Analysis of mimetic finite volume schemes on classical and moist shallow water models considering topography based local refinement in spherical Voronoi grids
Autor(a) principal: | |
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Data de Publicação: | 2020 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Biblioteca Digital de Teses e Dissertações da USP |
Texto Completo: | https://www.teses.usp.br/teses/disponiveis/45/45132/tde-07052020-154350/ |
Resumo: | The latitude-longitude grid has been used in global atmospheric models since the early 1960s until today. Nevertheless, the use of this grid creates drawbacks for scalability on massively parallel machines, mainly due to excessive data communication requirements near the poles. Thus, to achieve the required degree of parallelism for the efficient use of massively parallel architectures, the interest in quasi-uniform geodesic grids has increased. Much consideration has been given to icosahedral grids and its pentagonal/hexagonal dual grid. This grid might be optimized using centroidal Voronoi tesselation algorithms that allows us to build local refinements based on a density function. Grids with local refinements have been developed aiming to solve local phenomena without requiring the use of a uniform global grid which can be computationally prohibitive. In this work, aiming to benefit weather forecasting in Brazil, we propose a grid that captures well the Andes mountains and the South American continent. This grid is built through a density function based on topography using centroidal Voronoi tesselation algorithms. The developed density function uses smoothing data techniques on the topography data and has a parameter that allows us to approximately define the ratio between the cell diameters in low and high-resolution regions. The grids developed have a smooth transition between low and high-resolution regions. Using the grids developed, we analyze the use of a mimetic finite volume method for the shallow water equations. Using standard, and more recent shallow-water tests available in the literature, our results show that the refined region generates localized numerical noise in the solution. However, we show how a small amount of diffusion is already enough to mitigate this problem. Additionally, we also implemented a moist shallow water model, where physical precipitation processes are included in the classical shallow-water model. This model is used to investigate the impact of the local refinement on the cloud and rain formation in the South American continent, with results indicating that the refinement greatly affects the model, generating more cloud and rain when compared to the uniform resolution model. |
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Analysis of mimetic finite volume schemes on classical and moist shallow water models considering topography based local refinement in spherical Voronoi gridsAnálise de métodos de volumes finitos miméticos para modelos de águas rasas clássicos e com umidade considerando malhas esféricas de Voronoi com refinamento local baseado em topografiaEquações de água rasaFinite volumeGeodesic gridsLocal refinementMalhas geodésicasMalhas não-estruturadasMoist shallow water modelNon structured gridsRefinamento localShallow water equationsUmidadeVolumes finitosThe latitude-longitude grid has been used in global atmospheric models since the early 1960s until today. Nevertheless, the use of this grid creates drawbacks for scalability on massively parallel machines, mainly due to excessive data communication requirements near the poles. Thus, to achieve the required degree of parallelism for the efficient use of massively parallel architectures, the interest in quasi-uniform geodesic grids has increased. Much consideration has been given to icosahedral grids and its pentagonal/hexagonal dual grid. This grid might be optimized using centroidal Voronoi tesselation algorithms that allows us to build local refinements based on a density function. Grids with local refinements have been developed aiming to solve local phenomena without requiring the use of a uniform global grid which can be computationally prohibitive. In this work, aiming to benefit weather forecasting in Brazil, we propose a grid that captures well the Andes mountains and the South American continent. This grid is built through a density function based on topography using centroidal Voronoi tesselation algorithms. The developed density function uses smoothing data techniques on the topography data and has a parameter that allows us to approximately define the ratio between the cell diameters in low and high-resolution regions. The grids developed have a smooth transition between low and high-resolution regions. Using the grids developed, we analyze the use of a mimetic finite volume method for the shallow water equations. Using standard, and more recent shallow-water tests available in the literature, our results show that the refined region generates localized numerical noise in the solution. However, we show how a small amount of diffusion is already enough to mitigate this problem. Additionally, we also implemented a moist shallow water model, where physical precipitation processes are included in the classical shallow-water model. This model is used to investigate the impact of the local refinement on the cloud and rain formation in the South American continent, with results indicating that the refinement greatly affects the model, generating more cloud and rain when compared to the uniform resolution model.Malhas do tipo latitude longitude são usadas em modelos atmosféricos globais desde o início dos anos 60. Porém, estas malhas apresentam problemas de escalabilidade em máquinas massivamente paralelas devido ao excesso de comunicação de dados dos pontos que se acumulam nos polos. Assim o interesse em malhas geodésicas quase uniformes tem aumentado visando atingir o grau de paralelismo necessário para o uso eficiente de máquinas paralelas. A malha icosaédrica e a sua malha dual pentagonal/hexagonal tem se destacado. Esta malha pode ser otimizada usando algoritmos de Diagramas centroidais de Voronoi que permitem construir refinamentos locais através de uma função de densidade. Malhas com refinamento local são desenvolvidas visando resolver fenômenos locais sem utilizar uma malha uniforme global que pode ser computacionalmente proibitiva. Neste trabalho, visando beneficiar a previsão do tempo no Brasil, propomos desenvolver malhas que capturam bem a cordilheira dos Andes e o continente sul-americano. Esta malha é construída através de uma função de densidade que é baseada na topografia terrestre usando algoritmos de Diagramas centroidais de Voronoi. A função de densidade desenvolvida usa técnicas de suavização de dados e tem um parâmetro que permite definir a razão dos diâmetros entre células da região refinada e da região de malha grossa. A malha desenvolvida tem uma transição suave entre a região de malha fina e malha grossa. Utilizando as malhas desenvolvidas, nós analisamos um método de volumes finitos mimético para as equações de água rasa. Usando testes clássicos e mais recentes para o modelo de água rasa propostos na literatura, nossos resultados mostram que a região refinada gera ruído numérico local na solução. No entanto, mostramos que uma pequena quantidade de difusão é suficiente para resolver esse problema. Além disso, também implementamos um modelo de água rasa com umidade, onde os processos de precipitação física são incluídos no modelo clássico de água rasa. Este modelo é usado para analisarmos o impacto do refinamento local na formação de nuvens e chuvas no continente sul-americano, com resultados indicando que o refinamento afeta bastante o modelo, gerando mais nuvens e chuva quando comparado ao modelo de resolução uniforme.Biblioteca Digitais de Teses e Dissertações da USPPeixoto, Pedro da SilvaSantos, Luan da Fonseca2020-03-27info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttps://www.teses.usp.br/teses/disponiveis/45/45132/tde-07052020-154350/reponame:Biblioteca Digital de Teses e Dissertações da USPinstname:Universidade de São Paulo (USP)instacron:USPLiberar o conteúdo para acesso público.info:eu-repo/semantics/openAccesseng2021-01-21T02:30:01Zoai:teses.usp.br:tde-07052020-154350Biblioteca Digital de Teses e Dissertaçõeshttp://www.teses.usp.br/PUBhttp://www.teses.usp.br/cgi-bin/mtd2br.plvirginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.bropendoar:27212021-01-21T02:30:01Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
Analysis of mimetic finite volume schemes on classical and moist shallow water models considering topography based local refinement in spherical Voronoi grids Análise de métodos de volumes finitos miméticos para modelos de águas rasas clássicos e com umidade considerando malhas esféricas de Voronoi com refinamento local baseado em topografia |
title |
Analysis of mimetic finite volume schemes on classical and moist shallow water models considering topography based local refinement in spherical Voronoi grids |
spellingShingle |
Analysis of mimetic finite volume schemes on classical and moist shallow water models considering topography based local refinement in spherical Voronoi grids Santos, Luan da Fonseca Equações de água rasa Finite volume Geodesic grids Local refinement Malhas geodésicas Malhas não-estruturadas Moist shallow water model Non structured grids Refinamento local Shallow water equations Umidade Volumes finitos |
title_short |
Analysis of mimetic finite volume schemes on classical and moist shallow water models considering topography based local refinement in spherical Voronoi grids |
title_full |
Analysis of mimetic finite volume schemes on classical and moist shallow water models considering topography based local refinement in spherical Voronoi grids |
title_fullStr |
Analysis of mimetic finite volume schemes on classical and moist shallow water models considering topography based local refinement in spherical Voronoi grids |
title_full_unstemmed |
Analysis of mimetic finite volume schemes on classical and moist shallow water models considering topography based local refinement in spherical Voronoi grids |
title_sort |
Analysis of mimetic finite volume schemes on classical and moist shallow water models considering topography based local refinement in spherical Voronoi grids |
author |
Santos, Luan da Fonseca |
author_facet |
Santos, Luan da Fonseca |
author_role |
author |
dc.contributor.none.fl_str_mv |
Peixoto, Pedro da Silva |
dc.contributor.author.fl_str_mv |
Santos, Luan da Fonseca |
dc.subject.por.fl_str_mv |
Equações de água rasa Finite volume Geodesic grids Local refinement Malhas geodésicas Malhas não-estruturadas Moist shallow water model Non structured grids Refinamento local Shallow water equations Umidade Volumes finitos |
topic |
Equações de água rasa Finite volume Geodesic grids Local refinement Malhas geodésicas Malhas não-estruturadas Moist shallow water model Non structured grids Refinamento local Shallow water equations Umidade Volumes finitos |
description |
The latitude-longitude grid has been used in global atmospheric models since the early 1960s until today. Nevertheless, the use of this grid creates drawbacks for scalability on massively parallel machines, mainly due to excessive data communication requirements near the poles. Thus, to achieve the required degree of parallelism for the efficient use of massively parallel architectures, the interest in quasi-uniform geodesic grids has increased. Much consideration has been given to icosahedral grids and its pentagonal/hexagonal dual grid. This grid might be optimized using centroidal Voronoi tesselation algorithms that allows us to build local refinements based on a density function. Grids with local refinements have been developed aiming to solve local phenomena without requiring the use of a uniform global grid which can be computationally prohibitive. In this work, aiming to benefit weather forecasting in Brazil, we propose a grid that captures well the Andes mountains and the South American continent. This grid is built through a density function based on topography using centroidal Voronoi tesselation algorithms. The developed density function uses smoothing data techniques on the topography data and has a parameter that allows us to approximately define the ratio between the cell diameters in low and high-resolution regions. The grids developed have a smooth transition between low and high-resolution regions. Using the grids developed, we analyze the use of a mimetic finite volume method for the shallow water equations. Using standard, and more recent shallow-water tests available in the literature, our results show that the refined region generates localized numerical noise in the solution. However, we show how a small amount of diffusion is already enough to mitigate this problem. Additionally, we also implemented a moist shallow water model, where physical precipitation processes are included in the classical shallow-water model. This model is used to investigate the impact of the local refinement on the cloud and rain formation in the South American continent, with results indicating that the refinement greatly affects the model, generating more cloud and rain when compared to the uniform resolution model. |
publishDate |
2020 |
dc.date.none.fl_str_mv |
2020-03-27 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.teses.usp.br/teses/disponiveis/45/45132/tde-07052020-154350/ |
url |
https://www.teses.usp.br/teses/disponiveis/45/45132/tde-07052020-154350/ |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
|
dc.rights.driver.fl_str_mv |
Liberar o conteúdo para acesso público. info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Liberar o conteúdo para acesso público. |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.coverage.none.fl_str_mv |
|
dc.publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
dc.source.none.fl_str_mv |
reponame:Biblioteca Digital de Teses e Dissertações da USP instname:Universidade de São Paulo (USP) instacron:USP |
instname_str |
Universidade de São Paulo (USP) |
instacron_str |
USP |
institution |
USP |
reponame_str |
Biblioteca Digital de Teses e Dissertações da USP |
collection |
Biblioteca Digital de Teses e Dissertações da USP |
repository.name.fl_str_mv |
Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP) |
repository.mail.fl_str_mv |
virginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.br |
_version_ |
1809090479009038336 |