Conveners
RCE and Processes in Deep Convective Organization: Interactive Session
- There are no conveners in this block
RCE and Processes in Deep Convective Organization: Introduction
- There are no conveners in this block
RCE and Processes in Deep Convective Organization: Guiding questions
- Adrian Tompkins (ICTP)
- Caroline Muller (Laboratoire de Météorologie Dynamique, LMD, Paris)
- Allison Wing (Florida State University)
RCE and Processes in Deep Convective Organization: Panel Discussion
- Allison Wing (Florida State University)
- Adrian Tompkins (ICTP)
- Caroline Muller (Laboratoire de Météorologie Dynamique, LMD, Paris)
RCE and Processes in Deep Convective Organization: Poster Pitches
- There are no conveners in this block
Cloud-radiation interactions play an important role in convective self-aggregation in idealised simulations of radiative-convective equilibrium and in real-world organised convection. This work aims to explore the radiative feedbacks of different cloud types to enable a deeper understanding of which cloud types play key roles in aggregation. We use three domain setups of the Met Office’s...
There is increasing evidence that local rainfall extremes can increase with warming at a higher rate than expected from the Clausius-Clapeyron (CC) relation. The exact mechanisms behind this so-called super-CC scaling phenomenon are still unsolved. Recent studies highlight invigorated local dynamics as a contributor to enhanced precipitation rates with warming. Here, cold pools play an...
Multicellular organization of deep convection is commonly observed, but ignored in contemporary global circulation model parameterizations. Is it important, and if so how? In an atmosphere destabilized by homogenous forcing, would a region of more organized convection out-compete regions with spotty convection for the resulting moist convective instability?
A set of idealized simulations is...
Numerical simulations of radiative-convective equilibrium (RCE) in high-resolution cloud-resolving models (CRMs) have pointed out the tendency of atmospheric convection to self-aggregate on periods of several weeks when the domain is large enough. Nevertheless, even though CRM simulations are able to identify some of the physical mechanisms driving convective clustering, the occurrence of...
Convective organization at mesoscales (hundreds of kilometers) is ubiquitous in the tropics, but the physical processes behind it are still poorly understood, despite its strong societal and climatic impact. Organization can be forced by the large scales, such as surface temperature gradients. But convective organization can also arise from internal feedbacks, such as "self-aggregation"...
In radiative-convective equilibrium (RCE) simulations, convective self-aggregation (CSA) is the spontaneous organization into segregated cloudy and cloud-free regions. Evidence exists for how CSA is stabilized, but how it arises favorably on large domains is not settled. Using large-eddy simulations (LES), we link the spatial organization emerging from the interaction of cold pools (CPs) to...
We investigate ocean feedbacks and the diurnal cycle impact convective aggregation, introducing a new adaptive Q-flux method to control SST. Aggregation onset occurs after 25 days with thick ocean layers that suppress feedbacks. Thinner ocean layers slow the onset of clustering, with a 1m ocean layer needing around 43 days, but with clustering onset time also becoming more variable. The...
The impact of microphysics on tropical precipitation extremes is explored with a global storm-resolving model by modifying the terminal velocity of raindrops. Depending on the time scales, precipitation extremes respond differently. Hourly extremes are influenced dynamically through convective updraft speed, as a faster terminal velocity of raindrops increases the updraft speed by reducing the...
A series of cloud-resolving model experiments is used to investigate the response of convection to imposed large-scale subsidence. Subsidence is favorable to convective aggregation in a non-linear fashion. In our model configuration, the radiative-convective equilibrium exhibits scattered convection and this non-aggregated stationary state exists also for weak subsidence. For large subsidence,...
Under radiative convective equilibrium (RCE), cloud populations can spontaneously segregate into cloudy and cloud-free subregions, a process known as convective self-aggregation (CSA).
Cold pools (CPs) have been shown to inhibit and sometimes prevent CSA. Here, we suppress CPs by removing the re-evaporation of rain in Large Eddy Simulations and cloud resolving simulations, which we run for...
Idealised large-eddy simulations (LES) of isolated or colliding CPs have proven to be a useful tool to investigate the life cycle of CPs, their mutual interaction and the derivation of simple theories about CP properties such as the propagation speed. On the contrary, the formation of CPs by rain evaporation and specifically their relation to the parent rain event has so far gained little...
In idealized cloud-resolving models, convective self-aggregation, or organization, develops from small dry patches that expand until they cover a large fraction of the domain. This study investigates the drying tendency associated with radiatively-driven subsidence and its possible link to the timescale of transition from a non-organized to an organized state. Indeed, understanding the...
The Simple-Cloud-E3SM-Atmosphere-Model (SCREAM) is currently being developed as the high resolution (~3 km grid spacing) version of the US Department of Energy’s new Energy Exascale Earth System Model (E3SM). A new suite of cloud physics parameterizations has been implemented to accommodate the partially cloud resolving resolution of SCREAM. In particular, turbulence, shallow convection, and...
Radiative convective equilibrium (RCE) simulations have now widely demonstrated the ability of convection to organize on its own, a process called self-aggregation. Given the stark idealization of such simulations, in particular due to the use of homogeneous boundary conditions and the absence of large-scale forcing, the relevance of self-aggregation for the real world remains under debate....
The Radiative-Convective Equilibrium Model Intercomparison Project (RCEMIP) is an intercomparison of multiple types of numerical models, including atmospheric general circulation models (GCMs), cloud-resolving models (CRMs), global cloud-resolving models (GCRMs), large eddy simulation models (LES), and single column models (SCMs), configured in radiative-convective equilibrium (RCE). In...
Convective organization has been associated with extreme precipitation in the tropics. Here we investigate the impact of convective self-aggregation on extreme rainfall rates. We find that convective self-aggregation significantly increases precipitation extremes, for 3-hourly accumulations (+70%) consistent with earlier studies, but also surprisingly for instantaneous rates (+30%). We show...
Under radiative‐convective equilibrium (RCE) surface moisture fluxes drive convection, while convection‐driven winds regulate surface fluxes. Most simulations of RCE do not resolve the boundary‐layer turbulence that drives near‐surface winds due to too coarse grid spacing and instead parameterize its effects by enforcing a minimum wind speed in the computation of the ocean‐atmosphere exchange....
In a general circulation model (ECHAM6) configured to represent radiative-convective equilibrium coupled to a slab ocean, we explore a wide range of CO$_2$ concentrations. We obtain reliable statistical quantities from thousand-year-long simulations, and we characterize the horizontal scale of ascending and subsiding regions by the so-called integral length scale of the vertical velocity field...
