Four years ago, torrential rains battered the Southern US, mudslides struck in Peru - and the inhabitants of Canada`s west coast saved up to 30% on their winter heating bills. The cause? El Niño, a huge temperature shift in the Pacific Ocean which spawns climate changes globally. Today, using satellite Earth observation data, scientists are detecting the early warning signs of a new El Niño event and predicting that it will develop over the next 3 to 6 months, bringing climate changes to countries thousands of miles from the western Pacific, birthplace of the event itself.
"In normal years, there`s a large area of warm water in the western Pacific and colder water at the eastern side. In El Niño years, that warm water shifts eastward, which has major effects on the atmosphere above the ocean and thus the climate of the nearby countries," explains Joel Picaut, of France`s Centre National d`Etudes Spatiales.
Imaging from space using radar altimetry and sea surface temperature measurements reveals that the trade winds near the Equator pile up a mass of water, warmed by the sun on its journey across the Pacific, which covers an area the size of Europe. This so-called `warm pool` off the Philippine coast is in fact a plateau in the sea some 30 cm high and with a temperature of approximately 29°C - 5°C above average. In contrast, the water off the Galapagos Islands on the other side of the Pacific is normally a mere 20°C. When an El Niño event takes place, all this changes.
"No one is yet quite sure of the mechanism that causes an El Niño," comments Picaut. "It`s clear that the movement of the warm water and the change in the wind patterns are closely linked, but we do not yet know which is the cause and which the effect." The warm water in the west causes convection in the atmosphere and a relatively constant wind from east to west - the trade winds. When the El Niño cycle begins, the trade winds reduce, no longer pushing water toward the warm pool and the mass of warm water begins to flow eastward, toward the Galapagos Islands and the Peruvian coast. "Over a period of 1-2 weeks, we see so-called `westerly wind bursts`, in which the direction of the trade winds reverses. At the equator, you see a very interesting effect, where the wind and the Earth`s rotation combine to trigger `Kelvin waves`, which are like a wall of water 30 cm high moving across the pacific at about 200 km per day. You can see the Kelvin waves clearly and monitor their progress using radar altimeter and sea surface temperature data," says Picaut. These fast-moving Kelvin waves are the heralds of the more sedate progress of the main body of water, which travels at only 30 km per day. In January, scientists detected such a Kelvin wave near the International Date Line in the central Pacific.
Jerome Benveniste | alphagalileo
Strength of tectonic plates may explain shape of the Tibetan Plateau, study finds
25.07.2017 | University of Illinois at Urbana-Champaign
NASA flights gauge summer sea ice melt in the Arctic
25.07.2017 | NASA/Goddard Space Flight Center
Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers
Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...
Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.
At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
25.07.2017 | Physics and Astronomy
25.07.2017 | Earth Sciences
25.07.2017 | Life Sciences