Video 
Video 
Video 
Video 
Video A quick look at the map rainfall of the world shows that increased rainfall Tropical fall in the Northern Hemisphere . A new study from the University of Washington, in the U.S., and published in Nature Geoscience , explains that the pattern is due to ocean currents from the poles, thousands of miles away.
The Palmyra Atoll , 6 degrees north, supports 175 inches of rain a year, while an equal distance in the opposite of the equator gets only 45 inches . Scientists always thought it was a quirk of the geometry of the Earth, the ocean basins are inclined diagonally while the planet rotates tropical bands pushed north of Ecuador.
The results exhibit a fundamental characteristic of the climate of the planet and icy waters show that seasonal rains affect , which are crucial for the growth of crops in places like the Sahel region of Africa and southern India. In general, the hot spots are more moist because hot air rises and moisture precipitates.
hottest places are more moist because hot air rises and moisture precipitates
“It rains more in the Northern Hemisphere because it is warmer – Dargan Frierson explained lead author, associate professor of atmospheric sciences at the University of Washington -.’ve found the answer to what makes it warmer Northern Hemisphere is circulation of the oceans. “
Frierson and colleagues used first detailed measurements of the clouds of NASA satellites and Radiant Energy System, or CERES Earth to show that sunlight actually provides more heat in the Southern Hemisphere and thus by atmospheric radiation, the Southern Hemisphere should be the wettest.
After to use other observations to calculate ocean heat transport, the authors used computer models to demonstrate the key role of the ocean conveyor belt that plunges close Greenland, traveling along the bottom of the ocean to Antarctica and then rises and flows northward along the surface. If this current is eliminated, it would turn rainbands south.
The reason is that as the water moves toward the north for many decades gradually warms , bringing about 400 billion watts through Ecuador. For many years, it was accepted that the sloping ocean basins were the cause of the asymmetry of the tropical rains, but at the same time, many people did not believe this explanation to be a complicated argument and believe that such an important issue often have a simpler explanation, according Frierson.
Global warming may reverse the trend
The ocean current that appear to be responsible was made famous in the 2004 film The Day After Tomorrow , in which the premise is that this circulation closes and freezes New York. Although the speaker’s sudden closing film will not sucecer, a gradual slowdown, to a recent United Nations report said “very likely” to 2100, could change the rains tropical south, as this research suggests, as probably happened in the past.
The current slowdown is predicted by increased rainfall and fresh water in the North Atlantic. “This is part of a large and growing body of evidence that has emerged in the last 10 or 15 years showing how important are the latitudes high for other parts of the world,” he said Frierson.
Frierson’s previous work shows how the changing balance temperature between hemispheres affect tropical rainfall. A recent analysis of this researcher and collaborators saw how pollution of the industrial revolution blocked the sunlight in the Northern Hemisphere in the 1970s and 80s and changed the tropical rains in the south.
Many of the changes are due to air pollution
“Many of the changes in recent years have been due to air pollution – warned Frierson -. The future depends on air pollution and global warming and changes in ocean circulation. That will make tropical rains are particularly difficult to predict. “
No comments:
Post a Comment