Document Type

Article

Publication Date

July 2013

Publication Title

Geophysical Research Letters

Volume

40

Issue Number

13

DOI

10.1002/grl.50665

Keywords

cirrus, ice crystal, nucleation, ice supersaturation, cloud lifetime, cloud life cycle

Disciplines

Climate | Meteorology

Abstract

[1] Microphysical properties of cirrus clouds largely influence their atmospheric radiative forcing. However, uncertainties remain in simulating/parameterizing the evolution of ice crystals. These uncertainties require more analyses in the Lagrangian view, yet most in situ observations are in the Eulerian view. Here we demonstrate a new method to separate out five phases of ice crystal evolution, using the horizontal spatial relationships between ice supersaturated regions (ISSRs) and ice crystal regions (ICRs). Based on global in situ data sets, we show that the samples of clear-sky ISSRs, ice crystal formation/growth, and evaporation/sedimentation are ~20%, 10%, and 70% of the total ISSR + ICR samples, respectively. In addition, the variance of number-weighted mean diameter (Dc) becomes narrower during the evolution, while the distribution of ice crystal number density (Nc) becomes wider. The new method helps to understand the evolution of ICRs and ISSRs on the microscale by using in situ Eulerian observations.

Comments

© 2013. American Geophysical Union. All Rights Reserved.
This article, the Version of Record, originally appeared in Geophysical Research Letters in Volume 40, Issue 13 and can be found at this link.
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