Parameterization of Atmospheric Convection

Plant, Raymond; Yano, Jun–Ichi

doi:10.1142/p1005

Cited by 42 publications

(29 citation statements)

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“…Historically, the development of convection parameterizations was largely motivated by the hot-tower hypothesis [3] proposed to explain the transport of moist static energy into the upper troposphere. Since then, different approaches have been proposed (for a review, see [4]), with the most popular one based on the mass-flux concept [5][6][7]. For this approach, the non-local vertical transport is solely controlled by the well-organized convective structures.…”

Section: Introductionmentioning

confidence: 99%

Towards Unifying the Planetary Boundary Layer and Shallow Convection in CAM5 with the Eddy-Diffusivity/Mass-Flux Approach

et al. 2019

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The modular structure of the boundary layer and convection parameterizations in atmospheric models have long been affecting the numerical representation of subgrid-scale motions and their mutual interactions. A promising alternative, the eddy-diffusivity/mass-flux approach (EDMF), has the potential for unifying the existing formulations into a consistent scheme and improving some of the long-standing issues. This study documents a step towards developing such a unified approach by implementing a stochastic multi-plume EDMF scheme into the Community Atmosphere Model (Version 5.0). Its performance in single-column mode is evaluated against the control parameterization and large-eddy simulation (LES) for two benchmark cases: marine and continental shallow convection. Overall, the results for the two parameterizations agree well with each other and with LES in terms of mean profiles of moist conserved variables and their vertical fluxes, as well as the updraft properties. However, systematic differences between the two schemes, especially for transient continental convection, are also documented. Using EDMF helps improve some of the parameterized features of shallow convection. In particular, for the highest tested vertical resolution, the EDMF cloud base and top heights and the vertical fluxes of energy and water are remarkably close to LES.

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Section: Introductionmentioning

confidence: 99%

Towards Unifying the Planetary Boundary Layer and Shallow Convection in CAM5 with the Eddy-Diffusivity/Mass-Flux Approach

et al. 2019

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“…Typically, we represent precipitating convective cells as a mathematically one-dimensional convective ''element'' like a buoyancy-driven ascending parcel or plume (for a broad survey rich in details see Plant & Yano, 2015). This gross simplification translates already into a fairly onerous body of code in serious global models (thousands of lines of FORTRAN in our case), with several tunable parameters.…”

Section: Introductionmentioning

confidence: 99%

Effects of a Simple Convective Organization Scheme in a Two‐Plume GCM

Chen

Mapes

2018

J Adv Model Earth Syst

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A set of experiments is described with the Community Atmosphere Model (CAM5) using a two‐plume convection scheme. To represent the differences of organized convection from General Circulation Model (GCM) assumptions of isolated plumes in uniform environments, a dimensionless prognostic “organization” tracer Ω is invoked to lend the second plume a buoyancy advantage relative to the first, as described in Mapes and Neale (2016). When low‐entrainment plumes are unconditionally available (Ω = 1 everywhere), deep convection occurs too easily, with consequences including premature (upstream) rainfall in inflows to the deep tropics, excessive convective versus large‐scale rainfall, poor relationships to the vapor field, stable bias in the mean state, weak and poor tropical variability, and midday peak in diurnal rainfall over land. Some of these are shown to also be characteristic of CAM4 with its separated deep and shallow convection schemes. When low‐entrainment plumes are forbidden by setting Ω = 0 everywhere, some opposite problems can be discerned. In between those extreme cases, an interactive Ω driven by the evaporation of precipitation acts as a local positive feedback loop, concentrating deep convection: In areas of little recent rain, only highly entraining plumes can occur, unfavorable for rain production. This tunable mechanism steadily increases precipitation variance in both space and time, as illustrated here with maps, time‐longitude series, and spectra, while avoiding some mean state biases as illustrated with process‐oriented diagnostics such as conserved variable profiles and vapor‐binned precipitation curves.

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“…All the terms gathered in the left hand side is equivalent to the leading order problem (A11) except for that is for φ (1) c . Furthermore, they are modified by a temporal tendency, ∂φ…”

Section: Author Contributionsmentioning

confidence: 99%

“…Our major achievement as a deliverable is a monograph [1]. Reference to this monograph is made frequently throughout the report for this reason.…”

Section: Introductionmentioning

confidence: 99%

Basic Concepts for Convection Parameterization in Weather Forecast and Climate Models: COST Action ES0905 Final Report

et al. 2014

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The research network "Basic Concepts for Convection Parameterization in Weather Forecast and Climate Models" was organized with European funding (COST Action ES0905) for the period of 2010-2014. Its extensive brainstorming suggests how the subgrid-scale parameterization problem in atmospheric modeling, especially for convection, Atmosphere 2015, 6 89 can be examined and developed from the point of view of a robust theoretical basis. Our main cautions are current emphasis on massive observational data analyses and process studies. The closure and the entrainment-detrainment problems are identified as the two highest priorities for convection parameterization under the mass-flux formulation. The need for a drastic change of the current European research culture as concerns policies and funding in order not to further deplete the visions of the European researchers focusing on those basic issues is emphasized.

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Parameterization of Atmospheric Convection

Cited by 42 publications

References 0 publications

Towards Unifying the Planetary Boundary Layer and Shallow Convection in CAM5 with the Eddy-Diffusivity/Mass-Flux Approach

Towards Unifying the Planetary Boundary Layer and Shallow Convection in CAM5 with the Eddy-Diffusivity/Mass-Flux Approach

Effects of a Simple Convective Organization Scheme in a Two‐Plume GCM

Basic Concepts for Convection Parameterization in Weather Forecast and Climate Models: COST Action ES0905 Final Report

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