Gustavo Montero

University of Las Palmas de Gran Canaria | ULPGC · Instituto Universitario de Sistemas Inteligentes y Aplicaciones Numéricas en Ingeniería (SIANI)

Dust events in the Canary Islands have been documented since the late 19th century. However, during the past few years, several severe dust episodes have occurred in the Canary Islands, resulting in significant impacts on various sectors, such as aviation, air quality, and health, among others. These recent severe events have drawn the attention of...

The result of the multidisciplinary collaboration of researchers from different areas of knowledge to validate a solar radiation model is presented. The MAPsol is a 3D local-scale adaptive solar radiation model that allows us to estimate direct, diffuse, and reflected irradiance for clear sky conditions. The model includes the adaptation of the mes...

The result of the multidisciplinary collaboration of researchers from different areas of knowledge to validate a solar radiation model is presented. The MAPsol is a 3D local-scale adaptive solar radiation model that allows to estimate direct, diffuse and reflected irradiance for clear sky conditions. The model includes the adaptation of the mesh to...

In this paper, the performances of two approaches for solar probabilistic are evaluated using a set of metrics previously tested by the meteorology verification community. A particular focus is put on several scores and the decomposition of a specific probabilistic metric: the continuous rank probability score (CRPS) as they give extensive informat...

A novel phenomenological epidemic model is proposed to characterize the state of infectious diseases and predict their behaviors. This model is given by a new stochastic partial differential equation that is derived from foundations of statistical physics. The analytical solution of this equation describes the spatio-temporal evolution of a Gaussia...

Canary Islands and other regions have been greatly damaged by weather events during the last decades. For this reason, the main duty of National Meteorological Services is to minimize socio-economic losses by forecasting adverse weather episodes with enough time in advance. To achieve this goal, the use of numerical weather prediction models is hig...

Solar maps are very interesting tools to describe the characteristics of a region from the solar radiation point of view, and can be applied in atmospheric sciences and for energy engineering. To make them possible, a solar radiation numerical model is proposed. This one allows us to estimate radiation values on any point on earth. The model takes...

This chapter describes Wind3D, a mass-consistent diagnostic model with an updated vertical wind profile and atmospheric parameterization. First, a description of Wind3D is provided, along with their governing equations. Next, the finite element formulation of the model and the description of the solver of the corresponding linear system are present...

This chapter is devoted to the introduction of some geographical and meteorological information involved in the numerical modeling of wind fields and solar radiation. First, a brief description of the topographical data given by a Digital Elevation Model and Land Cover databases is provided. In particular, the Information System of Land Cover of Sp...

The characterisation of the aerodynamic roughness length (z0) and the displacement height (d) is critical when modelling the wind field using the log vertical profile. It is known that the values of these parameters depend on land coverage and weather conditions. Thus, many authors have studied their relationship, providing typical values for each...

Solar radiation numerical models need the implementation of an accurate method for determining cast shadows on the terrain or on solar collectors. The aim of this work is the development of a new methodology to detect the shadows on a particular terrain. The paper addresses the detection of self and cast shadows produced by the orography as well as...

A solar radiation numerical model is presented. With it, the user can estimate the radiation values in any location easily and compute the solar power generation taking into account not only the radiation level, but also the terrain surface conditions considering the cast shadows. The terrain surface is taken into account, using 2-D adaptive meshes...

A predictive solar radiation numerical model for the estimation of the photovoltaic power generation in the medium term is presented. This tool allows the user to predict the solar radiation as well as the photovoltaic power generation, with a given probability. The work has been applied in Gran Canaria (Canary Islands – Spain), but the model is us...

A solar radiation numerical model is presented. With it, the user can estimate the radiation values in any location easily and compute the solar power generation taking into account not only the radiation level, but also the terrain surface conditions considering the cast shadows. The terrain surface is taken into account, using 2-D adaptive meshes...

In this paper, we introduce a new method for wind field forecasting over complex terrain. The main idea is to use the predictions of the HARMONIE meso-scale model as the input data for an adaptive finite element mass-consistent wind model. The HARMONIE results (obtained with a maximum resolution of about 1 km) are refined in a local scale (about a...

A three-dimensional finite element model for the pollutant dispersion is presented. In these environmental processes over a complex terrain, a mesh generator capable of adapting itself to the topographic characteristics is essential. The first stage of the model consists on the construction of an adaptive tetrahedral mesh of a rectangular region bo...

Nowadays the solar power is one of the most appreciate renewable energies in the world. In order to maximise the solar radiation collection, many numerical models have been developed. There are three groups of factors that determines the interaction of solar radiation with the earths atmosphere and surface (see e.g. (1)): a. The Earths geometry, re...

In this paper we propose a finite element method approach formodelling the air quality in a local scale over complex terrain. The area of interest is up to tens of kilometres and it includes pollutant sources. The proposed methodology involves the generation of an adaptive tetrahedral mesh, the computation of an ambient wind field, the inclusion of...

In this paper we propose a finite element method approach for modelling the air quality in a local scale over complex terrain. The area of interest is up to tens of kilometres and it includes pollutant sources. The proposed methodology involves the generation of an adaptive tetrahedral mesh, the computation of an ambient wind field, the inclusion o...

Conventional air quality models uses Lagrangian [1,2] or Eulerian [3] strategies, and the numerical approach is normally obtained by using finite difference schemes. In this paper, we introduce a local scale Eulerian air pollution model that is related to unsteady propagation problems which may be mathematically described by convection-diffusion-re...

The efficiency of a finite element mass consistent model for wind field adjustment depends on the stability parameter αα which allows adjustment from a strictly horizontal wind to a pure vertical one. Each simulation with the wind model leads to the resolution of a linear system of equations, the matrix of which depends on a function ε(α)ε(α), i.e....

In this work we develop a procedure to deform a given surface triangulation to obtain its alignment with inte-rior curves. These curves are defined by splines in a paramet-ric space and, subsequently, mapped to the surface triangu-lation. We have restricted our study to orthogonal mapping, so we require the curves to be included in a patch of the s...

In previous works, many authors have widely used mass consistent models for wind field simulation by the finite element method. On one hand, we have developed a 3-D mass consistent model by using tetrahedral meshes which are simultaneously adapted to complex orography and to terrain roughness length. In addition, we have included a local refinement...

In this paper, we present significant advances of the novel meccano technique for simultaneously constructing adaptive tetrahedral meshes of 3-D complex solids and their volume parametrization. Specifically, we will consider a solid whose boundary is a surface of genus zero. In this particular case, the automatic procedure is defined by a surface t...

The meccano method is a novel and promising mesh generation method for simultaneously creating adaptive tetrahedral meshes and volume parametrizations of a complex solid. We highlight the fact that the method requires minimum user intervention and has a low computational cost. The method builds a 3-D triangulation of the solid as a deformation of a...

Solute transport in soils is commonly simulated with the advective-dispersive equation, or ADE. It has been reported that this model cannot take into account several important features of solute movement through soil. Recently, a new model has been suggested ...

Title: Photovoltaic Power Estimation Tool Using a Solar Radiation Numerical Model Abstract/Summary: A tool based on a solar radiation numerical model for the evaluation of the suitability of different possible locations for photovoltaic power stations is presented. It allows the user to estimate the solar radiation in a given place as well as th...

Title: Typical Meteorological Year (TMY) Evaluation for Power Generation in Gran Canaria Island, Spain Abstract/Summary: This paper analyses the suitability of V. Ruiz model for both, daily global solar irradiation and sunshine duration, to obtain TMY for the island of Gran Canaria. There are daily data available from seven measurement stations...

A numerical model for generating solar radiation maps to be used for the evaluation of different power generation strategies is proposed. The solar radiation model is implemented taking into account the terrain surface with the use of 2-D adaptive meshes of triangles, which are made using a refinement/derefinement procedure in accordance with the v...

In this paper, we present significant advances of the novel meccano technique to construct adaptive tetrahedral meshes of 3-D complex solids. Specifically, we will consider a solid whose boundary is a surface of genus 0, i.e. a surface that is homeomorphic to the surface of a sphere. In this particular case, the automatic procedure is defined by a...

This paper introduces a new automatic strategy for adaptive tetrahedral mesh generation. A local refinement/derefinement algorithm for nested triangulations and a simultaneous untangling and smoothing procedure are the main involved techniques. The mesh generator is applied to 3-D complex domains whose boundaries are projectable on external faces o...

In this work, we propose a numerical model for generating solar radiation maps with the use of 2-D adaptive meshes of triangles. These triangulations are constructed by using a refinement/derefinement procedure in accordance with the variations of terrain surface orography and albedo. This discretization has the advantage of defining the terrain ch...

In this paper we introduce an automatic tetrahedral mesh generator for complex genus-zero solids, based on the novel meccano technique. Our method only demands a surface triangulation of the solid, and a coarse approximation of the solid, called meccano, that is just a cube in this case. The procedure builds a 3-D triangulation of the solid as a de...

Palabras clave: Modelo de viento, Masa consistente, MM5, Algoritmos genéticos Resumen El uso de energías renovables es uno de los temas de actualidad en el mundo entero. Muchos gobiernos están impulsando la generación de energía eléctrica a partir de fuentes renovables, como la del viento. Es previsible, por tanto, que en un futuro cercano sean nec...

Mass consistent models have been widely use in 3-D wind modelling by finite element method. We have used a method for constructing tetrahedral meshes which are simultaneously adapted to the terrain orography and the roughness length by using a refinement/derefinement process in a 2-D mesh corresponding to the terrain surface, following the techniqu...

In this work we develop a procedure to deform a given surface triangulation to obtain its alignment with interior curves. At present, we consider that these curves are defined by the orthogonal projection from plane cubic splines to the initial surface triangulation. For example, the curves can represent interfaces between different materials or bo...

A 3-D model for atmospheric pollutant transport is proposed considering a set of coupled convection-diffusion-reaction equations. The convective phenomenon is mainly produced by a wind field obtained from a 3-D mass consistent model. In particular, the modelling of oxidation and hydrolysis of sulphur and nitrogen oxides released to the surface laye...

This paper introduces a new automatic strategy for adaptive tetrahedral mesh generation. A local refinement/derefinement algorithm for nested triangulations and a simultaneous untangling and smoothing procedure are the main involved techniques. The mesh generator is applied to 3-D complex domains whose boundaries are projectable on external faces o...

This paper presents a new procedure to improve the quality of triangular meshes defined on surfaces. The improvement is obtained by an iterative process in which each node of the mesh is moved to a new position that minimizes a certain objective function. This objective function is derived from algebraic quality measures of the local mesh (the set...

This paper introduces a new automatic tetrahedral mesh generator on the adaptive finite element ALBERTA code. The procedure can be applied to 3- D domains with boundary surfaces which are projectable on faces of a cube. The generalization of the mesh generator for complex domains which can be split into cubes or hexahedra is straightforward. The do...

Mass consistent models have been widely use in three-dimensional wind modelling by finite element method. In general, these problems are defined over regions with complex terrain and variable roughness length, therefore a suitable discretization of the studied zone will be necessary. In addition, there often exist points where more accuracy is requ...

We consider the preconditioning of linear systems with matrices depending on a parameter, i.e., A εχ ε = b ε with A ε = M + εN symmetric positive definite. Instead of using extreme strategies as to apply the same preconditioner along the process, or on the contrary, to compute a different preconditioner for each value of ", we propose an intermedia...

The refinement technique is used to adapt meshes to the singularities of the numerical solution of any problem. Local refinement is applied is mesh areas where the solution must be accurate and it is necessary to dispose of reliable error indicators or estimators which define the elements that must be refined. Usually, this indicators or estimators...

The improvement in the mesh quality without changing its connectivity is bounded. This bound is associated with the topology of the mesh and with the constraints imposed by the boundary of the domain. To solve this problem, we propose in this work to combine the tetrahedral mesh optimization technique introduced in (1,2) with the local mesh refinem...

Quasi-minimal residual algorithms, these are QMR, TFQMR and QMRCGSTAB, are biorthogonalisation methods for solving nonsymmetric linear systems of equations which improve the irregular behaviour of BiCG, CGS and BiCGSTAB algorithms, respectively. They are based on the quasi-minimisation of the residual using the standard Givens rotations that lead t...

The efficiency of a mass consistent model for wind field adjustment depends on several parameters that arise in various stages of the process. On one hand, those involved in the construction of the initial wind field using horizontal interpolation and vertical extrapo- lation of the wind measures registered at meteorological stations. On the other...

This paper presents a new procedure to improve the quality of triangular meshes defined on surfaces. The improvement is obtained by an iterative process in which each node of the mesh is moved to a new position that minimizes certain objective function. This objective function is derived from an algebraic quality measures of the local mesh (the set...

The data structures used to model meshes for solving problems by finite element methods is based on different arrays. In these arrays information is stored related to, among other components, nodes, edges, faces, tetrahedra and connectivities. These structures provide optimum results but, in many cases, they need additional programming to be mainta...

Air pollution models usually start from the computation of the velocity field of a fluid. In this paper, we present a model for computing that field based on the contribution of the observed wind flow and the vertical buoyancy or momentum plume rise defined by a Gaussian plume model. This initial velocity field is adjusted to verify incompressibili...

Air pollution models usually start from the computation of the velocity field of the fluid. In this paper, we present a model for computing such a field based on the contribution of the observed wind flow and the vertical buoyancy or momentum plume rise defined by a Gaussian plume model. This initial velocity field is adjusted to verify incompressi...

To solve problems using finite element method it is necessary to obtain a good domain discretization. Once the problem geometry has been approached by an initial mesh, it must be able to adapt itself to the singularities of the numerical solution. The refinement process introduces new elements in zones of the mesh where the solution needs to be imp...

Combinations of mathematical models with data at particular points from observational networks are required in order to generate physically consistent wind fields and atmospheric pollutant distributions. We describe a methodology used to evaluate the modifications to wind flow and pollutant dispersion, mainly caused by the interaction of the air fl...

The quality improvement in mesh optimisation techniques that preserve its connectivity are obtained by an iterative process in which each node of the mesh is moved to a new position that minimises a certain objective function. In general, objective functions are derived from some quality measure of the local submesh, that is, the set of tetrahedra...

The quality improvement in mesh optimisation techniques that preserve its connectivity are obtained by an iterative process in which each node of the mesh is moved to a new position that minimises a certain objective function. The objective function is derived from some quality measure of the local submesh, that is, the set of tetrahedra connected...

En la simulación con el método de elementos finitos de procesos que tienen lugar en un dominio tridimensional definido sobre un terreno de orografía irregular es fundamental disponer de un mallador que se adapte a las características topográficas. El objetivo de este trabajo es desarrollar un código capaz de generar automáticamente una malla de tet...

We experimentally study how reordering techniques affect the rate of convergence of preconditioned Krylov subspace methods for non-symmetric sparse linear systems, where the preconditioner is a sparse approximate inverse. In addition, we show how the reordering reduces the number of entries in the approximate inverse and thus, the amount of storage...

The efficiency of a mass consistent model for wind field adjustment depends on several parameters that arise in various stages of the process. First, those involved in the construction of the initial wind field using horizontal interpolation and vertical extrapolation of the wind measures registered at meteorological stations. On the other hand, th...

In the finite element simulation of environmental processes that occur in a three-dimensional domain defined over an irregular terrain, a mesh generator capable of adapting itself to the topographic characteristics is essen tial. The present study develops a code for generating a tetrahedral mesh from an "optimal" node distribution in the domain. T...

In the FEM simulation of processes that occur in a three-dimensional domain defined over an irregular terrain, it is fundamental to have a mesh generator being capable of adapting itself to the topographic characteristics. The objective of this work is to develop a code able to generate a tetrahedral mesh from an "optimal" node distribution in the...

Parallel preconditioners are presented for the solution of general linear systems of equations. The computation of these preconditioners is achieved by orthogonal projections related to the Frobenius inner product. So, minM∈∥AM−I∥ F and matrix M0∈ corresponding to this minimum ( being any vectorial subspace of ℳn(ℝ)) are explicitly computed using a...

We experimentally study how reordering techniques affect the rate of convergence of preconditioned Krylov subspace methods for nonsymmetric sparse linear systems, where the preconditioner is a sparse approximate inverse. In addition, we show how the reordering reduces the number of entries in the approximate inverse and thus, the amount of storage...

The data structures used to model meshes for solving problems by finite element methods is based on different arrays. In these arrays information is stored related to, among other components, nodes, edges, faces, tetrahedral and connectivity. These structures provide optimum results which, in many cases, incur additional programming. In adaptively...

A three-dimensional finite element model for wind field adjustment was made. In general, these problems were defined over regions with complex terrain, therefore a suitable discretization of the studied zone will be necessary. As such, a technique for constructing tetrahedral meshes which are adapted to the terrain orography and has a higher densit...

A mass consistent model is developed in order to obtain a wind field which adjusts to an initial one. For the construction of the initial field, horizontal interpolation is considered at the level of the measure stations over the terrain. From these values, vertical wind profiles are built according to atmospheric stability conditions, terrain roug...

Estabilidad de sistemas dinámicos. Asociados a modelos neuronales, diseñados para el cálculo de autovectores de operadores lineales y no linealesPedro José Zufiria Zatarain, Piedad Tolmos Rodríguez-Piñero, José Manuel Vegas Montaner

The main objective of this work is to develop a suitable three-dimensional finite element code for solving the wind field adjustment problem [Solar Energy 54 (1995) 49] in an efficient way. A new triangulation technique is proposed for a 3-D domain, considering the Cartesian coordinate system with both variable horizontal and vertical spacing possi...

In order to find a map of wind velocities, this study tries to obtain an incompressible wind field that adjusts to an experimental one: also verifying the corresponding boundary conditions of physical interest. This problem has been solved by several authors using finite differences or standard finite element techniques. In this paper, this problem...

This is a study about one of the core questions in the GMRES(k) method regarding the obtaining of vector yk for the least-squares problem, argminy |Hky - β(n)e1|2 (see Saad and Schultz1). We propose a simple but efficient approach to the resolution of this problem and a low cost computation of the residual and the residual norm, including both in a...

En este trabajo se presentan formulaciones implícitas y explícitas para la resolución numérica del problema evolutivo de convección-difusión en 2-D, basadas en el método de las características. Se aborda un estudio comparativo sobre el comportamiento numérico de las distintas formulaciones propuestas. Se realizan diferentes aplicaciones numéricas u...

Resumen. La aplicación de técnicas de discretización para resolver diversos problemas definidos por ecuaciones en derivadas parciales da lugar a sistemas de ecuaciones lineales cuyas respectivas matrices se pueden escribir de la forma A ε = M + εN con M y N ma-trices simétricas y definidas positivas. Para precondicionar estos sistemas para distinto...

Palabras clave: Inversas aproximadas sparse, precondicionamiento, sistemas lineales no simétricos, técnicas de renumeración, métodos iterativos. Resumen. Se presentan precondicionadores en paralelo para la solución general de sistemas de ecuaciones lineales obtenidas mediante proyecciones ortogonales relacionadas con el pro-ducto escalar de Frobeni...

Palabras clave: Sistemas de ecuaciones lineales, Matrices variables, Gradiente Conjugado precondicionado, Inversa aproximada factorizada Resumen. Se plantea el precondicionamiento de sistemas de ecuaciones de la forma A ε x ε = b ε con A ε = M + εN simétrica definida positiva. Hay dos estrategias extremas para efectuar este precondicionamiento. Com...

Palabras clave: Sistemas lineales no simétricos, matrices sparse, métodos de Krylov, métodos de cuasi-mínimo residuo, reordenación, precondicionamiento. Resumen. Los métodos de cuasi-mínimo residuo QMR [6], TFQMR [5] y QMRCGSTAB [1], son métodos de biortogonalización para la resolución de sistemas de ecuaciones lineales no si-métricos que mejoran e...

The objective of this work is to present our recent results in the numerical solution of a mass consistent wind field model, which could be also introduced in an air pollution model. We summarize the evaluation of the wind field based on the contribution of the observed wind flow. Besides, this mass consistent model includes effects of chimney emis...