Numerical Simulation of Pollutant Transport in a Shallow-Water System on the Cell Heterogeneous Processor

[Abstract] This paper presents an implementation, optimized for the Cell processor, of a finite volume numerical scheme for 2D shallow-water systems with pollutant transport. A description of the special architecture and programming required by the Cell processor motivates the methodology to develop optimized implementations for this platform. This process involves parallelization, data structure reorganization, explicit transfers of data and computation vectorization. Our implementation, tested using a realistic problem, achieves very good speedups with respect to the sequential execution on a standard CPU.This work was partially supported by the Science and Innovation Ministry of Spain (Projects TIN2010-16735, MTM2010-21135-C02-01 and MTM2009-11923), Xunta de Galicia CN2012/211 (partially supported by FEDER funds), and the FPU program of the Spanish Government (ref AP2009-4752)Xunta de Galicia; CN 2012/21

Parallelization of shallow water simulations on current multi-threaded systems

Lobeiras, J., Viñas, M., Amor, M., Fraguela, B.B., Arenaz, M., García, J., Castro, M. Parallelization of shallow water simulations on current multi-threaded systems. The International Journal of High Performance Computing Applications 27, 493–512. © 2013 The Author(s), © SAGE Publications. https://doi.org/10.1177/1094342012464800[Abstract]: In this work, several parallel implementations of a numerical model of pollutant transport on a shallow water system are presented. These parallel implementations are developed in two phases. First, the sequential code is rewritten to exploit the stream programming model. And second, the streamed code is targeted for current multi-threaded systems, in particular, multi-core CPUs and modern GPUs. The performance is evaluated on a multi-core CPU using OpenMP, and on a GPU using the streaming-oriented programming language Brook+, as well as the standard language for heterogeneous systems, OpenCL.Funding This work was supported by the Galician Government (Consolidation of Competitive Research Groups, Xunta de Galicia ref. 2010/6, projects INCITE08PXIB105161PR and 08TIC001206PR), the Ministry of Science and Innovation, cofunded by the FEDER funds of the European Union (grant number TIN2010-16735, and project numbers MTM2009-11923 and MTM2010-21135).Xunta de Galicia; INCITE08PXIB105161PRXunta de Galicia; 08TIC001206P

DisPar Methods and Their Implementation on a Heterogeneous PC Cluster

Esta dissertação avalia duas áreas cruciais da simulação de advecção- difusão. A primeira parte é dedicada a estudos numéricos. Foi comprovado que existe uma relação directa entre os momentos de deslocamento de uma partícula de poluente e os erros de truncatura. Esta relação criou os fundamentos teóricos para criar uma nova família de métodos numéricos, DisPar. Foram introduzidos e avaliados três métodos. O primeiro é um método semi-Lagrangeano 2D baseado nos momentos de deslocamento de uma partícula para malhas regulares, DisPar-k. Com este método é possível controlar explicitamente o erro de truncatura desejado. O segundo método também se baseia nos momentos de deslocamento de uma partícula, sendo, contudo, desenvolvido para malhas uniformes não regulares, DisParV. Este método também apresentou uma forte robustez numérica. Ao contrário dos métodos DisPar-K e DisParV, o terceiro segue uma aproximação Eulereana com três regiões de destino da partícula. O método foi desenvolvido de forma a manter um perfil de concentração inicial homogéneo independentemente dos parâmetros usados. A comparação com o método DisPar-k em situações não lineares realçou as fortes limitações associadas aos métodos de advecção-difusão em cenários reais. A segunda parte da tese é dedicada à implementação destes métodos num Cluster de PCs heterogéneo. Para o fazer, foi desenvolvido um novo esquema de partição, AORDA. A aplicação, Scalable DisPar, foi implementada com a plataforma da Microsoft .Net, tendo sido totalmente escrita em C#. A aplicação foi testada no estuário do Tejo que se localiza perto de Lisboa, Portugal. Para superar os problemas de balanceamento de cargas provocados pelas marés, foram implementados diversos esquemas de partição: “Scatter Partitioning”, balanceamento dinâmico de cargas e uma mistura de ambos. Pelos testes elaborados, foi possível verificar que o número de máquinas vizinhas se apresentou como o mais limitativo em termos de escalabilidade, mesmo utilizando comunicações assíncronas. As ferramentas utilizadas para as comunicações foram a principal causa deste fenómeno. Aparentemente, o Microsoft .Net remoting 1.0 não funciona de forma apropriada nos ambientes de concorrência criados pelas comunicações assíncronas. Este facto não permitiu a obtenção de conclusões acerca dos níveis relativos de escalabilidade das diferentes estratégias de partição utilizadas. No entanto, é fortemente sugerido que a melhor estratégia irá ser “Scatter Partitioning” associada a balanceamento dinâmico de cargas e a comunicações assíncronas. A técnica de “Scatter Partitioning” mitiga os problemas de desbalanceamentos de cargas provocados pelas marés. Por outro lado, o balanceamento dinâmico será essencialmente activado no inicio da simulação para corrigir possíveis problemas nas previsões dos poderes de cada processador.This thesis assesses two main areas of the advection-diffusion simulation. The first part is dedicated to the numerical studies. It has been proved that there is a direct relation between pollutant particle displacement moments and truncation errors. This relation raised the theoretical foundations to create a new family of numerical methods, DisPar. Three methods have been introduced and appraised. The first is a 2D semi- Lagrangian method based on particle displacement moments for regular grids, DisPar-k. With this method one can explicitly control the desired truncation error. The second method is also based on particle displacement moments but it is targeted to regular/non-uniform grids, DisParV. The method has also shown a strong numerical capacity. Unlike DisPar-k and DisParV, the third method is a Eulerian approximation for three particle destination units. The method was developed so that an initial concentration profile will be kept homogeneous independently of the used parameters. The comparison with DisPar-k in non-linear situations has emphasized the strong shortcomings associated with numerical methods for advection-diffusion in real scenarios. The second part of the dissertation is dedicated to the implementation of these methods in a heterogeneous PC Cluster. To do so, a new partitioning method has been developed, AORDA. The application, Scalable DisPar, was implemented with the Microsoft .Net framework and was totally written in C#. The application was tested on the Tagus Estuary, near Lisbon (Portugal). To overcome the load imbalances caused by tides scatter partitioning was implemented, dynamic load balancing and a mix of both. By the tests made, it was possible to verify that the number of neighboring machines was the main factor affecting the application scalability, even with asynchronous communications. The tools used for communications mainly caused this. Microsoft .Net remoting 1.0 does not seem to properly work in environments with concurrency associated with the asynchronous communications. This did not allow taking conclusions about the relative efficiency between the partitioning strategies used. However, it is strongly suggested that the best approach will be to scatter partitioning with dynamic load balancing and with asynchronous communications. Scatter partitioning mitigates load imbalances caused by tides and dynamic load balancing is basically trigged at the begging of the simulation to correct possible problems in processor power predictions

Stochastic Approach In Groundwater Modeling: A Case Study Of The Buffalo Creek Watershed

Simulation and prediction of groundwater flow and solute (contaminant) transport highly depends upon aquifer parameters and their spatial distribution. Since this variability in space is in fact random, solutions for groundwater flow and contaminants transport are better defined through a statistical approach. This study acknowledges and considers spatial variability of horizontal hydraulic conductivity values and compares calibrated steady-state condition groundwater flow both in deterministic and stochastic approach using MODFLOW model. Based upon the discretized model, for each model run 10, 495 different horizontal hydraulic conductivity values (set) were generated using Kriging statistical distribution method and results of groundwater depth was compared with measured depth, R2 value equal to 0.7471. Seven of the eight (87 %) sets of hydraulic conductivity values ranging from 10-3 m/second to 10-7 m/second generated less error than the deterministic approach. Similarly, using the calibrated parameter, contaminant plume path has also been defined using MT3D model, with five of the eight (62 %) sets of spatially varied hydraulic conductivity values generating less error than the deterministic value for solute mass balance. Potential groundwater paths were also determined and indicated using velocity vectors calculated by MODPATH model. Moreover, contaminant plume propagation in flat slope regions of the watershed showed little advance towards the predefined exits. Rather, higher concentration contours were observed in a limited area, indicating potentially polluted regions of the watershed in shallow aquifer zones that include South Buffalo wetland. Out of the total annual base flow, about 3 %, with expected rise during dry seasons, is contributed by impaired streams through groundwater-stream flow exchange

Stochastic Approach In Groundwater Modeling: A Case Study Of The Buffalo Creek Watershed

Simulation and prediction of groundwater flow and solute (contaminant) transport highly depends upon aquifer parameters and their spatial distribution. Since this variability in space is in fact random, solutions for groundwater flow and contaminants transport are better defined through a statistical approach. This study acknowledges and considers spatial variability of horizontal hydraulic conductivity values and compares calibrated steady-state condition groundwater flow both in deterministic and stochastic approach using MODFLOW model. Based upon the discretized model, for each model run 10, 495 different horizontal hydraulic conductivity values (set) were generated using Kriging statistical distribution method and results of groundwater depth was compared with measured depth, R2 value equal to 0.7471. Seven of the eight (87 %) sets of hydraulic conductivity values ranging from 10-3 m/second to 10-7 m/second generated less error than the deterministic approach. Similarly, using the calibrated parameter, contaminant plume path has also been defined using MT3D model, with five of the eight (62 %) sets of spatially varied hydraulic conductivity values generating less error than the deterministic value for solute mass balance. Potential groundwater paths were also determined and indicated using velocity vectors calculated by MODPATH model. Moreover, contaminant plume propagation in flat slope regions of the watershed showed little advance towards the predefined exits. Rather, higher concentration contours were observed in a limited area, indicating potentially polluted regions of the watershed in shallow aquifer zones that include South Buffalo wetland. Out of the total annual base flow, about 3 %, with expected rise during dry seasons, is contributed by impaired streams through groundwater-stream flow exchange

Improving the Turbulence Coupling between High Resolution Numerical Weather Prediction Models and Lagrangian Particle Dispersion Models

For the modelling of the transport and diffusion of atmospheric pollutants during accidental releases, sophisticated emergency response systems are used. These modelling systems usually consist of three main parts. The atmospheric flow conditions can be simulated with a numerical weather prediction (NWP) model. The evolution of the pollutant cloud is described with a dispersion model of variable complexity. The NWP and the dispersion models have to be coupled with a so-called meteorological pre-processor. This means that all the necessary – in most cases turbulence related – variables which are not available from the standard output of the NWP model have to be diagnosed. The main difficulty of the turbulence coupling is that these subgrid scale variables of NWP models are not routinely verified and thus little is known concerning their quality and impact on dispersion processes. The general aim of the present work is to better understand and improve this coupling mechanism. For this purpose all the three main components of the emergency response system of MeteoSwiss are carefully evaluated and possible improvement strategies are suggested. In the first part, the NWP component of the system, namely the COSMO model, is investigated focusing on the model performance in the Planetary Boundary Layer (PBL). Three case studies, representing both unstable and stable situations, are analyzed and the COSMO simulations are validated with turbulence measurements and Large Eddy Simulation (LES) data. It is shown that the COSMO model is able to reproduce the main evolution of the boundary layer in dry convective situations with the operational parameter setting. However, it is found that the COSMO model tends to simulate a too moist and too cold PBL with shallower PBL heights than observed. During stable conditions the operational parameter setting has to be significantly modified (e.g., the minimum diffusion coefficient) to obtain a good model performance. The turbulence scheme of COSMO, which carries a prognostic equation for Turbulent Kinetic Energy (TKE), is studied in detail to understand the shortcomings of the simulations. The turbulent transport term (third order moment) in the TKE equation is found to be significantly underestimated by the COSMO model during unstable situations. This results in inaccurate TKE profiles and hence missing entrainment fluxes at the top of the PBL. A solution to increase the TKE transport in the PBL is proposed in the present work and evaluated during a three-month continuous period. While improving the TKE profile substantially, the modification is demonstrated to not impair other model output characteristics. The second component of the emergency response system, namely the meteorological pre-processor, is also validated on case studies and a continuous period. The main objective of this analysis is to compare the currently operational coupling approach, which is based on the direct usage of the prognostic TKE from the COSMO model, to a classical approach based on similarity theory considerations, thereby using turbulence measurements on the one hand and LES data on the other hand. To be able to use similarity theory approaches for the determination of turbulence characteristics, the PBL height has first to be diagnosed from the NWP model. In the present study, several approaches for the determination of PBL height have been implemented and validated with radio sounding measurements. Based on the verification results and the operational convenience, the method based on the bulk Richardson number method has been chosen for the diagnosis of the PBL height. Validation results of post-diagnosed turbulence characteristics show that during convective situations, the similarity approach tends to overestimate the turbulence intensity, while the approach based on the direct usage of TKE yields more accurate results. For stable conditions the different approaches are closer to each other and both give reasonable predictions. It is found that the main drawback of the direct approach is the isotropic assumption in the horizontal direction. A new hybrid method is proposed which uses similarity considerations for the partitioning of horizontal TKE between along-wind and cross-wind directions. In the last part, pollutant dispersion in complex terrain is studied using a new scaling approach for TKE that is suited for steep and narrow Alpine valleys. This scaling approach is introduced in the interface between COSMO and a Lagrangian particle dispersion model (LPDM), and its results are compared to those of a classical similarity theory approach and to the operational coupling type, which uses the TKE from the COSMO model directly. For the validation of the modelling system, the TRANSALP-89 tracer experiment is used, which was conducted in highly complex terrain in southern Switzerland. The ability of the COSMO model to simulate the valley-wind system is assessed with several meteorological surface stations. The dispersion simulation is evaluated with the measurements from 25 surface samplers. The sensitivity of the modelling system towards the soil moisture, horizontal grid resolution, and boundary layer height determination is investigated. It is shown that if the flow field is correctly reproduced, the new scaling approach improves the tracer concentration simulation compared to the classical coupling methods

Numerical modeling for groundwater protection in the Venetian plain between the Brenta and Piave Rivers

The Ph.D. project tackled the scientific challenges that a water utility company in the northeast of Italy, Alto Trevigiano Servizi, must face in the elaboration of the Water Safety Plan (WSP), which is the most effective preventive tool to ensure good quality water and consumers health protection. The WSPs guidelines were defined by the World Health Organization and were subsequently implemented in a European Directive and Italian law. The thesis, after an introduction on the scientifical issues, started with the description of the work done to reproduce in CATHY the model that the PhD student Tommaso Trentin built using the software FeFlow. The study area has an extension of around 900 km2 and is delimited to the north-east by the Piave river, to the west side by a flow line parallel to the Brenta river, while the southern boundary is closed by the Risorgive area, and the North boundary by the Montello and colli Asolani. The north part is characterized by an undifferentiated aquifer, while the southern part hosts a multilayer system with 8 confined aquifers. Some modifications, e.g., the mesh refining, the sensitivity analysis, were implemented in the model to try to improve its performance. Also, the soil conductivity of the shallowest soil layer (1 m) was changed following the indications of Carta della permeabilità dei suoli from ARPAV site and the boundary conditions of the norther part of the domain were better defined. Before the calibration step, the initial mesh that hosts the multilayers systems of 8 aquitards and 8 aquifers was cut at the bottom of the first unconfined aquifer. This allowed to speed up the calibration and focus on the aquifer directly influenced by the atmospheric boundary conditions and subject to recharge variability. The calibration was performed alternating FePESt and CATHY. FePEST, having already implemented the PEST algorithm, allowed to easily implement the pilot points method that in CATHY would have require too much time. Both the bottom of the unconfined aquifer and the hydraulic conductivity field were calibrated. The improvement in terms of RMSE was relevant, the errors being reduced to 1/3. Once the calibrated model was obtained, also a validation step was performed. The resulting model allowed us to investigate an irrigation variation scenario, planned in compliance with the European directive indication, to save water: currently a large area of the domain is interested by flood irrigation considered no more sustainable, since it requires a large amount of water. The scenario considered a switch to sprinkler irrigation only. The results show a slight groundwater head decrease in the wells located in the area affected by the irrigation technique conversion. This result was confirmed by the difference of the total cumulative recharge over the domain in case of sprinkler and flood irrigation and sprinkler irrigation only. The model seems to be not particularly affected by the irrigation modification but more sensitive to the hydraulic conductivity values: a map of the mean distribution of the recharge shows that the larger fraction of the recharge occurs where hydraulic conductivity is larger. Parallelly to the continuation of this project, also a study on the analysis of numerical dispersion affecting CATHY model was carry out. This study will be useful for future simulations on vulnerability to contaminations that require an accurate solute transport modeling. Due to lack of time it was not possible to investigate the contaminants transport phenomenon in the area of study to accurately define the wells’ head protection areas, important part of the WSPs, but the preliminary results obtained from the model we built can be considered a good starting point for future transport studies.The Ph.D. project tackled the scientific challenges that a water utility company in the northeast of Italy, Alto Trevigiano Servizi, must face in the elaboration of the Water Safety Plan (WSP), which is the most effective preventive tool to ensure good quality water and consumers health protection. The WSPs guidelines were defined by the World Health Organization and were subsequently implemented in a European Directive and Italian law. The thesis, after an introduction on the scientifical issues, started with the description of the work done to reproduce in CATHY the model that the PhD student Tommaso Trentin built using the software FeFlow. The study area has an extension of around 900 km2 and is delimited to the north-east by the Piave river, to the west side by a flow line parallel to the Brenta river, while the southern boundary is closed by the Risorgive area, and the North boundary by the Montello and colli Asolani. The north part is characterized by an undifferentiated aquifer, while the southern part hosts a multilayer system with 8 confined aquifers. Some modifications, e.g., the mesh refining, the sensitivity analysis, were implemented in the model to try to improve its performance. Also, the soil conductivity of the shallowest soil layer (1 m) was changed following the indications of Carta della permeabilità dei suoli from ARPAV site and the boundary conditions of the norther part of the domain were better defined. Before the calibration step, the initial mesh that hosts the multilayers systems of 8 aquitards and 8 aquifers was cut at the bottom of the first unconfined aquifer. This allowed to speed up the calibration and focus on the aquifer directly influenced by the atmospheric boundary conditions and subject to recharge variability. The calibration was performed alternating FePESt and CATHY. FePEST, having already implemented the PEST algorithm, allowed to easily implement the pilot points method that in CATHY would have require too much time. Both the bottom of the unconfined aquifer and the hydraulic conductivity field were calibrated. The improvement in terms of RMSE was relevant, the errors being reduced to 1/3. Once the calibrated model was obtained, also a validation step was performed. The resulting model allowed us to investigate an irrigation variation scenario, planned in compliance with the European directive indication, to save water: currently a large area of the domain is interested by flood irrigation considered no more sustainable, since it requires a large amount of water. The scenario considered a switch to sprinkler irrigation only. The results show a slight groundwater head decrease in the wells located in the area affected by the irrigation technique conversion. This result was confirmed by the difference of the total cumulative recharge over the domain in case of sprinkler and flood irrigation and sprinkler irrigation only. The model seems to be not particularly affected by the irrigation modification but more sensitive to the hydraulic conductivity values: a map of the mean distribution of the recharge shows that the larger fraction of the recharge occurs where hydraulic conductivity is larger. Parallelly to the continuation of this project, also a study on the analysis of numerical dispersion affecting CATHY model was carry out. This study will be useful for future simulations on vulnerability to contaminations that require an accurate solute transport modeling. Due to lack of time it was not possible to investigate the contaminants transport phenomenon in the area of study to accurately define the wells’ head protection areas, important part of the WSPs, but the preliminary results obtained from the model we built can be considered a good starting point for future transport studies

Analysis of Air Quality with Numerical Simulation (CMAQ), and Observations of Trace Gases

Ozone, a secondary pollutant, is a strong oxidant that can pose a risk to human health. It is formed from a complex set of photochemical reactions involving nitrogen oxides (NOx) and volatile organic compounds (VOCs). Ambient measurements and air quality modeling of ozone and its precursors are important tools for support of regulatory decisions, and analyzing atmospheric chemical and physical processes. I worked on three methods to improve our understanding of photochemical ozone production in the Eastern U.S.: a new detector for NO2, a numerical experiment to test the sensitivity to the timing to emissions, and comparison of modeled and observed vertical profiles of CO and ozone. A small, commercially available cavity ring-down spectroscopy (CRDS) NO2 detector suitable for surface and aircraft monitoring was modified and characterized. The CRDS detector was run in parallel to an ozone chemiluminescence device with photolytic conversion of NO2 to NO. The two instruments measured ambient air in suburban Maryland. A linear least- squares fit to a direct comparison of the data resulted in a slope of 0.960±0.002 and R of 0.995, showing agreement between two measurement techniques within experimental uncertainty. The sensitivity of the Community Multiscale Air Quality (CMAQ) model to the temporal variation of four emissions sectors was investigated to understand the effect of emissions' daily variability on modeled ozone. Decreasing the variability of mobile source emissions changed the 8-hour maximum ozone concentration by ±7 parts per billion by volume (ppbv). Increasing the variability of point source emissions affected ozone concentrations by ±6 ppbv, but only in areas close to the source. CO is an ideal tracer for analyzing pollutant transport in AQMs because the atmospheric lifetime is longer than the timescale of bound- ary layer mixing. CO can be used as a tracer if model performance of CO is well understood. An evaluation of CO model performance in CMAQ was carried out using aircraft observations taken for the Regional Atmospheric Measurement, Mod- eling and Prediction Program (RAMMPP) in the summer of 2002. Comparison of modeled and observed CO total columns were generally in agreement within 5-10%. There is little evidence that the CO emissions inventory is grossly overestimated. CMAQ predicts the same vertical profile shape for all of the observations, i.e. CO is well mixed throughout the boundary layer. However, the majority of observations have poorly mixed air below 500 m, and well mixed air above. CMAQ appears to be transporting CO away from the surface more quickly than what is observed. Turbulent mixing in the model is represented with K-theory. A minimum Kz that scales with fractional urban land use is imposed in order to account for subgrid scale obstacles in urban areas and the urban heat island effect. Micrometeorological observations suggest that the minimum Kz is somewhat high. A sensitivity case where the minimum Kz was reduced from 0.5 m2/s to 0.1 m2/s was carried out. Model performance of surface ozone observations at night increased significantly. The model better captures the observed ozone minimum with slower mixing, and increases ozone concentrations in the residual layer. Model performance of CO and ozone morning vertical profiles improves, but the effect is not large enough to bring the model and measurements into agreement. Comparison of modeled CO and O3 vertical profiles shows that turbulent mixing (as represented by eddy diffusivity) appears to be too fast, while convective mixing may be too slow

The Brazilian developments on the Regional Atmospheric Modeling System (BRAMS 5.2): an integrated environmental model tuned for tropical areas

We present a new version of the Brazilian developments on the Regional Atmospheric Modeling System (BRAMS), in which different previous versions for weather, chemistry, and carbon cycle were unified in a single integrated modeling system software. This new version also has a new set of state-of-the-art physical parameterizations and greater computational parallel and memory usage efficiency. The description of the main model features includes several examples illustrating the quality of the transport scheme for scalars, radiative fluxes on surface, and model simulation of rainfall systems over South America at different spatial resolutions using a scale aware convective parameterization. Additionally, the simulation of the diurnal cycle of the convection and carbon dioxide concentration over the Amazon Basin, as well as carbon dioxide fluxes from biogenic processes over a large portion of South America, are shown. Atmospheric chemistry examples show the model performance in simulating near-surface carbon monoxide and ozone in the Amazon Basin and the megacity of Rio de Janeiro. For tracer transport and dispersion, the model capabilities to simulate the volcanic ash 3-D redistribution associated with the eruption of a Chilean volcano are demonstrated. The gain of computational efficiency is described in some detail. BRAMS has been applied for research and operational forecasting mainly in South America. Model results from the operational weather forecast of BRAMS on 5 km grid spacing in the Center for Weather Forecasting and Climate Studies, INPE/Brazil, since 2013 are used to quantify the model skill of near-surface variables and rainfall. The scores show the reliability of BRAMS for the tropical and subtropical areas of South America. Requirements for keeping this modeling system competitive regarding both its functionalities and skills are discussed. Finally, we highlight the relevant contribution of this work to building a South American community of model developers.CNPqFAPESPEarth System Research Laboratory at the National Oceanic and Atmospheric Administration (ESRL/NOAA), Boulder, USAInst Nacl Pesquisas Espaciais, Ctr Previsao Tempo & Estudos Climat, Cachoeira Paulista, SP, BrazilDiv Ciência da Computação, Instituto Tecnológico de Aeronáutica, São José dos Campos, SP, BrazilUniv Estadual Paulista Unesp, Fac Ciencias, Bauru, SP, BrazilCtr Meteorol Bauru IPMet, Bauru, SP, BrazilUniv Fed Sao Paulo, Dept Ciencias Ambientais, Diadema, SP, BrazilUniv Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Sao Paulo, SP, BrazilUniv Fed Campina Grande, Dept Ciencias Atmosfer, Campina Grande, PB, BrazilEmbrapa Informat Agr, Campinas, SP, BrazilUniv Fed Sao Paulo, Inst Ciencia & Tecnol, Sao Jose Dos Campos, SP, BrazilUniv Fed Rio Grande do Norte, Dept Ciencias Atmosfer & Climat, Programa Pos Grad Ciencias Climat, Natal, RN, BrazilInst Nacl Pesquisas Espaciais, Ctr Ciencias Sistema, Sao Jose Dos Campos, SP, BrazilUniv Fed Sao Joao Del Rei, Dept Geociencias, Sao Joao Del Rei, MG, BrazilInst Nacl Pesquisas Espaciais, Lab Associado Computacao & Matemat Aplica, Sao Jose Dos Campos, BrazilUniv Evora, Inst Ciencias Agr & Ambientais Mediterr, Evora, PortugalUniv Lusofona Humanidades & Tecnol, Ctr Interdisciplinar Desenvolvimento Ambient Gest, Lisbon, PortugalUniv Fed Pelotas, Fac Meteorol, Pelotas, RS, BrazilUnive Tecnol Fed Parana, Londrina, PR, BrazilNASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Goddard Earth Sci Technol & Res Global Modeling &, Greenbelt, MD USAUniv Fed Sao Paulo, Inst Ciencia & Tecnol, Sao Jose Dos Campos, SP, BrazilUniv Fed Sao Paulo, Inst Ciencia & Tecnol, Sao Jose Dos Campos, SP, BrazilCNPq: 306340/2011-9FAPESP: 2014/01563-1FAPESP: 2015/10206-0FAPESP: 2014/01564-8Web of Scienc

The Brazilian Developments On The Regional Atmospheric Modeling System (brams 5.2): An Integrated Environmental Model Tuned For Tropical Areas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We present a new version of the Brazilian developments on the Regional Atmospheric Modeling System (BRAMS), in which different previous versions for weather, chemistry, and carbon cycle were unified in a single integrated modeling system software. This new version also has a new set of state-of-the-art physical parameterizations and greater computational parallel and memory usage efficiency. The description of the main model features includes several examples illustrating the quality of the transport scheme for scalars, radiative fluxes on surface, and model simulation of rainfall systems over South America at different spatial resolutions using a scale aware convective parameterization. Additionally, the simulation of the diurnal cycle of the convection and carbon dioxide concentration over the Amazon Basin, as well as carbon dioxide fluxes from biogenic processes over a large portion of South America, are shown. Atmospheric chemistry examples show the model performance in simulating near-surface carbon monoxide and ozone in the Amazon Basin and the megacity of Rio de Janeiro. For tracer transport and dispersion, the model capabilities to simulate the volcanic ash 3-D redistribution associated with the eruption of a Chilean volcano are demonstrated. The gain of computational efficiency is described in some detail. BRAMS has been applied for research and operational forecasting mainly in South America. Model results from the operational weather forecast of BRAMS on 5km grid spacing in the Center for Weather Forecasting and Climate Studies, INPE/Brazil, since 2013 are used to quantify the model skill of near-surface variables and rainfall. The scores show the reliability of BRAMS for the tropical and subtropical areas of South America. Requirements for keeping this modeling system competitive regarding both its functionalities and skills are discussed. Finally, we highlight the relevant contribution of this work to building a South American community of model developers. © Author(s) 2017.1011892222014/01563-1, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo2014/01564-8, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo2015/10206-0, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo306340/2011-9, Conselho Nacional de Desenvolvimento Científico e TecnológicoFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq