El Niño is a major climatic event affecting not only the tropical Pacific Ocean but many other regions from South Africa to North America. If they are to be effective, seasonal climate predictions systems must therefore be able to predict an El Niño above all else.

The solar wind consists of a constant stream of charged particles flowing outward from the Sun. Most of these particles are deflected by the Earth's magnetic field.

The combined attraction of the Moon and the Sun generates tides on Earth. Calculating their effects is not as easy as it might seem, since we have to factor in the distance and inclination of the Sun and Moon with respect to Earth, and with respect to each other.

Topex/Poseidon was launched on August 10, 1992, but the first altimetric measurements came later, on August 21, 1992 for Poseidon and September 1st, 1992 for Topex.

Lake Vostok is a liquid, freshwater lake lying under a three-kilometer blanket of ice in the middle of the Antarctic continent and it is of great interest to researchers seeking to retrace the history of Earth's climate.

The Agulhas system is a key region for understanding the ocean. By combining dynamic topography, sea surface temperature and ocean color we obtain better scenarios to describe the variability of phytoplankton.

The world's oceans are subjected to many movements and variations. These movements are a lot "livelier" in some regions than others.

Pressures on the Earth's surface cause it to move it out of shape in much the same way as a ball does when pressed.

Observing the ocean surface is not the only application of satellite altimetry. Satellites also serve to measure the surface topography of sea ice and glaciers on land-although ice and sea water do not, of course, reflect the radar altimeter beam in the same way.

The Topex altimeters, and Poseidon-2 in the near future, operate at two frequencies (13.6 GHz and 5.3 GHz). They first measure electron content in the atmosphere.

Like a stone skimming across the water creates ripples on the surface, perturbations in the oceans form waves that propagate.

What is the speed of light? Easy... 300,000 kilometers per second (well, 299,792,458 km/s to be precise). Yes, but that's in a vacuum.