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Vaughan Phillips

Research in the Area of Clouds, Aerosols and Climate

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

Author

  • Arti Jadav
  • Deepak Waman
  • Chandra Shekhar Pant
  • Sachin Patade
  • Martanda Gautam
  • Vaughan Phillips
  • Aaron Bansemer
  • Donifan Barahona
  • Trude Storelmov

Summary, in English

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.

Department/s

  • LTH Profile Area: Aerosols
  • MERGE: ModElling the Regional and Global Earth system
  • Dept of Physical Geography and Ecosystem Science
  • eSSENCE: The e-Science Collaboration
  • BECC: Biodiversity and Ecosystem services in a Changing Climate

Publishing year

2025-01

Language

English

Pages

197-231

Publication/Series

Journal of the Atmospheric Sciences

Volume

82

Issue

1

Document type

Journal article

Publisher

Amer Meteorological Soc

Topic

  • Meteorology and Atmospheric Sciences

Keywords

  • Cloud microphysics
  • Convective parameterization
  • Cumulus clouds
  • Glaciation
  • Secondary ice production
  • Single column models

Status

Published

ISBN/ISSN/Other

  • ISSN: 0022-4928