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...

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Autores principales:	Bosong Zhang, Brian J. Soden, Gabriel A. Vecchi, Wenchang Yang
Formato:	article
Lenguaje:	EN
Publicado:	American Geophysical Union (AGU) 2021
Materias:	convective aggregation radiative coupling extreme precipitation GCM Physical geography GB3-5030 Oceanography GC1-1581
Acceso en línea:	https://doaj.org/article/bf6fdc6797c24762bf1ef51bf6bed730
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spelling	oai:doaj.org-article:bf6fdc6797c24762bf1ef51bf6bed7302021-11-30T08:40:33ZInvestigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCM1942-246610.1029/2021MS002675https://doaj.org/article/bf6fdc6797c24762bf1ef51bf6bed7302021-11-01T00:00:00Zhttps://doi.org/10.1029/2021MS002675https://doaj.org/toc/1942-2466Abstract 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 extreme 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.Bosong ZhangBrian J. SodenGabriel A. VecchiWenchang YangAmerican Geophysical Union (AGU)articleconvective aggregationradiative couplingextreme precipitationGCMPhysical geographyGB3-5030OceanographyGC1-1581ENJournal of Advances in Modeling Earth Systems, Vol 13, Iss 11, Pp n/a-n/a (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	convective aggregation radiative coupling extreme precipitation GCM Physical geography GB3-5030 Oceanography GC1-1581
spellingShingle	convective aggregation radiative coupling extreme precipitation GCM Physical geography GB3-5030 Oceanography GC1-1581 Bosong Zhang Brian J. Soden Gabriel A. Vecchi Wenchang Yang Investigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCM
description	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 extreme 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.
format	article
author	Bosong Zhang Brian J. Soden Gabriel A. Vecchi Wenchang Yang
author_facet	Bosong Zhang Brian J. Soden Gabriel A. Vecchi Wenchang Yang
author_sort	Bosong Zhang
title	Investigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCM
title_short	Investigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCM
title_full	Investigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCM
title_fullStr	Investigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCM
title_full_unstemmed	Investigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCM
title_sort	investigating the causes and impacts of convective aggregation in a high resolution atmospheric gcm
publisher	American Geophysical Union (AGU)
publishDate	2021
url	https://doaj.org/article/bf6fdc6797c24762bf1ef51bf6bed730
work_keys_str_mv	AT bosongzhang investigatingthecausesandimpactsofconvectiveaggregationinahighresolutionatmosphericgcm AT brianjsoden investigatingthecausesandimpactsofconvectiveaggregationinahighresolutionatmosphericgcm AT gabrielavecchi investigatingthecausesandimpactsofconvectiveaggregationinahighresolutionatmosphericgcm AT wenchangyang investigatingthecausesandimpactsofconvectiveaggregationinahighresolutionatmosphericgcm
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Investigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCM

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