Tag: science

Blog, coast, coastal flooding, extreme events, flooding, science, sea level, storm surge

New paper just published – Variability in coastal flood risk

ihaigh

We have just had a new paper (Assessing the variability in extreme high water levels for coastal flood risk assessment) published in the Journal of Geophysical Research-Oceans – see here.

The probability of extreme storm-tide events has been extensively studied, however the variability within the duration of such events, and implications to flood risk, is less well understood. This research quantifies such variability during extreme storm-tide events (the combined elevation of the tide, surge, and their interactions) at 44 national tide gauges around the UK. Extreme storm-tide events were sampled from water level measurements taken every 15 minutes between 1993 and 2012. At each site, the variability in elevation at each time step, relative to a given event peak, was quantified. The magnitude of this time-series variability was influenced both by gauge location (and hence the tidal, and non-tidal residual characteristics) and the time relative to high water. The potential influence of this variability on coastal inundation was assessed across all UK gauge sites, followed by a detailed case study of Portsmouth. A two-dimensional hydrodynamic model of the Portsmouth region was used to demonstrate that given a current 1 in 200 year storm-tide event, the predicted number of buildings inundated differed by more than 30% when contrasting simulations forced with the upper and lower bounds of the observed time-series variability. The results indicate that variability in the time-series of the storm-tide event can have considerable influence upon overflow volumes, hence with implications for coastal flood risk assessments. Therefore, further evaluating and representing this uncertainty in future flood risk assessments is vital, while the envelopes of variability defined in this research provides a valuable tool for coastal flood modellers.

 

MATLAB Handle Graphics

 

Blog, coast, Journal paper, science, sea level

New paper in Nature Climate Change – Shifting perspectives on coastal impacts and adaptation

ihaigh

Here is our new paper in Nature Climate Change. The below is from our press release:

Coastal regions under threat from climate change and sea-level rise need to tackle the more immediate threats of human-led and other non-climatic changes, according to a team of international scientists.

The team of 27 scientists from five continents, led by Dr Sally Brown at the University of Southampton, reviewed 24 years of Intergovernmental Panel on Climate Change (IPCC) assessments (the fifth and latest set being published in 2013 and 2014). They focused on climate change and sea-level rise impacts in the coastal zone, and examined ways of how to better manage and cope with climate change. 

They found that to better understand climate change and its impacts, scientists need to adopt an integrated approach into how coasts are changing. This involves recognising other causes of change, such as population growth, economic development and changes in biodiversity. Dr Brown emphasised that: “Over the last two and half decades, our scientific understanding of climate change and sea-level rise, and how it will affect coastal zones has greatly increased. We now recognise that we need to analyse all parts of our human and natural environments to understand how climate change will affect the world.”

The scientists also acknowledged that long-term adaptation to climate change can greatly reduce impacts, but further research and evaluation is required to realise the potential of adaptation. “Many parts of the coast can, with forward planning, adapt to sea-level rise, but we need to better understand environments that will struggle to adapt, such as developing countries with large low-lying river deltas sensitive to salinisation, or coral reefs and particularly small, remote islands or poorer communities,” said Dr Brown.

For example, in the Maldives, many small, remote low-lying islands are at risk from climate change and will struggle to adapt. But around the densely populated capital city and airport, adaptation has already occurred as land claim is a common practice in order to relive population pressure. Sea-level rise has already been considered into newly claimed land. Thus in decades to come, potential climate change impacts, such as flooding, will be reduced for this island, benefiting both the local population and economy.

Dr Jochen Hinkel from Global Climate Forum in Germany, who is a co-author of this paper and a Lead Author of the coastal chapter for the 2014 IPCC Assessment Report added: “The IPCC has done a great job in bringing together knowledge on climate change, sea-level rise and is potential impacts but now needs to complement this work with a solution-oriented perspective focusing on overcoming barriers to adaptation, mobilising resources, empowering people and discovering opportunities for strengthening coastal resilience in the context of both climate change as well as existing coastal challenges and other issues.”

This new research, published as a commentary in Nature Climate Change, will help in the understanding of the impacts of climate change and how to reduce impacts via adaptation. Its multi-disciplinary approach could be useful if future IPCC assessment reports are commissioned.

Australia, Blog, coastal flooding, Journal paper, science, sea level, storm surge

New paper just published – land sinks around parts of Australia with passage of tropical cyclones.

ihaigh

We have just had a new paper (‘Non-linear motions of Australian geodetic stations induced by non-tidal ocean loading and the passage of tropical cyclones’) published in the journal of Journal of Geodesy – see here.

In this paper we examined movements in land around Australia using time-series from stations fitted with continuous GPS. Most people think the land is completely stable, but actually the land moves each day by a few millimetres for a variety of reasons. Here we show that land around parts of Australia sunk when cyclone Yasi crossed the Australian coast in January/February 2011. This cyclone generated a large storm surge and the extra weight of this large volume of water near the coast actually resulting in the land dropping slightly.

A earlier study (see here) showed the same thing happens around the North Sea coastlines when big storm surges happen there.

 

 

 

 

Blog, coast, science, sea level

Back to the future to determine if sea level rise is accelerating

ihaigh

Here is the press release from my recent paper published in Nature Communications – ‘Time-scales for detecting a significant acceleration in sea level rise’.

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Scientists from Ocean and Earth Southampton and National Oceanography Centre Southampton have developed a new method for revealing how sea levels might rise around the world throughout the 21st century to address the controversial topic of whether the rate of sea level rise is currently increasing.

The international team of researchers, led by the University of Southampton and including scientists from the National Oceanography Centre, the University of Western Australia, the University of South Florida, the Australian National University and the University of Seigen in Germany, analysed data from 10 long-term sea level monitoring stations located around the world. They looked into the future to identify the timing at which sea level accelerations might first be recognised in a significant manner.

Lead author Dr Ivan Haigh, Lecturer in Coastal Oceanography at the University of Southampton, says: “Our results show that by 2020 to 2030, we could have some statistical certainty of what the sea level rise situation will look like for the end of the century. That means we’ll know what to expect and have 70 years to plan. In a subject that has so much uncertainty, this gives us the gift of long-term planning.

“As cities, including London, continue to plan for long-term solutions to sea level rise, we will be in a position to better predict the long-term situation for the UK capital and other coastal areas across the planet. Scientists should continue to update the analysis every 5 to 10 years, creating more certainty in long-term planning – and helping develop solutions for a changing planet.”

The study found that the most important approach to the earliest possible detection of a significant sea level acceleration lies in improved understanding (and subsequent removal) of interannual (occurring between years, or from one year to the next) to multidecadal (involving multiple decades) variability in sea level records.

“The measured sea levels reflect a variety of processes operating at different time scales,” says co-author Dr Francisco Calafat, from the National Oceanography Centre. He adds, “One of the main difficulties in detecting sea level accelerations is the presence of decadal and multi-decadal variations. For example, processes associated with the North Atlantic Oscillation have a strong influence on the sea levels around the UK over multi-decadal periods.  Such processes introduce a large amount of ‘noise’ into the record, masking any underlying acceleration in the rate of rise. Our study shows, that by adequately understanding these processes and removing their influence, we can detect accelerations much earlier.”

Co-author Professor Eelco Rohling, from the Australian National University and formerly of the University of Southampton, adds: “By developing a novel method that realistically approximates future sea level rise, we have been able to add new insight to the debate and show that there is substantial evidence for a significant recent acceleration in the sea level rise on a global and regional level. However, due to the large ‘noise’ signals at some local coastal sites, it won’t be until later this decade or early next decade before the accelerations in sea level are detection at these individual tide gauge sites.”

The findings of the study, funded by the Natural Environmental Research Council (iGlass consortium), are published in this months issue of the journal Nature Communications.

Blog, coast, rip currents

Seb Pitman awarded best first year PhD presentatio

ihaigh

Congratulations to my new PhD student Seb Pitman,  who was awarded the prize for the best presentation by a first year PhD student at the Postgraduate Research in Marine and Earth Science Conference, held at the National Oceanography Centre, University of Southampton in November 2013. This conference is primarily aimed at PhD and early-career researchers in a broad range of earth and marine disciplines, providing a platform to practice presentation skills and poster production. The event was a huge success with 80 delegates from a range of institutions, key note speakers from the University of Cambridge and Durham University, and industry representation in the form of Gardline Ltd.

Seb Pitman gave a presentation on the formation, persistence and spacing of rip currents. The talk outlined the basic form of rip currents and the great hazard they pose to casual and recreational users of the coastal zone, as well as the likely direction the PhD project will take. Seb’s research is a collaboration between the University of Southampton (Shari Gallop, myself, Sasan Mahmoodi), Plymouth University (Gerd Masselink), and UNESCO-IHE (Roshanka Ranasinghe). His research aims to create an automated method of detecting rip currents from video imagery to generate quantitative data sets from sites around the world.

Sebastian Pitman presenting
Blog, Current Studebts

Interviews with two current MsC ECE students, Edgar and Bryce (2012/2013)

ihaigh

Interviews with two of my current MSc students.

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Southampton MsC ECE

As part of our series of mini interviews featuring past and present ECE students, here are two with current students Edgar Peter Dabbi, and Bryce Corlett:

Edgar:

1. Where are you from and what was your first degree?
Malaysia. My first degree was Bachelor (Hons) in Civil Engineering.

2. Why did you choose to undertake the ECE course at Southampton?
Following my internship with DHI Malaysia, I decided to undertake postgraduate study in coastal engineering and management to deepen my knowledge within this area. I chose to study in Southampton because it has an excellent academic reputation for both engineering and oceanography studies in the UK. I found the ECE course to be well-structured with modules that are highly practical and relevant for consulting practices as well.

3. What have you most enjoyed about the course?
Getting to know the experts and learning from them (both ECE lecturers and visiting…

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Blog, coast, Current Studebts, flooding, NOC, Past Students, science

New blog – Engineering in the Coastal Environment MSc

ihaigh

I am the co-director (together with Robert Nicholls) and admissions officer of the MSc Engineering in the Coastal Environment. This programe is uniquely provided jointly by academics from the Faculty of Engineering and the Environment, based at Highfield Campus and Ocean and Earth Science, based at the National Oceanography Centre. The programme is strongly linked to industry and focussed on applied issues in the coastal zone. The overall goal is to educate technically-orientated coastal practitioners for suitable employment in coastal engineering, both in consultancies and relevant areas of government. I am pleased to say we have just launched a new blog with details about the course and interviews with past and present students. Our current students are finishing off their research projects. Our next intake start the last week in September 2013.

Blog, flooding, Past Students, science, sea level

All the best Bryce Corlett

ihaigh

I want to wish Bryce Corlett all the best as he moves back to the USA to start a PhD at Wood’s Hole. Bryce has spent a year at the NOC undertaking the Engineering in the Coastal Environment MSc that I co-direct with Prof Robert Nicholls and Carl Amos. Byrce undertook his research project with me, looking at relative sea level trends and vertical land movements around the UK. We are in the process of writing that work up as a journal paper. All the best with this next stage of your life!

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