Moisture rings at cold pool fronts have been identified as playing a key role in convective propagation in numerical simulations. However, it is not clear if these are features of real cold pools due to the uncertainties of model microphysics and representation of turbulence at the cold pool front. We therefore analyse more than a decade of station observations from two islands in the tropical...
Our work aims to understand the structure and organization of cloud systems by exploiting the self-learning capability of a deep neural network. The neural network utilizes deep clustering and non-parametric instance-level discrimination for decision-making at any learning stage.
The data augmentation in the data pipeline, multi-clustering of the dense vectors, and Multilayer perceptron...
Atmospheric self-organization and activator-inhibitor dynamics in biology provide examples of checkerboard-like spatio-temporal organization. We study a simple model for local activation-inhibition processes. Our model, first introduced in the context of atmospheric moisture dynamics, is a continuous-energy and non-Abelian version of the fixed-energy sandpile model. Each...
The cellular structure of stratocumulus clouds decks and their evolution has been modeled by describing them as cellular, nearest-neighbor networks (Glassmeier& Feingold, 2017, PNAS). We review this approach and discuss options and challenges for its generalization to shallow cumulus cloud fields.
Tradewind shallow cumulus clouds cover vast areas of the subtropical oceans, and are associated with various modes of mesoscale organization. During the EUREC4A field campaign in the subtropical Atlantic in early 2020, unique in-situ and remote sensing measurements were made that allow characterization of Trade wind cloud organization as well as the large-scale environment in which this...
We consider the clouds that form in Lagrangian high-resolution and single-column model simulations based on different days of the EUREC4A/ATOMIC field campaign. These simulations are driven using ERA5 reanalysis, and contain examples of flower type and gravel type organisation. In particular, we consider the spacing and thermodynamic properties of updraughts and detrained air during different...
Shallow cumuli are the most frequent types of clouds over the subtropical oceans where they occur in several shapes and patterns. These types of clouds potentially play a major role in regulating the radiative budget of the Earth system. An important question is to what extent cloud patterns alter under climate change and how this will feedback onto a rising of temperature. In this study, we...
Studying the marine atmospheric boundary layer (MABL) processes at play to organize cloudiness through satellite products is challenging. Here, we propose an innovative approach to investigate the MABL dynamical structures by combining spaceborne Synthetic Aperture Radar (SAR) images, and brightness temperature measurements from the Geostationary Operational Environmental Satellite...
Simulations of a marine cold air outbreak with the mesoscale weather model HARMONIE suggest that parameterized shallow convective momentum transport acts to diminish circulations that accompany cellular cloud structures. In this study we test this hypothesis in the trade-wind region where various type of shallow cumulus cloud patterns occur using a hierarchy of model simulations of the EUREC4A...
The organization of shallow convection in the trades influences precipitation development, cold pool formation, clouds’ radiative effects, and, thus, climate sensitivity. Deep learning techniques, especially in computer vision and self-supervision, are suitable tools to understand cloud organization purely from a machine’s perspective. Yet, the physical interpretation of the network’s classes...
This study evaluates the ability of the French Convection-Permitting model AROME-OM to represent shallow cumulus and their main organisations for boreal winter conditions in the North Atlantic trades.
It uses a set of three winter seasons (January-February 2018-2020) of high-resolution (1.3 and 2.5 km) simulations over the Caribbean domain (9.7-22.9°N, 75.3°W-51.7°W).
The model is assessed...
This study first aims to address why mesoscale convective patterns are important and investigate the effects on both dynamics and thermodynamics using a cyclic cloud-permitting model, CM1. A set of idealized experiments to address the competition between isolated and agglomerated, organized convection using large-domain simulations with explicit representations of both convective-scale and...
The traditional view of monsoons as continental sea breezes generated by land-sea contrasts was shown to have serious limitations. Therefore, it remains unclear if the surface temperature contrast matters for the monsoon precipitation, and why there is a non-linear intensification of precipitation intensity with surface temperature forcing. Here, we aim to determine if monsoon non-linearities...
The diurnal cycle in trade-wind cloudiness is thought to be driven by the diurnal cycle in the relative occurrence frequency of mesoscale cloud morphologies (i.e., Vial et al. 2021). These morphologies can be grouped by their distinct appearance and size into four categories: Sugar, Gravel, Flowers, and Fish. The diurnal cycle in cloudiness is associated with a late afternoon maximum in the...
