Publication Date

5-28-2020

Document Type

Article

Department

Meteorology and Climate Science

Publication Title

Geophysical Research Letters

Volume

47

Issue

10

DOI

10.1029/2019GL086550

Abstract

Cirrus clouds have large climate impacts, yet aerosol indirect effects on cirrus microphysical properties remain highly uncertain. There is a lack of observational analysis on thermodynamic, dynamical, and aerosol indirect effects simultaneously, which limits the quantification of each effect. Using seven National Science Foundation aircraft campaigns, impacts of temperature, relative humidity, vertical velocity, and aerosols are individually quantified. Nonmonotonic correlations of ice water content, ice crystal number concentration (Ni), and mean diameter (Di) with respect to aerosol number concentrations (Na) are consistently seen at various conditions. Positive correlations become significant when Na > 500 nm (Na500) and >100 nm (Na100) are 3 and 10 times higher than average, respectively. While Na500 are more effective at temperatures closer to −40 °C with small vertical velocity fluctuations and are less sensitive to ice supersaturation, Na100 are more effective at colder temperatures with higher updraft and higher ice supersaturation, indicating heterogeneous and homogeneous nucleation mechanisms, respectively.

Funding Number

1642291

Funding Sponsor

National Science Foundation

Keywords

aerosol indirect effects, cirrus clouds, ice nucleation, aircraft observations, thermodynamic impact, dynamical impact

Comments

Copyright 2020 American Geophysical Union. All rights reserved.

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