesis is addressed using a large set of idealized numerical simulations of highly organized convective storms, specifically, supercells. Quantifications of the convective components show strong interrelationships between updraft area, downdraft area, and cold pool depth, thus supporting our primary hypothesis. These interrelationships are highly sensitive to the parcel buoyancy and vertical wind shear, with large convective available potential energy, strong wind shear, and a deep mixed layer ultimately contributing to the deepest (and strongest) cold pools. Diagnoses of the forcings of vertical accelerations show that draft width, and therefore cold pool depth, are initially influenced by the buoyancy and linear dynamic forcings, but thereafter are controlled mostly by the nonlinear dynamic forcings. These results, overall, have implications on the development (or improvement) of cold pool parameterizations in weather and climate models.

Original languageEnglish (US)
Pages (from-to)664-683
Number of pages20
JournalJournal of Geophysical Research: Atmospheres
Volume124
Issue number2
DOIs
StatePublished - Jan 27 2019

Fingerprint

vertical air currents
cold pool
Thunderstorms
supercell
thunderstorms
updraft
thunderstorm
wind shear
Buoyancy
buoyancy
Climate models
draft
climate models
shear stress
Parameterization
Potential energy
parameterization
weather
wind power
convection

Keywords

  • cold pool
  • downdraft
  • supercell
  • updraft

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)
  • Palaeontology

Cite this

The Dynamical Coupling of Convective Updrafts, Downdrafts, and Cold Pools in Simulated Supercell Thunderstorms. / Marion, G. R.; Trapp, Robert.

In: Journal of Geophysical Research: Atmospheres, Vol. 124, No. 2, 27.01.2019, p. 664-683.

Research output: Contribution to journalArticle

@article{b394c6b9ba594b72b3cd6be9e07decae,
title = "The Dynamical Coupling of Convective Updrafts, Downdrafts, and Cold Pools in Simulated Supercell Thunderstorms",
abstract = "The initiation of second-generation convective storms by the cold pools of first-generation storms is known to depend on cold pool characteristics such as depth and speed. It is not clear, however, how these characteristics relate back to the convective storm components and, in turn, to the environment. Here we investigate the hypothesis that wider updraft cores result in wider downdraft cores, which subsequently lead to the development of deeper cold pools that are more likely to initiate new convection. This hypothesis is addressed using a large set of idealized numerical simulations of highly organized convective storms, specifically, supercells. Quantifications of the convective components show strong interrelationships between updraft area, downdraft area, and cold pool depth, thus supporting our primary hypothesis. These interrelationships are highly sensitive to the parcel buoyancy and vertical wind shear, with large convective available potential energy, strong wind shear, and a deep mixed layer ultimately contributing to the deepest (and strongest) cold pools. Diagnoses of the forcings of vertical accelerations show that draft width, and therefore cold pool depth, are initially influenced by the buoyancy and linear dynamic forcings, but thereafter are controlled mostly by the nonlinear dynamic forcings. These results, overall, have implications on the development (or improvement) of cold pool parameterizations in weather and climate models.",
keywords = "cold pool, downdraft, supercell, updraft",
author = "Marion, {G. R.} and Robert Trapp",
year = "2019",
month = "1",
day = "27",
doi = "10.1029/2018JD029055",
language = "English (US)",
volume = "124",
pages = "664--683",
journal = "Journal of Geophysical Research D: Atmospheres",
issn = "0148-0227",
publisher = "American Geophysical Union",
number = "2",

}

TY - JOUR

T1 - The Dynamical Coupling of Convective Updrafts, Downdrafts, and Cold Pools in Simulated Supercell Thunderstorms

AU - Marion, G. R.

AU - Trapp, Robert

PY - 2019/1/27

Y1 - 2019/1/27

N2 - The initiation of second-generation convective storms by the cold pools of first-generation storms is known to depend on cold pool characteristics such as depth and speed. It is not clear, however, how these characteristics relate back to the convective storm components and, in turn, to the environment. Here we investigate the hypothesis that wider updraft cores result in wider downdraft cores, which subsequently lead to the development of deeper cold pools that are more likely to initiate new convection. This hypothesis is addressed using a large set of idealized numerical simulations of highly organized convective storms, specifically, supercells. Quantifications of the convective components show strong interrelationships between updraft area, downdraft area, and cold pool depth, thus supporting our primary hypothesis. These interrelationships are highly sensitive to the parcel buoyancy and vertical wind shear, with large convective available potential energy, strong wind shear, and a deep mixed layer ultimately contributing to the deepest (and strongest) cold pools. Diagnoses of the forcings of vertical accelerations show that draft width, and therefore cold pool depth, are initially influenced by the buoyancy and linear dynamic forcings, but thereafter are controlled mostly by the nonlinear dynamic forcings. These results, overall, have implications on the development (or improvement) of cold pool parameterizations in weather and climate models.

AB - The initiation of second-generation convective storms by the cold pools of first-generation storms is known to depend on cold pool characteristics such as depth and speed. It is not clear, however, how these characteristics relate back to the convective storm components and, in turn, to the environment. Here we investigate the hypothesis that wider updraft cores result in wider downdraft cores, which subsequently lead to the development of deeper cold pools that are more likely to initiate new convection. This hypothesis is addressed using a large set of idealized numerical simulations of highly organized convective storms, specifically, supercells. Quantifications of the convective components show strong interrelationships between updraft area, downdraft area, and cold pool depth, thus supporting our primary hypothesis. These interrelationships are highly sensitive to the parcel buoyancy and vertical wind shear, with large convective available potential energy, strong wind shear, and a deep mixed layer ultimately contributing to the deepest (and strongest) cold pools. Diagnoses of the forcings of vertical accelerations show that draft width, and therefore cold pool depth, are initially influenced by the buoyancy and linear dynamic forcings, but thereafter are controlled mostly by the nonlinear dynamic forcings. These results, overall, have implications on the development (or improvement) of cold pool parameterizations in weather and climate models.

KW - cold pool

KW - downdraft

KW - supercell

KW - updraft

UR - http://www.scopus.com/inward/record.url?scp=85060570985&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85060570985&partnerID=8YFLogxK

U2 - 10.1029/2018JD029055

DO - 10.1029/2018JD029055

M3 - Article

AN - SCOPUS:85060570985

VL - 124

SP - 664

EP - 683

JO - Journal of Geophysical Research D: Atmospheres

JF - Journal of Geophysical Research D: Atmospheres

SN - 0148-0227

IS - 2

ER -