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An Improved Convection Parameterization with Detailed Aerosol–Cloud Microphysics for a Global Model

Jadav, Arti LU orcid ; Waman, Deepak LU orcid ; Pant, Chandra Shekhar ; Patade, Sachin LU ; Gautam, Martanda ; Phillips, Vaughan LU orcid ; Bansemer, Aaron ; Barahona, Donifan and Storelmov, Trude (2025) In Journal of the Atmospheric Sciences 82(1). p.197-231
Abstract

A new microphysical treatment that includes aerosol–cloud interactions and secondary ice production (SIP) mechanisms is implemented in the convection scheme of the Community Atmosphere Model, version 6 (CAM6). The approach is to embed a 1D Lagrangian parcel model in the bulk convective plume of the existing deep convection parameterization. Aerosol activation, growth processes including collision/coalescence, and three processes of SIP mechanisms, two of which are normally overlooked in atmospheric models, are represented in this embedded parcel model. These microphysical processes are treated with a hybrid bin/bulk scheme and a high spatial and temporal resolution for the integration of the embedded parcel in 1D, allowing vertical... (More)

A new microphysical treatment that includes aerosol–cloud interactions and secondary ice production (SIP) mechanisms is implemented in the convection scheme of the Community Atmosphere Model, version 6 (CAM6). The approach is to embed a 1D Lagrangian parcel model in the bulk convective plume of the existing deep convection parameterization. Aerosol activation, growth processes including collision/coalescence, and three processes of SIP mechanisms, two of which are normally overlooked in atmospheric models, are represented in this embedded parcel model. These microphysical processes are treated with a hybrid bin/bulk scheme and a high spatial and temporal resolution for the integration of the embedded parcel in 1D, allowing vertical velocity to determine the microphysical evolution following the in-cloud motion during ascent. Simulations of an observed case (Midlatitude Continental Convective Clouds Experiment) of a mesoscale convective system in Oklahoma, United States, with a single-column model (SCAM) version of CAM, are compared with aircraft in situ and ground-based observations of microphysical properties from the convection and precipitation. Results from the validation show the new microphysical scheme has a good representation of the ice initiation in the bulk convective plume, including the known and empirically quantified pathways of primary and secondary initiation, with benefits for the accuracy of properties of its supercooled cloud liquid. The sensitivity simulations and use of tagging tracers for the validated simulation confirm that the newly included SIP mechanisms are of paramount importance for convective microphysics and can be successfully treated in the global model.

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author
; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cloud microphysics, Convective parameterization, Cumulus clouds, Glaciation, Secondary ice production, Single column models
in
Journal of the Atmospheric Sciences
volume
82
issue
1
pages
35 pages
publisher
Amer Meteorological Soc
external identifiers
  • scopus:85215676281
ISSN
0022-4928
DOI
10.1175/JAS-D-23-0175.1
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025 American Meteorological Society.
id
7d93dd1d-8171-448a-bb20-6ce474da8f38
date added to LUP
2025-05-05 14:18:33
date last changed
2025-05-05 14:19:22
@article{7d93dd1d-8171-448a-bb20-6ce474da8f38,
  abstract     = {{<p>A new microphysical treatment that includes aerosol–cloud interactions and secondary ice production (SIP) mechanisms is implemented in the convection scheme of the Community Atmosphere Model, version 6 (CAM6). The approach is to embed a 1D Lagrangian parcel model in the bulk convective plume of the existing deep convection parameterization. Aerosol activation, growth processes including collision/coalescence, and three processes of SIP mechanisms, two of which are normally overlooked in atmospheric models, are represented in this embedded parcel model. These microphysical processes are treated with a hybrid bin/bulk scheme and a high spatial and temporal resolution for the integration of the embedded parcel in 1D, allowing vertical velocity to determine the microphysical evolution following the in-cloud motion during ascent. Simulations of an observed case (Midlatitude Continental Convective Clouds Experiment) of a mesoscale convective system in Oklahoma, United States, with a single-column model (SCAM) version of CAM, are compared with aircraft in situ and ground-based observations of microphysical properties from the convection and precipitation. Results from the validation show the new microphysical scheme has a good representation of the ice initiation in the bulk convective plume, including the known and empirically quantified pathways of primary and secondary initiation, with benefits for the accuracy of properties of its supercooled cloud liquid. The sensitivity simulations and use of tagging tracers for the validated simulation confirm that the newly included SIP mechanisms are of paramount importance for convective microphysics and can be successfully treated in the global model.</p>}},
  author       = {{Jadav, Arti and Waman, Deepak and Pant, Chandra Shekhar and Patade, Sachin and Gautam, Martanda and Phillips, Vaughan and Bansemer, Aaron and Barahona, Donifan and Storelmov, Trude}},
  issn         = {{0022-4928}},
  keywords     = {{Cloud microphysics; Convective parameterization; Cumulus clouds; Glaciation; Secondary ice production; Single column models}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{197--231}},
  publisher    = {{Amer Meteorological Soc}},
  series       = {{Journal of the Atmospheric Sciences}},
  title        = {{An Improved Convection Parameterization with Detailed Aerosol–Cloud Microphysics for a Global Model}},
  url          = {{http://dx.doi.org/10.1175/JAS-D-23-0175.1}},
  doi          = {{10.1175/JAS-D-23-0175.1}},
  volume       = {{82}},
  year         = {{2025}},
}