Surface‐Atmosphere Decoupling Prolongs Cloud Lifetime Under Warm Advection Due To Reduced Entrainment Drying
[1];
[3];
[1]
- Department of Atmospheric and Oceanic Science &, Earth System Science Interdisciplinary Center University of Maryland College Park MD USA
- Program in Atmospheric and Oceanic Sciences Princeton University Princeton NJ USA, Department of Atmospheric and Earth Science University of Houston Houston TX USA
- Department of Atmospheric and Oceanic Science &, Earth System Science Interdisciplinary Center University of Maryland College Park MD USA, Science and Technology Corporation Hampton VA USA, Research Center for Climate Sciences Pusan National University Busan Republic of Korea
Abstract An initially well‐mixed stratocumulus deck can remain overcast for several tens of hours under warm‐advection conditions, although moisture supply is cut off from the ocean due to surface‐atmosphere decoupling (stabilization of the surface‐atmosphere interface). In this study, a set of idealized large‐eddy simulations were performed to investigate the physical mechanism of how warm‐air advection impacts the evolution of a pre‐existing stratocumulus deck. To mimic warm‐air advection, we decrease the sea surface temperature linearly over time in a doubly periodic domain. Given the same initial conditions, the stratocumulus deck is more persistent when experiencing warm‐air advection than cold‐air advection. This persistence is caused by reduced cloud‐top entrainment drying due to decoupling, a process more influential than the decoupling‐induced cutoff of moisture supply. This mechanism is more notable when the free troposphere becomes more humid. The relevance of the mechanism to previous observations of less low‐level cloudiness under warm‐advection conditions is discussed.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Atmospheric Radiation Measurement (ARM) Data Center
- Sponsoring Organization:
- National Research Foundation of Korea (NRF); National Science Foundation (NSF); USDOE; USDOE Office of Science (SC), Biological and Environmental Research (BER)
- Contributing Organization:
- Argonne National Laboratory (ANL); Brookhaven National Laboratory (BNL); Pacific Northwest National Laboratory (PNNL)
- Grant/Contract Number:
- SC0022919
- OSTI ID:
- 1974099
- Journal Information:
- Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 10 Vol. 50; ISSN 0094-8276
- Publisher:
- American Geophysical Union (AGU)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Episodes of Warm-Air Advection Causing Cloud-Surface Decoupling During the MARCUS
Estimating the Decoupling Degree of Subtropical Marine Stratocumulus Decks From Satellite