A centennial catalogue of hydro-geomorphological compound events and corresponding atmospheric forcing

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Catálogo de eventos hidro-geomorfológicos em Portugal Continental (1865-2015)

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Extreme precipitation and floods in the Iberian Peninsula and its socio-economic impacts.

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Eventos hidrogeomorfológicos em Portugal e a sua associação com os "weather types"

In recent years it has been possible to improve the characterization of past floods and landslides that caused human and economic impact in Portugal for the 1865-2015 period. In this regard there is an urge for a more systematic assessment of the atmospheric circulation at the synoptic scale associated to flood and landslide damaging events to correctly characterize the climatic forcing of hydro-geomorphologic risk in Portugal. Here we provide a comprehensive analysis of the atmospheric circulation based on the weather type classification, an automated version of the Lamb weather type procedure, initially developed for the United Kingdom and often named circulation weather types (CWT) and latter adapted for Portugal.info:eu-repo/semantics/publishedVersio

Assessing the role played by meteorological conditions on the interannual variability of fire activity in four subregions of Iberia

The Iberian Peninsula is recurrently affected by severe wildfires resulting from an interplay of human activities, landscape features and atmospheric conditions. Aims. The role played by atmospheric conditions on wildfire activity in 2001–2020 is assessed in four pyror- egions of the Iberian Peninsula. Methods. Wildfire activity is characterised by Fire Radiative Power (FRP) and meteorological danger is rated by the Fire Weather Index (FWI). The distribution of log 10 FRP in each pyroregion consists of a truncated lognormal central body with Generalised Pareto distributions as tails, and the model is improved using FWI as covariate. Synthetic time series of total annual FRP are generated using the models with and without FWI as covariate, and compared against observed FRP. Key results. Pyroregions NW, N, SW and E present increases of 1, 5, 6 and 7% in interannual explained variance of FRP when progressing from the model without to that with FWI as covariate. Conclusions. The models developed characterise the role of meteorological conditions on fire activity in the Iberian Peninsula, and are especially valuable when comparing expected impacts for different scenarios of climate change. Implications. The largest effects of atmospheric conditions on fire activity are in regions of the IP where the strongest impact of climate change is expectedinfo:eu-repo/semantics/publishedVersio

Rainfall-triggered landslides in the Lisbon region over 2006 and relationships with the North Atlantic Oscillation

Landslides occurred in the Lisbon area during the last 50 years were almost always induced by rainfall and have been used to establish rainfall thresholds for regional landslide activity. In 2006, three new rainfall-triggered landslide events occurred in the study area, namely on the 20 March, the 25–27 October, and the 28 November. Landslide events occurred in March and October 2006 include shallow translational slides and few debris flows, and the corresponding absolute antecedent rainfall was found to be above the threshold for durations ranging from 4 to 10 days. These events also fit the combined threshold of daily precipitation and 5 days calibrated antecedent rainfall values. Likewise the landslide event that took place in late November 2006 includes some slope movements with deeper slip surfaces, when compared with landslides dating from March and October. Moreover, the corresponding absolute antecedent rainfall was also found to be above the 40-day period rainfall threshold. Here we characterize in detail the short and long-term atmospheric circulation conditions that were responsible for the intense rainfall episodes that have triggered the corresponding landslide events. It is shown that the three rainfall episodes correspond to considerably different synoptic atmospheric patterns, with the March episode being associated to an intense cut-off low system while the October and November episodes appear to be related to more typical Atlantic low pressure systems (and associated fronts) travelling eastwards. Finally, we analyse the role played by the North Atlantic Oscillation (NAO) during those months marked by landslide activity. It is shown that the NAO index was consistently negative (usually associated with above average precipitation) for the months prior to the landslide events, i.e. between October 2005 and March 2006, and again between August and October 2006.info:eu-repo/semantics/publishedVersio

The Rivillas flood of 5–6 November 1997 (Badajoz, Spain) revisited: an approach based on Iber+ modelling

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThe flash flood registered in November 1997 in the city of Badajoz (Spain) in the basin of Rivillas river is analysed by means of the numerical code Iber+. This event constitutes one of the most destructive flash-floods registered in an urban area in the Iberian Peninsula. Starting from precipitation data obtained from rain stations, the runoff of the entire river basin was simulated to obtain the discharge of the Rivillas river in Badajoz. The flood maps obtained with Iber+ reproduce accurately the field data registered during the actual event. Likewise, the numerical time evolution of the flood and water depths are in accordance with testimonies of the witnesses. Once the capability of Iber+ to reproduce the event was assessed, several scenarios were considered in order to analyse the main causes of the event. In particular, simulations show that the catastrophic magnitude of the flood was mainly due to the blockage of bridges. Different hypothetical scenarios were simulated to analyze the role of rain intensity and bridge maintenance, concluding that similar floods can occur under much lower rainfall but with poor bridge maintenance.Xunta de Galicia | Ref. ED431C 2021/44Xunta de Galicia | Ref. ED481B-2021-10

Revisiting the outstanding flooding episode of November 1967 in the greater metropolitan Lisbon area

The deadliest storm affecting Portugal since, at least, the early 19th century, took place on the 25 and 26 November 1967 causing more than 500 fatalities. Here we provide a comprehensive multi-disciplinary assessment of this episode, including the main socio-economic impacts, particularly the numbers and location of victims (dead, injured, homeless and evacuated). Based on the sub-daily time series of a representative station, and its Intensity-Duration-Frequency curves, we have found that the exceptionality of this rainfall event is particularly linked to rainfall intensities ranging in duration from 4 to 9 hours compatible with return periods of 100-years or more. This range of time scale is similar to the estimated concentration time values of the hydrographic basins affected by the flash flood event. Most victims were sleeping or were caught by surprise at home in the small river catchments within the greater metropolitan Lisbon area. The majority of people who died or who were severely affected by the flood lived in degraded housing conditions often raised in a clandestine way, occupying flood plains near the stream beds. This level of destruction observed at the time is in stark contrast to what was observed in subsequent episodes of similar amplitude. In particular, since 1967 the Lisbon area, was struck by two comparable intense precipitation events in 1983 and 2008 but generating considerably fewer deaths and evacuated people.info:eu-repo/semantics/publishedVersio

Heteroaromatic polyamides with Improved thermal and mechanical properties

We prepared high-performance aromatic copolyamides, containing bithiazole and thiazolo-thiazole groups in their main chain, from aromatic diamines and isophthaloyl chloride, to further improve the prominent thermal behavior and exceptional mechanical properties of commercial aramid fibers. The introduction of these groups leads to aramids with improved strength and moduli compared to commercial meta-oriented aromatic polyamides, together with an increase of their thermal performance. Moreover, their solubility, water uptake, and optical properties were evaluated in this work.Fondo Europeo de Desarrollo Regional and both the Spanish Ministerio de Economía, Industria y Competitividad (MAT2017-84501-R) and the Consejería de Educación, Junta de Castilla y León (BU306P18) is gratefully acknowledged. M.T.L. also thankfully acknowledges the Spanish Ministerio de Ciencia e Innovación (PID2019-108583RJ-I00/AEI/10.13039/501100011033