Distortions of the Rain Distribution With Warming, With and Without Self-Aggregation

Fildier, Benjamin, Collins, William D. ORCID: https://orcid.org/0000-0002-4463-9848 and Muller, Caroline (2021) Distortions of the Rain Distribution With Warming, With and Without Self-Aggregation. Journal of Advances in Modeling Earth Systems, 13 (2). ISSN 1942-2466

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Abstract

We investigate how mesoscale circulations associated with convective aggregation can modulate the sensitivity of the hydrologic cycle to warming. We quantify changes in the full distribution of rain across radiative-convective equilibrium states in a cloud-resolving model. For a given Sea Surface Temperature (SST), the shift in mean rainfall between disorganized and organized states is associated with a shift in atmospheric radiative cooling, and is roughly analogous to the effect of a 4K SST increase. With rising temperatures, the increase in mean rain rate is insensitive to the presence of organization, while extremes can intensify faster in the aggregated state, leading to a faster amplification in the sporadic nature of rain. When convection aggregates, heavy rain is enhanced by 20%–30% and nonlinear behaviors are observed as a function of SST and strength of aggregation feedbacks. First, radiative- and surface-flux aggregation feedbacks have multiplicative effects on extremes, illustrating a non-trivial sensitivity to the degree of organization. Second, alternating Clausius-Clapeyron and super-Clausius-Clapeyron regimes in extreme rainfall are found as a function of SST, corresponding to varying thermodynamic and dynamic contributions, and a large sensitivity to precipitation efficiency variations in some SST ranges. The potential for mesoscale circulations in amplifying the hydrologic cycle is established. However, these nonlinear distortions question the quantitative relevance of idealized self-aggregation. This calls for a deeper investigation of relationships which capture the coupling between global energetics, aggregation feedbacks and local convection, and for systematic tests of their sensitivity to domain configurations, surface boundary conditions, microphysics, and turbulence schemes.

Item Type:	Article
Additional Information:	Data Availability Statement: Scripts developed to launch simulations and for the analysis are archived and accessible under https://zenodo.org/record/4299060. Because of the large volume of model outputs, the simulation results are available from the authors upon request (benjamin.fildier@lmd.ens.fr) and are archived at the National Energy Research Scientific Computing Center (NERSC). This project uses a package developed for easy computation of statistical distributions and conditional statistics, that can be used for analyses of extreme rainfall and other statistical analyses in atmospheric science. Interested users should refer to https://zenodo.org/record/4299070.
Uncontrolled Keywords:	cloud-resolving simulations,convective aggregation,extreme rainfall,hydrologic cycle,global and planetary change,environmental chemistry,general earth and planetary sciences ,/dk/atira/pure/subjectarea/asjc/2300/2306
Faculty \ School:	Faculty of Science > School of Environmental Sciences
Related URLs:	https://www.scopus.com/pages/publication...
Depositing User:	LivePure Connector
Date Deposited:	08 Jul 2026 09:20
Last Modified:	12 Jul 2026 05:38
URI:	https://ueaeprints.uea.ac.uk/id/eprint/103785
DOI:	10.1029/2020MS002256

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