Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Huge waves from one storm slam coasts some 6000 km apart

Huge waves that struck Reunion Island and coastlines across Indonesia earlier this month all originated from the same storm that occurred south of Cape Town, South Africa, and were tracked across the entire Indian Ocean for some 10 000 kilometres over a nine-day period by ESA’s Envisat satellite.

Waves reaching up to 11 metres devastated France’s Reunion Island in the Indian Ocean when it slammed into the southern port of Saint Pierre on 12 May. Six days later waves created from the same storm measuring as high as seven metres began crashing into Indonesia coastlines from Sumatra to Bali, killing at least one person and causing some 1200 people to flee their homes.

Dr Bertrand Chapron of IFREMER, the French Research Institute for Exploitation of the Sea, and Dr Fabrice Collard of France's BOOST Technologies in Brest located and tracked the swells using standard processed Synthetic Aperture Radar (SAR) ESA Wave Mode products, as shown in the animation above.

"The extreme swell systems originated from the same storm, which moved rapidly and had two main strong wind periods," Chapron said. "As illustrated in the animation, the resulting waves were organised into two main swell systems that followed each other across the entire Indian Ocean, hitting Reunion Island, Mauritius, Australia and Indonesia."

According to the Reuters news agency, no official warning about the huge waves that hit Indonesia were issued. Although the waves that hit Reunion Island were forecasted, their intensity was predicted to be 20 to 30% below measurements, Collard explained.

"Although swells are still surprise factors, these particular swells were created by natural events so they could be tracked," Chapron said. "By using the SAR Wave Mode product, we can locate and systematically track swells globally, making it possible to put a network of early warning systems in place in the near future."

"Because of its unique capacity to restitute wavelength and directional information of the propagation of swells, the SAR instrument is about to bring a remarkable contribution to the monitoring of energetic wave systems," Collard said.

Chapron and Collard are working on a global swell-tracking project, which was presented for the first time at the Envisat Symposium held in Montreux, Switzerland, from 23 to 27 April 2007, using the Advanced Synthetic Aperture Radar (ASAR) aboard Envisat to follow these waves in order to refine their propagation paths and determine their arrival times and intensities.

Once in place, this system will be the equivalent of deploying a global network of virtual buoys that are able to detect and track large swell systems carrying large energy from all available remote sensing measurements of waves, such as SAR and radar altimetry.

Each virtual buoy will have the capacity to detect and measure the wavelength and the direction of propagation as well as the height of the swell systems crossing the oceans, complementing the sea forecast models used by weather centres and allowing alarms to be raised a few hours before these devastating swells hit coasts.

Storms are capable of generating waves of different wavelengths that travel in several directions upon leaving the storm system, with the longest wavelengths travelling the fastest. As these waves cross open seas, they can accumulate energy at precise locations and become very dangerous for marine safety.

In addition, wave systems slow down as they approach the coastline, and individual waves increase to reach at least two times the mean average of their initial wave height. For instance, a 5-metre significant wave height system can hit the coast with the height of 10 metres.

Today, the ASAR Wave Mode acquires 10 by 5 km small images, or 'imagettes', of the sea surface every 100 km along the satellite orbit. These small ‘imagettes’ are then mathematically transformed into averaged-out breakdowns of wave energy and direction, called ocean-wave spectra, which ESA makes available to scientists and weather centres.

As part of the Global Monitoring for Environment and Security (GMES), a joint initiative of the European Commission and ESA, the space agency has undertaken the development of Sentinel-1, a European polar-orbiting satellite system for the continuation of SAR operational applications.

The Sentinel-1 SAR instrument will also have a dedicated enhanced Wave Mode capability to double the present ASAR Envisat Wave Mode samplings, to improve the actual demonstrations for a Near Real Time tracking and forecasting of swell for European users.

ESA and IFREMER will sponsor an ocean wave data user workshop at IFREMER in Brest, France, on 20 and 21 September 2007 that will address and capture user requirements for a possible future wave data service.

In January 2008, ESA will host its second SAR oceanography workshop, SEASAR 2008, entitled "Advances in SAR Oceanography from Envisat and ERS missions," at ESRIN, ESA’s Earth Observation centre, in Frascati, Italy.

Mariangela D'Acunto | alfa
Further information:

More articles from Earth Sciences:

nachricht UCI and NASA document accelerated glacier melting in West Antarctica
26.10.2016 | University of California - Irvine

nachricht Ice shelf vibrations cause unusual waves in Antarctic atmosphere
25.10.2016 | American Geophysical Union

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Prototype device for measuring graphene-based electromagnetic radiation created

28.10.2016 | Power and Electrical Engineering

Gamma ray camera offers new view on ultra-high energy electrons in plasma

28.10.2016 | Physics and Astronomy

When fat cells change their colour

28.10.2016 | Life Sciences

More VideoLinks >>>