Numerical Analysis and Diagnosis of the Hydrodynamic Effects Produced by Hurricane Gordon along the Coast of Spain

This paper presents a detailed hindcast for the generation and propagation of sea state variables—significant wave heightHs, peak period Tp,mean direction u, and spectral shape g –s —associated with cyclonic events to numerically diagnose their possible hydrodynamic effects over the northeastern Atlantic. An example of such cyclonic events is Hurricane Gordon, which occurred during the second half of August 2012. Extreme hurricane-strength winds produced new and atypically low-frequency (about 14 s) packs of energy. The preexistent wave spectrum suddenly experienced an addition of low-frequency energy along the coast of Cadiz, Spain. This study presents the results of a comprehensive analysis developed to reconstruct the events produced by Hurricane Gordon (2012) along the coast of Cadiz. The analysis features the use of (i) parametric models for the characterization of hurricane winds and pressure fields, (ii) implementation of the Simulating Waves Nearshore (SWAN) model for the generation and propagation of waves in the northeast Atlantic Ocean, and (iii) its coupling with theMOPLA—taken fromthe Spanish acronym for wave propagation model, current, and morphodynamic evolution of beaches—model for the evaluation of longshore currents. The numerical wave characterization, generation, and propagation were validated with instrumental data from deep-water and coastal buoys.This work was partially funded by projects ‘‘GRACCIE’’ (SD 2007- 00067, CONSOLIDER INGENIO2010) and ‘‘iMar21’’ (BiA2011-2890) from the Spanish government

Directional calibration of wave reanalysis databases using instrumental data

Wave reanalysis databases (WRDBs) offer important advantages for the statistical characterization of wave climate (continuous time series, good spatial coverage, constant time span, homogeneous forcing, and more than a 40-yr-long time series) and for this reason, they have become a powerful tool for the design of offshore and coastal structures. However, WRDBs are not quantitatively perfect and corrections using instrumental observations must be addressed before they are used; this process is called calibration. The calibration is especially relevant near the coast and in areas where the orography is complex, since in these places the inaccuracy of WRDB is evident because of the bad description of the wind fields (i.e., insufficient forcing resolution). The quantitative differences between numerical and instrumental data suggest that different corrections should be applied depending on the mean direction of the sea state. This paper proposes a calibration method based on a nonlinear regression problem, where the corresponding correction parameters vary smoothly along the possible wave directions by means of cubic splines. The correction of significant wave height is performed using instrumental data: (i) buoy records and/or (ii) satellite data. The performance of the method is illustrated considering data from different locations around SpainThe authors thank Puertos del Estado (Spanish State Port) for providing the information from the wave reanalysis data base. R. Mínguez is indebted to the Spanish Ministry MICINN for the funding provided within the Ramon y Cajal program. This work was partly funded by projects GRACCIE (CSD2007-00067, ProgramaConsolider-Ingenio 2010) and AMVAR (CTM2010-15009) from the Spanish Ministry MICINN, by Project C3E (200800050084091) from the Spanish Ministry MAMRM, and by Project MARUCA (E17/08) from the Spanish Ministry MF

Regression models for outlier identification (Hurricanes and typhoons) in wave hindcast databases

ABSTRACT: he development of numerical wave prediction models for hindcast applications allows a detailed description of wave climate in locations where long-term instrumental records are not available. Wave hindcast databases (WHDBs) have become a powerful tool for the design of offshore and coastal structures, offering important advantages for the statistical characterization of wave climate all over the globe (continuous time series, wide spatial coverage, constant time span, homogeneous forcing, and more than 60-yr-long time series). However, WHDBs present several deficiencies reported in the literature. One of these deficiencies is related to typhoons and hurricanes, which are inappropriately reproduced by numerical models. The main reasons are (i) the difficulty of specifying accurate wind fields during these events and (ii) the insufficient spatiotemporal resolution used. These difficulties make the data related to these events appear as "outliers" when compared with instrumental records. These bad data distort results from calibration and/or correction techniques. In this paper, several methods for detecting the presence of typhoons and/or hurricane data are presented, and their automatic outlier identification capabilities are analyzed and compared. All the methods are applied to a global wave hindcast database and results are compared with existing hurricane and buoy databases in the Gulf of Mexico, Caribbean Sea, and North Atlantic Ocean

Observability analysis for structural system identification based on state estimation

The concept of observability analysis (OA) has garnered substantial attention in the field of Structural System Identification. Its primary aim is to identify a specific set of structural characteristics, such as Young's modulus, area, inertia, and possibly their combinations (e.g., flexural or axial stiffness). These characteristics can be uniquely determined when provided with a suitable subset of deflections, forces, and/or moments at the nodes of the structure. This problem is particularly intricate within the realm of Structural System Identification, mainly due to the presence of nonlinear unknown variables, such as the product of vertical deflection and flexural stiffness, in accordance with modern methodologies. Consequently, the mechanical and geometrical properties of the structure are intricately linked with node deflections and/or rotations. The paper at hand serves a dual purpose: firstly, it introduces the concept of State Estimation (SE), specially tailored for the identification of structural systems; and secondly, it presents a novel OA method grounded in SE principles, designed to overcome the aforementioned challenges. Computational experiments shed light on the algorithm's potential for practical Structural System Identification applications, demonstrating significant advantages over the existing state-of-the-art methods found in the literature. It is noteworthy that these advantages could potentially be further amplified by addressing the SE problem, which constitutes a subject for future research. Solving this problem would help address the additional challenge of developing efficient techniques that can accommodate redundancy and uncertainty when estimating the current state of the structure

Análisis numérico del huracán Gordon y diagnóstico de sus efectos hidrodinámicos en las costas de Cádiz.

El objetivo del estudio es evaluar numéricamente el comportamiento espacio-temporal de las variables medioambientales oceánicas (altura de ola significante Hs, periodo de pico Tp, dirección media ? y forma espectral y), su generación y propagación, asociados al huracán Gordon, acontecido durante la segunda mitad del mes de agosto de 2012, con el objetivo general de poder realizar un diagnostico de los efectos hidrodinámicos de este evento ciclónico sobre las costas de Cádiz, España. La acción de los vientos extremales asociados al huracán sobre la superficie del océano, fomentaron la adición de energía en frecuencias atípicamente bajas del espectro del oleaje (alrededor de 14 s), en la zona costera de Cádiz. Este efecto se tradujo en la creación de una componente de mar de fondo que llego a acoplarse con el oleaje preexistente en la zona, llegando a inducir un importante y súbito aumento en las corrientes costeras del litoral Gaditano. En el presente estudio se presentan los resultados de un análisis integral para analizar los eventos relacionados a la generación del oleaje y su propagación hacia las costas de Cádiz, en relación con el paso del huracán Gordon (2012). A través del empleo de la modelación numérica de la generación, propagación e interacción del oleaje en costa en el dominio oceánico del Atlántico Nororiental

Análisis numérico del huracán Gordon y diagnóstico de sus efectos hidrodinámicos en las costas de Cádiz.

El objetivo del estudio es evaluar numéricamente el comportamiento espacio-temporal de las variables medioambientales oceánicas (altura de ola significante Hs, periodo de pico Tp, dirección media ? y forma espectral y), su generación y propagación, asociados al huracán Gordon, acontecido durante la segunda mitad del mes de agosto de 2012, con el objetivo general de poder realizar un diagnostico de los efectos hidrodinámicos de este evento ciclónico sobre las costas de Cádiz, España. La acción de los vientos extremales asociados al huracán sobre la superficie del océano, fomentaron la adición de energía en frecuencias atípicamente bajas del espectro del oleaje (alrededor de 14 s), en la zona costera de Cádiz. Este efecto se tradujo en la creación de una componente de mar de fondo que llego a acoplarse con el oleaje preexistente en la zona, llegando a inducir un importante y súbito aumento en las corrientes costeras del litoral Gaditano. En el presente estudio se presentan los resultados de un análisis integral para analizar los eventos relacionados a la generación del oleaje y su propagación hacia las costas de Cádiz, en relación con el paso del huracán Gordon (2012). A través del empleo de la modelación numérica de la generación, propagación e interacción del oleaje en costa en el dominio oceánico del Atlántico Nororiental

Solving ordinary differential equations with range conditions. Applications

This paper introduces the problem of solving ordinary differential equations with extra linear conditions written in terms of ranges, and deals with the corresponding existence and uniqueness problems. Some methods for analyzing the existence of solutions and obtaining the set of all solutions, based on the theory of cones and polyhedra, are given. These solutions are found by first converting the problem to a system of linear algebraic equations and then applying the corresponding well-known theory for solving and discussing the existence and uniqueness of solutions of these systems. Finally, the methods are illustrated by their application to some practical examples of the beam problem

Extremes of maximum temperatures over Iberia from ENSEMBLES regional projections

RESUMEN: El presente estudio se centra en la estimación de cambios en la temperatura máxima en el sur de Europa considerando dos modelos regionales de circulación del proyecto europeo ENSEMBLES. Los extremos son expresados en términos de los valores característicos obtenidos mediante la aplicación de un modelo basado en la distribución generalizada de extremos (GEV) dependiente del tiempo. El estudio se centra a finales del siglo XX (1961-2000), considerado como periodo de calibración/validación, y analiza los cambios proyectados en el periodo 2061-2100 considerando el escenario de emisiones A1B. El aumento de los valores característicos para un periodo de retorno de 40 años (que duplica el correspondiente a los valores medios en algunas zonas) indica un mayor impacto del cambio climático en los eventos extremos, como también se ha mostrado en otros estudios. Además los resultados obtenidos considerando diferentes periodos de retorno (40 o 100 años) son muy parecidos, siendo estas diferencias más pequeñas que las producidas por la señal de cambio climático mencionada antes.ABSTRACT: Two state-of-the-art regional circulation models from the EU ENSEMBLES project are used to estimate changes of maximum temperatures over Southern Europe. Extremes are expressed in terms of return values using a time-dependent generalized extreme value (GEV) model fitted to monthly maxima. The study focuses on the end of the 20th century (1961-2000), used as a calibration/validation period, and analyzes the changes projected for the period 2061-2100 considering the A1B emission scenario. The increments of the 40-year return values (up to 2 times higher than those corresponding to the mean in some areas) indicate a higher impact of global climate changes in extremes, in agreement with other studies. Moreover, the results for different return periods (40 or 100 years) are very similar (due to the bounded character of the corresponding extreme distributions) with differences smaller than those produced by the climate change driving signal above mentioned