Propiedades radiativas de los aerosoles atmosféricos en la región de Canarias

Memoria presentada en la Universidad de La Laguna para optar al grado de doctor en Ciencias Físicas.Las propiedades radiativas de los aerosoles atmosféricos son un ode los factores que mayores incertidumbres presentan en cuanto al posible papel que juegan en el balance de energía en el sistema Teirra-atmósfera. Los objetivos concretos de este trabajo se resumen en los siguientes: 1) Medida de espesores ópticos de aerosoles en condiciones defondo y de alta concentración de aerosoles minerales, 2) Cálculo de la distribución en tamaño de los aerosoles en estas condiciones, 3) Cálculo de las principales propiedades radiativas: función de fase, factor de asimetría, albedo de dispersión simple y factor de retrodispersión, 4) Construcción de un equipo con capacidad para determinar todas las magnitudes necesarias para determinar los espesores ópticos de aerosoles en el rango UV-VIS-NIR. Los principales resultados obtenidos se resumen en los siguientes: 1) Se ha determinado que durante 1994 seguían siendo patente los efectos en la estratosfera de la erupción del Pinatubo, 2) Se ha determinado que las propiedades radiativas estudiadas muestran un comportamiento de atmósfera tipo Rayleigh hasta Septiembre de 1994, para pasar a uno tipo Mie a partir de Octubre. El forzamiento radiativo calculado para los aerosoles minerales varía entre -1,43 y -1,64 W/m2

Entanglement entropy of an accelerating universe

We have considered the existence of a dependence of the entanglement entropy on the cosmological horizon surface area also in several accelerating models of the current universe both for a quintessence scalar field and for a phantom-energy scenario. It is shown that if a quintessence vacuum cosmic field is considered then, though the case for w>-1 satisfies a second law for entanglement entropy, when w<-1 such a law is violated. It is finally noted that the entanglement entropy and the distinct formulations of cosmic holography share common future surfaces which are optimal screen for the latter descriptions. © 2012 American Physical Society.This work was supported by MICINN under Research Project FIS2008- 06332.Peer Reviewe

Radiative forcing under mixed aerosol conditions

The mixture of mineral dust with biomass burning or urban-industrial aerosols presents significant differences in optical properties when compared to those of the individual constituents, leading to different impacts on solar radiation levels. This effect is assessed by estimating the direct radiative forcing (ΔF) of these aerosols from solar flux models using the radiative parameters derived from the Aerosol Robotic Network (AERONET). These data reveal that, in oceanic and vegetative covers (surface albedo (SA) 0.30 are not present in East Asia region. At the bottom of atmosphere (BOA) the maximum ΔF values are associated with the highest AOD levels obtained for the mixture of mineral dust and biomass burning aerosols (−130 ± 44 Wm−2 with AOD = 0.8 ± 0.4 for SA < 0.30).Support for this study was given by Spanish Ministry of Education and Science, projects CGL2005‐03428‐C04‐02, CGL2007‐66477‐C02‐02/CLI, PI042005/033, and CGL2008‐04740/CLI

Different involvement of medial prefrontal cortex and dorso-lateral striatum in automatic and controlled processing of a future conditioned stimulus

Recent studies support the idea that stimulus processing in latent inhibition can vary during the course of preexposure. Controlled attentional mechanisms are said to be important in the early stages of preexposure, while in later stages animals adopt automatic processing of the stimulus to be used for conditioning. Given this distinction, it is possible that both types of processing are governed by different neural systems, affecting differentially the retrieval of information about the stimulus. In the present study we tested if a lesion to the dorso-lateral striatum or to the medial prefrontal cortex has a selective effect on exposure to the future conditioned stimulus (CS). With this aim, animals received different amounts of exposure to the future CS. The results showed that a lesion to the medial prefrontal cortex enhanced latent inhibition in animals receiving limited preexposure to the CS, but had no effect in animals receiving extended preexposure to the CS. The lesion of the dorso-lateral striatum produced a decrease in latent inhibition, but only in animals with an extended exposure to the future conditioned stimulus. These results suggest that the dorsal striatum and medial prefrontal cortex play essential roles in controlled and automatic processes. Automatic attentional processes appear to be impaired by a lesion to the dorso-lateral striatum and facilitated by a lesion to the prefrontal cortex.Ministerio de Economía, Industria y Competitividad PSI2015-65500-

Optimisation of electric field uniformity in microwave heating systems by means of multi-feeding and genetic algorithms

In most of microwave heating applications obtaining uniform heating patterns in certain regions of the applicator is a key issue. In this paper, the proposed solution for achieving electric field uniformity consists of designing the configuration of the feeding system in a multimode cavity by means of Genetic Algorithms. The feeding system is constituted by waveguides or slots arrays. The electric field pattern inside the cavity depends on the location of these sources and an improvement in the electric field uniformity on the product can be obtained by means of a proper design of this feeding system. Results for the curing of epoxy resin over a marble slab are presented and they show a significant improvement in the electric field uniformity over the epoxy resin.This work was supported in part by the CICYT, Spain, under project reference TIC 2004- 05037-C02-02 and Consejería de Economía, Industria e Innovación, Región de Murcia, Spain, under the project reference 2I04SU063

Proyecciones climáticas de índices de temperaturas extremas en Canarias

Ponencia presentada en: XII Congreso de la Asociación Española de Climatología celebrado en Santiago de Compostela entre el 19 y el 21 de octubre de 2022.[ES]Las proyecciones de extremos climáticos son esenciales para el diseño de planes estratégicos de adaptación/mitigación a los posibles efectos adversos del cambio climático. Para obtener las proyecciones de los índices de temperaturas extremas en Canarias se aplicó una metodología de downscaling dinámico. Para ello se empleó el modelo WRF con una resolución espacial de 3 km en los periodos 2030-2059 (MID) y 2070-2099 (END), y para los escenarios RCPs 4.5 y 8.5. Las condiciones iniciales se definieron mediante los modelos GFDL-ESM2M, MIROC-ESM e IPSL-CM5. Los cambios a futuro se calcularon frente al período de referencia 1980-2009 (HIS) para los índices extremos dados por el Equipo de Expertos en Detección e Índices de Cambio Climático (ETCCDI): temperaturas máxima y mínima mensual (TX y TN), máximo mensual del rango de temperatura diurna diaria (DTR), noches tropicales (TR), días cálidos (noches frías) TX90p (TN10p), índice de duración de olas de calor (WSDI) y de olas de frío (CSDI). Además, se analizaron los niveles y periodos de retorno para la temperatura máxima anual utilizando la distribución de valores extremos generalizados (GEV).[EN]Projections of climate extremes are essential data for the design of strategic plans for adaptation/mitigation to the possible adverse effects of climate change. To obtain projections of extreme temperature indices in the Canary Islands, a dynamic downscaling methodology was applied. For this purpose, the WRF modeling system was configured with a spatial resolution of 3 km, for the periods 2030-2059 (MID) and 2070-2099 (END), and the RCPs 4.5 and 8.5 scenarios. Initial conditions were defined using three models of the Coupled Model Intercomparison Project 5 (CMIP5): GFDL-ESM2M, MIROC-ESM and IPSL-CM5. Future changes were calculated against the reference period 1980-2009 (HIS). The extreme indices selected were those defined by the Expert Team on Climate Change Detection and Indices (ETCCDI): monthly maximum and minimum temperature (TX and TN), monthly maximum of the daily diurnal temperature range (DTR), tropical nights (TR), warm days (cold nights) TX90p (TN10p), warm spell duration index (WSDI) and cold spell duration index (CSDI). In addition, return levels and return periods for annual maximum temperature were analyzed using the generalized extreme value (GEV) distribution.Este trabajo fue financiado por los proyectos CGL2015-67508-R, y RTC-2017-6409-3, Ministerio de Ciencia e Innovación, España

Aerosol radiative forcing and forcing efficiency in the UVB for regions affected by Saharan and Asian mineral dust

The influence of mineral dust on ultraviolet energy transfer is studied for two different mineralogical origins. The aerosol radiative forcing ΔF and the forcing efficiency at the surface ΔFeff in the range 290–325 nm were estimated in ground-based stations affected by the Saharan and Asian deserts during the dusty seasons. UVB solar measurements were taken from the World Ozone and Ultraviolet Data Center (WOUDC) for four Asian stations (2000–04) and from the Santa Cruz Observatory, Canary Islands (2002–03), under Gobi and Sahara Desert influences, respectively. The Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth at 550 nm was used to characterize the aerosol load τ, whereas the aerosol index provided by the Total Ozone Mapping Spectrometer (TOMS) sensor was employed to identify the mineral dust events. The ΔF is strongly affected by the aerosol load, the values found being comparable in both regions during the dusty seasons. Under those conditions, ΔF values as large as −1.29 ± 0.53 W m−2 (τ550 = 0.48 ± 0.24) and −1.43 ± 0.38 W m−2 (τ550 = 0.54 ± 0.26) were reached under Saharan and Asian dust conditions, respectively. Nevertheless, significant differences have been observed in the aerosol radiative forcing per unit of aerosol optical depth in the slant path, τS. The maximum ΔFeff values associated with dust influences were −1.55 ± 0.20 W m−2 τS550−1 for the Saharan region and −0.95 ± 0.11 W m−2 τS550−1 in the Asian area. These results may be used as a benchmark database for establishing aerosol corrections in UV satellite products or in global climate model estimations.We acknowledge the MCYT (Ministry of Science and Technology, Spain) and F.E.D.E.R. foundations (E.U.) for their economic support of projects CGL2004-05984-C07-05, CGL2005-03428-C04-02, CGL2007-66477-C02-02/CLI, CGL2008-04740/CLI and PI042005/033

Entanglement entropy of an accelerating universe

We have considered the existence of a dependence of the entanglement entropy on the cosmological horizon surface area also in several accelerating models of the current universe both for a quintessence scalar field and for a phantom-energy scenario. It is shown that if a quintessence vacuum cosmic field is considered then, though the case for w &gt; À1 satisfies a second law for entanglement entropy, when w &lt; À1 such a law is violated. It is finally noted that the entanglement entropy and the distinct formulations of cosmic holography share common future surfaces which are optimal screen for the latter descriptions. [7]). Actually, entanglement entropy measures a degree of the correlation between subsystems of a given quantum system All the above results allow us to confidently extrapolate the above horizon area-entanglement entropy proportionality law to any system where quantum entanglement takes place in a cosmic space-time. The results that we are going to get later on are all consistent with that extrapolation. In fact, in this brief report we are going to extend the existence of such a dependence of entanglement entropy on the cosmological horizon surface area also in accelerating models for the current universe both for a quintessence scalar dark-energy field and for a phantom-energy scenario. It will be shown that if an usual quintessence vacuum cosmic field is considered [11], then, though the case for w &gt; À1 (note that along this report we shall only consider an equation of state for the Universe with the perfect-fluid form p ¼ w, with p the pressure and the energy density) satisfies a second law for entanglement entropy, when w &lt; À1 such a law would be violated. We want to estimate the entanglement entropy that corresponded to a quantum field in an accelerating spacetime which is inexorable endowed with a future event horizon where w ¼ p= is the parameter of the equation of state, a 0 and t 0 are the initial values of the scale factor and time, and the constant C is given by C ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 8G=3 p , with an integration constant. We introduce then a conformal time defined by so tha

Análisis de precipitaciones extremas en Canarias a partir de resultados de regionalizaciones estadísticas y dinámicas

Ponencia presentada en: XII Congreso de la Asociación Española de Climatología celebrado en Santiago de Compostela entre el 19 y el 21 de octubre de 2022.[ES]En este trabajo se presenta un análisis de eventos extremos de precipitación diaria en la Islas Canarias, utilizando la teoría de valores extremos (GEV, generalized extreme value), con el fin de predecir los cambios a final de siglo para el escenario de emisión de gases de efecto invernadero más desfavorable (RCP8.5). Para ello, los datos de diferentes regionalizaciones climáticas, tanto estadísticas como dinámicas, y para dos periodos diferentes, histórico (1980-2009) y futuro (2070-2099), han sido utilizados. Los resultados obtenidos de estimaciones estadísticas corresponden a los datos diarios de proyecciones regionalizadas de cambio climático publicados por Aemet, para los que se utilizaron tres tipos de algoritmos empíricos basados en las técnicas de análogos, regresión, y redes neuronales. Los datos de las simulaciones dinámicas se obtuvieron a partir de simulaciones con el modelo WRF (Weather Research and Forecasting) utilizando tres dominios anidados, de los que se han analizado los dos de mayor resolución espacial, 9 y 3 km respectivamente. Las condiciones de contorno para dichas simulaciones corresponden a los resultados de tres modelos climáticos globales: GFDL-ESM2M, MIROC-ESM e IPSL-CM5. Los datos observacionales utilizados para la validación de los resultados de los modelos se obtuvieron de la base de datos SPREAD. Debido a alta heterogeneidad del territorio y con el fin de simplificar el análisis se realizó una regionalización basada en un análisis de componentes principales y técnicas de agrupamiento automático, obteniendo cuatro regiones principales, que presentan, entre sí, diferencias apreciables en los extremos observados. Como resultados destacables, se ha encontrado una subestimación general tanto de la precipitación media como de los fenómenos extremos por parte de los métodos estadísticos en comparación a los dinámicos. Sin embargo, ambos métodos coinciden en la predicción de un incremento de los tiempos de retorno de los fenómenos de precipitación extrema a finales de siglo.[EN]A generalized extreme value theory (GEV) analysis for precipitation events in Canary Islands, aimed to predict changes of some main hydrological parameters until the end of the present century and for RCP8.5 greenhouse gas scenario is presented in this work. To this end two different approximations for simulations, i.e. dynamicaldownscaling and statistical methods have been taken into account for comparison and validation. For statistical simulations, data from the Spanish Meteorological Agency AEMET, comprising analogues, neural network and linear regression methods have been analysed for two time periods, 1980-2009 (historical) and 2071-2100, and on the other hand, dynamical-downscaling simulations using WRF nested domains with resolutions of 3 and 9 km have been studied along the century using three global contour conditions as inputs: GFDL-ESM2M, MIROC-ESM and IPSL-CM5. The historical precipitation data for validations has been taken from 110 stations of the SPREAD database over the Canarian archipelago. Due to the high orographical changes along the small distances on the islands, we also present a spatial regionalisation in four different areas to highlight the appreciable differences on the studied extreme precipitation events. As relevant results it can be appreciated noticeable differences between statistical values, which are clearly lower than observations, and the ones obtained by dynamical methods that remain closer to the observations. Nevertheless both methods are in good agreement with the prediction of an augmentation of the return times of the extreme precipitation events for the end of the century.Este trabajo fue financiado por los proyectos CGL2015-67508-R, y RTC-2017-6409-3, Ministerio de Ciencia e Innovación, España. Los autores agradecen el apoyo del Proyecto PLANCLIMAC (MAC / 3.5b / 244), el cual está financiado por el Programa INTERREG MAC 2014-2020 de la Unión Europea, cofinanciado por el Fondo Europeo de Desarrollo Regional (FEDER-FEDER)

Origin and SEM analysis of aerosols in the high mountain of Tenerife (Canary Islands)

Focusing on aerosolized matter of relevance to respiratory health, a major public health issue worldwide, we studied mineral and biological aerosol (bioaerosol) composition (TSP and PM2.5) and geographical origins during dust intrusions in the Canary Islands. Seven days’ back- ward trajectories were assessed daily during March 2004 with the ends of back trajectories being the sampling station of Iza?a (high moun- tain, 2360 m a.s.l. at the Ca?adas del Teide National Park, Tenerife island), a free troposphere site allowing characterization of dust with low influence of other pollutant sources. Scanning electron microscopy (SEM) was used to survey major types of airborne particles in the dust plumes. Control, non-intrusion conditions correspond to Atlantic oceanic middle troposphere (OMT) air masses. Of the 14 samples taken, 1 corresponded to a control (clear atmosphere conditions), and the remaining 13 to dust intrusions, with the following sources: African Dust; EAM: mixture of Europe, Africa and Oceanic; MaA: maritime aerosols. Of the air masses, 79% were directly transported to the islands from Africa, and an increase of African dust events was detected when comparing with a 52-year previous data sequence. Quartz microcristals and aggregates of quartz and platy clay were the dominant minerals identified, with marine salt and gypsum also present. Freshwater diatom tests (from two Aulacoseira species) represented the most important biogenic aerosols, although fungi and pollen were also detected. The diverse and complex mixture of respirable particles in large quantities in airborne dust, especially from nearby Sahara and from the Sahelian region, is of maximum interest for air- way pathology in the Canaries, including the highly visited highlands in Tenerife.We acknowledge to the MEC (Ministry of Education and Science, Spain) and F.E.D.E.R. founds (E.U.) for the economical support of the following projects: CGL2005-03428-C04-02, CGL2007-66477-C02-02/CLI, CGL2008- 04740 and PI042005/033