Mathematical modelling of moist convection and transport of gaseous pollutants and aerosols in clouds

2015 ◽  
Vol 30 (3) ◽  
Author(s):  
Artash E. Aloyan ◽  
Vardan O. Arutyunyan ◽  
Alexander N. Yermakov
Keyword(s):  
Gas Phase ◽  
Transport Model ◽  
Liquid Droplet ◽  
Three Dimensional ◽  
Medium Size ◽  
Moist Convection ◽  
Convective Clouds ◽  
Physical Mechanisms ◽  
Mechanisms Of Formation ◽  
Microphysical Processes

AbstractA joint three-dimensional numerical model of formation of convective clouds in the atmosphere is constructed with a detailed description of microphysical processes. A transport model of multicomponent gaseous admixtures and aerosols is also a constructed subject to gas-phase and liquid-phase chemical reactions. Basic physical mechanisms of formation of liquid droplet clouds of medium size and the transport of gases with different reactivity and solubility are considered. The calculations performed with the use of the data on emission of NO

scholarly journals Description and evaluation of a detailed gas-phase chemistry scheme in the TM5-MP global chemistry transport model (r112)

2020 ◽  
Author(s):  
Stelios Myriokefalitakis ◽  
Nikos Daskalakis ◽  
Angelos Gkouvousis ◽  
Andreas Hilboll ◽  
Twan van Noije ◽  
...  
Keyword(s):  
Gas Phase ◽  
Transport Model ◽  
Vertical Mixing ◽  
Three Dimensional ◽  
Chemical Mechanism ◽  
Aerosol Formation ◽  
Chemistry Transport Model ◽  
Mixing Ratios ◽  
Time Requirements ◽  
Phase Chemistry

Abstract. This work documents and evaluates the tropospheric gas-phase chemical mechanism MOGUNTIA in the three-dimensional chemistry transport model TM5-MP. Compared to the modified CB05 chemical mechanism previously used in the model, the MOGUNTIA includes a detailed representation of the light hydrocarbons (C1-C4) and isoprene, along with a simplified chemistry representation of terpenes and aromatics. Another feature implemented in TM5-MP for this work is the use of the Rosenbrock solver in the chemistry code, which can replace the classical Euler Backward Integration method of the model. Global budgets of ozone (O3), carbon monoxide (CO), hydroxyl radicals (OH), nitrogen oxides (NOX) and volatile organic compounds (VOCs) are here analyzed and their mixing ratios are compared with a series of surface, aircraft and satellite observations for the year 2006. Both mechanisms appear to be able to represent satisfactorily observed mixing ratios of important trace gases, with the MOGUNTIA chemistry configuration yielding lower biases compared to measurements in most of the cases. However, the two chemical mechanisms fail to reproduce the observed mixing ratios of light VOCs, indicating insufficient primary emission source strengths, too weak vertical mixing in the boundary layer, and/or a low bias in the secondary contribution of C2-C3 organics via VOC atmospheric oxidation. Relative computational memory and time requirements of the different model configurations are also compared and discussed. Overall, compared to other chemistry schemes in use in global CTMs, the MOGUNTIA scheme simulates a large suite of oxygenated VOCs that are observed in the atmosphere at significant levels and are involved in aerosol formation, expanding, thus, the applications of TM5-MP.

scholarly journals Toward unification of the multiscale modeling of the atmosphere

2011 ◽  
Vol 11 (8) ◽  
pp. 3731-3742 ◽  
Author(s):  
A. Arakawa ◽  
J.-H. Jung ◽  
C.-M. Wu
Keyword(s):  
General Circulation ◽  
Three Dimensional ◽  
General Circulation Models ◽  
Moist Convection ◽  
Modeling Framework ◽  
Continuous Transition ◽  
Convective Clouds ◽  
Multi Scale ◽  
Scale Modeling ◽  
Deep Moist Convection

Abstract. As far as the representation of deep moist convection is concerned, only two kinds of model physics are used at present: highly parameterized as in the conventional general circulation models (GCMs) and explicitly simulated as in the cloud-resolving models (CRMs). Ideally, these two kinds of model physics should be unified so that a continuous transition of model physics from one kind to the other takes place as the resolution changes. With such unification, the GCM can converge to a global CRM (GCRM) as the grid size is refined. This paper suggests two possible routes to achieve the unification. ROUTE I continues to follow the parameterization approach, but uses a unified parameterization that is applicable to any horizontal resolutions between those typically used by GCMs and CRMs. It is shown that a key to construct such a unified parameterization is to eliminate the assumption of small fractional area covered by convective clouds, which is commonly used in the conventional cumulus parameterizations either explicitly or implicitly. A preliminary design of the unified parameterization is presented, which demonstrates that such an assumption can be eliminated through a relatively minor modification of the existing mass-flux based parameterizations. Partial evaluations of the unified parameterization are also presented. ROUTE II follows the "multi-scale modeling framework (MMF)" approach, which takes advantage of explicit representation of deep moist convection and associated cloud-scale processes by CRMs. The Quasi-3-D (Q3-D) MMF is an attempt to broaden the applicability of MMF without necessarily using a fully three-dimensional CRM. This is accomplished using a network of cloud-resolving grids with large gaps. An outline of the Q3-D algorithm and highlights of preliminary results are reviewed.

scholarly journals SIMULATION OF ELECTRICAL PROCESSES IN THUNDERSTORMS IN THE NORTH CAUCASUS REGION

2017 ◽  
Author(s):  
А.В. Шаповалов ◽  
М.Ю. Пашкевич ◽  
В.И. Рязанов ◽  
В.А. Шаповалов ◽  
Н.А. Березинский ◽  
...  
Keyword(s):  
Electric Field ◽  
Three Dimensional ◽  
Volume Charge ◽  
North Caucasus ◽  
Electrical Parameters ◽  
Caucasus Region ◽  
Convective Clouds ◽  
The North ◽  
Cloud Microphysical Processes ◽  
Microphysical Processes

В работе представлена трехмерная численная модель конвективного облака с учетом электрических процессов. На основе модели получены следующие параметры: плотности объемных зарядов в облаке, потенциал и напряженность электрического поля, создаваемого этими зарядами, детально рассматривается влияние электрического поля облака на микрофизические процессы взаимодействия облачных частиц и обратное влияние – микроструктуры на электрические параметры. Приведены результаты исследований формирования термогидродинамических, микроструктурных и электрических параметров грозовых облаков в Северо-Кавказском регионе. The paper presents three-dimensional numerical model of convective clouds with the account of electrical processes. Based on the model obtained the following parameters: density of volume charge in the cloud, the potential and the electric field created by these charges, considers in detail the influence of the electric field of the cloud microphysical processes of interaction of cloud particles and the reverse influence of the microstructure on the electrical parameters. The results of thermohydrodynamic studies of the formation, microstructure and electrical parameters of storm clouds in the North Caucasus region.

scholarly journals Description and evaluation of a detailed gas-phase chemistry scheme in the TM5-MP global chemistry transport model (r112)

2020 ◽  
Vol 13 (11) ◽  
pp. 5507-5548 ◽  
Author(s):  
Stelios Myriokefalitakis ◽  
Nikos Daskalakis ◽  
Angelos Gkouvousis ◽  
Andreas Hilboll ◽  
Twan van Noije ◽  
...  
Keyword(s):  
Gas Phase ◽  
Transport Model ◽  
Three Dimensional ◽  
Chemical Mechanism ◽  
Chemistry Transport Model ◽  
Chemical Mechanisms ◽  
Mixing Ratios ◽  
Gas Phase Chemistry ◽  
Time Requirements ◽  
Phase Chemistry

Abstract. This work documents and evaluates the tropospheric gas-phase chemical mechanism MOGUNTIA in the three-dimensional chemistry transport model TM5-MP. Compared to the modified CB05 (mCB05) chemical mechanism previously used in the model, MOGUNTIA includes a detailed representation of the light hydrocarbons (C1–C4) and isoprene, along with a simplified chemistry representation of terpenes and aromatics. Another feature implemented in TM5-MP for this work is the use of the Rosenbrock solver in the chemistry code, which can replace the classical Euler backward integration method of the model. Global budgets of ozone (O3), carbon monoxide (CO), hydroxyl radicals (OH), nitrogen oxides (NOx), and volatile organic compounds (VOCs) are analyzed, and their mixing ratios are compared with a series of surface, aircraft, and satellite observations for the year 2006. Both mechanisms appear to be able to satisfactorily represent observed mixing ratios of important trace gases, with the MOGUNTIA chemistry configuration yielding lower biases than mCB05 compared to measurements in most of the cases. However, the two chemical mechanisms fail to reproduce the observed mixing ratios of light VOCs, indicating insufficient primary emission source strengths, oxidation that is too fast, and/or a low bias in the secondary contribution to C2–C3 organics via VOC atmospheric oxidation. Relative computational memory and time requirements of the different model configurations are also compared and discussed. Overall, the MOGUNTIA scheme simulates a large suite of oxygenated VOCs that are observed in the atmosphere at significant levels. This significantly expands the possible applications of TM5-MP.

scholarly journals Toward unification of the multiscale modeling of the atmosphere

2011 ◽  
Vol 11 (1) ◽  
pp. 3181-3217 ◽  
Author(s):  
A. Arakawa ◽  
J.-H. Jung ◽  
C.-M. Wu
Keyword(s):  
General Circulation ◽  
Three Dimensional ◽  
General Circulation Models ◽  
Moist Convection ◽  
Modeling Framework ◽  
Continuous Transition ◽  
Convective Clouds ◽  
Multi Scale ◽  
Deep Moist Convection ◽  
Fine Resolution

Abstract. This paper suggests two possible routes to achieve the unification of model physics in coarse- and fine-resolution atmospheric models. As far as representation of deep moist convection is concerned, only two kinds of model physics are used at present: highly parameterized as in the conventional general circulation models (GCMs) and explicitly simulated as in the cloud-resolving models (CRMs). Ideally, these two kinds of model physics should be unified so that a continuous transition of model physics from one kind to the other takes place as the resolution changes. With such unification, the GCM can converge to a global CRM (GCRM) as the grid size is refined. ROUTE I for unification continues to follow the parameterization approach, but uses a unified parameterization that is applicable to any horizontal resolutions between those typically used by GCMs and CRMs. It is shown that a key to construct such a unified parameterization is to eliminate the assumption of small fractional area covered by convective clouds, which is commonly used in the conventional cumulus parameterizations either explicitly or implicitly. A preliminary design of the unified parameterization is presented, which demonstrates that such an assumption can be eliminated through a relatively minor modification of the existing mass-flux based parameterizations. Partial evaluations of the unified parameterization are also presented. ROUTE II for unification follows the "multi-scale modeling framework (MMF)" approach, which takes advantage of explicit representation of deep moist convection and associated cloud-scale processes by CRMs. The Quasi-3-D (Q3-D) MMF is an attempt to broaden the applicability of MMF without necessarily using a fully three-dimensional CRM. This is accomplished using a network of cloud-resolving grids with gaps. An outline of the Q3-D algorithm and highlights of preliminary results are reviewed.

scholarly journals A Theory for Buoyancy and Velocity Scales in Deep Moist Convection

2009 ◽  
Vol 66 (11) ◽  
pp. 3449-3463 ◽  
Author(s):  
Antonio Parodi ◽  
Kerry Emanuel
Keyword(s):  
Three Dimensional ◽  
Wrf Model ◽  
Domain Size ◽  
Terminal Velocity ◽  
Statistical Equilibrium ◽  
Limited Area ◽  
Moist Convection ◽  
Convective Structures ◽  
Convective Clouds ◽  
Deep Moist Convection

Abstract Buoyancy and velocity scales for dry convection in statistical equilibrium were derived in the early twentieth century by Prandtl, but the scaling of convective velocity and buoyancy, as well as the fractional area coverage of convective clouds, is still unresolved for moist convection. In this paper, high-resolution simulations of an atmosphere in radiative–convective equilibrium are performed using the Weather Research and Forecasting (WRF) model, a three-dimensional, nonhydrostatic, convection-resolving, limited-area model. The velocity and buoyancy scales for moist convection in statistical equilibrium are characterized by prescribing different constant cooling rates to the system. It is shown that the spatiotemporal properties of deep moist convection and buoyancy and velocity scales at equilibrium depend on the terminal velocity of raindrops and a hypothesis is developed to explain this behavior. This hypothesis is evaluated and discussed in the context of the numerical results provided by the WRF model. The influence of domain size on radiative–convective equilibrium statistics is also assessed. The dependence of finescale spatiotemporal properties of convective structures on numerical and physical details is investigated.

Fundamental Issues and Recent Advancements in Analysis of Aircraft Brake Natural Convective Cooling

1998 ◽  
Vol 120 (4) ◽  
pp. 840-857 ◽  
Author(s):  
M. P. Dyko ◽  
K. Vafai
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Flow Field ◽  
Three Dimensional ◽  
Convective Cooling ◽  
Cooling Flow ◽  
Physical Mechanisms ◽  
Braking System ◽  
Flow And Heat Transfer ◽  
Convection Cooling

A heightened awareness of the importance of natural convective cooling as a driving factor in design and thermal management of aircraft braking systems has emerged in recent years. As a result, increased attention is being devoted to understanding the buoyancy-driven flow and heat transfer occurring within the complex air passageways formed by the wheel and brake components, including the interaction of the internal and external flow fields. Through application of contemporary computational methods in conjunction with thorough experimentation, robust numerical simulations of these three-dimensional processes have been developed and validated. This has provided insight into the fundamental physical mechanisms underlying the flow and yielded the tools necessary for efficient optimization of the cooling process to improve overall thermal performance. In the present work, a brief overview of aircraft brake thermal considerations and formulation of the convection cooling problem are provided. This is followed by a review of studies of natural convection within closed and open-ended annuli and the closely related investigation of inboard and outboard subdomains of the braking system. Relevant studies of natural convection in open rectangular cavities are also discussed. Both experimental and numerical results obtained to date are addressed, with emphasis given to the characteristics of the flow field and the effects of changes in geometric parameters on flow and heat transfer. Findings of a concurrent numerical and experimental investigation of natural convection within the wheel and brake assembly are presented. These results provide, for the first time, a description of the three-dimensional aircraft braking system cooling flow field.

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