Publication Abstracts

Lin et al. 2021

Lin, L., Q. Fu, X. Liu, Y. Shan, S.E. Giangrande, G.S. Elsaesser, K. Yang, and D. Wang, 2021: Improved convective ice microphysics parameterization in the NCAR CAM model. J. Geophys. Res. Atmos., 126, no. 9, e2020JD034157, doi:10.1029/2020JD034157.

Partitioning deep convective cloud condensates into components that sediment and detrain, known to be a challenge for global climate models, is important for cloud vertical distribution and anvil cloud formation. In this study, we address this issue by improving the convective microphysics scheme in the National Center for Atmospheric Research Community Atmosphere Model version 5.3 (CAM5.3). The improvements include: (1) considering sedimentation for cloud ice crystals that do not fall in the original scheme, (2) applying a new terminal velocity parameterization that depends on the environmental conditions for convective snow, (3) adding a new hydrometeor category, "rimed ice", to the original four-class (cloud liquid, cloud ice, rain, and snow) scheme, and (4) allowing convective clouds to detrain snow particles into stratiform clouds.

Results from the default and modified CAM5.3 models were evaluated against observations from the U.S. Department of Energy Tropical Warm Pool-International Cloud Experiment (TWP-ICE) field campaign. The default model overestimates ice amount, which is largely attributed to the underestimation of convective ice particle sedimentation. By considering cloud ice sedimentation and rimed ice particles and applying a new convective snow terminal velocity parameterization, the vertical distribution of ice amount is much improved in the mid- and upper-troposphere when compared to observations. The vertical distribution of ice condensate also agrees well with observational best estimates upon considering snow detrainment. Comparison with observed convective updrafts reveals that current bulk model fails to reproduce the observed updraft magnitude and occurrence frequency, suggesting spectral distributions be required to simulate the subgrid updraft heterogeneity.

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BibTeX Citation

  author={Lin, L. and Fu, Q. and Liu, X. and Shan, Y. and Giangrande, S. E. and Elsaesser, G. S. and Yang, K. and Wang, D.},
  title={Improved convective ice microphysics parameterization in the NCAR CAM model},
  journal={Journal of Geophysical Research: Atmospheres},

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RIS Citation

ID  - li08110o
AU  - Lin, L.
AU  - Fu, Q.
AU  - Liu, X.
AU  - Shan, Y.
AU  - Giangrande, S. E.
AU  - Elsaesser, G. S.
AU  - Yang, K.
AU  - Wang, D.
PY  - 2021
TI  - Improved convective ice microphysics parameterization in the NCAR CAM model
JA  - J. Geophys. Res. Atmos.
JO  - Journal of Geophysical Research: Atmospheres
VL  - 126
IS  - 9
SP  - e2020JD034157
DO  - 10.1029/2020JD034157
ER  -

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