The soil-moisture feedback describes how precipitation amount, timing and intensity react to spatial anomalies in surface moisture. Given such a positive or negative feedback, spatial patterns in soil-moisture will be reflected in the spatial organisation of the convective cloud field.
For heterogeneous moisture distributions with moist/dry patches on the scale of 10− 50km, numerical studies...
Using the observational network of the Netherlands we study cold pools (CPs) developing from summer convection and their role in triggering new convective events over land. Detailed information about CP gust fronts in terms of temperature, wind speed, heat fluxes, moisture and pressure at high vertical resolution are obtained from time series, measured at the 213 meter Cabauw tower. We aim to...
Updraft entrainment and surface flux feedbacks have been shown to be
potentially important to clustering in cloud resolving simulations of
deep convection in a state of radiative-convective equilibrium. Using the work of
Emanuel et al. (2014) and Craig and Mack(2013) as inspiration, we
present the results of idealized models of deep convection,
investigating the instability that can lead...
Observational studies from the past decades indicate that tropical convection may be an instance of self-organized criticality (SOC):
(i) Rain rate as a function of column water vapor follows a clear "pickup curve", shifting from essentially zero to sharply increasing, once surpassing a critical moisture value.
(ii) Rain events and clusters, defined as groups of contiguous rainy points in...
When studying the spatial organization and size distribution of shallow convection, the most widely looked at characteristic is the 2D projected cloud field. This approach has many practical benefits. 2D cloud fields can be easily detected with high precision from satellite or aerial retrievals, and generating a 2D cloud mask from model output is trivial. There are some drawbacks though. ...
The Moist Parcel-In-Cell (MPIC) model provides an essentially Lagrangian approach to moist convection. In this approach, parcels represent both the thermodynamic and the dynamical prognostic properties of the flow. The parcels have a finite volume and carry part of the circulation and thermodynamic attributes (liquid water potential temperature and total water content).
The representation...
Self-aggregation of convective cloud activity has attracted a lot of attention due to its role in the emergence of large scale weather phenomena such as the formation of hurricanes. Simulations with uniform boundary conditions show self-aggregation occurring on the time-scale of a few weeks [1]. Recently, numerical experiments demonstrated that spatial clustering can form withing a few days,...
Existing methods for characterising cloud organisation rely on metrics which measure specific features of the cloud structures present, however existing features lead to ambiguity in identifying the convective regimes and formulating new metrics which are physically relevant is a challenging task. By automatically extracting spacial features necessary to solve a specific task (here...
Shallow cumuli fields exhibit patterns of various shape and structure, commonly denoted as mesoscale organization, and often associated with precipitation. Because clouds, their organization and precipitation are strongly interlinked, understanding either might require understanding both. Therefore, we investigate the role of precipitation for the organization of shallow convection and vice...
Typical explanations for convective self-aggregation invoke the radiative convective equilibrium concept together with a form of circulation feedback. We here show, that the latter would not be needed when considering that cold pool interact. Building a simple model for this interaction, that is, that the probability for new convective cells is increased where cells already exist (essentially...
Preliminary results of an ongoing analysis is made of the relationships between sea surface temperature, water vapour, clouds and precipitation in warm pool deep convective regimes. These will show that in some circumstances these covarying relationships reflect characteristics of idealized simulations of deep convection clustered states in radiative convective equilibrium on scales of...
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....
