Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

World Ocean Day: how satellites safeguard our waters

09.06.2005


Earth’s oceans are what make this a Blue Planet. Our seas influence the climate, produce most of the oxygen we breathe, serve as a means of transport and a major source of food and resources. Today’s World Ocean Day is a chance to learn more about the seas that surround us – and how satellite monitoring helps protect them.



Wednesday 8 June is the 13th annual World Ocean Day. Created in 1992 at the Earth Summit at Rio de Janeiro, World Ocean Day is an opportunity to celebrate our world ocean, its abundant life, and the ways we are all connected to the sea, no matter how far we live from its edge. More than 600 aquariums, zoos, museums and conservation organisations are participating in global activities today.

The ocean is no longer so abundant and clean as it once was: many of the world’s fisheries are in decline, coral ecosystems are deteriorating and fragile coastal habitats being choked by pollution. But today and every day, Earth Observation spacecraft continuously acquire data across the seven tenths of our planet covered by the sea.


These data increase our scientific understanding and support a range of environmental monitoring services in support of ocean conservation.

Global ocean temperature measurements

Space-based instruments measure sea surface temperature, which is important because it helps improve weather forecasting and is also a key indicator of the likely extent of future climate change – the oceans working like batteries that store incoming solar energy.

For example, the family of Along Track Scanning Radiometer (ATSR) sensors carried on ESA’s ERS and Envisat satellites have compiled a continuous dataset of ocean temperatures that stretches back 14 years that could be used to prove a heating trend beyond the range of natural variation.

An ambitious plan aims at merging all available sea surface temperature data including satellite sources into a worldwide high-resolution product known as the Global Ocean Data Assimilation Experiment (GODAE) High-Resolution Sea Surface Temperature Pilot Project (GHRSST-PP).

The European component of this global effort is an ESA activity called Medspiration, producing daily-updated high-resolution heat maps of European waters including the Mediterranean Sea.

Three-dimensional ocean mapping

The ever-changing topography of the ocean is also monitored from orbit. Radar imagery and scatterometer data reveal ocean waves and sea surface wind fields. Sea surface height is acquired with the Radar Altimeter (RA) family of sensors - as carried aboard the ERS and Envisat spacecraft - which function by measuring the precise time a radar pulse takes to bounce back to its satellite.

The French firm CLS (Collecte, Localisation Satellites), with support from French space agency CNES, processes altimetry data from the satellites ERS-2, Envisat, GFO, TOPEX/Poseidon and Jason-1 in the frame of a project called SSALTO/DUACS (Segment for ALTimetry, Orbitography and precise localisation/ Developing Use of Altimetry for Climate Studies). Mercator Ocean, the French contribution to GODAE, assimilates those data in its three-dimensional forecasting model of the global ocean, updated weekly.

Slight centimetre-scale height variations in sea height provide information on ocean currents and temperature – warm currents can stand around half a metre higher than colder surrounding waters – plus salinity, the current surface state, the underlying bathymetry of the seabed and even variations in the planet’s gravity field.

Additional, operational applications include marine routing, ensuring safety at sea, laying marine cables and optimising fishing fleet performance.

Altimetry also provides authoritative global measurements of sea level change – one of the most important ocean-related variables, because a large enough upward shift (due to polar melting or other factors) might erode human habitats and alter the very face of our planet. The evidence from space so far suggests a steady average rise of 0.3 millimetres a year.

Monitoring water quality

With around a third a third of EU territory covered by seas, the ocean is an important area of activity within Global Monitoring for Environment and Security (GMES) - a joint initiative of ESA and the European Union (EU) to integrate all available space- and ground-based information sources to yield accurate portraits of the current state of our planet.

ESA’s initial portfolio of Earth Observation-based services known as the GMES Services Element (GSE) includes a focus on water quality monitoring, with a focus on two important applications: the detection and tracking of oil spills – both chemically and physically hazardous to the marine environment - and forecasting toxic algae blooms, which threaten costly contamination of Europe’s growing aquaculture – fish or shellfish farming - industry.

Ocean colour satellite sensors such as Envisat’s Medium Resolution Imaging Spectrometer (MERIS) can reveal a lot about the contents of seawater: the ocean tint seen from space can be run through specialised algorithms to pinpoint its suspended contents, including marine phytoplankton, sediment loading and pollution.

Identifying oil spills

For detecting oil pollution, radar sensors such as Envisat’s Advanced Synthetic Aperture Radar (ASAR) are effective. Oil has a dampening affect on the water it floats on, returning less signal backscatter to show up blacker in a radar image.

Radar surveillance of accidental oil spills has shown its worth repeatedly, notably during the Prestige tanker accident off Spain’s Galician coast in November 2002. An Envisat image revealed the spill had split in two, providing a novel insight into the extent of coastline in danger.

However 90% of oil pollution at sea is not accidental but actually due to deliberate dumping. Systematic wide-area surveillance foreseen as part of GMES promises to help deter such illegal activity.

Mariangela D’Acunto | alfa
Further information:
http://www.esa.int

More articles from Ecology, The Environment and Conservation:

nachricht Dune ecosystem modelling
26.06.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Understanding animal social networks can aid wildlife conservation
23.06.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>