2009 Images of the Month

Oceanographic satellites observations, including altimetry, enable to study and understand marine areas, and help protect them.

Although it was believed that El Niño was essentially defined by the flow of warm waters of the tropical west Pacific ("Warm Pool") towards the coasts of Ecuador and Peru, it has recently been discovered that it can also appear as a localised warming of the eastern part ("Warm Pool El Niño" or "El Niño Modoki"). Global warming should lead more frequently to such events. The current event is thought to be an El Niño Modoki.

Better knowledge of polar caps variations is important to better estimate their reactions to climate changes. Systems like Doris enable studying the sources of their variations.

Sea birds like great frigates are flying over ocean dynamic features. Studies mixing their tracking and high-resolution filaments computed from altimetry enable to better understand these birds and the underlying environment.

Gliders are new in situ means of measuring the ocean. Merged with altimetry data, they can bring a whole new dimension to our understanding of the ocean

One year after launch, Jason-2 is providing data of a very good quality; since the shift of Jason-1, Moreover, the tandem of the two satellites is enhancing data resolution.

More than 16 years of altimetry data enable to discover new permanent features in the ocean dynamics, such as a corridor South of Canaries Islands where eddies propagate. Those are confirmed by in-situ measurements.

Water levels in major rivers of the Zambezi basin are examined using altimetry data from the Jason-2 satellite, showing severe floods during the beginning of 2009.

Use of altimetry data during an oceanographic cruise help better place the deployed instruments. And, vice-versa, these instruments help in validating altimetry data.

The availability of a long series of altimetry data had enabled to discover "striations" in the geostrophic velocities computed from the dynamic topography. Studies are ongoing to understand such a phenomena.

To properly take into account altimetry measurements, one has to know over which kind of surface it was taken. Using both altimeter and radiometer, ice and water can be classified.

Altimetry ability to monitor lakes level has been demonstrated. Other sensors -- imagery sensors -- enable to estimate the water surface area. Mixing altimetry and water surface area estimates give hydrologists the water volume needed to study lakes and reservoirs variations.