Publication Abstracts

Silber et al. 2021

Silber, I., A.M. Fridlind, J. Verlinde, A.S. Ackerman, G.V. Cesana, and D.A. Knopf, 2021: The prevalence of precipitation from polar supercooled clouds. Atmos. Chem. Phys., 21, no. 5, 3949-3971, doi:10.5194/acp-21-3949-2021.

Supercooled clouds substantially impact polar surface energy budgets, but large-scale models often underestimate their occurrence, which motivates accurately establishing metrics of basic processes. An analysis of long-term measurements at Utqiaġvik, Alaska, and McMurdo Station, Antarctica, combines lidar-validated use of soundings to identify supercooled cloud layers and colocated ground-based profiling radar measurements to quantify cloud base precipitation. We find that more than 85% (75%) of sampled supercooled layers are precipitating over the Arctic (Antarctic) site, with more than 75% (50%) precipitating continuously to the surface. Such high frequencies can be reconciled with substantially lesser spaceborne estimates by considering differences in radar hydrometeor detection sensitivity. While ice precipitation into supercooled clouds from aloft is common, we also find that the great majority of supercooled cloud layers without ice falling into them are themselves continuously generating precipitation. Such sustained primary ice formation is consistent with continuous activation of immersion-mode ice-nucleating particles (INPs), suggesting that supercooled cloud formation is a principal gateway to ice formation at temperatures greater than ∼ -38°C over polar regions. The prevalence of weak precipitation fluxes is also consistent with supercooled cloud longevity and with well-observed and widely simulated case studies. An analysis of colocated microwave radiometer retrievals suggests that weak precipitation fluxes can be nonetheless consequential to moisture budgets for supercooled clouds owing to small liquid water paths. The results here also demonstrate that the observed abundance of mixed-phase clouds can vary substantially with instrument sensitivity and methodology. Finally, we suggest that these ground-based precipitation rate statistics offer valuable guidance for improving the representation of polar cloud processes in large-scale models.

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BibTeX Citation

  author={Silber, I. and Fridlind, A. M. and Verlinde, J. and Ackerman, A. S. and Cesana, G. V. and Knopf, D. A.},
  title={The prevalence of precipitation from polar supercooled clouds},
  journal={Atmos. Chem. Phys.},

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RIS Citation

ID  - si09300n
AU  - Silber, I.
AU  - Fridlind, A. M.
AU  - Verlinde, J.
AU  - Ackerman, A. S.
AU  - Cesana, G. V.
AU  - Knopf, D. A.
PY  - 2021
TI  - The prevalence of precipitation from polar supercooled clouds
JA  - Atmos. Chem. Phys.
VL  - 21
IS  - 5
SP  - 3949
EP  - 3971
DO  - 10.5194/acp-21-3949-2021
ER  -

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