Convective Heating Leads to Self‐Aggregation by Generating Available Potential Energy

Journal Article · 29 September 2019 · Geophysical Research Letters

DOI: https://doi.org/10.1029/2019GL083805 · OSTI ID:1567901

Yang, Da  ^[1]

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1. University of California Davis CA USA, Lawrence Berkeley National Laboratory Berkeley CA USA

Abstract The moisture‐entrainment‐convection (MEC) feedback posits that a moist environment favors deep convection, which further moistens the atmosphere through its associated circulation and detrainment. The MEC feedback has been proposed to be crucial to spontaneous convective aggregation. Here we test this hypothesis by performing minimal cloud‐resolving simulations, without the buoyancy effect due to water vapor, evaporation of rain, or radiative and surface‐flux feedbacks. Convection can self‐aggregate in this minimal simulation, in which the MEC feedback is active. We then switch off this feedback by relaxing moisture to its horizontal mean over a time scale of 3 hr. Convection still self‐aggregates in this mechanism‐denial experiment, suggesting that the MEC feedback is not essential to self‐aggregation. We further show that convective heating coincides with positive temperature anomalies, generating available potential energy. Therefore, we propose that this convective heating‐overturning circulation feedback can lead to spontaneous development of large‐scale circulations.

• Sponsoring Organization: USDOE
• Grant/Contract Number: NONE; AC02-05CH11231
• OSTI ID: 1567901
• Journal Information: Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 17-18 Vol. 46; ISSN 0094-8276
• Publisher: American Geophysical Union (AGU)Copyright Statement
• Country of Publication: United States
• Language: English