Altimetry applications in videos

: (Credits Mira Productions).

Thanks to satellite oceanography, mankind is just about beginning to understand the ocean machine, which has a decisive influence on the environment and the climate. The successful launch, on 20th June 2008, of the Jason-2 altimetry satellite complements the constellation of satellites currently in flight, initiated with ERS-1 and Topex/Poseidon in 1992 and then continued with Jason-1 and Envisat in 2002. Jason-2 comes at a perfect time to combine all these data and provide a resolution that is ideal for mapping the ocean, and for modelling smaller-scale phenomena.

This column on "Altimetry applications in videos" produced by Cnes on the occasion of the Jason-2 launch, traces the many fields where this technique is involved: El Niño, the mean sea level, Venice, the ocean circulation, the Mediterranean Sea, operational oceanography, the oil spills, the maritime transport and safety, biology, the fishing management, the tsunamis, the monitoring hurricanes, hydrology (Aral Sea, lake Chad, rivers). Click on each title to see short video footages and further information to monitor the Earth pulse :

El Niño: El Niño and La Niña are well-known climate events occurring in the tropical Pacific Ocean. On the eve of the launch of Jason-2, what more can we learn about these phenomena?
Mean sea level: Altimetry satellites are a crucial tool for observing variations in mean sea level. With greater quantities of data, we are able to confirm trends, and attempt to mitigate their effects.
Aral Sea: Satellite altimetry is an efficient tool in monitoring the level of enclosed seas, lakes and even large rivers. Since 1991, the Aral Sea is flown over - or was overflown - by a serie of altimetry satellites that measure the two seas antagonistic fluctuations.
Venice: The city of Venice has suffered assaults from the sea for many years. By improving the quality and quantity of altimetry measurements, the Jason-2 satellite will contribute to its protection.
Oil spill: The contribution of satellites to the detection, monitoring and forecasting of oil drifts has been demonstrated. Thanks to synergies between stakeholders, a continuous monitoring procedure is about to become operational in certain pre-defined areas of interest.
Transport and security: The ocean is a challenging environment for sailors. Satellite altimetry is an important source of data for sea state forecasting models.
Life in the ocean: The ocean is very fertile. By combining biological data with circulation models it is now possible to simulate the complex interactions between ocean physics and chemistry and marine life.
Fishing management: Sustainable management of marine resources is important given the enormous stakes involved. The launch of the Jason-2 in June 2008 will contribute to this effort by providing a physical description of the oceans.
Mediterranean Sea: Observations of the Mediterranean sea by means of in situ or satellite measurements are essential for monitoring, forecasting and managing it.
Tsunamis: Tsunamis are huge waves which can result in devastating waves breaking on the shore. By measuring sea surface height, altimetry satellites can theoretically detect tsunami waves in open ocean.
Monitoring hurricanes: Cyclones are intense meteorological phenomena that get their energy from the ocean's heat. Altimetry satellites have made a significant contribution to the prediction of trajectories and intensities by collecting data on sea surface height, wind speed and wave height.
Hydrology: Although initially developed for studying ocean surfaces, satellite altimetry rapidly broadened its scope to include monitoring the levels of continental waters.
Lake Chad: Lake Chad's large surface in a topographical setting with low relief makes it an excellent object for study using altimetry satellites.
Ocean circulation: Because the currents transport heat and energy, they are major players in the Earth's climate. Observations by altimetry, combined with in situ surveys, give us a precise view of them, both at the surface and at depth.
Operational oceanography: The new Jason-2 altimetry satellite complements the constellation of satellites currently in flight, and provides Mercator Ocean with a resolution that is ideal for improving ocean forecasting in coastal areas, and for modelling smaller-scale phenomena.
Waves forecasting: By integrating satellites and in situ measurements in meteorological models, we can determine and forecast the sea state as well as the wave height at a global scale.
Seasonal forecasting: By integrating oceanographic and meteorological data in models, it is possible to describe major seasonal trends several months in advance.