Dust plays larger than expected role in determining Atlantic temperature
March 26, 2009 by Jill Sakai
A dust storm off the coast of Morocco was imaged by NASA’s MODIS Aqua meteorological satellite on March 12, 2009. A new study by UW-Madison researcher Amato Evan shows that variability of African dust storms and tropical volcanic eruptions can account for 70 percent of the warming North Atlantic Ocean temperatures observed during the past three decades. Since warmer water is a key ingredient in hurricane formation and intensity, dust and other airborne particles will play a critical role in developing a better understanding of these storms in a changing climate. Photo: courtesy Amato Evan
(PhysOrg.com) -- The recent warming trend in the Atlantic Ocean is largely due to reductions in airborne dust and volcanic emissions during the past 30 years, according to a new study.
Since 1980, the tropical North Atlantic has been warming by an average of a quarter-degree Celsius (a half-degree Fahrenheit) per decade. Though this number sounds small, it can translate to big impacts on hurricanes, which thrive on warmer water, says Amato Evan, a researcher with the University of Wisconsin-Madison's Cooperative Institute for Meteorological Satellite Studies and lead author of the new study. For example, the ocean temperature difference between 1994, a quiet hurricane year, and 2005's record-breaking year of storms, was just one degree Fahrenheit.
More than two-thirds of this upward trend in recent decades can be attributed to changes in African dust storm and tropical volcano activity during that time, report Evan and his colleagues at UW-Madison and the National Oceanic and Atmospheric Administration in a new paper. Their findings will appear in an upcoming issue of the journal Science and publish online March 26.
Evan and his colleagues have previously shown that African dust and other airborne particles can suppress hurricane activity by reducing how much sunlight reaches the ocean and keeping the sea surface cool. Dusty years predict mild hurricane seasons, while years with low dust activity — including 2004 and 2005 — have been linked to stronger and more frequent storms.
In the new study, they combined satellite data of dust and other particles with existing climate models to evaluate the effect on ocean temperature. They calculated how much of the Atlantic warming observed during the last 26 years can be accounted for by concurrent changes in African dust storms and tropical volcanic activity, primarily the eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo in the Philippines in 1991.
In fact, it is a surprisingly large amount, Evan says. "A lot of this upward trend in the long-term pattern can be explained just by dust storms and volcanoes," he says. "About 70 percent of it is just being forced by the combination of dust and volcanoes, and about a quarter of it is just from the dust storms themselves."
The result suggests that only about 30 percent of the observed Atlantic temperature increases are due to other factors, such as a warming climate. While not discounting the importance of global warming, Evan says this adjustment brings the estimate of global warming impact on Atlantic more into line with the smaller degree of ocean warming seen elsewhere, such as the Pacific.
"This makes sense, because we don't really expect global warming to make the ocean [temperature] increase that fast," he says.
Volcanoes are naturally unpredictable and thus difficult to include in climate models, Evan says, but newer climate models will need to include dust storms as a factor to accurately predict how ocean temperatures will change.
"We don't really understand how dust is going to change in these climate projections, and changes in dust could have a really good effect or a really bad effect," he says.
Satellite research of dust-storm activity is relatively young, and no one yet understands what drives dust variability from year to year. However, the fundamental role of the temperature of the tropical North Atlantic in hurricane formation and intensity means that this element will be critical to developing a better understanding of how the climate and storm patterns may change.
"Volcanoes and dust storms are really important if you want to understand changes over long periods of time," Evan says. "If they have a huge effect on ocean temperature, they're likely going to have a huge effect on hurricane variability as well."
Source: University of Wisconsin-Madison (news : web)
May 20, 2008 |
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We are after all, just a big, semi-sealed container....
But on that same hand, we are upon the time for the axis shift of the earth, and this may very well be normal behavior as we near the supermassive blackhole at the center.
My beleif, stupid as you may take it or not, is that the axis shift occurs when we pass in front of the black hole due to the increased gravitational pull on our solar system..I wouldnt doubt that all planets change their axis when it happens...those with stable axis points anyways....with my background thinking being, if gravity from a single star can cause tidal fluctuations within a planet to keep it heated internally, wouldnt it stand to reason that something a few light years away with millions or billions of times the gravitational influence of our star could cause tidal influences that heat the earth internally to cause the mass ice sheet meltings that change the "balance" of the planet thereby causing a shift in axis of earth or other planets?? Some of the timeframes match up...sounds doomsday-ish, but food for thought....and going on that thought, an experiment to see what would happen with a direct flip in axis of the earth ...basically at any degree more than 10...fill a glass with water until its about 1 inch from the top...now tilt it at a 23 degree angle to the right...now swiftly change to the same axis on the left....did the water spill???? could explain some major mysteries for flood evidence far in-land in some places couldnt it...sorry...yammering....
The earth axis idea seems a bit more solid than Al Gore's money making scheme claiming that emissions and CO2 from USA automobiles and factories (for the whopping 50 years of unregulated CO2 emissions that is). Compare 50 years of man made CO2 to how many millions of years of life on this muddy rock?
The oceans are not recending and what water that is changing locations/elevations/sea level is from simple land erosion.. all natural of course.
As for the pole reversal theory, there's no definite period of time between pole reversals. It can happen in 10,000 years or several million as referenced by earth's paleomagnetic field evidence.
But I guess if you'll believe a falsehood like AGW, the 2012 pole flip idea doesn't sound too crazy.
Does this region interact with the arctic equatorial systems??
Back to the drawing board?
I can disregard their hypothesis, ... because it is demonstrably wrong. these people are wrong. Its obvious. Just the fact that water vapor masks the effect of CO2 is enough to prove them fools or charlatans. thats just one problem with AGW. Ignoring the sun variations should be evidence for insanity.