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This contribution aims to explore the role of oceanographic parameters on the damage caused by storms at the eastern Cantabrian coast (1996–2016). All wave storms affecting the study area were characterized in terms of several oceanographic parameters; among them, damaging storms (responsible for direct and tangible loss) were identified. Cross-referencing both databases makes it possible to find some thresholds that explain storm conditions associated with property damage. Particularly relevant are those responsible for significant and widespread damage: maximum significant offshore wave height >6.5 m, maximum total water level >6 m, SPI > 1700 m2h, and a storm duration >48 h. These values are exceptionally high, mostly exceeding the 95th percentile. A comparison has been made with other thresholds described in the literature. The concurrence of high wave height and high tidal level is crucial as the greatest damage is caused by the combination of wave impact and over-wash, so a long duration of the storm is necessary to coincide with high tide. An empirical Intensity-Duration threshold has also been obtained with the following function I = 248.7D -⁰·⁴⁵. Damage can occur with moderate storms, but with severe effects only with exceptional wave and sea-level values, during long-lasting storms. This research was funded by the research project 17.JU11.64661 “Climatología Histórica de temporales en el área cantábrica (1851–2015)”, funded by SODERCAN S.A. (Sociedad para el Desarrollo Regional de Cantabria) and Programa Operativo FEDER, and the support of Biodiversity Foundation of the Ministry for Ecological Transition of Spain.

The spatial and temporal variability of the summer (July–August) climate beach-based tourism aptitude along the Atlantic coast of SW Europe from 1973 to 2017 and its links with the atmospheric circulation has been analyzed, combining an empirical index and a circulation pattern approach. Three different coastal sectors were defined from a PCA analysis: Galicia-N of Portugal, the Gulf of Biscay, and the western coast of France and the English Channel. Each region experienced a contrasted evolution due to geographical factors such as latitude, orography and exposure to the prevailing circulation patterns. No significant increase in aptitude was found because the background warming has not been balanced by trends in cloudiness or precipitation. Several possible causes are discussed, from local to large-scale, such as the recent evolution of the summer NAO pattern impacting the northernmost region.

A correct simulation of the dispersion during wintertime thermal inversion is important not only to improve the physical understanding of the phenomena but also to design and evaluate strategies to improve air quality. In Part II of this study the simulations performed in Part I using WRF with the multilayer urban canopy scheme BEP-BEM, are used to simulate the dispersion during one of those episodes over Madrid, Spain, using a passive tracer representing NOx. The results are compared against NOx measurements obtained at 24 ground stations, grouped in 5 zones. Coherently with Part I, the analysis shows that the best results for dispersion are obtained when BEP-BEM is used and the soil moisture is reduced to 25% of the value provided by the global model. The results also show a strong spatial variability of dispersive conditions, with a tendency of the pollutants to accumulate in the topographical depressions. Furthermore, a simple methodology is proposed to derive NO2 from NOx concentrations based on an empirical fitting of two months of observations. The statistical indicators for NO2 computed in this way are similar to those obtained with photochemical models, making this approach a valid, and computationally efficient, alternative, in particular for forecasting purposes. In the last part of this contribution, the model is used to design and evaluate simple air pollution reduction strategies. In particular, it has been found that: 1) there is no pollutant accumulation from one day to the following one, so the air quality of one day is entirely determined by the emissions and meteorological conditions of that day, 2) displacing part of the emissions of the rush hours to the central hours of the day, when the dispersive conditions are more favorable, can significantly reduce the peaks, and to a lesser extent the daily mean, without changing the total amount of pollutants emitted.

Persistent wintertime inversions over cities are the most critical conditions for air quality, and also one of the most challenging situations to simulate with a meteorological model. In the first part of this study, the ability of the meteorological model WRF, coupled with the multilayer urban canopy parameterization BEP-BEM, to simulate the evolution of the Planetary Boundary Layer Structure over the city of Madrid, Spain, during a multiday inversion episode, is assessed. The model results are evaluated against airport soundings, fourteen meteorological stations within and around the urban area, and remotely sensed surface temperatures. The study indicates that PBL structure is determined by the interaction between the urban and rural heat and momentum fluxes, the topography, and the downward turbulent transport of heat. The best air temperature spatial distribution is obtained when the 6th order horizontal filter is applied only to wind and not to temperature, and when the soil moisture is reduced to 25% of the initial value provided by the global scale model. However, the comparison against satellite surface temperature data indicates that with such a dry soil the model underestimates the surface temperatures during the night and overestimates them during the day in rural areas. This error compensation points to a likely deficiency in the PBL and surface schemes during the persistent inversions. In urban areas, the simulations with the urban canopy parameterization tend to overestimate the nocturnal surface and air temperatures, while they reproduce wind speed correctly. Finally, a new methodology to assess the model's capability to reproduce the spatial variability of air temperature is introduced, and the results show that the use of the multilayer urban canopy scheme and the adjustment of the soil moisture are both needed to improve the reproduction of such spatial distribution.

Persistent wintertime inversions over cities are the most critical conditions for air quality, and also one of the most challenging situations to simulate with a meteorological model. In this study, the ability of the meteorological Weather Research and Forecasting (WRF) model, coupled with the multilayer urban canopy parameterization BEP-BEM (Building Effect Parameterization - Building Energy Model), to simulate the evolution of the Planetary Boundary Layer (PBL) structure over the city of Madrid, Spain, during a multiday inversion episode, is assessed. The model results are evaluated against airport soundings, fourteen meteorological stations within and around the urban area, and remotely sensed surface temperatures. The study indicates that the PBL structure is determined by the interaction between the urban and rural heat and momentum fluxes, the topography, and the downward turbulent transport of heat. The best air temperature spatial distribution is obtained when the 6th order horizontal filter is applied only to wind and not to temperature, and when the soil moisture is reduced to 25% of the initial value provided by the global scale model. However, the comparison against satellite surface temperature data indicates that with such a dry soil the model underestimates the surface temperatures during the night and overestimates them during the day in rural areas. This compensating error points to a likely deficiency in the PBL and surface schemes during the persistent inversions. In urban areas, the simulations with the urban canopy parameterization tend to overestimate the nocturnal surface and air temperatures, while they reproduce wind speed correctly. Finally, a new methodology, based on a comparison of the differences between maximum and minimum temperatures for couples of stations, to assess the model's capability to reproduce the spatial variability of air temperature, is introduced, and the results show that the use of the multilayer urban canopy scheme and the adjustment of the soil moisture are both needed to improve the reproduction of such spatial distribution.

Objectives Chronic obstructive pulmonary disease (COPD) is a common respiratory condition and one of the leading causes of death. Our aim was to analyze the association between emergency room visits due to this disease and meteorological variables and atmospheric contaminant levels in Santander, depending on the origin and trajectory of air masses. Methods Data from emergency room visits at Hospital Marques de Valdecilla were collected on a daily basis during an 8-year period. Data on concentrations of the main atmospheric pollutants and meteorological variables were also recorded. Retrotrajectories leading to Santander at a height of 1500 m above sea level were then calculated. Finally, a correlation model was produced to evaluate the effect of the contaminants on emergency visits due to COPD. Results There is a direct association between PM10 levels and the number of visits to the emergency room due to COPD. For every 10 μg/m3 increase in pollutant levels, emergency visits increase by3.34% (P=.00005), and this effect is enhanced in individuals over 74 years of age. This effect is heightened when PM10 levels depend on air masses from the South and when air recirculation occurs. There is no association between other pollutants and the number of visits to the emergency room. Conclusions Exposure to high levels of PM10 causes exacerbations in COPD patients. By studying the atmospheric circulation pattern, we can predict whether PM10 levels will be inappropriately high, and we can also obtain information about the particle components.

Resumen Objetivos La enfermedad pulmonar obstructiva cronica es una enfermedad de alta prevalencia y una de las principales causas de muerte a nivel mundial. El presente trabajo analiza la relacion de esta enfermedad con las variables meteorologicas y los niveles de contaminantes atmosfericos en Santander, atendiendo al origen y trayectoria de las masas de aire. Metodos Se recogieron datos diarios de visitas a urgencias en el Hospital Marques de Valdecilla de un periodo de 8 anos, asi como la concentracion de los principales contaminantes atmosfericos y de las variables meteorologicas. Posteriormente se calcularon las retrotrayectorias con destino en Santander, a una altura de 1.500 m sobre el nivel del terreno. Finalmente, se elaboro un modelo de correlacion para evaluar el efecto de los contaminantes sobre las urgencias por EPOC. Resultados Existe una asociacion directa entre los niveles de PM10 y las urgencias por EPOC. Por cada 10 μg/m 3 de aumento del contaminante, las urgencias incrementan un 3,34% (p = 0,00005), y el efecto se intensifica en las personas mayores de 74 anos. Cuando los niveles de PM10 son dependientes de masas de aire procedentes del Sur, asi como ante situaciones de recirculacion, el efecto es mayor. Con el resto de contaminantes la relacion con las urgencias no es estadisticamente significativa. Conclusiones La exposicion a PM10 provoca descompensaciones en los pacientes con EPOC. Atendiendo al patron de circulacion atmosferica se puede estimar si los niveles de PM10 van a ser elevados, y tambien se obtiene informacion sobre los componentes de las particulas.

This paper examines the characteristics and long-term variability of storminess for the Spanish coast of the Bay of Biscay for the period 1948 to 2015, by coupling wave (observed and modelled) and atmospheric datasets. The diversity of atmospheric mechanisms that are responsible for wave storms are highlighted at different spatial and temporal scales: synoptic (cyclone) and low frequency (teleconnection patterns) time scales. Two types of storms, defined mostly by wave period and storm energy, are distinguished, resulting from the distance to the forcing cyclones, and the length of the fetch area. No statistically significant trends were found for storminess and the associated atmospheric indices over the period of interest. Storminess reached a maximum around the decade of the 1980s, while less activity occurred at the beginning and end of the period of study. In addition, the results reveal that only the WEPI (West Europe Pressure Anomaly Index), EA (Eastern Atlantic), and EA/WR (Eastern Atlantic/Western Russia) teleconnection patterns are able to explain a substantial percentage of the variability in storm climate, suggesting the importance of local factors (W-E exposition of the coast) in controlling storminess in this region. This paper has been possible within the framework of the research project 17.JU11.64661 “Climatología Histórica de temporales en el área cantábrica (1851–2015)”, funded by SODERCAN S.A. (Sociedad para el Desarrollo Regional de Cantabria) and Programa Operativo FEDER, and the support of Biodiversity Foundation of the Ministry for Ecological Transition of Spain.

Kawasaki disease (KD) is a vasculitis of unelucidated pathogenesis that usually occurs in paediatric patients. In this study we analyse the temporal pattern and geographical distribution of the disease in Spain, and its relationship with atmospheric circulation patterns. We performed a retrospective study in which we collected all hospital admissions due to KD in the country between 2005 and 2015 and explored their relationship with demographic and geographical characteristics. Moreover, we calculated daily surface atmospheric patterns over Spain to study the relationship between weather types (WT) and KD Admissions. The average admission rate for KD in the paediatric population was 3.90 per 100,000, with a male to female ratio of 1.56:1. The highest rate of admissions was found in the 0–4-year-old group, with an incidence of 11.7 cases per 100,000. Admissions followed an annual cyclic pattern with a peak of incidence in January (p = 0.022) and a nadir in September. There was an upwards trend in the number of KD admissions in male sex during the study period (p = 0.004). However, there were marked geographical differences in the incidence rate. Finally, the analysis of the relationship between the WT and the number of admissions by KD revealed no statistically significant association. KD admissions follow a peculiar seasonal and spatial distribution, that suggest the involvement of environmental factors in the disease; however, the absence of an association with WT should be interpreted with caution and regional studies should be done to explore this relationship.

This work focuses on the spatial and temporal variability of burnt area (BA) in the entire Iberian Peninsula (IP) and on the construction of statistical models to reproduce the inter-annual variability. A novel common dataset was assembled for the whole IP by merging the registered BA from 66 administrative regions of both Portugal and Spain. We applied a cluster analysis to identify larger regions with similar fire regimes and results point to the existence of four clusters (Northwestern, Northern, Southwestern and Eastern) whose spatial patterns and seasonal fire regimes are shown to be related with constraining factors such as topography, vegetation cover and climate conditions. The relationship between BA at monthly time scale with both long-term climatic pre-conditions and short-term synoptic forcing was assessed using correlation and regression analysis based on: (1) temperature and precipitation from 2 to 7 months in advance to fire peak season, (2) synoptic weather patterns derived from 11 distinct Weather Types Classifications (WTC). Different relations were obtained for each IP region with a relevant link being identified between BA and short-term synoptic forcing for all clusters, while the relation with long-term climatic preconditioning was relevant for all but one cluster. Stepwise regression models based on the best climatic and synoptic circulation predictors were developed with cross-validation to avoid over fitting. The performance of the models varies within IP regions, though models exclusively based on WTC tend to better reproduce the annual BA time series than those merely based on pre-conditioning climatic information. Nevertheless, the use of both synoptic and climatic predictors provides the best results, particularly for the two western clusters, with Pearson correlation coefficient values higher than 0.7. Finally, it is shown that typical synoptic configurations that favour high values of BA correspond to dry and warm wind flows associated with anti-cyclonic regimes.

This contribution analyzes the impact on Iberian water resources of anthropogenic climatic change, using the output from four simulations obtained from two coupled general circulation models (HadCM2 and PCM) under the A2 and B2 emissions scenarios. The results show that the magnitude of those impacts will depend on the level of global warming and the geographical characteristics of each watershed, although a reduction in runoff, principally in spring and summer, and a change in the timing of the maximum discharge, especially in high-altitude basins, will be two the most noteworthy features.

Daily weather variability is a major factor affecting the behaviour of wildfires. This paper analyzes the links between atmospheric circulation at synoptic scale, weather conditions influencing fires at regional scale and the occurrence of very large forest fires in continental. A synoptic climatology of the 850 hPa geopotential heights was derived employing multivariate techniques (Principal Component Analysis and Clustering). The catalogue displays the spatial and temporal variability of the atmospheric circulation over the area, reproducing distinctive pressure patterns and seasonal frequency variations. Each pattern shows substantial region-wide differences in the magnitude of weather-related fire risk conditions, corresponding to combinations of controlling climatic factors. Finally, the results emphasise the obligation to combine both short term and long term climate variability to explain the occurrence of episodes of very large wildfires.