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Convective available potential energy

About: Convective available potential energy is a research topic. Over the lifetime, 936 publications have been published within this topic receiving 43773 citations. The topic is also known as: CAPE.


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Journal ArticleDOI
TL;DR: In this article, the current distribution of severe thunderstorms as a function of large-scale environmental conditions is presented, and it is shown that the intensity of tornadoes and large hail, given that they occur, tends to be almost entirely dependent on the convective available potential energy (CAPE) and deep-tropospheric wind shear.

265 citations

Journal ArticleDOI
TL;DR: In this paper, the problem of the simulation of the diurnal cycle of convective precipitation over land is addressed with the aid of cloud-resolving (CRM) and single-column (SCM) model simulations.
Abstract: In the context of the European Cloud Systems project, the problem of the simulation of the diurnal cycle of convective precipitation over land is addressed with the aid of cloud-resolving (CRM) and single-column (SCM) model simulations of an idealized midlatitude case for which observations of large-scale and surface forcing are available. The CRM results are compared to different versions of the European Centre for Medium-Range Weather Forecasts (ECMWF) convection schemes using different convective trigger procedures and convective closures. In the CRM, maximum rainfall intensity occurs at 15 h (local time). In this idealized midlatitude case, most schemes do not reproduce the afternoon precipitation peak, as (i) they cannot reproduce the gradual growth (typically over 3 hours) of the deep convective cloud layer and (ii) they produce a diurnal cycle of precipitation that is in phase with the diurnal cycle of the convective available potential energy (CAPE) and the convective inhibition (CIN), consistent with the parcel theory and CAPE closure used in the bulk mass-flux scheme. The scheme that links the triggering to the large-scale vertical velocity gets the maximum precipitation at the right time, but this may be artificial as the vertical velocity is enforced in the single-column context. The study is then extended to the global scale using ensembles of 72-hour global forecasts at resolution T511 (40 km), and long-range single 40-day forecasts at resolution T159 (125 km) with the ECMWF general-circulation model. The focus is on tropical South America and Africa where the diurnal cycle is most pronounced. The forecasts are evaluated against analyses and observed radiosonde data, as well as observed surface and satellite-derived rainfall rates. The ECMWF model version with improved convective trigger produces the smallest biases overall. It also shifts the rainfall maximum to 12 h compared to 9.5 h in the original version. In contrast to the SCM, the vertical-velocity-dependent trigger does not further improve the phase of the diurnal cycle. However, further work is necessary to match the observed 15 h precipitation peak.

265 citations

Journal ArticleDOI
TL;DR: In this paper, an idealized, high-resolution simulation of a gradually forced transition from shallow, nonprecipitating to deep, precipitating cumulus convection is described; how the cloud and transport statistics evolve as the convection deepens is explored; and the collected statistics are used to evaluate assumptions in current cumulus schemes.
Abstract: In this paper, an idealized, high-resolution simulation of a gradually forced transition from shallow, nonprecipitating to deep, precipitating cumulus convection is described; how the cloud and transport statistics evolve as the convection deepens is explored; and the collected statistics are used to evaluate assumptions in current cumulus schemes. The statistical analysis methodologies that are used do not require tracing the history of individual clouds or air parcels; instead they rely on probing the ensemble characteristics of cumulus convection in the large model dataset. They appear to be an attractive way for analyzing outputs from cloud-resolving numerical experiments. Throughout the simulation, it is found that 1) the initial thermodynamic properties of the updrafts at the cloud base have rather tight distributions; 2) contrary to the assumption made in many cumulus schemes, nearly undiluted air parcels are too infrequent to be relevant to any stage of the simulated convection; and 3) a simple model with a spectrum of entraining plumes appears to reproduce most features of the cloudy updrafts, but significantly overpredicts the mass flux as the updrafts approach their levels of zero buoyancy. A buoyancy-sorting model was suggested as a potential remedy. The organized circulations of cold pools seem to create clouds with larger-sized bases and may correspondingly contribute to their smaller lateral entrainment rates. Our results do not support a mass-flux closure based solely on convective available potential energy (CAPE), and are in general agreement with a convective inhibition (CIN)-based closure. The general similarity in the ensemble characteristics of shallow and deep convection and the continuous evolution of the thermodynamic structure during the transition provide justification for developing a single unified cumulus parameterization that encompasses both shallow and deep convection.

252 citations

Journal ArticleDOI
TL;DR: In this paper, satellite observations of lightning flash rate have been merged with proximal surface station thermodynamic observations toward improving the understanding of the response of the updraft and lightning activity in the tropical atmosphere to temperature.

248 citations

Journal ArticleDOI
TL;DR: In this article, the structure of convectively generated rear-inflow jets and their role in the evolution of long-lived mesoconvective systems are investigated through an analysis of idealized three-dimensional simulations using a nonhydrostatic cloud model.
Abstract: In this study, the structure of convectively generated rear-inflow jets and their role in the evolution of long-lived mesoconvective systems are investigated through an analysis of idealized three-dimensional simulations using a nonhydrostatic cloud model. Rear-inflow jets are generated within these systems in response to the upshear-tilting of the convective circulation, as the horizontal buoyancy gradients along the back edge of the expanding system create a circulation that draws midlevel air in from the rear. Within this framework, a wide range of rear-inflow strengths and structures are produced, depending on the magnitude of the ambient convective available potential energy (CAPE) and the vertical wind shear. In general, for environments characterized by weak-to-moderate vertical wind shear and weak-to moderate CAPE, the rear-inflow jet descends and spreads along the surface well behind the leading edge of the gust front, and the subsequent convective activity becomes weaker. However, for e...

247 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202365
202291
202151
202038
201932
201827