scholarly journals Classifying compound coastal storm and heavy rainfall events in the north-western Spanish Mediterranean

2021 ◽  
Vol 25 (6) ◽  
pp. 3759-3781
Author(s):  
Marc Sanuy ◽  
Tomeu Rigo ◽  
José A. Jiménez ◽  
M. Carmen Llasat

Abstract. The north-west (NW) Mediterranean coastal zone is a populous and well-developed area in which the impact of natural hazards like flash floods and coastal storms can result in frequent and significant damages. Although the occurrence and impacts of such hazards have been widely covered, few studies have considered their combined impact on the region, which would result in more damage. Within this context, this study analyses the occurrence and characteristics of compound extreme events of heavy rainfall episodes (as a proxy for flash floods) and coastal storms (using the maximum significant wave height) along the Catalan coast as a paradigm of the NW Mediterranean. Two different types of events are considered: multivariate, in which the two hazards occur at the same location, and spatially compounding, in which they occur within the same limited time window, and their impacts accumulate at distinct and separate locations. The analysis is regionally performed along a coastline extension of about 600 km by considering seven coastal sectors and their corresponding river catchment basins. Once the compound events are analysed, the synoptic atmospheric pressure fields are analysed to determine the prevailing weather conditions that generated them. Finally, a Bayesian network is used to fully characterize these events over the territory. The obtained results show that the NW Mediterranean, represented by the Catalan coast, has a high probability of experiencing compound extreme events. Despite the relatively small size of the study area, there are significant variations in the event characteristics along the territory, with the most frequent type being spatially compound, except in the northernmost sectors where multivariate events dominate. These northern sectors also present the highest correlation in the intensity of both hazards. Three representative synoptic situations have been identified as dominant for the occurrence of these events, with different relative importance levels of the compounding drivers (rainfall and waves) and different distributions of impacts across coastal basins. Overall, results obtained from specific events indicated that heavy rainfall is related to the most significant impacts despite having a larger spatial reach.

2020 ◽  
Author(s):  
Marc Sanuy ◽  
Tomeu Rigo ◽  
José A. Jiménez ◽  
M. Carmen Llasat

Abstract. The Northwest (NW) Mediterranean coastal zone is a populous and well-developed area in which the impact of natural hazards like flash floods and coastal storms can result in frequent and significant damages. Although the occurrence and impacts of such hazards have been widely covered, few studies have considered their combined impact on the region, which would result in more damage. Within this context, this study analyses the occurrence and characteristics of compound extreme events of heavy rainfall episodes (as a proxy for flash floods) and coastal storms (using the maximum significant wave height) along the Catalan coast as a paradigm of the NW Mediterranean. Two different types of events are considered: multivariate, in which the two hazards occur at the same location, and spatially compounding, in which they occur within the same limited time window and their impacts accumulate at distinct and separate locations. The analysis is regionally performed along a coastline extension of about 600 km by considering seven coastal sectors and their corresponding river catchment basins. Once the compound events are analysed, the synoptic atmospheric pressure fields are analysed to determine the prevailing weather conditions that generated them. Finally, a Bayesian network is used to fully characterise these events over the territory. The obtained results show that the NW Mediterranean, represented by the Catalan coast, has a high probability of experiencing compound extreme events (3.4 events per year). Despite the relatively small size of the study area (600 km of coastline), there are significant variations in the event characteristics along the territory, with the most frequent type being spatially compound, except in the northernmost sectors where multivariate events dominate. These northern sectors also present the highest correlation in the intensity of both hazards. Three representative synoptic situations have been identified as dominant for the occurrence of these events, with different relative importance levels of the compounding drivers (rainfall and waves) and different distributions of impacts across coastal basins. Overall, the results indicate that heavy rainfall has the more significant damage impact despite the wave damage having a larger spatial reach.


2020 ◽  
Author(s):  
Marc Sanuy Vazquez ◽  
Montserrat Llasat-Botija ◽  
Tomeu Rigo ◽  
Jose A. Jiménez ◽  
M. Carme Llasat

<p>The Mediterranean coastal zone is a hotspot to the impact of extreme events due to the combination of high values at exposure (concentration of population, large urban areas, infrastructures), large vulnerability (natural protection provided by beaches decreasing due to coastal erosion) and presence of extreme hydro-meteorological events of marine (storms) and terrestrial (flash floods) origins. The Catalan coast (NE Spain) can be considered a paradigm of Med hotspots. On one hand, due to its climatic conditions, orography and land use, flash floods are one of the main causes of inundation risks in the coastal fringe, inducing numerous damages and even casualties (e.g. Llasat et al. 2013). On the other hand, coastal damage associated to the impact of marine storms have been increasing during the last decades along this coast (Jiménez et al. 2012). However, existing studies have not analysed their joint impact to assess the most hazardous conditions, when the coastal zone would be subjected to the combined action of both types of extreme events.</p><p>Within this context, this works analyses the combined presentation of extreme events of terrestrial (flash floods) and marine (storms) origin in the Catalan coast. First, extreme events causing significant damage (based on reported damages, insurance costs and casualties) along the coast were identified for the period 1981-2014. 69 events were identified and classified according their origin (marine and/or terrestrial). Each event was characterized in terms of their marine (wave height, period, direction, storm duration) and rainfall characteristics. Since the coastline length is about 600 km, these events verify at specific locations. To cover this spatial variability, storms were locally characterized by using data from existing rain gauges and radar stations along the territory as well as hindcasted wave conditions along the entire coastal fringe. To fully characterize these events, synoptic conditions were also recorded.</p><p>From this, first, we directly obtained the corresponding marginal probabilities of each event. Then, compound frequencies were assessed and compared to the marginal ones. Finally, we identified synoptic situations with higher probability of associated compound hazards and bound the range of corresponding wave and rain conditions. By jointly considering the location where they verified, we identify coastal areas (and corresponding geomorphologic conditions) with higher probabilities of suffering damages due to impact of compound extreme events.</p><p>This work was carried out within the framework of the M-CostAdapt (CTM2017-83655-C2-1-R) research project, funded by the Spanish Ministry of Economy and Competitiveness (MINECO/AEI/FEDER, UE).</p><p>Jiménez et al. 2012. Storm-induced damages along the Catalan coast (NW Mediterranean) during the period 1958–2008. Geomorphology 143, 24-33.</p><p>Llasat et al. 2013.  Towards a database on societal impact of Mediterranean floods within the framework of the HYMEX project. NHESS, 13, 1337-1350.</p>


Author(s):  
Marc Baeta ◽  
Claudia Rubio ◽  
Françoise Breton

Abstract There is an important small-scale fishery using mechanized dredges and targeting clams (mainly wedge clam Donax trunculus and striped venus clam Chamelea gallina) along the Catalan coast (NW Mediterranean Sea). This study evaluated for the first time the discards and impact of mechanized clam dredging on the Catalan coast. To this end, three surveys were performed on board standard clam vessels (September and November 2016 and January 2017). Surveys were conducted in the three main clam fishing areas (Rosas Bay, South Barcelona and Ebro Delta). The composition of discards and the impact caused to discarded species was assessed using a three-level scale (undamaged; minor or partial damage; and lethal damage). Our study revealed that a large proportion of the catch (between 67–82% weight) is discarded. Even though about 63% of the discarded species were undamaged, 11% showed minor or partial damage and 26% lethal damage. Infaunal and epifaunal species with soft-body or fragile shells were the most impacted by the fishing activity (e.g. the sea urchin Echinocardium mediterraneum (~89%) and the bivalve Ensis minor (~74%)). Our results showed different levels of impact by target species and fishing area.


2016 ◽  
Author(s):  
M. Venkat Ratnam ◽  
S. Ravindra Babu ◽  
S. S. Das ◽  
Ghouse Basha ◽  
B. V. Krishnamurthy ◽  
...  

Abstract. Tropical cyclones play an important role in modifying the tropopause structure and dynamics as well as stratosphere-troposphere exchange (STE) process in the Upper Troposphere and Lower Stratosphere (UTLS) region. In the present study, the impact of cyclones that occurred over the North Indian Ocean during 2007–2013 on the STE process is quantified using satellite observations. Tropopause characteristics during cyclones are obtained from the Global Positioning System (GPS) Radio Occultation (RO) measurements and ozone and water vapor concentrations in UTLS region are obtained from Aura-Microwave Limb Sounder (MLS) satellite observations. The effect of cyclones on the tropopause parameters is observed to be more prominent within 500 km from the centre of cyclone. In our earlier study we have observed decrease (increase) in the tropopause altitude (temperature) up to 0.6 km (3 K) and the convective outflow level increased up to 2 km. This change leads to a total increase in the tropical tropopause layer (TTL) thickness of 3 km within the 500 km from the centre of cyclone. Interestingly, an enhancement in the ozone mixing ratio in the upper troposphere is clearly noticed within 500 km from cyclone centre whereas the enhancement in the water vapor in the lower stratosphere is more significant on south-east side extending from 500–1000 km away from the cyclone centre. We estimated the cross-tropopause mass flux for different intensities of cyclones and found that the mean flux from stratosphere to troposphere for cyclonic stroms is 0.05 ± 0.29 × 10−3 kg m−2 and for very severe cyclonic stroms it is 0.5 ± 1.07 × 10−3 kg m−2. More downward flux is noticed in the north-west and south-west side of the cyclone centre. These results indicate that the cyclones have significant impact in effecting the tropopause structure, ozone and water vapour budget and consequentially the STE in the UTLS region.


Finisterra ◽  
2012 ◽  
Vol 31 (62) ◽  
Author(s):  
Andrew Pike ◽  
Mário Vale

The industrial policy in the UK and in Portugal, as in most EU countries, seeks to attract new investment capacity, to create jobs and to promote the impact of the so-called "demonstration efect" of "greenfield" development strategies pursued in the new plants of inward investors on existing or "brownfield" plants. This industrial policy focus is particularly evident in the automobile industry.This paper compares the industrial policy oriented towards the automobile industry in the UK and in Portugal. Two recent "greenfield" investments are analised: Nissan in the North-East region (UK) and Ford/VW in the Setúbal Peninsula (Portugal), as well as three "brownfield" plants: Ford Halewood and GM Vauxhall Ellesmere Port in the North-West region (UK) and Renault in Setúbal (Portugal). The first part starts with a discussion of industrial policy in the automobile sector, the role of "greenfield" development strategies and the "demonstration effect" on "brownfield" plants. Then, the limits of new inward investment are pointed out, basically their problems and restrictions. Afterwards, the structural barriers to the "demonstration effect" within "brownfield" plants are outlined and some possabilities for alternative "brownfield" development strategies are presented.


Pakistan ◽  
2020 ◽  
pp. 131-144
Author(s):  
Mariam Abou Zahab

This chapter attempts to analyse the dynamics of the Pashtun–Punjabi nexus and the areas of competition and cooperation between Sunni sectarian groups and the Pakistani Taliban. It outlines the links between Sunni sectarian groups and the Afghan Taliban, the impact of the collapse of the Taliban regime in Afghanistan and the implications of the relocation of Punjabi jihadi/sectarian groups in the North West Frontier Province (NWFP) and the Federally Administered Tribal Areas (FATA). It also focuses on the consequences of the storming of Islamabad's Lal Masjid in July 2007, and it investigates the re-emergence of sectarian groups in Karachi and in the Punjab and its implications for Pakistan. The Punjab and Karachi have been the primary hubs of sectarian violence in Pakistan since the 1980s, but in the post-9/11 environment the Sunni-Shia conflict has assumed a new dimension.


2010 ◽  
Vol 75 (5) ◽  
pp. 703-715 ◽  
Author(s):  
Snezana Nenadovic ◽  
Ljiljana Matovic ◽  
Misko Milanovic ◽  
Sava Janicevic ◽  
Jasmina Grbovic-Novakovic ◽  
...  

In this paper, the impacts of some meteorological parameters on the SO2 concentrations in the City of Obrenovac are presented. The City of Obrenovac is located in the north-west part of Serbia on the banks of the River Sava. The observed source emission, the power plants TENT A and TENT B are situated on the bank of the Sava River in the vicinity of Obrenovac. During the period from January to November 2006, the concentrations of sulfur dioxide in the air at 4 monitoring sites in Obrenovac were measured. It was noticed that the maximal measured daily concentrations of sulfur dioxide ranged from 1 ?g/m3 (16th November, 2006) to 98 ?g/m3 (29th January 2006) and lie under the maximal allowed concentration value according to the Serbian Law on Environmental Protection. The measured sulfur dioxide concentrations mostly showed characteristics usual for a daily acidification sulfur dioxide cycle, excluding the specificities influenced by the measuring site itself. Sulfur dioxide transport was recorded at increased wind speeds, primarily from the southeast direction. Based on the impact of meteorological parameters on the sulfur dioxide concentration, a validation of the monitoring sites was also performed from the aspect of their representivity.


2016 ◽  
Vol 56 (2) ◽  
pp. 556
Author(s):  
Sergey Birdus ◽  
Vincent Ganivet ◽  
Alexey Artemov ◽  
Ray Teakle ◽  
Paul Phythian

This extended abstract presents a two-step sequence to estimate uncertainties in lateral positioning of fault planes on 3D PSDM (pre-stack depth migration) seismic images. This analysis can be applied to any localised detail on a seismic image but, in the majority of geological settings, it is most important for the faults. The first step provides an approximate evaluation of what causes the uncertainties, how the uncertainties are distributed in a 3D space, and what to expect within target zones. The authors assume that every complex detail within a 3D PSDM velocity model causes some uncertainties to the seismic image below. Thus, the uncertainties at a target level depend on the complexity of the overburden and the seismic acquisition parameters. At this step a qualitative 3D volume of lateral fault position uncertainties is created. In the second step the authors focus on a single fault of practical interest. Based on the results of the first step, the authors modify the existing 3D PSDM anisotropic velocity model by introducing additional anomalies that cause maximal changes to the lateral position of the fault on seismic image. Then the authors iteratively re-migrate a small sub-volume around the fault and check the PSDM images and residual moveout. The objective is to find out how far the velocity variations can move the image of the fault and still satisfy available seismic data. The second step gives more reliable quantitative estimations of the impact of velocity on fault positioning. A real multi-azimuth 3D seismic dataset from the North West Shelf is used to illustrate this sequence.


Ocean Science ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 147-159 ◽  
Author(s):  
Alexander Harker ◽  
J. A. Mattias Green ◽  
Michael Schindelegger ◽  
Sophie-Berenice Wilmes

Abstract. An established tidal model, validated for present-day conditions, is used to investigate the effect of large levels of sea-level rise (SLR) on tidal characteristics around Australasia. SLR is implemented through a uniform depth increase across the model domain, with a comparison between the implementation of coastal defences or allowing low-lying land to flood. The complex spatial response of the semi-diurnal M2 constituent does not appear to be linear with the imposed SLR. The most predominant features of this response are the generation of new amphidromic systems within the Gulf of Carpentaria and large-amplitude changes in the Arafura Sea, to the north of Australia, and within embayments along Australia's north-west coast. Dissipation from M2 notably decreases along north-west Australia but is enhanced around New Zealand and the island chains to the north. The diurnal constituent, K1, is found to decrease in amplitude in the Gulf of Carpentaria when flooding is allowed. Coastal flooding has a profound impact on the response of tidal amplitudes to SLR by creating local regions of increased tidal dissipation and altering the coastal topography. Our results also highlight the necessity for regional models to use correct open boundary conditions reflecting the global tidal changes in response to SLR.


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