Title: Investigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCM

Abstract

A ~50 km resolution atmospheric general circulation model (GCM) is used to investigate the impact of radiative interactions on spatial organization of convection, the model's mean state, and extreme precipitation events in the presence of realistic boundary conditions. Mechanism-denial experiments are performed in which synoptic-scale feedbacks between radiation and dynamics are suppressed by overwriting the model-generated atmospheric radiative cooling rates with its monthly varying climatological values. When synoptic-scale radiative interactions are disabled, the annual mean circulation and precipitation remain almost unchanged, however tropical convection becomes less aggregated, with an increase in cloud fraction and relative humidity in the free troposphere but a decrease in both variables in the boundary layer. Changes in cloud fraction and relative humidity in the boundary layer exhibit more sensitivity to the presence of radiative interactions than variations in the degree of aggregation. The less aggregated state is associated with a decrease in the frequency of extreme precipitation events, coincident with a decrease in the dynamical contribution to the magnitude of extreme precipitation. At regional scales, the spatial contrast in radiative cooling between dry and moist regions diminishes when radiative interactions are suppressed, reducing the upgradient transport of energy, degree of aggregation, and frequency of extrememore » precipitation events. However, the mean width of the tropical rain belt remains almost unaffected when radiative interactions are disabled. These results offer insights into how radiation-circulation coupling affects the spatial organization of convection, distributions of clouds and humidity, and weather extremes.« less

Authors:

Zhang, Bosong  ^[1];

• Search DOE PAGES for author "Zhang, Bosong"
• Search DOE PAGES for ORCID "0000-0002-0334-7128"

Soden, Brian J.  ^[2];

• Search DOE PAGES for author "Soden, Brian J."
• Search DOE PAGES for ORCID "0000-0001-9693-8236"

Vecchi, Gabriel A.  ^[3];

• Search DOE PAGES for author "Vecchi, Gabriel A."
• Search DOE PAGES for ORCID "0000-0002-5085-224X"

Yang, Wenchang  ^[4]

• Search DOE PAGES for author "Yang, Wenchang"
• Search DOE PAGES for ORCID "0000-0003-0053-9527"

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+ Show Author Affiliations

1. Rosenstiel School of Marine and Atmospheric Science University of Miami Miami FL USA, Now at Program in Atmospheric and Oceanic Sciences Princeton University Princeton NJ USA, Now at NOAA/Geophysical Fluid Dynamics Laboratory Princeton NJ USA
2. Rosenstiel School of Marine and Atmospheric Science University of Miami Miami FL USA
3. Department of Geosciences Princeton University Princeton NJ USA, High Meadows Environmental Institute Princeton University Princeton NJ USA
4. Department of Geosciences Princeton University Princeton NJ USA

Publication Date:

Tue Nov 09 00:00:00 EST 2021

Research Org.:

Univ. of Miami, FL (United States)

Sponsoring Org.:

USDOE; National Oceanic and Atmospheric Administration (NOAA)

OSTI Identifier:

1829511

Alternate Identifier(s):

OSTI ID: 1831055; OSTI ID: 1833721; OSTI ID: 1864756

Grant/Contract Number:  

DE‐SC0021333; SC0021333; NA18OAR4310269; NA18OAR4310418

Resource Type:

Published Article

Journal Name:

Journal of Advances in Modeling Earth Systems

Additional Journal Information:

Journal Name: Journal of Advances in Modeling Earth Systems Journal Volume: 13 Journal Issue: 11; Journal ID: ISSN 1942-2466

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; convective aggregation; radiative coupling; extreme precipitation; GCM