Regional assessment of the Jenkinson-Collison weather types classification and observational uncertainty based on different reanalyses over the Mediterranean region

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]El algoritmo de clasificación en tipos de tiempo de Jenkinson y Collison (JC-WT, Jenkinson and Collison 1977) es una técnica de agrupamiento usada para clasificar la circulación atmosférica en un número reducido de patrones de presión a nivel del mar. Esta metodología se basa en el cálculo de 6 parámetros intermedios relacionados con las características del flujo del viento. Este método ha tenido numerosas aplicaciones, siendo una de ellas la caracterización objetiva de la circulación atmosférica tanto a nivel global como regional, esencial para la evaluación de modelos climáticos y para su aplicabilidad en regionalización dinámica y estadística. La primera definición del método JC-WT centraba el estudio sobre las Islas Británicas pero puede ser, en principio, aplicado en latitudes medias-altas (Jones et al., 2013). El presente estudio examina la aplicabilidad la metodología JC-WT sobre la región Mediterránea y explora las diferencias entre cinco reanálisis a la hora de representar las características de los 27 JC-WT (sus frecuencias relativas y las probabilidades de transición entre tipos). Los resultados muestran diferencias importantes entre los distintos catálogos, sobre todo en verano. Además, se analizan estas diferencias entre reanálisis a nivel de los 6 parámetros intermedios de JC-WT con el fin de arrojar luz sobre la naturaleza sinóptica de las mismas. Estas discrepancias pueden comprometer la robustez de los estudios relacionados con la evaluación de modelos basada en procesos para esta región y desaconsejan el uso de un único reanálisis como referencia.[EN]The Jenkinson-Collison Weather Type (JC-WT; Jenkinson and Collison, 1977) classification is a clustering method used to classify the regional atmospheric circulation into a reduced number of typical recurrent sea-level pressure patterns. This methodology is a function of six parameters related to wind-flow characteristics. Originally developed for the British Isles, the method since then has seen many applications. One of its applications is serving for an objective characterization of either global or regional atmospheric circulation, a key feature for the assessment of climate models and their suitability for driving dynamical and statistical modeling experiments. Encouraged by the estimate that the JC-WT approach can in principle be applied to any mid-to-high latitude region (Jones et al, 2013), this study assesses the general application of JC-WT over the Mediterranean region, extending from the Iberian Peninsula in the west to the Levant in the east. We also explore to what extent the JC-WT features (such as frequencies of the 27 weather types and transition probabilities between pairs of types) obtained from five distinct reanalysis products agree with each other. Our results unveil important discrepancies among reanalyses, accentuated in summer. We furtherly explore these discrepancies deepening on the JC-WT base parameters in order to shed some light on the synoptic nature of these inconsistencies, that may compromise the robustness of circulation-based model assessments relying on a single reanalysis in these regions.The authors acknowledge funding from the R+D+i projects CORDyS (PID2020- 116595RB-I00) and ATLAS (PID2019-111481RB-I00), funded by MCIN/AEI/10.13039/501100011033. J.A.F. acknowledge funding from grant PRE2020-094728 funded by MCIN/AEI/10.13039/501100011033

El reto de publicar una revista de lingüística gallega en Galicia: Estudos de Lingüística Galega [Póster]

Póster presentado na 5ª Conferencia internacional sobre calidad de revistas de ciencias sociales y humanidades (CRECS 2015). Universidad de Murcia, 7-8 de maio de 2015

Functional anthocyanin-rich sausages diminish colorectal cancer in an animal model and reduce pro-inflammatory bacteria in the intestinal microbiota

Colorectal cancer is the fourth most common neoplasia in Europe, where it accounts for 28.2 new cases per 100,000 inhabitants. In an effort to decrease the incidence of this disease, various prevention measures are being studied, one of which are anthocyanin-rich foods. Anthocyanins are potent antioxidant flavonoids mainly found in flowers and colorful fruits and vegetables. These nutraceuticals have diverse biological functions once ingested, including immunomodulatory, anti-inflammatory and antitumor functions. In order to test the preventive effect of these flavonoids against colorectal cancer, an animal model (Rattus norvegicus F344) was developed. In this model two doses of azoxymethane (10 mg/kg) and two treatments with dextran sodium sulfate (DSS) were administered to the animals. For 20 weeks they were fed either control rat feed, control sausages, or functional sausages containing 0.1% (w/w) of anthocyanins from a mixture of dehydrated blackberries and strawberries. At the end of that period, the animals were sacrificed and their antioxidant plasma levels and digestive tract tissues were analyzed. The results revealed a statistically significant reduction in the number of colon tumors in the functional sausages cohort with respect to the control animals and an increase in the FRAP (ferric reducing ability of plasma) total antioxidant activity in that same cohort. Colon microbiota differences were also examined via metagenomics 16S ribosomal RNA (rRNA) sequencing, revealing a significant reduction in populations of the pro-inflammatory Bilophila wadsworthia. Therefore, the design of functional processed meat products, such as ones enriched with anthocyanins, may be an effective strategy for preventing inflammatory digestive diseases and colorectal cancer in human populations

Performance of the CMIP6 global climate models over the Iberian Peninsula and relationships with the simulated climate system complexity

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 el presente estudio se muestra una evaluación del rendimiento de las diferentes configuraciones de los modelos climáticos globales que han aportado experimentos históricos a CMIP6 (Coupled Model Intercomparison Project 6) para la Península Ibérica (IB), utilizando un dominio similar al aplicado en iniciativas de downscalling anteriores. La evaluación se basa en los patrones típicos de circulación atmosférica regional definidos por Jenkinson y Collison (1977), que se sabe que están vinculados con un gran número de variables de la física y la química atmosféricas. Los resultados se comparan con los obtenidos de la generación anterior de los modelos (CMIP5) y con los obtenidos de un análisis hemisférico (Brands 2022a), para comprobar 1) si los modelos han mejorado con el tiempo y 2) si los resultados específicos concuerdan con los obtenidos en un dominio más grande, lo que los hace menos propensos a la propagación de errores durante períodos de tiempo no observados.[EN]performance assessment of the global climate model configurations contributing historical experiments to CMIP6 is provided for the Iberian Peninsula (IB), using a spatial domain similar to that applied in previous downscaling initiatives. The evaluation is based on typical recurrent regional atmospheric circulation patterns as defined by Jenkinson & Collison (1977), which are well known to be linked with a large number of variables from atmospheric physics and chemistry. Results are compared to those obtained from the previous model generation (CMIP5), and to those retrieved from a hemispheric-wide analysis (Brands 2022) in order to see 1) if the models have improved over time, and 2) whether the region-specific findings agree with those obtained on a larger domain, thereby making them less prone to error propagation during unobserved time periods. It is found that the model version changes from CMIP5 and 6 lead to slight improvements, mainly associated with an increase in horizontal model resolution, but that the selection of the right model family is more important to obtain good model performance

MPPT for a semi-rigid airship powered by solar energy

[ES] Los MPPT son una etapa de control vital para obtener la máxima potencia de los paneles solares. Si esto además se aplica a un dirigible que va a estar únicamente alimentado mediante energía solar, el problema de lograr un sistema de control que sea capaz de obtener la máxima potencia se hace aún más complejo. Para lograr el funcionamiento óptimo, es necesario conocer cuál será la radiación que recibirá el dirigible en función de donde se sitúen los paneles, el sistema ha de ser capaz de soportar térmicamente la radiación y poder obtener la máxima potencia disponible por los paneles en cada instante, asegurando así una mayor eficiencia. En el trabajo se realiza un análisis geométrico, un análisis térmico del dirigible y la colocación de los paneles solares, se comparan las topologías de convertidores DC-DC que pueden resultar interesantes, según lo plasmado por la literatura para realizar la reducción o elevación de la tensión y se compara el rendimiento de los algoritmos MPPT P&O e Incremental Conductance y modificaciones de los mismos para ver su respuesta ante diferentes esquemas de radiación. Las simulaciones realizadas muestran que el convertidor elegido y los algoritmos comparados son capaces de realizar la conversión con gran eficiencia para todos los casos salvo el caso de sombra parcial, para el cual sólo un algoritmo consigue resultados satisfactorios.[EN] MPPTs are a vital control stage to get the maximum power from solar panels. If this is also applied to an airship that is going to be solely powered by solar energy, the problem of achieving a control system that is capable of obtaining maximum power becomes even more complex. To achieve optimal operation, it is necessary to know what radiation the airship will receive depending on where the panels are located around the envelope. The system must be able to withstand the radiation thermally and be able to obtain the maximum power available from the panels at any given moment. Thus, ensuring greater efficiency. In the work, a geometric analysis, a thermal analysis of the airship and the placement of the solar panels are carried out. According to what is reflected in the literature the topologies of DC-DC converters that can be interesting are compared to carry out the reduction or elevation of the voltage and, at last, the performance of the MPPT P&O and Incremental Conductance algorithms and their modifications are compared to see their response to different radiation schemes. The simulations carried out show that the chosen converter and the compared algorithms can perform the conversion with great efficiency for all cases except for the case of partial shading, for which only one algorithm achieves satisfactory results

A global climate model performance atlas for the southern hemisphere extratropics based on regional atmospheric circulation patterns

The performance of 61 global climate models participating in CMIP5 and 6 is evaluated for the Southern Hemisphere extratropics in terms of typical regional-scale atmospheric circulation patterns. These patterns are known to be linked with a number of key variables in atmospheric physics and chemistry and provide an overarching concept for model evaluation. First, hemispheric-wide error and ranking maps are provided for each model and regional details are described. Then, the results are compared with those obtained in a companion study for the Northern Hemisphere. For most models, the average error magnitude and ranking position is similar on both hemispheres, ruling out systematic tuning toward either of the two. CMIP6 models perform better on average than CMIP5 models and the interactive simulation of more climate system components does not deteriorate the results for most model families. Better performance is associated with higher resolution in the atmosphere, following a non-linear relationship.This research work was funded by the European Commission – Next-GenerationEU (Regulation EU 2020/2094), through CSIC's Interdis-ciplinary Thematic Platform Clima (PTI Clima)/Development of Oper-ational Climate Services and by the I+D+i project CORDyS (PID2020-116595RB-I00), funded by MCIN/AEI/10.13039/501100011033. J.A.F. acknowledges support from project ATLAS (PID2019-111481RB-I00), grant PRE2020-094728 funded by MCIN/AEI/10.13039/501100011033 and ESF investing in your future. A.C. acknowl-edges support from Project COMPOUND (TED2021-131334A-I00) funded by MCIN/AEI/10.13039/501100011033 and by the European Union NextGener-ationEU/PRTR. S.B. would like to thank CESGA and AMTEGA for providing computational resources. The authors acknowledge the public availability of the CMIP datasets via the ESGF data portals, as well the free distribution of the ECMWF and JMA reanalysis products

The signature of the main modes of climatic variability as revealed by the Jenkinson-Collison classification over Europe

The Jenkinson-Collison Weather Typing (JC-WT) method uses sea-level pressure gradients to create 27 types based on the geostrophic flow and vorticity around any extratropical target location. Typically, JC-WTs are applied over specific locations or limited domains, thus hampering the understanding of the impact of large-scale mechanisms on regional climate. This study explores the links between regional climate variability, as represented by the JC-WTs, and large-scale phenomena, to describe the synoptic-scale variability in the North Atlantic-European region and evaluate the JC-WT methodology. Largescale circulation is here characterized by major atmospheric low-frequency modes, namely the North Atlantic Oscillation, the East Atlantic and the Scandinavian teleconnection indices, and by atmospheric blockings. Results show that JC-WTs coherently capture the spatial and temporal variability of the large-scale modes and yields a characteristic response to blocking events. Overall, our results underpin the exploratory potential of this method for the analysis of the near-surface circulation. These findings endorse the use of JC-WTs and support the reliability and utility of the JC-WT classification for processbased model assessments and model selection, a crucial task for climate impact studies.CORDyS project (PID2020-116595RB-I00) and ATLAS(PID2019-111481RB-I00) funded by Ministerio de Cienciae Innovaci on / Agencia Estatal de Investigaci on (MCIN/AEI/10.13039/501100011033). Project COMPOUND(TED2021-131334A-I00) funded by MCIN/AEI/10.13039/501100011033 and by the European Union NextGenera-tionEU/PRTR. Ph.D. grant PRE2020-094728 (MCIN/AEI/10.13039/501100011033); PTI-Clima, MITECO andNextGenerationEU (Regulation EU 2020/2094) IMPET-US4CHANGE, grant agreement no. 101081555, from theEuropean Union's Horizon Europe research and innova-tion programm

Exploring the limits of the Jenkinson–Collison weather types classification scheme: a global assessment based on various reanalyses

The Jenkinson-Collison weather typing scheme (JC-WT) is an automated method used to classify regional sea-level pressure into a reduced number of typical recurrent patterns. Originally developed for the British Isles in the early 1970´s on the basis of expert knowledge, the method since then has seen many applications. Encouraged by the premise that the JC-WT approach can in principle be applied to any mid-to-high latitude region, the present study explores its global extra-tropical applicability, including the Southern Hemisphere. To this aim, JC-WT is applied at each grid-box of a global 2.5º regular grid excluding the inner tropics (± 5º band). Thereby, 6-hourly JC-WT catalogues are obtained for 5 distinct reanalyses, covering the period 1979-2005, which are then applied to explore (1) the limits of method applicability and (2) observational uncertainties inherent to the reanalysis datasets. Using evaluation criteria, such as the diversity of occurring circulation types and the frequency of unclassified situations, we extract empirically derived applicability thresholds which suggest that JC-WT can be generally used anywhere polewards of 23.5º, with some exceptions. Seasonal fluctuations compromise this finding along the equatorward limits of the domain. Furthermore, unreliable reanalysis sea-level pressure estimates in elevated areas with complex orography (such as the Tibetan Plateau, the Andes, Greenland and Antarctica) prevent the application of the method in these regions. In some other regions, the JC-WT classifications obtained from the distinct reanalyses substantially differ from each other, which may bring additional uncertainties when the method is used in model evaluation experiments.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This paper is part of the R+D+i projects CORDyS (PID2020-116595RB-I00) and ATLAS (PID2019-111481RBI00), funded by MCIN/AEI/10.13039/501100011033. J.A.F. has received research support from grant PRE2020-094728 funded by MCIN/AEI/10.13039/501100011033. J.B. and A.C. received research support from the project INDECIS, part of the European Research Area for Climate Services Consortium (ERA4CS) with co-funding by the European Union (grant no. 690462)

Clustering-based analysis of climate time series. Development and applications.

RESUMEN: La cantidad de datos climáticos aumenta continuamente en volumen y complejidad a la vez que lo hace el número de usuarios dentro de la comunidad científica y su público. En este contexto, las técnicas de procesamiento de señales permiten resumir el contenido y facilitan su utilización en múltiples aplicaciones. El objetivo de este trabajo está orientado al tratamiento de señales (en concreto series temporales de situaciones atmosféricas a escala sinóptica) y su clasificación y agrupamiento en conjuntos más sencillos que facilitan su análisis e interpretación. Para ello se implementarán una serie de métodos estadísticos de tratamiento de datos relacionados con las técnicas de segmentación o clustering, las cuales se aplicarán a señales correspondientes a Modelos Climáticos Globales (GCMs) con el fin de crear patrones de tiempo (clusters), agrupando las señales más similares entre sí. La comparación de los clusters extraídos de los modelos con los de productos de reanálisis (pseudo-observaciones) permite evaluar la capacidad de los GCMs para representar de manera fidedigna la circulación atmosférica de larga escala. Esta validación resulta de gran interés para las aplicaciones del ámbito de las técnicas de regionalización del clima y de estudios de cambio climático, donde la elección de un GCM u otro tiene un gran impacto en los resultados finales.ABSTRACT: The amount of climate data is constantly expanding in volume and complexity as the number of users within the scientific community and its public increase. In this context, signal processing allows summarizing the data and facilitate its use in multiple applications. The aim of this work is oriented to the signal processing (in particular, climate time series of atmospheric situations at a synoptic scale) and their classification into simpler sets that facilitate their analysis and interpretation. A series of statistical data processing methods related to clustering techniques will be implemented for this purpose. Clustering analysis will be applied to signals from Global Climate Models (GCMs) in order to create climate types, grouping the most similar signals among them. The comparison between the clusters extracted from the models with those from reanalysis products (pseudo-observations) allows to perform an evaluation of the capacity of GCMs to accurately represent large-scale atmospheric circulation patterns. This validation exercise is of paramount importance in climate science applications, such as the application of downscaling techniques in climate change studies, where the choice of the driving GCM has a great impact on the final results.Máster en Ingeniería de Telecomunicació

La ciudad de Tuy la fundó Diomedes de Etolia / por el presbítero Joaquín Fernández de la Granja

VII, 147 páxinas ; 24 c