Showing posts with label The atmosphere. Show all posts
Showing posts with label The atmosphere. Show all posts

Tuesday, November 17, 2015

Gulf Stream is slowing down and may affect higher latitude climates in the Northern Hemisphere, according to a NASA



Accuweather

NASA: North Atlantic 'Cold Blob' May be Culprit Behind Ocean Current Slowdown

By Mark Leberfinger, AccuWeather.com Staff Writer
November 17, 2015; 12:34 AM ET
A major player in the transportation of heat in the Atlantic Ocean is slowing down and may affect higher latitude climates in the Northern Hemisphere, according to a NASA analysis of satellite data.
The "cold blob" that developed off Greenland may be the drag on the Atlantic Meridional Overturning Circulation (AMOC) by producing very chilly to record cold water, the National Oceanic and Atmospheric Administration (NOAA) said earlier this year.



Global warming may be responsible for AMOC's slowdown but natural forces may also be at work, NASA said. AMOC is part of the complex circulation of currents that help take the warmer Gulf Stream water and move it through the basin.

Data from the Gravity Recovery and Climate Experiment (GRACE) satellites correspond with similar findings that were not satellite-based. The GRACE findings were published in the journal Geophysical Research Letters.

An AMOC slowdown would impact other currents throughout the Atlantic.



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Tuesday, September 29, 2015

Something is Affecting the Entire Solar System

 

 

 

 

 

nemesis maturity

Wednesday, August 28, 2013

Global sea level rise dampened by Australia floods

SHAKE AND BLOW

by Staff Writers
Boulder CO (SPX) Aug 26, 2013



Heavy rains transformed Australia's landscape, as show in these two NASA satellite images of floodplains in southwestern Queensland. The first image was taken on September 26, 2009. By the time of the second image, on March 26, 2011, so much rain had been driven over Australia instead of falling on the ocean that global sea levels temporarily dropped. (Image taken with the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite.)
When enough raindrops fall over land instead of the ocean, they begin to add up. New research led by the National Center for Atmospheric Research (NCAR) shows that when three atmospheric patterns came together over the Indian and Pacific oceans, they drove so much precipitation over Australia in 2010 and 2011 that the world's ocean levels dropped measurably.
Unlike other continents, the soils and topography of Australia prevent almost all of its precipitation from running off into the ocean. The 2010-11 event temporarily halted a long-term trend of rising sea levels caused by higher temperatures and melting ice sheets.
Now that the atmospheric patterns have snapped back and more rain is falling over tropical oceans, the seas are rising again. In fact, with Australia in a major drought, they are rising faster than before.
"It's a beautiful illustration of how complicated our climate system is," says NCAR scientist John Fasullo, the lead author of the study.
"The smallest continent in the world can affect sea level worldwide. Its influence is so strong that it can temporarily overcome the background trend of rising sea levels that we see with climate change."
The study, with co-authors from NASA's Jet Propulsion Laboratory and the University of Colorado at Boulder, will be published next month in Geophysical Research Letters. It was funded by the National Science Foundation, which is NCAR's sponsor, and by NASA.
Consistent rising, interrupted
As the climate warms, the world's oceans have been rising in recent decades by just more than 3 millimeters (0.1 inches) annually. This is partly because the heat causes water to expand, and partly because runoff from retreating glaciers and ice sheets is making its way into the oceans.
But for an 18-month period beginning in 2010, the oceans mysteriously dropped by about 7 millimeters (about 0.3 inches), more than offsetting the annual rise.
Fasullo and his co-authors published research last year demonstrating that the reason had to do with the increased rainfall over tropical continents. They also showed that the drop coincided with the atmospheric oscillation known as La Nina, which cooled tropical surface waters in the eastern Pacific and suppressed rainfall there while enhancing it over other portions of the tropical Pacific, Africa, South America, and Australia.
But an analysis of the historical record showed that past La Nina events only rarely accompanied such a pronounced drop in sea level.


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Monday, June 24, 2013

Reduced atmospheric pollution may have increased the ferocity and frequency of hurricanes



Lower pollution levels linked to worse hurricanes




Tropical storm Sandy batters US coast
 
If North Atlantic hurricanes are more destructive or more frequent, it may be linked to lower levels of atmospheric pollution. Photograph: Scott Eisen/Reuters
 
 

Scientists from Britain's Meteorological Office have fingered a new suspect in their attempt to solve the mystery of tropical storms. It is, unexpectedly, air quality.
If North Atlantic hurricanes are more destructive or more frequent, it may be linked to lower levels of atmospheric pollution. Conversely, sulphate aerosols and other particles from factory chimneys, vehicle exhausts, domestic fires, power stations and other human economic advances may have played a role in keeping tropical storms under control, at least a little, during the 20th century.
Climate scientist Nick Dunstone and fellow-researchers at the Met Office's Hadley Centre in Exeter, Devon, report in the Nature Geoscience journal there is at least circumstantial evidence that aerosols play a more significant role in the storm cycle than anyone had expected.
The reason it has been difficult to separate the effect is a simple one: when humans burn fossil fuels, they release greenhouse gases that slowly but inexorably warm the atmosphere, and therefore the oceans. Atmosphere and ocean are together a climate system: put more energy in, and it must go somewhere. The likely consequences, most people have thought, are extremes of wind and rain.
However, for most of the 20th century, humans released greenhouse gases and also all sorts of other waste at the same time: specifically, sulphate aerosols that, as urban smog, darkened buildings, increased the acidity of the falling rain, rotted limestone structures and condemned hundreds of thousands to bronchial illnesses and, ultimately, to early graves.
It didn't seem possible to separate the effects – at least, not until Britain, western European nations and North America introduced increasingly strict clean air legislation.
This started to give scientists and climate modellers a chance to tease out the different effects of the two pollutants. Aerosols are important absorbers of sunlight, and they are also important in cloud chemistry – water vapour droplets have to condense on something. But important in what way? Do clouds reflect sunlight and cool the region? Or do they build up prodigious quantities of moving water and turn into the frenzies of a tropical storm? Or, overall, do sulphates cool the atmosphere a little and counteract global warming − and, if so, under what conditions?

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