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...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2021-11-01
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| Series: | Journal of Advances in Modeling Earth Systems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2021MS002675 |
| _version_ | 1819126773163491328 |
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| 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 |
| collection | DOAJ |
| 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. |
| first_indexed | 2024-12-22T08:01:21Z |
| format | Article |
| id | doaj.art-bf6fdc6797c24762bf1ef51bf6bed730 |
| institution | Directory Open Access Journal |
| issn | 1942-2466 |
| language | English |
| last_indexed | 2024-12-22T08:01:21Z |
| publishDate | 2021-11-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Journal of Advances in Modeling Earth Systems |
| spelling | doaj.art-bf6fdc6797c24762bf1ef51bf6bed7302022-12-21T18:33:14ZengAmerican Geophysical Union (AGU)Journal of Advances in Modeling Earth Systems1942-24662021-11-011311n/an/a10.1029/2021MS002675Investigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCMBosong Zhang0Brian J. Soden1Gabriel A. Vecchi2Wenchang Yang3Rosenstiel School of Marine and Atmospheric Science University of Miami Miami FL USARosenstiel School of Marine and Atmospheric Science University of Miami Miami FL USADepartment of Geosciences Princeton University Princeton NJ USADepartment of Geosciences Princeton University Princeton NJ USAAbstract 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.https://doi.org/10.1029/2021MS002675convective aggregationradiative couplingextreme precipitationGCM |
| spellingShingle | Bosong Zhang Brian J. Soden Gabriel A. Vecchi Wenchang Yang Investigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCM Journal of Advances in Modeling Earth Systems convective aggregation radiative coupling extreme precipitation GCM |
| title | 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_short | 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 |
| topic | convective aggregation radiative coupling extreme precipitation GCM |
| url | https://doi.org/10.1029/2021MS002675 |
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