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Title: Characteristics of vertical air motion in isolated convective clouds

The vertical velocity and air mass flux in isolated convective clouds are statistically analyzed using aircraft in situ data collected from three field campaigns: High-Plains Cumulus (HiCu) conducted over the midlatitude High Plains, COnvective Precipitation Experiment (COPE) conducted in a midlatitude coastal area, and Ice in Clouds Experiment-Tropical (ICE-T) conducted over a tropical ocean. The results show that small-scale updrafts and downdrafts (<  500 m in diameter) are frequently observed in the three field campaigns, and they make important contributions to the total air mass flux. The probability density functions (PDFs) and profiles of the observed vertical velocity are provided. The PDFs are exponentially distributed. The updrafts generally strengthen with height. Relatively strong updrafts (>  20 m s −1) were sampled in COPE and ICE-T. The observed downdrafts are stronger in HiCu and COPE than in ICE-T. The PDFs of the air mass flux are exponentially distributed as well. The observed maximum air mass flux in updrafts is of the order 10 4 kg m −1 s −1. The observed air mass flux in the downdrafts is typically a few times smaller in magnitude than that in the updrafts. Since this study only deals with isolated convective clouds, and there are many limitations and sampling issues in aircraftmore » in situ measurements, more observations are needed to better explore the vertical air motion in convective clouds.« less
Authors:
 [1] ;  [1] ;  [2] ;  [1]
  1. Univ. of Wyoming, Laramie, WY (United States). Dept. of Atmospheric Science
  2. National Center for Atmospheric Research, Boulder, CO (United States)
Publication Date:
Grant/Contract Number:
SC0006974
Type:
Published Article
Journal Name:
Atmospheric Chemistry and Physics (Online)
Additional Journal Information:
Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 16; Journal Issue: 15; Journal ID: ISSN 1680-7324
Publisher:
European Geosciences Union
Research Org:
Univ. of Wyoming, Laramie, WY (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES
OSTI Identifier:
1290300
Alternate Identifier(s):
OSTI ID: 1437160