Posted by Benjamin Roudenis on July 17, 2010 0 comments
An upper layer of Earth’s atmosphere recently shrank so much that researchers are at a loss to adequately explain it, NASA said on Thursday.
The thermosphere, which blocks harmful ultraviolet rays, expands and contracts regularly due to the sun’s activities. As carbon dioxide increases, it has a cooling effect at such high altitudes, which also contributes to the contraction.
But even these two factors aren’t fully explaining the extraordinary contraction which, though unlikely to affect the weather, can affect the movement of satellites, researchers said.
“This is the biggest contraction of the thermosphere in at least 43 years,” John Emmert of the Naval Research Lab was quoted as saying in NASA news report.
Emmert is the lead author of a paper announcing the finding in the June 19 issue of the journal Geophysical Research Letters.
“We cannot explain the abnormally low densities, which are about 30 percent lower” than from previous contractions, Emmert told CNN.com.
Posted by Benjamin Roudenis on May 26, 2010 0 comments
At the University of Oklahoma, researchers captured unprecedented high-resolution radar data during the May 10, 2010, tornadoes using one of the most advanced weather radars in the world.
“This unique polarimetric data set is likely to reveal new discoveries about tornado genesis and severe storms for years to come,” said the Director of OU’s Atmospheric Radar Research Center, Robert D. Palmer.
Palmer’s team is currently processing the data using advanced techniques developed at OU and preparing it for distribution.
“The close proximity of the tornadoes to the OU radar has produced data with fine details of the storms never seen before with any radar.”
Located on the OU Research Campus within walking distance of the National Weather Center, the C-band, polarimetric, research weather radar known as OU-PRIME (Polarimetric Radar for Innovations in Meteorology and Engineering) was built to provide OU students and faculty with a platform for research and education in the field of radar meteorology.
Posted by Benjamin Roudenis on May 10, 2010 0 comments
Shooting lasers at the sky can make the germ of a raincloud, a new study shows. In an experiment that smacks of science fiction, scientists used a high-powered laser to squeeze water from air, both indoors and out.
. . . . .
“This is the first time that a laser was used to condense water from both laboratory experiments and from the atmosphere,” says Jérôme Kasparian of the University of Geneva, a coauthor of the study. The work appeared in the May 2 Nature Photonics.
. . . . .
“It’s just like when you take a shower with hot water — it’s very humid in your bathroom, but it’s not raining,” Kasparian says. Water droplets need a surface to condense on, like a mirror in a bathroom or a speck of dust or pollen in the atmosphere.
. . . . .
Kasparian and his colleagues tested this idea by shooting a high-powered infrared laser into a cloud chamber. The laser shot extremely short pulses of intense light, which each carrying several terawatts — or a trillion watts — of energy.
The view fogged up immediately. Droplets about 50 micrometers in diameter formed first, and grew to about 80 micrometers in diameter over the next three seconds. “The effect in the cloud chamber was very spectacular and visible by bare eye,” Kasparian says. “We expected an effect, definitely. But that magnitude was pretty much a surprise.”
Next, the researchers took the laser out in the backyard to try it on the sky. They rolled the laser, called “Teramobile” for its terawatt power and its mobility, onto the lawn behind the physics building at the Free University of Berlin on several nights in the fall of 2008. The clouds, if they formed, would be too distant to see with the naked eye, so the team used a second laser to confirm the cloudy view.
“It also worked quite well in the free atmosphere,” Kasparian says. “That was quite surprising, and a very good surprise.”
Posted by Benjamin Roudenis on January 9, 2010 0 comments
On January 5, the National Weather Service changed the criteria for severe thunderstorms by upping the minimum size hail from ¾ to 1 inch—quarter size. The wind threshold—50 knots, or 58 mph—remains the same.
The reason for the change, according to a statement issued by the Fire and Public Weather Services Branch of the NWS, is that research reveals “significant damage” doesn’t occur from hail smaller than an inch. Hailstones the size of quarters or larger are the ones most destructive to cars, homes, buildings, and crops.
Over the years, and particularly in the Plains states, the statement reads, “the frequency of severe thunderstorm warnings issued for penny-size and nickel-size hail might have desensitized the public to take protective action during a severe thunderstorm warning.” Too many warnings for events that were not damaging garnered complaints and made the warnings somewhat meaningless.
Posted by Benjamin Roudenis on January 5, 2010 0 comments
This is my favorite speech from my favorite author. Here is an excerpt:
I regard consensus science as an extremely pernicious development that ought to be stopped cold in its tracks. Historically, the claim of consensus has been the first refuge of scoundrels; it is a way to avoid debate by claiming that the matter is already settled. Whenever you hear the consensus of scientists agrees on something or other, reach for your wallet, because you’re being had.
Let’s be clear: the work of science has nothing whatever to do with consensus. Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right, which means that he or she has results that are verifiable by reference to the real world. In science consensus is irrelevant. What is relevant is reproducible results. The greatest scientists in history are great precisely because they broke with the consensus.
Finally, I would remind you to notice where the claim of consensus is invoked. Consensus is invoked only in situations where the science is not solid enough. Nobody says the consensus of scientists agrees that E=mc2. Nobody says the consensus is that the sun is 93 million miles away. It would never occur to anyone to speak that way.
Posted by Benjamin Roudenis on January 1, 2010 0 comments
Most of the carbon dioxide emitted by human activity does not remain in the atmosphere, but is instead absorbed by the oceans and terrestrial ecosystems. In fact, only about 45 percent of emitted carbon dioxide stays in the atmosphere.
However, some studies have suggested that the ability of oceans and plants to absorb carbon dioxide recently may have begun to decline and that the airborne fraction of anthropogenic carbon dioxide emissions is therefore beginning to increase.
Many climate models also assume that the airborne fraction will increase. Because understanding of the airborne fraction of carbon dioxide is important for predicting future climate change, it is essential to have accurate knowledge of whether that fraction is changing or will change as emissions increase.
To assess whether the airborne fraction is indeed increasing, Wolfgang Knorr of the Department of Earth Sciences at the University of Bristol reanalyzed available atmospheric carbon dioxide and emissions data since 1850 and considers the uncertainties in the data.
In contradiction to some recent studies, he finds that the airborne fraction of carbon dioxide has not increased either during the past 150 years or during the most recent five decades.
