A More General Paradigm for Understanding the Decoupling of Stratocumulus‐Topped Boundary Layers: The Importance of Horizontal Temperature Advection

Abstract Most prior studies on decoupling of a stratocumulus‐topped boundary layer (STBL) are focused on subtropics where cold air advection with moderate strength is dominant. This study expands across a wider spectrum of temperature advection spanning from moderately strong warm air advection to e...

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Main Authors: Youtong Zheng, Daniel Rosenfeld, Zhanqing Li
Format: Article
Language:English
Published: Wiley 2020-07-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2020GL087697
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author Youtong Zheng
Daniel Rosenfeld
Zhanqing Li
author_facet Youtong Zheng
Daniel Rosenfeld
Zhanqing Li
author_sort Youtong Zheng
collection DOAJ
description Abstract Most prior studies on decoupling of a stratocumulus‐topped boundary layer (STBL) are focused on subtropics where cold air advection with moderate strength is dominant. This study expands across a wider spectrum of temperature advection spanning from moderately strong warm air advection to extremely strong cold air advection. A STBL undergoing warm advection is found to be more mixed than a STBL undergoing cold advection. This finding is consistent with the cold advection facilitating turbulent mixing in the boundary layer. When cold advection becomes sufficiently strong (<−5 K/day), the STBL becomes more stably stratified again because of emergence of the cumulus‐coupled STBL regime induced by the “deepening‐warming” mechanism. Such a “deepening‐warming” induced STBL decoupling, however, is still much weaker than that caused by warm advection flows (even weak ones), suggesting that the direction and strength of temperature advection must be considered for any STBL decoupling studies.
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publishDate 2020-07-01
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series Geophysical Research Letters
spelling doaj-art-f7671fc2e4bf4228922dcbf979cf4b982025-08-20T03:47:41ZengWileyGeophysical Research Letters0094-82761944-80072020-07-014714n/an/a10.1029/2020GL087697A More General Paradigm for Understanding the Decoupling of Stratocumulus‐Topped Boundary Layers: The Importance of Horizontal Temperature AdvectionYoutong Zheng0Daniel Rosenfeld1Zhanqing Li2Earth System Science Interdisciplinary Center University of Maryland College Park MD USAInstitute of Earth Science Hebrew University of Jerusalem Jerusalem IsraelEarth System Science Interdisciplinary Center University of Maryland College Park MD USAAbstract Most prior studies on decoupling of a stratocumulus‐topped boundary layer (STBL) are focused on subtropics where cold air advection with moderate strength is dominant. This study expands across a wider spectrum of temperature advection spanning from moderately strong warm air advection to extremely strong cold air advection. A STBL undergoing warm advection is found to be more mixed than a STBL undergoing cold advection. This finding is consistent with the cold advection facilitating turbulent mixing in the boundary layer. When cold advection becomes sufficiently strong (<−5 K/day), the STBL becomes more stably stratified again because of emergence of the cumulus‐coupled STBL regime induced by the “deepening‐warming” mechanism. Such a “deepening‐warming” induced STBL decoupling, however, is still much weaker than that caused by warm advection flows (even weak ones), suggesting that the direction and strength of temperature advection must be considered for any STBL decoupling studies.https://doi.org/10.1029/2020GL087697boundary layer decouplingstratocumulus cloudstemperature advection
spellingShingle Youtong Zheng
Daniel Rosenfeld
Zhanqing Li
A More General Paradigm for Understanding the Decoupling of Stratocumulus‐Topped Boundary Layers: The Importance of Horizontal Temperature Advection
Geophysical Research Letters
boundary layer decoupling
stratocumulus clouds
temperature advection
title A More General Paradigm for Understanding the Decoupling of Stratocumulus‐Topped Boundary Layers: The Importance of Horizontal Temperature Advection
title_full A More General Paradigm for Understanding the Decoupling of Stratocumulus‐Topped Boundary Layers: The Importance of Horizontal Temperature Advection
title_fullStr A More General Paradigm for Understanding the Decoupling of Stratocumulus‐Topped Boundary Layers: The Importance of Horizontal Temperature Advection
title_full_unstemmed A More General Paradigm for Understanding the Decoupling of Stratocumulus‐Topped Boundary Layers: The Importance of Horizontal Temperature Advection
title_short A More General Paradigm for Understanding the Decoupling of Stratocumulus‐Topped Boundary Layers: The Importance of Horizontal Temperature Advection
title_sort more general paradigm for understanding the decoupling of stratocumulus topped boundary layers the importance of horizontal temperature advection
topic boundary layer decoupling
stratocumulus clouds
temperature advection
url https://doi.org/10.1029/2020GL087697
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