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Title: An observational study of entrainment rate in deep convection

This study estimates entrainment rate and investigates its relationships with cloud properties in 156 deep convective clouds based on in-situ aircraft observations during the TOGA-COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment) field campaign over the western Pacific. To the authors’ knowledge, this is the first study on the probability density function of entrainment rate, the relationships between entrainment rate and cloud microphysics, and the effects of dry air sources on the calculated entrainment rate in deep convection from an observational perspective. Results show that the probability density function of entrainment rate can be well fitted by lognormal, gamma or Weibull distribution, with coefficients of determination being 0.82, 0.85 and 0.80, respectively. Entrainment tends to reduce temperature, water vapor content and moist static energy in cloud due to evaporative cooling and dilution. Inspection of the relationships between entrainment rate and microphysical properties reveals a negative correlation between volume-mean radius and entrainment rate, suggesting the potential dominance of homogeneous mechanism in the clouds examined. The entrainment rate and environmental water vapor content show similar tendencies of variation with the distance of the assumed environmental air to the cloud edges. Their variation tendencies are non-monotonic due to the relatively shortmore » distance between adjacent clouds.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4]
  1. Nanjing Univ. of Information Science and Technology, Nanjing (China); Jiangsu Research Institute of Meteorological Science, Nanjing (China)
  2. Nanjing Univ. of Information Science and Technology, Nanjing (China)
  3. Univ. of California, San Diego, La Jolla, CA (United States)
  4. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
OSTI Identifier:
1222608
Report Number(s):
BNL--108399-2015-JA
Journal ID: ISSN 2073-4433; ATMOCZ; R&D Project: 2016-BNL-EE631EECA-Budg; KP1703020
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
Atmosphere (Basel)
Additional Journal Information:
Journal Name: Atmosphere (Basel); Journal Volume: 6; Journal Issue: 9; Journal ID: ISSN 2073-4433
Publisher:
MDPI
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES entrainment rate; deep convection; aircraft observations