Title: Drizzle, Turbulence, and Density Currents Below Post Cold Frontal Open Cellular Marine Stratocumulus Clouds

Abstract

Abstract Nine cases of postcold frontal marine stratocumulus clouds exhibiting open cellular mesoscale organization are analyzed to characterize the drizzle, turbulence, and density currents below them. Data collected by the vertically pointing Doppler cloud radar and multiple lidars part of the Atmospheric Radiation Measurement (ARM) Eastern North Atlantic (ENA) site are used in these analyses. A total of 251 drizzle shafts passed over the site with 76 shafts sampled for more than 15 min by the vertically pointing instruments. On average the drizzle shafts were ~18 km wide with below‐cloud drizzle water path of ~40 g m ⁻² , cloud base rain rate of 7.78 mm day ⁻¹ , and cloud base drizzle modal diameter of 393 μm. The widths of the drizzle shafts did not exhibit any relationship with the cloud base rain rate, below‐cloud drizzle water path, and the total water removed from the cloud. The downdrafts in the lowest 500 m within the drizzle cells strengthened with increasing cloud base rain rates, while the updrafts within drizzle cells did not exhibit this behavior. On average, the surface air density, pressure, water vapor mixing ratio, and wind speed along the background wind during the drizzle shaft were higher by 1.88 g m ⁻³ , 8.60 Pa, 0.24 g kg ⁻¹ ,more » and 1.22 m s ⁻¹ , respectively, from their background values. On the other hand, the surface air temperature was lower by 0.43 K during the drizzle shaft than its background value. The coincident measurements highlight the drizzle‐turbulence‐surface coupling in these cloud systems.« less

Authors:

Ghate, Virendra P.  ^[1];

• Search DOE PAGES for author "Ghate, Virendra P."
• Search DOE PAGES for ORCID "0000-0001-6068-609X"

Cadeddu, Maria P.  ^[1];

• Search DOE PAGES for author "Cadeddu, Maria P."
• Search DOE PAGES for ORCID "0000-0002-6430-0585"

Wood, Robert  ^[2]

• Search DOE PAGES for author "Wood, Robert"
• Search DOE PAGES for ORCID "0000-0002-1401-3828"

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+ Show Author Affiliations

1. Argonne National Laboratory Lemont IL USA
2. Department of Atmospheric Sciences University of Washington Seattle WA USA

Publication Date:

Mon Sep 28 00:00:00 EDT 2020

Research Org.:

Argonne National Laboratory (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1681070

Alternate Identifier(s):

OSTI ID: 1786823; OSTI ID: 1856036

Grant/Contract Number:  

DE‐AC02‐06CH11357; AC02-06CH11357

Resource Type:

Published Article

Journal Name:

Journal of Geophysical Research: Atmospheres

Additional Journal Information:

Journal Name: Journal of Geophysical Research: Atmospheres Journal Volume: 125 Journal Issue: 19; Journal ID: ISSN 2169-897X

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; stratocumulus; drizzle