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1.
During 23–30 September 1997, a rare cyclonic storm has developed close to the Andhra coast, and it has later travelled parallel to coastline northward and finally crossed the land at Chittagong (22°N, 91°E) on 27 September. While translating along the east coast of India, it has produced heavy to very heavy rainfall on the coastal stations causing devastating floods. In this study, we made an attempt to understand the salient causes of this unique cyclone movement. We have analyzed daily fields of wind and relative humidity for 850, 700, 500 hPa and mean daily OLR data to understand the plausible reasons for its movement. The buoy data deployed by National Institute of Ocean Technology, Chennai, Viz. DS5 (15°N, 81°E), DS4 (19°N, 88°E) and SW7 (20°N, 86°E) were analyzed to understand the ocean–atmosphere interaction processes in the west Bay of Bengal during formation of the system. Analysis of OLR over the cyclonic storm region has revealed that the heavy rainfall areas coincide with low OLR (120–180 W m?2). The persistent southward movement of 500 hPa ridge on the eastern wedge of the system along with the steering current at 200 hPa has helped in maintaining the movement of the system parallel to the east coast of India during its life cycle. 相似文献
2.
Amy C. Ruocco Robert J. Nicholls Ivan D. Haigh Matthew P. Wadey 《Natural Hazards》2011,59(3):1773-1796
Using newly digitised sea-level data for the ports of Southampton (1935–2005) and Portsmouth (1961–2005) on the south coast
of the UK, this study investigates the relationship between the 100 highest sea-level events recorded at the two cities and
the incidence of coastal floods in the adjoining Solent region. The main sources of flood data are the daily newspapers The Southern Daily Echo, based in Southampton and The News, based in Portsmouth, supported by a range of local publications and records. The study indicates a strong relationship between
the highest measured sea levels and the incidence of coastal floods and highlights the most vulnerable areas to coastal flooding
which include parts of Portsmouth, Southampton, Hayling Island, Fareham and Cowes. The most severe flood in the dataset resulted
from the storm surge events of 13–17 December 1989 when eight consecutive extreme high waters occurred. The data suggest that
while extreme sea-level events are becoming more common, the occurrence of flood events is not increasing. This is attributed
to improved flood remediation measures combined with a reduction of storm intensity since the 1980s. However, several recent
events of significance were still recorded, particularly 3 November 2005 when Eaststoke on Hayling Island (near Portsmouth)
was flooded due to high sea levels combined with energetic swell waves. 相似文献
3.
Coastal regions are the areas most threatened by natural hazards, with floods being the most frequent and significant threat in terms of their induced impacts, and therefore, any management scheme requires their evaluation. In coastal areas, flooding is a hazard associated with various processes acting at different scales: coastal storms, flash floods, and sea level rise (SLR). In order to address the problem as a whole, this study presents a methodology to undertake a preliminary integrated risk assessment that determines the magnitude of the different flood processes (flash flood, marine storm, SLR) and their associated consequences, taking into account their temporal and spatial scales. The risk is quantified using specific indicators to assess the magnitude of the hazard (for each component) and the consequences in a common scale. This allows for a robust comparison of the spatial risk distribution along the coast in order to identify both the areas at greatest risk and the risk components that have the greatest impact. This methodology is applied on the Maresme coast (NW Mediterranean, Spain), which can be considered representative of developed areas of the Spanish Mediterranean coast. The results obtained characterise this coastline as an area of relatively low overall risk, although some hot spots have been identified with high-risk values, with flash flooding being the principal risk process. 相似文献
4.
Antony Joseph R. G. Prabhudesai Prakash Mehra V. Sanil Kumar K. V. Radhakrishnan Vijay Kumar K. Ashok Kumar Yogesh Agarwadekar U. G. Bhat Ryan Luis Pradhan Rivankar Blossom Viegas 《Natural Hazards》2011,57(2):293-312
Response of the coastal regions of eastern Arabian Sea (AS) and Kavaratti Island lagoon in the AS to the tropical cyclonic storm `Phyan??, which developed in winter in the south-eastern AS and swept northward along the eastern AS during 9?C12 November 2009 until its landfall at the northwest coast of India, is examined based on in situ and satellite-derived measurements. Wind was predominantly south/south-westerly and the maximum wind speed (U10) of ~16 m/s occurred at Kavaratti Island region followed by ~8 m/s at Dwarka (Gujarat) and ~7 m/s at Diu (located south of Dwarka) as well as two southwest Indian coastal locations (Mangalore and Malpe). All other west Indian coastal sites recorded maximum wind speed of ~5?C6 m/s. Gust factor (i.e., gust-to-speed ratio) during peak storm event was highly variable with respect to topography, with steep hilly stations (Karwar and Ratnagiri) and proximate thick and tall vegetation-rich site (Kochi) exhibiting large values (~6), whereas Island station (Kavaratti) exhibiting ~1 (indicating consistently steady wind). Rainfall in association with Phyan was temporally scattered, with the highest 24-h accumulated precipitation (~60 mm) at Karwar and ~45 mm at several other west Indian coastal sites. Impact of Phyan on the west Indian coastal regions was manifested in terms of intensified significant waves (~2.2 m at Karwar and Panaji), sea surface cooling (~5°C at Calicut), and moderate surge (~50 cm at Verem, Goa). The surface waves were south-westerly and the peak wave period (T p) shortened from ~10?C17 s to ~5?C10 s during Phyan, indicating their transition from the long-period `swell?? to the short-period `sea??. Reduction in the spread of the mean wave period (T z) from ~5?C10 s to a steady period of ~6 s was another manifestation of the influence of the cyclone on the surface wave field. Several factors such as (1) water piling-up at the coast supported by south/south-westerly wind and seaward flow of the excess water in the rivers due to heavy rains, (2) reduction of piling-up at the coast, supported by the upstream penetration of seawater into the rivers, and (3) possible interaction of upstream flow with river run-off, together resulted in the observed moderate surge at the west Indian coast. Despite the intense wind forcing, Kavaratti Island lagoon experienced insignificantly weak surge (~7 cm) because of lack of river influx and absence of a sufficiently large land boundary required for the generation and sustenance of wave/wind-driven water mass piling-up at the land?Csea interface. 相似文献
5.
6.
Indications of an extreme event deposits along the west coast of India: evidences from GPR investigations 总被引：1，自引：1，他引：0
V. J. Loveson A. R. Gujar S. D. Iyer P. Srivastava G. M. Tirodkar R. A. A. Luis 《Environmental Earth Sciences》2014,72(10):4155-4166
The ground-penetrating radar (GPR) was used to trace the subsurface details in the Palshet coastal zone (Maharashtra) as it exhibits an interesting array of geomorphological features. Furthermore, our main goal was to identify and locate features that might have formed during a reported extreme event and its effects on the flow of the nearby Sundri River. Two profiles (8 and 4 m depth) were collected across the beach and along the backshore, respectively. While the 8-m depth profile (west to east; across the beach) indicates a series of coastline regression in this area, the 4-m depth profile along the coastline (north to south) in the backshore zone reveals two significant incidents viz., (1) stages of development of the paleo-channels that indicate the migration of the Sundri River towards south and (2) huge sediment deposits up to 2.5-m thick in the backshore area. The erosional relict surface (~2.5 m depth) was traced along with various spells of sediments that perhaps occurred due to an extreme event. Sand samples were collected from two trial pits along the GPR profiles to understand the sedimentology and mineralogy in the backshore area. These data together with beach profiles and geomorphological maps suggest that the sands were deposited by an extreme event perhaps during the 1854 cyclonic storm. The sands were trapped in suitable geomorphological sites along the Palshet coast and these sand deposits of about 2.5 m thickness forced the River Sundri to shift its course towards the south. This new revelation facilitates a further study that could focus on the nearby coastal areas to document such extreme event deposits and their influence on the geomorphic set-up. 相似文献
7.
A. D. Rao P. L. N. Murty Indu Jain R. S. Kankara S. K. Dube T. S. Murty 《Natural Hazards》2013,66(3):1431-1441
The devastation due to storm surge flooding caused by extreme wind waves generated by the cyclones is a severe apprehension along the coastal regions of India. In order to coexist with nature’s destructive forces in any vulnerable coastal areas, numerical ocean models are considered today as an essential tool to predict the sea level rise and associated inland extent of flooding that could be generated by a cyclonic storm crossing any coastal stretch. For this purpose, the advanced 2D depth-integrated (ADCIRC-2DDI) circulation model based on finite-element formulation is configured for the simulation of surges and water levels along the east coast of India. The model is integrated using wind stress forcing, representative of 1989, 1996, and 2000 cyclones, which crossed different parts of the east coast of India. Using the long-term inventory of cyclone database, synthesized tracks are deduced for vulnerable coastal districts of Tamil Nadu. Return periods are also computed for the intensity and frequency of cyclones for each coastal district. Considering the importance of Kalpakkam region, extreme water levels are computed based on a 50-year return period data, for the generation of storm surges, induced water levels, and extent of inland inundation. Based on experimental evidence, it is advocated that this region could be inundated/affected by a storm with a threshold pressure drop of 66 hpa. Also it is noticed that the horizontal extent of inland inundation ranges between 1 and 1.5 km associated with the peak surge. Another severe cyclonic storm in Tamil Nadu (November 2000 cyclone), which made landfall approximately 20 km south of Cuddalore, has been chosen to simulate surges and water levels. Two severe cyclonic storms that hit Andhra coast during 1989 and 1996, which made landfall near Kavali and Kakinada, respectively, are also considered and computed run-up heights and associated water levels. The simulations exhibit a good agreement with available observations from the different sources on storm surges and associated inundation caused by these respective storms. It is believed that this study would help the coastal authorities to develop a short- and long-term disaster management, mitigation plan, and emergency response in the event of storm surge flooding. 相似文献
8.
Mohammad Karamouz Ali Razmi Sara Nazif Zahra Zahmatkesh 《Environmental Earth Sciences》2017,76(11):395
Due to increasing flood severities and frequencies, studies on coastal vulnerability assessment are of increasing concern. Evaluation of flood inundation depth and extent is the first issue in flood vulnerability analysis. This study has proposed a practical framework for reliable coastal floodplain delineation considering both inland and coastal flooding. New York City (NYC) has been considered as the case study because of its vulnerability to storm surge-induced hazards. For floodplain delineation, a distributed hydrologic model is used. In the proposed method, the severities of combined inland and coastal floods for different recurrence intervals are determined. Through analyzing past storms in the study region, a referenced (base) configuration of rainfall and storm surge is selected to be used for defining flood scenarios with different return periods. The inundated areas are determined under different flooding scenarios. The inundation maps of 2012 superstorm Sandy in NYC is simulated and compared with the FEMA revised maps which shows a close agreement. This methodology could be of significant value to the planners and engineers working on the preparedness of coastal urban communities against storms by providing a platform for updating inundation maps as new events are observed and new information becomes available. 相似文献
9.
Coastal hazard mapping in the Cuddalore region, South India 总被引：1，自引：0，他引：1
It is estimated that nearly one-third of India’s population lives on the coast and is dependent on its resources. Shoreline erosion, storm surges and extreme events have resulted in severe loss of human life, damage to ecosystems and to property along the coast of India. Studies carried out in the Cuddalore region of South India reveal that this low-lying coastal zone, which suffered significant erosion during the last century, has been severely affected by the tsunami of 2004, storm floods and cyclones. In response to these impacts, a variety of coastal defense measures and adaptation strategies have been implemented in the region, although with only limited success. In order to inform future coastal planning in this region, the work reported here identifies a composite hazard line, seaward of which coastal flooding events will have a return interval of less than 1 in 100 years. The area landward of the coastal hazard line will be unaffected by 100 years of coastal erosion at present day rates. The study directly supports the Integrated Coastal Zone Management (ICZM) Plan of the Tamil Nadu State through the identification and assessment of coastal hazards and the overall vulnerability to coastal flooding and erosion. The key results from this pilot study will be used directly by the State of Tamil Nadu in the protection of the coastal livelihoods, better conservation measures and sustainable development along the coast. This study is a step toward mapping the hazard line for the entire coast of India that helps protect human lives and property. 相似文献
10.
根据暴雨洪涝灾害致灾因子危险性、孕灾环境敏感性、承载体易损性和防灾减灾能力4个一级因子,以山东地区为研究对象,综合考虑降雨、地形地势、河网密度、植被、人口和经济实力、道路交通信息等因子进行风险区划与分析。利用地理信息系统软件（ArcGIS）将上述因子进行归一化来获得标准化的多源栅格数据,结合层次分析法和自然断点法确定相关指标的权重,建立了暴雨洪涝灾害的风险评估模型,最后得到了山东地区暴雨洪涝灾害综合风险区划等级评估图。对研究区进行定性和定量分析后得出结论,山东地区暴雨洪涝灾害发生的高风险区在鲁中西部、鲁南及山东半岛东部沿海部分地区,此结论与历史数据基本吻合。研究结果为预防山东暴雨洪涝灾害提供了参考信息。 相似文献
11.
Extreme sea-level events (e.g. caused by storm surges) can cause coastal flooding, and considerable disruption and damage. To understand the impacts or hazards expected by different sea levels, waves and defence failures, it is useful to monitor and analyse coastal flood events, including generating numerical simulations of floodplain inundation. Ideally, any such modelling should be calibrated and validated using information recorded during real events, which can also add plausibility to synthetic flood event simulations. However, such data are rarely compiled for coastal floods. This paper demonstrates the capture of such a flood event dataset, and its integration with defence and floodplain modelling to reconstruct, archive and better understand the regional impacts of the event. The case-study event comprised a significant storm surge, high tide and waves in the English Channel on 10 March 2008, which resulted in flooding in at least 37 distinct areas across the Solent, UK (mainly due to overflow and outflanking of defences). The land area flooded may have exceeded 7 km2, with the breaching of a shingle barrier at Selsey contributing to up to 90 % of this area. Whilst sea floods are common in the Solent, this is the first regional dataset on flood extent. The compilation of data for the validation of coastal inundation modelling is discussed, and the implications for the analysis of future coastal flooding threats to population, business and infrastructure in the region. 相似文献
12.
Han Song Tang Steven I-Jy Chien Marouane Temimi Cheryl Ann Blain Qu Ke Liuhui Zhao Simon Kraatz 《Natural Hazards》2013,69(1):141-163
Catastrophic flooding associated with sea-level rise and change of hurricane patterns has put the northeastern coastal regions of the United States at a greater risk. In this paper, we predict coastal flooding at the east bank of Delaware Bay and analyze the resulting impact on residents and transportation infrastructure. The three-dimensional coastal ocean model FVCOM coupled with a two-dimensional shallow water model is used to simulate hydrodynamic flooding from coastal ocean water with fine-resolution meshes, and a topography-based hydrologic method is applied to estimate inland flooding due to precipitation. The entire flooded areas with a range of storm intensity (i.e., no storm, 10-, and 50-year storm) and sea-level rise (i.e., current, 10-, and 50-year sea level) are thus determined. The populations in the study region in 10 and 50 years are predicted using an economic-demographic model. With the aid of ArcGIS, detailed analysis of affected population and transportation systems including highway networks, railroads, and bridges is presented for all of the flood scenarios. It is concluded that sea-level rise will lead to a substantial increase in vulnerability of residents and transportation infrastructure to storm floods, and such a flood tends to affect more population in Cape May County but more transportation facilities in Cumberland County, New Jersey. 相似文献
13.
Chen Changsheng Lin Zhaolin Beardsley Robert C. Shyka Tom Zhang Yu Xu Qichun Qi Jianhua Lin Huichan Xu Danya 《Natural Hazards》2021,106(1):375-399
Natural Hazards - Hurricanes (tropical cyclones) and nor'easters (extratropical cyclones) are two major storm systems for flood risk over the Massachusetts coast. Severe coastal inundation... 相似文献
14.
Under the background of climate warming, the occurrence time, frequency, intensity, and impact of snowmelt flood disasters have changed significantly. Thus, establishing a global snowmelt flood disaster database is particularly important for disaster risk management. With the help of a web crawler, and based on multiple data sources such as natural disaster databases, documents, books, government agency websites, and news media, this study collected relevant information of snowmelt floods and mixed floods and established standards for identifying snowmelt flood events and their disaster impacts based on data from the different sources. Following the screening, sorting, fusion, and integration of snowmelt flood events, a global snowmelt flood disaster dataset containing 579 pieces of data with strong pertinence and reliability was constructed. The temporal and spatial distribution characteristics of global snowmelt flood disasters from 1900 to 2020 were preliminarily analyzed. The results showed that the snowmelt floods were mainly distributed between 30° N and 60° N, with more mixed floods south of 50° N and more snowmelt floods north of 50° N. Spring was the period of highest incidence of snowmelt flood disasters, followed by winter, summer, and autumn, respectively. The snowmelt floods that occurred in spring, autumn, and winter were mainly at 40°~50° N, and the snowmelt floods that occurred in summer were mainly at 30°~40° N. Compared with the snowmelt floods, the mixed floods were more frequent and more destructive, and their frequency increased with climate warming. The results provide a scientific basis for risk prevention and loss assessment of global snowmelt flood disasters. © 2022 Science Press (China). 相似文献
15.
Ben Daoued Amine Mouhous-Voyneau Nassima Hamdi Yasser Duluc Claire-Marie Sergent Philippe 《Natural Hazards》2020,100(3):1059-1088
Many coastal urban areas and many coastal facilities must be protected against pluvial and marine floods, as their location near the sea is necessary. As part of the development of a Probabilistic Flood Hazard Approach (PFHA), several flood phenomena have to be modelled at the same time (or with an offset time) to estimate the contribution of each one. Modelling the combination and the dependence of several flooding sources is a key issue in the context of a PFHA. As coastal zones in France are densely populated, marine flooding represents a natural hazard threatening the coastal populations and facilities in several areas along the shore. Indeed, marine flooding is the most important source of coastal lowlands inundations. It is mainly generated by storm action that makes sea level rise above the tide. Furthermore, when combined with rainfall, coastal flooding can be more consequent. While there are several approaches to analyse and characterize marine flooding hazard with either extreme sea levels or intense rainfall, only few studies combine these two phenomena in a PFHA framework. Thus this study aims to develop a method for the analysis of a combined action of rainfall and sea level. This analysis is performed on the city of Le Havre, a French urban city on the English Channel coast, as a case study. In this work, we have used deterministic materials for rainfall and sea level modelling and proposed a new approach for estimating the probabilities of flooding.
相似文献16.
The Travenanzes Formation is a terrestrial to shallow‐marine, siliciclastic–carbonate succession (200 m thick) that was deposited in the eastern Southern Alps during the Late Triassic. Sedimentary environments and depositional architecture have been reconstructed in the Dolomites, along a 60 km south–north transect. Facies alternations in the field suggest interfingering between alluvial‐plain, flood‐basin and shallow‐lagoon deposits, with a transition from terrestrial to marine facies belts from south to north. The terrestrial portion of the Travenanzes Formation consists of a dryland river system, characterized by multicoloured floodplain mudstones with scattered conglomeratic fluvial channels, merging downslope into small ephemeral streams and sheet‐flood sandstones, and losing their entire discharge subaerially before the shoreline. Calcic and vertic palaeosols indicate an arid/semi‐arid climate with strong seasonality and intermittent discharge. The terrestrial/marine transition shows a coastal mudflat, the flood basin, which is usually exposed, but at times is inundated by both major river floods and sea‐water storm surges. Locally coastal sabkha deposits occur. The marine portion of the Travenanzes Formation comprises carbonate tidal‐flat and shallow‐lagoon deposits, characterized by metre‐scale shallowing‐upward peritidal cycles and subordinate intercalations of dark clays from the continent. The depositional architecture of the Travenanzes Formation suggests an overall transgressive pattern organized in three carbonate–siliciclastic cycles, corresponding to transgressive–regressive sequences with internal higher‐frequency sedimentary cycles. The metre‐scale sedimentary cyclicity of the Travenanzes Formation continues without a break in sedimentation into the overlying Dolomia Principale. The onset of the Dolomia Principale epicontinental platform is marked by the exhaustion of continental sediment supply. 相似文献
17.
Flash floods associated with heavy precipitation has become a hazardous phenomenon along the Mediterranean coasts of Turkey in recent years. During 3 and 4 November 1995 heavy and intense rainstorm activity over the Aegean coast led to flash flooding in the city of zmir. Damage exceeded $50 million and 61 people died as a result of the flood. The Karyaka district suffered the most severe damage. This study presents an analysis of the meteorological settings that led to the development of these intense storms and describes the role of the terrain features involved in the zmir flood.The important mesoscale features which initiated the severe weather outbreak included pronounced low-level advection, positive vorticity and strong upper level divergence. A surface low centered over the Aegean Sea enhanced the advection of warm and moist unstable air masses coming from the southwest over the Mediterranean Sea along a southwesterly low level jet (LLJ). A squall line oriented NE-SW over the Aegean Sea also contributed to the storm development, and intensity of the storms was further enhanced by the orographic effect. The presence of a frontal system, the stability indices associated with the event, and other meteorological features are all reminiscent of the synoptic type flash floods identified by Maddox. While the pressure and moisture patterns were favorable for severe storm activity, nonmeteorological factors including the topography, geomporphology, and and land-use contributed to the flooding to a great extent. Settling in the flood-prone zone, insufficient floodwater structures, and the lack of channel improvements in the creeks enhanced flood damage to the city. Many of the deaths occurred in the settlements located in the flood-prone zone of the Ilca and Dallk creeks. 相似文献
18.
J. B. Connelly 《Australian Journal of Earth Sciences》2013,60(4):459-469
During a marine geophysical survey of the Bismarck Sea by the Australian Bureau of Mineral Resources in 1970, magnetic, gravity, and seismic reflection recordings were made along north‐south traverses with a spacing of 30 to 40 km. The magnetic data have been interpreted, first by visual inspection of magnetic and topographic trends and then by two‐dimensional computer modelling along typical profiles. The interpretation indicates that the Bismarck Sea is divided into two main tectonic provinces separated by a boundary which roughly coincides with a line joining Manus Island and the Willaumez Peninsula of New Britain. An area of apparently nonmagnetic basement about 10 km wide coincides with a well defined band of shallow earthquakes which runs east‐west across the centre of the Sea. A major boundary is present at the eastern end of the Sea along the west coast of the Gazelle Peninsula of New Britain; it continues along an offset in the band of earthquakes to New Hanover. 相似文献
19.
JUNKO KOMATSUBARA OSAMU FUJIWARA KEITA TAKADA YUKI SAWAI THAN TIN AUNG TAKANOBU KAMATAKI 《Sedimentology》2008,55(6):1703-1716
Four sand units deposited by tsunamis and one sand unit deposited by storm surge(s) were identified in a muddy marsh succession in a narrow coastal lowland along the Pacific coast of central Japan. Tsunamis in ad 1498, 1605, 1707 and 1854 that were related to large subduction‐zone earthquakes along the Nankai Trough, and storm surges in 1680 and/or 1699 were responsible for the deposition of these sand units. These sand units are distinguished by lithofacies, sedimentary structures, grain‐size and mineral composition, and radiocarbon ages; their ages are supported by events in local historical records. The tsunami deposits in the study area are massive or parallel‐laminated sands, with associated intraclasts, gravels, draping mud layers and, rarely, a return‐flow subunit. The storm surge deposits are devoid of these characteristics, and are composed of groups of thin, current ripple‐laminated sand layers. The differences in sedimentary structures between the tsunami and storm surge deposits are attributed to the different characteristics of tsunami and storm waves. 相似文献
20.
L. Sheela Nair R. Prasad M. K. Rafeeque T. N. Prakash 《Journal of the Geological Society of India》2018,92(5):588-595
The part of southwest coast of India extending from Poovar in the south to Kasaragod in the north is considered as one of the highly dynamic coastal areas of Indian peninsula. Over the years due to rapid urbanization as well as other natural and anthropogenic activities, the coast is under severe pressure which in turn has reduced the percentage status of healthy / stable coast. Unscientific shoreline protection methods adopted without conducting appropriate studies to assess the suitability of the said method to a particular coastal stretch has often led to negative impacts. As a result, many areas that were once stable have turned eroding and in certain cases, the observed extent of erosion is severe warranting immediate protection measures. In this context, a study was carried out to assess the long-term shoreline changes along the southwest coast and to decipher the causative factors responsible for these changes. Accordingly, a 46 year period from 1968 to 2014 was studied using multi-dated shoreline images and Survey of India (SOI) topographic charts. The DSAS software (USGS) is used to compute the rate of shoreline changes along different sectors of the coast and accordingly the entire coastal stretch is classified into 7 classes depicting the present status (stable / dynamically stable / unstable) of the coast. The analysis revealed that almost 60 % of the coastline is eroding with about 29 % showing an accreting trend. 相似文献