About Storm Surges
Storm surges – where water is pushed onto a shoreline by extreme weather – are one of the most damaging natural phenomena. The recent “superstorm” Sandy graphically demonstrated this, with at least 130 people killed and $63bn of damage done in the US alone. Many parts of the world’s coastline are at risk of storm surges, including those of Europe. The famous 1953 North sea floods killed 2000 and led directly to the construction of coastal defences in the UK and the Netherlands. The city of Venice is frequently flooded during the winter storm period.
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A particular area of concern is the North Indian Ocean, where frequent severe cyclones make landfall on a shallow, low-lying coastline with few defences, either natural or man-made. Up to 140,000 fatalities were estimated in Myanmar (Burma) from Cyclone Nargis in 2008, and up to 10,000 in Bangladesh from Cyclone Sidr in 2007. In such cases, improving the predictions even marginally could help to save a significant number of lives.
The eSurge project
| Satellite data already plays an important role in forecasting severe storms. However the available data is not used as widely as it could be. In particular, newer types of data such as coastal altimetry and high-resolution scatterometry are yet not widely used. Recognising this, in 2011 the European Space Agency initiated the eSurge project (www.storm-surge.info), to make such data more widely available and to work with users to encourage its uptake. eSurge is now entering its operational phase, with a wide range of data for historic surge events being available through the project website (www.storm-surge.info/data-access), including scatterometry, wave data, altimetry, sea surface temperature and more. Many of these data sets are already available, however by bringing them together in one place makes it easier for researchers and modellers (who may not be experienced using satellite data) to access and use them. However making data available is only the first step; the next is to ensure that it is actually used. This is partly about helping users to get familiar with new types of data, for example through training sessions and workshops. In addition, the project is performing modelling experiments to investigate the best ways to add new data to existing numerical models, and to look at the resulting benefits. A parallel project, eSurge Venice has been set up to look at the special conditions of the Adriatic sea and Venetian lagoon; see their website at www.esurge-venice.eu for more details. |
What can satellite data do?
There are several ways in which satellite data could be used to improve storm surge prediction. A simple way is to validate the numerical models used, for example by comparing model outputs with altimetry measurements of sea height (see below), or by comparing satellite images of inundation with forecasts. This can help with tuning of models, assessing which parameters work best.
A more sophisticated approach is to assimilate the new data types directly into the models as inputs. This is not a trivial problem and different approaches have been proposed, some of which will be investigated as part of the project. Once promising approaches have been identified, they must be thoroughly validated before they can be added to actual working models.
Coastal Altimetry
In recent years there has been much work done in the field of coastal altimetry, looking at recovering sea-level measurements from existing data that had previously been rejected as being too close to land. This allows us to directly measure sea level (and also wave heights) in areas where it could not be measured before, which is especially useful in regions without much infrastructure (tide gauges etc).
This has obvious applications for storm surge research, although limited by the number of available altimeter spacecraft, especially since the loss of Envisat, meaning that measurements are not always available where they are needed. However by using coastal altimetry techniques where possible, the project will validate the techniques for possible future use, especially looking forward to GMES Sentinel-3.
Where Next?
Over the coming months eSurge will be adding more historical surge events to its database, including looking in new areas. In spring 2013 eSurge-Live will be launched, this is a demonstration service to show that such data could in principle be used in near real time. There will also be a workshop and training events organised during the course of 2013.
eSurge exists to serve its users, and anyone with an interest is encouraged to contact the project and see how it can help you. Please see the project website (www.storm-surge.info) for more details, or contact Logica’s eSurge project manager Phillip Harwood at Phillip.Harwood@logica.com
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eSurge is funded by the European Space Agency (ESA) through its Data User Element (DUE) programme. It is being undertaken by a consortium consisting of Logica (UK) as prime contractor, with subcontractors NOC (UK), DMI (Denmark), CMRC (Ireland) and KNMI (NL).
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Source Logica