Sometimes I complain about the earthly weather, but mostly I like to post about astronomy and space events. Hope you enjoy the articles.
By: Susie77, 4:23 PM GMT on March 31, 2011
From: Space [dot] com
Cosmic Rose Blooms in Star Cluster Photo
Date: 30 March 2011 Time: 07:00 AM ET
The star cluster NGC 371 appears in this new image from ESO’s Very Large Telescope.
CREDIT: ESO/Manu Mejias, images
A bright star cluster surrounded by iridescent red gas looks like a blooming cosmic rose in a new photo from the European Southern Observatory's Very Large Telescope.
The photo depicts the star cluster NGC 371, a stellar nursery in our neighboring galaxy the Small Magellanic Cloud, a dwarf galaxy about 200 000 light-years from Earth. Such regions of ionized hydrogen — known as HII regions — are sites of recent star birth. [See the red rose star cluster photo]
NGC 371 is an open cluster surrounded by a nebula. The stars in open clusters all originate from the same diffuse HII region, and over time the majority of the hydrogen is used up by star formation, leaving behind a shell of hydrogen such as the one in this image, along with a cluster of hot young stars.
This cluster is of particular interest to astronomers due to the unexpectedly large number of variable stars it contains. These are stars that change in brightness over time. Variable stars play a pivotal role in astronomy: Some types are invaluable for determining distances to far-off galaxies and the age of the universe. [More Photos by the Very Large Telescope]
The Small Magellanic Cloud contains stars at all stages of their evolution, from the super-bright young stars found in the NGC 371 cluster to the supernova remnants of long-dead stars.
The energetic young stars emit copious amounts of ultraviolet radiation, causing surrounding gas, such as leftover hydrogen from the stars' parent nebula, to light up with a colorful glow that extends for hundreds of light-years in every direction.
This new image was created using the FORS1 instrument on the Very Large Telescope at the Paranal Observatory in Chile's Atacama desert.
By: Susie77, 6:59 PM GMT on March 21, 2011
Interesting article from NASA on space-based microbiology research, which may have implications for earth-bound patients.
From NASA Press Release
SPACEBOUND BACTERIA INSPIRE EARTHBOUND REMEDIES
WASHINGTON -- Recent research aboard the space shuttle is giving
scientists a better understanding of how infectious disease occurs in
space and could someday improve astronaut health and provide novel
treatments for people on Earth.
"With our space-based research efforts, including the International
Space Station, we are not only continuing our human presence in
space, but we are engaged in science that can make a real difference
in people's lives here on Earth," said NASA Administrator Charles
Bolden. "NASA's leadership in human spaceflight allows us to conduct
innovative and ground-breaking science that reveals the unknown and
unlocks the mysteries of how disease-causing agents work."
The research involves an opportunistic pathogen known as Pseudomonas
aeruginosa, the same bacterium that caused astronaut Fred Haise to
become sick during the Apollo 13 mission to the moon in 1970.
Scientists studying the bacterium aboard the shuttle hope to unlock
the mysteries of how disease-causing agents work. They believe the
research can lead to advanced vaccines and therapies to better fight
infections. The findings are based on flight experiments with
microbial pathogens on NASA shuttle missions to the International
Space Station and appear in a recent edition of the journal Applied
and Environmental Microbiology.
"For the first time, we're able to see that two very different species
of bacteria - Salmonella and Pseudomonas - share the same basic
regulating mechanism, or master control switch, that micro-manages
many of the microbes' responses to the spaceflight environment," said
Cheryl Nickerson, associate professor at the Center for Infectious
Diseases and Vaccinology, the Biodesign Institute at Arizona State
University (ASU) in Tempe. "We have shown that spaceflight affects
common regulators in both bacteria that invariably cause disease in
healthy individuals [Salmonella] and those that cause disease only in
people with compromised immune systems [Pseudomonas]."
By studying the global gene expression patterns in bacterial pathogens
like Pseudomonas and Salmonella, Nickerson's team learned more about
how they react to reduced gravity.
Pseudomonas aeruginosa can coexist as a benign microbe in healthy
individuals, but poses a serious threat to people with compromised
immune systems. It is the leading cause of death for those suffering
from cystic fibrosis and is a serious risk to burn victims. However,
a high enough dosage of Salmonella typhimurium always will cause
disease, even in healthy individuals.
During the initial study in 2006, two bacterial pathogens, Salmonella
typhimurium and Pseudomonas aeruginosa, and one fungal pathogen,
Candida albicans, were launched to the station aboard shuttles. They
were allowed to grow in appropriately contained vessels for several
days. Nickerson's team was the first to evaluate global gene and
protein expression (how the bacteria react at the molecular level)
and virulence changes in microbes in response to reduced gravity.
"We discovered that aspects of the environment that microbes
encountered during spaceflight appeared to mimic key conditions that
pathogens normally encounter in our bodies during the natural course
of infection, particularly in the respiratory system,
gastrointestinal system and urogenital tract," Nickerson said. NASA's
Advanced Capabilities Division Director, Benjamin Neumann added that,
"This means that in addition to safeguarding future space travelers,
such research may aid the quest for better therapeutics against
pathogens here on Earth."
The initial study and follow-on space experiments show that
spaceflight creates a low fluid shear environment, where liquids
exert little force as they flow over the surface of cells. The low
fluid shear environment of spaceflight affects the molecular genetic
regulators that can make microbes more infectious. These same
regulators might function in a similar way to regulate microbial
virulence during the course of infection in the human body.
"We have now shown that spaceflight conditions modified molecular
pathways that are known to be involved in the virulence of
Pseudomonas aeruginosa," said Aurelie Crabbe, a researcher in Dr.
Nickerson's lab at ASU and the lead author of the paper. "Future work
will establish whether Pseudomonas also exhibits increased virulence
following spaceflight as did Salmonella."
NASA's Fundamental Space Biology Program sponsored and funded the
research conducted by Crabbe and Nickerson along with their
colleagues at the Biodesign Institute at ASU. They collaborated with
the University of Colorado School of Medicine, University of Arizona,
Belgian Nuclear Research Center, Villanova University, Tulane
University, Affymetrix Inc, and NASA scientists.
For an abstract of the journal article on this research, visit:
By: Susie77, 7:37 PM GMT on March 18, 2011
From Science @ NASA
Historic First: A Spacecraft Orbits Mercury
March 18, 2011: NASA's MESSENGER spacecraft successfully achieved orbit around Mercury at approximately 9 p.m. EDT on Thursday, March 17. This marks the first time a spacecraft has accomplished this engineering and scientific milestone at our solar system's innermost planet.
"This mission will continue to revolutionize our understanding of Mercury during the coming year," said NASA Administrator Charles Bolden, who was at MESSENGER mission control at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., as engineers received telemetry data confirming orbit insertion. "NASA science is rewriting text books. MESSENGER is a great example of how our scientists are innovating to push the envelope of human knowledge."
At 9:10 p.m. EDT, engineers Operations Center, received the anticipated radiometric signals confirming nominal burn shutdown and successful insertion of the MESSENGER probe into orbit around the planet Mercury. NASA's Mercury Surface, Space Environment, Geochemistry, and Ranging, or MESSENGER, rotated back to the Earth by 9:45 p.m. EDT, and started transmitting data. Upon review of the data, the engineering and operations teams confirmed the burn executed nominally with all subsystems reporting a clean burn and no logged errors.
MESSENGER's main thruster fired for approximately 15 minutes at 8:45 p.m., slowing the spacecraft by 1,929 miles per hour and easing it into the planned orbit about Mercury. The rendezvous took place about 96 million miles from Earth.
"Achieving Mercury orbit was by far the biggest milestone since MESSENGER was launched more than six and a half years ago," said Peter Bedini, MESSENGER project manager of the Applied Physics Laboratory (APL). "This accomplishment is the fruit of a tremendous amount of labor on the part of the navigation, guidance-and-control, and mission operations teams, who shepherded the spacecraft through its 4.9-billion-mile journey."
For the next several weeks, APL engineers will be focused on ensuring the spacecraft's systems are all working well in Mercury's harsh thermal environment. Starting on March 23, the instruments will be turned on and checked out, and on April 4 the mission's primary science phase will begin.
"Despite its proximity to Earth, the planet Mercury has for decades been comparatively unexplored," said Sean Solomon, MESSENGER principal investigator of the Carnegie Institution of Washington. "For the first time in history, a scientific observatory is in orbit about our solar system's innermost planet. Mercury's secrets, and the implications they hold for the formation and evolution of Earth-like planets, are about to be revealed."
APL designed and built the spacecraft. The lab manages and operates the mission for NASA's Science Mission Directorate in Washington.
By: Susie77, 12:23 AM GMT on March 15, 2011
Usually in this blog, I post astronomy-related articles. Due to recent events in Japan, I thought people might be interested in this one. It explains how nuclear reactors work, what happens in the event of a coolant failure, and other facts regarding meltdowns. I didn't include the graphics; clink on the article link for those.
From Japan's Nuclear Reactor Disaster
ABCs of Japan's Nuclear Reactor Disaster
Clarifying Japan's Nuclear Reactor Disaster
* Reactor Building
* Fuel Damage
* Radioactivity Release Pathways
* Partial Meltdown
* Complete Meltdown
* Radioactive Isotopes
In reporting on the nuclear situation in Japan, terms describing the possible state of the reactors have been used by Japanese officials and international experts.Unfortunately, these terms are not always used consistently. We discuss some of them below.
The reactor core containing nuclear fuel is the “engine” of a nuclear power reactor. The reactor core resides in the lower region of a metal “pot” called the reactor vessel.
The reactor vessel is enclosed within the primary containment structure, consisting of the drywell and wetwell (see diagram), which is designed to contain radioactive materials released during a reactor accident.
The reactor building provides the secondary containment, which is intended to prevent any leaks from the primary containment from escaping to the environment. The air in the reactor building is sent through filters to remove any radiation before being released to the outside.
The fuel consists of uranium or uranium/plutonium pellets stacked inside long tubes made from zirconium metal. When a reactor is operating, the fuel gets very hot. The fuel is immersed in water, and the heat produces steam, which is used to drive a turbine to produce electricity.
The water also keeps the fuel from overheating, and is continuously circulated through the reactor core to carry away excess heat. Even if the reactor shuts down, the fuel will remain hot for a long time, so it must still be cooled.
If the pumps that circulate the cooling water are not operating, the water in the reactor vessel will heat up and evaporate, and the fuel can become uncovered inside the reactor vessel.
This situation also occurs if something like a pipe rupture causes the water to drain out of the reactor vessel. At this point, the zirconium cladding on the fuel rods will start to heat up, blister, and then rupture.
Radioactive material that normally collects in the gap between the fuel pellets and the cladding is then released into the reactor vessel.
Radioactivity Release Pathways
The radioactive material released from damaged fuel into the reactor vessel can get into the primary containment.
To protect the reactor vessel and attached piping from rupturing due to high pressure, relief valves automatically open to discharge steam—and the radioactive material along with it—into the primary containment structure.
Workers may also manually open the relief valves to prevent high pressure in the reactor vessel from impeding the flow of makeup water, such as the sea water that has reportedly been injected into some of the Japanese reactors.
In addition, a steam-driven emergency system called the reactor core isolation cooling (RCIC) system uses steam from the reactor vessel to spin a small turbine connected to a pump that transfers makeup water to the reactor vessel. After the steam is used for this purpose, the steam—along with the radioactive material—is deposited into the primary containment.
If the fuel is uncovered by water and exposed for a period of hours, it will start to melt. This makes cooling more difficult as the melted fuel clogs the spaces between the fuel rods. The melted fuel will start to collect on the bottom of the steel reactor vessel (sometimes called the lower head). The molten fuel will begin to burn its way through the reactor vessel.
If the water level is low enough, essentially all the fuel in the core can melt and will fall to the bottom of the reactor vessel. It will be a matter of hours before the fuel melts through the steel reactor vessel and onto the concrete floor of the primary containment.
The containment is designed to contain the melted fuel and its radioactive emissions, but there are ways in which the primary containment can fail in the event of a meltdown; this has been a concern with the Mark I containment, which the affected Japanese reactors use. The emissions will generate increasing pressure over a period of days and weeks, which can lead to collapse of the primary containment if it is not relieved.
The primary containment has a typical leak rate of roughly 1% of its volume per day, so some of the radioactive material will leak into the secondary containment (the reactor building). The reactor building is normally kept at a reduced pressure relative to the outside so any radioactive emissions will stay inside the building. However, this requires the building itself to be intact.
A meltdown does not necessarily mean that there will be a large release of radioactivity. This will depend on the integrity of the primary and secondary containments.
Radioactive materials decay, releasing particles that can damage living tissue and lead to cancer. Some elements have different forms, called isotopes, that differ in the number of neutrons in the nucleus.
The radioactive isotopes of greatest concern in a nuclear power accident are iodine-131 and cesium-137. Iodine-131 has a half-life of 8 days, meaning half of it will have decayed after 8 days, and half of that in another 8 days, etc. Therefore, it is of greatest concern in the days and weeks following an accident. It is also volatile so will spread easily.
In the human body, iodine is taken up by the thyroid, and becomes concentrated there, where it can lead to thyroid cancer in later life. Children who are exposed to iodine-131 are more likely than adults to get cancer later in life.
To guard against the absorption of iodione-131, people can proactively take potassium iodine pills so the thyroid becomes saturated with non-radioactive iodine and is not able to absorb any iodine-131.
Cesium-137 has a half-life of about 30 years, so will take more than a century to decay by a significant amount. Living organisms treat cesium-137 as if it was potassium, and it becomes part of the fluid electrolytes and is eventually excreted. Cesium-137 is passed up the food chain. It can cause many different types of cancer.
By: Susie77, 11:06 PM GMT on March 14, 2011
Catch Mercury near Jupiter after sunset in mid-March
Spring evenings are always the best for seeing our solar system’s most elusive planet Mercury. In 2011, watch for Mercury near Jupiter in mid-March.
If you haven’t seen tiny Mercury before, or if you simply love to glimpse this most elusive of planets, mid to late March 2011 provides the perfect time to search for it the western skies after sunset. Mercury, the closest planet to the sun, is never far from the rising or setting sun. So the key to seeing Mercury is having an unobstructed view of the horizon in the sunrise or sunset direction.
In March 2011, the very bright planet Jupiter will assist your search for the dimmer, but still bright, Mercury. You should look for Mercury about 30 to 40 minutes after sunset, as soon as the sky begins to darken.
Mercury and Jupiter close together from March 13 to 16, 2011 At conjunction on March 15, Mercury and Jupiter are only two degrees apart. That’s the width of one finger, as seen at an arm’s length. You can find Mercury to the right of Jupiter. Mercury is fainter, but both worlds will be surprisingly bright for being so low in the western twilight sky after sunset. They will be near the horizon, but will occupy the same binocular field for several days in succession. For more see Jupiter is your guide to Mercury in mid-March 2011.
Track Mercury from March 15-30, 2011. You will see that Mercury gets higher in the sky, while Jupiter drops toward the sunset. At some point, Jupiter will vanish in the sunset glare. On March 22, meanwhile, Mercury will have reached its greatest elongation, or greatest distance from the sun from our view on Earth. Then it’ll be 19 degrees from the sun on the sky’s dome. These springtime apparitions of Mercury are always best, because the ecliptic – or path of the sun, moon and planets – is nearly perpendicular to the evening horizon in spring. So March will bring Mercury’s best evening apparition for all of 2011. You should have no trouble spotting it!
Mercury and Venus, known as inner planets, orbit closer to the sun than Earth. As a result, these worlds exhibit phases like the moon. As they swing around the sun in their orbits we see the illuminated part of each planet wax or get wider – then wane or get thinner. When you first see Mercury in March 2011, it will be very bright. As Mercury gets higher in the sky it will become dimmer because its phase will be waning.
Mercury never lingers. Its quick 88-day orbit around the sun takes the planet out of the evening sky and back into the sun’s glare by the end of March. Mercury will pass between the Earth and sun on April 9, 2011.
Mercury will have a visitor in March 2011. On March 18, NASA’s MESSENGER spacecraft will be the first spacecraft to enter orbit around Mercury. Double-click the NASA video below to start:
MESSENGER has already completed three flybys of Mercury imaging more than 90 percent of the planet’s surface, studying elements in the thin atmosphere and on the surface and gaining critical gravitational assists that will help with the final phase of the mission. During the final phase, the spacecraft will enter orbit around Mercury for one year collecting data. Stay tuned for more exciting discoveries.
Mercury for the rest of 2011:
Mercury will re-emerge as a morning planet in May, to join Jupiter, Venus and Mars in the eastern predawn sky. The view will be best from the southern hemisphere, but, with some diligence, you can spot them from the northern hemisphere, too. The four planets will dance around near the horizon in the early part of May, and, although it’ll be tough to spot the fainter ones (Mercury and Mars), the brighter planets (Jupiter and Venus) can help you find them. All four together will be very interesting to see, either in a super clear sky, or with binoculars.
Mercury will be back in the evening sky in July, but will not be as far above the sunset horizon as in March. Still, you should be able to spot Mercury in July with the unaided eye, in the west after sunset.
Mercury will reappear as a morning star for northern hemisphere viewers in late August and early September. Its November evening apparition will be its worst for the year; chances of seeing it then are slim. Then it’s back up before dawn after mid-December, 2011.
And now you might see why Mercury is called elusive. Some think it’s because Mercury is faint, but that’s not so. In fact, this planet is rather bright. But its 88-day orbit around the sun carries it in and out of view frequently, as it moves from the morning to evening sky and back again, always staying near the sunrise or sunset as seen from Earth. But every year brings good opportunities to see Mercury, and 2011 is no exception. In general, spring evenings and autumn predawns are always best!
By: Susie77, 1:55 PM GMT on March 10, 2011
Space Weather News for March 10, 2011
X-CLASS SOLAR FLARE: March 9th ended with a powerful solar flare. Less than an hour before midnight (UT), Earth-orbiting satellites detected an X1.5-class explosion from behemoth sunspot 1166. First-look data suggest that the blast did hurl some material toward Earth. Check spaceweather.com for movies of the flare and updates on its possible effects.
[Blogger note: Here's an effect!!]
Updated: 3:18 PM GMT on March 10, 2011
By: Susie77, 11:02 PM GMT on March 07, 2011
Yeah buddy. :)
By: Susie77, 7:48 PM GMT on March 03, 2011
From Live Science
Twisted Science: Why Tornado Forecasting Is Tough
Brett Israel, Our Amazing Planet Staff Writer
Date: 02 March 2011 Time: 07:33 PM ET
The average tornado warning sounds 13 minutes before touchdown.
The warning time is so short that residents of towns in Tornado Alley are told not to flee their homes when they hear a siren. That would be too dangerous, especially during a tornado that strikes in the dead of night. Hunker down and hope for the best, people are often told.
Tornado warnings are so short because tornadoes are almost impossible to forecast until it's too late. Unlike hurricane season, there is no forecast for tornado season — and no straightforward climate change link. But the same atmospheric players that fueled this year's wild winter of bitter cold and tremendous snowfalls could create dangerous tornadoes this spring and summer, scientists said, which could cast the light on the limits of tornado prediction.
Beginning this year, a major upgrade to the nation's radar system could help with tornado spotting, which isn't easy to do, as evidenced by the 75-percent false alarm rate for tornado warnings. [In Images: Storm Spotters in Action]
"It's easier to predict a large outbreak of thunderstorms than how many tornadoes there might be," said Bob Henson, a meteorologist with the University Corporation of Atmospheric Research in Boulder, Colo.
Last year saw 1,280 tornadoes, about what is expected for a given year in the United States, said Greg Carbin, the warning coordination meteorologist with the Storm Prediction Center in Norman, Okla. The 2011 season is off to a slow start for tornadoes, Carbin said, with only about half as many tornado reports as usual for this time of the year.
Despite the slow start, tornado season jumped into action with 24 reported tornadoes on Feb. 24 and 17 more over the past two days. The year's first tornado-related death occurred yesterday (Feb. 28) in Franklin County, Tennessee.
The early storms are tied to an unusually prolonged Arctic outbreak, said climatologist Bill Patzert of NASA's Jet Propulsion Laboratory in Pasadena, Calif.
"Hopefully this pattern that's going on right now will not be a preview of coming attractions," Patzert told OurAmazingPlanet.
Do the twist
Tornado season typically starts in March and hits its stride from May to June, though it's possible for tornadoes to pop up during any time of the year (November is often called the second tornado season). During the spring and early summer, thousands of tornadoes will strike the United States. And tornadoes can strike anywhere at any time, day or night — a tornado hit New York City at night in September last year.
Most of the biggest and baddest tornadoes spin off supercell storms, which are up to 50,000 feet (15,000 meters) tall and can last for hours.Supercells need three main ingredients to form: energy, rotation and a cap. The United States has plenty of all three and once they mix, a supercell storm can spit out a tornado in minutes.
"That's why we're the tornado capital of the world. It's just geography," Patzert said.
The energy comes from the collision of warm, moist air from the Gulf of Mexico and the cool, dry Arctic air. The warm air rises and hits wind shear, a layer of the atmosphere where the winds change direction over a short height, and creates the rotation — think of a pinwheel with air pushing in opposite directions on the top and bottom. Below the pinwheel, a cap of warm air bottles up surface heat below about 10,000 feet (3,000 m).
Heat builds until it punches through the cap, triggering a thunderstorm. With enough air shooting up and down, the pinwheel is knocked on its side, creating a huge rotating mass of clouds called a mesocyclone — the hallmark of a tornado-spawning supercell storm. But there are a number of flies in the tornado-generating ointment, Carbin said — and because of that, a tornado is actually a rare event.
"It's easy enough to put a thunderstorm together. It's very difficult to get that thunderstorm to produce a significant tornado," Carbin said.
Only a fraction of supercell storms create tornadoes, and meteorologists are not exactly sure why. Meteorologists can't even say when during a supercell's lifetime a tornado will form. This is not what the good folks in Tornado Alley want to hear.
Tornado Capital, U.S.A.
Most of the Earth's tornadoes touch down in the hotbed known as Tornado Alley, bordered by the Dakotas to the north, the Gulf Coast to the south, the Rocky Mountains to the west and the Appalachian Mountains to the east. Tornadoes are so common here that tour guides often charge thousands of dollars to lead groups on weeklong tornado-watching tours.
Southeast of Tornado Alley is Dixie Alley, home to the deadliest tornadoes. Dixie Alley spreads from the Lower Mississippi Valley to the Upper Tennessee Valley, including Arkansas, Mississippi, Louisiana, Alabama, Georgia and the Florida panhandle.
Dixie Alley is where storm assessment teams are sifting through the damage from last week's tornadoes, which had estimated strengths up to EF2.
A tornado's strength is based on the amount of damage it causes. The Enhanced Fujita tornado damage scale runs from 0 (minor damage) to 5 (a storm that is powerful enough to destroy a house).
Tornadoes are also rated based on their wind speeds. An average tornado has maximum wind speeds of about 112 mph (180 kph) or less, measures around 250 feet (76 m) in width and travels approximately one mile before unraveling. Some chart toppers have had 300 mph (480 kph) winds— almost twice that of 1992's devastating Hurricane Andrew. The hurricane was a Category 5 storm, the highest hurricane rating.
The problem with how scientists count and rank tornadoes is that someone has to see it or it has to hit something. The biggest tornado of all time could have roared through an open field and no one would have known it.
"If nobody saw it, it wasn't in the record," Carbin said.
Tracking the unseen
This year, meteorologists are rolling out the latest in weather radar technology to help see the unseen. Say goodbye to Doppler radar and say hello to Dual Pol, or Dual Polarization radar. These radars can see debris such as grass and leaves circulating within a tornado, even when the twister is cloaked by a rain cloud. A Dual Pol radar will fire up in Oklahoma this week and five more will be tested this summer. Over the next two years, all 169 of the National Weather Service's Doppler radars will be replaced.
These radars will not help with forecasts, but they will help with so-called "now-casts," or tracking a tornado that is on the ground.
"Let's say they have a tornado warning out but they don't know if one is really there, then 'bingo!' – they can get this information out," said Paul Schlatter, the meteorologist with the National Weather Service in Norman that is training forecasters on the new radars.
New radar technology should help with public safety now, but without a complete history of tornadoes, climate scientists cannot say much about how the tornado threat will change in a warming world.
The authority on climate science, The Intergovernmental Panel on Climate Change's (IPCC) Fourth Assessment Report Summary for Policymakers, releasedin 2007, said: "There is insufficient evidence to determine whether trends exist in the meridional overturning circulation of the global ocean or in small scale phenomena such as tornadoes, hail, lightning and dust-storms."
At first glance, the number of tornadoes seems to have increased since 1950. But that could be due to more people reporting tornadoes, or more buildings being hit as the country's population grows and its cities and towns expand.In 1950, there were about 600 tornado reports.In 2010, there were about 1,500.
There are also more Doppler radars today — the 169 owned by the NWS were installed beginning in the 1990s — to keep an eye on supercells.
Yet there are reasons to think that climate change could create more severe tornadoes in Tornado Alley, since there is some indication that severe thunderstorms will increase. Global warming could change two of the basic ingredients for a severe thunderstorm — atmospheric instability and wind shear.
As temperature increases, so does instability. But as the poles warm, the large-scale temperature change across the atmosphere and vertical wind shear will decrease, said Harold Brooks, an atmospheric scientist at the U.S. National Oceanic and Atmospheric Administration's National Severe Storms Laboratory in Norman, Okla.
"So, you end up with one thing being more favorable, the other less," Brooks told OurAmazingPlanet."We don't even know if that means we should expect more tornadoes or less tornadoes."
Scientists need a better record of the number of tornadoes that form each year, but detecting every tornado isn't likely, Brooks said. The best hope is to do better with computer models to connect big changes in the environment with tornadoes, so scientists can say how often we'll have to put out tornado warnings in a warmer world.
What will this year bring?
There are clues in the climate about what this year's tornado season may bring.
If the La Niña climate pattern (governed by colder-than-normal Pacific Ocean waters and changes to prevailing atmospheric winds) continues to fade as expected, the Arctic outburst that was behind many of North America's winter storms could be more of a factor because it could add instability and vorticity (the tendency of fluids, such as air, to spin) to the atmosphere, Patzert said.
"At this point, La Niña is on the wane," Patzert said. "This strong negative Arctic oscillation pattern which has given such a fierce winter for Europe and the United States, that's the one we should definitely keep an eye on."
The Arctic Oscillation tends to be weekly to monthly, so there's really no way to create a tornado forecast based on it. Numerical models are becoming more advanced, but they take months to calculate the probabilities of a tornado forming, so that's not practical either, said Andrew Taylor, a meteorologist with the National Weather Service. So it's watch and wait for those hoping to avoid tornadoes.
"If you've got an inside track to the weather gods, you ask for a positive Arctic Oscillation and a resurgence of La Niña," Patzert said.
By: Susie77, 12:01 AM GMT on March 02, 2011
... and the aurora is active:
Live from Jokkmokk, Sweden
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.