Connect with us

Science

Dramatic Melting of Antarctica Under Record Heat Caught by Shocking NASA Satellite Images – SciTechDaily

Published

 on


On February 6, 2020, weather stations recorded the hottest temperature on record for Antarctica. Thermometers at the Esperanza Base on the northern tip of the Antarctic Peninsula reached 18.3°C (64.9°F)—around the same temperature as Los Angeles that day. The warm spell caused widespread melting on nearby glaciers.

The warm temperatures arrived on February 5 and continued until February 13, 2020. The images above show melting on the ice cap of Eagle Island and were acquired by the Operational Land Imager (OLI) on Landsat 8 on February 4 and February 13, 2020.

The heat is apparent on the map below, which shows temperatures across the Antarctic Peninsula on February 9, 2020. The map was derived from the Goddard Earth Observing System (GEOS) model, and represents air temperatures at 2 meters (about 6.5 feet) above the ground. The darkest red areas are where the model shows temperatures surpassing 10°C (50°F).

Mauri Pelto, a glaciologist at Nichols College observed that during the warming event, around 1.5 square kilometers (0.9 square miles) of snowpack became saturated with meltwater (shown in blue above). According to climate models, Eagle Island experienced peak melt—30 millimeters (1 inch)—on February 6. In total, snowpack on Eagle Island melted 106 millimeters (4 inches) from February 6- February 11. About 20 percent of seasonal snow accumulation in the region melted in this one event on Eagle Island.

“I haven’t seen melt ponds develop this quickly in Antarctica,” said Pelto. “You see these kinds of melt events in Alaska and Greenland, but not usually in Antarctica.” He also used satellite images to detect widespread surface melting nearby on Boydell Glacier.

Pelto noted that such rapid melting is caused by sustained high temperatures significantly above freezing. Such persistent warmth was not typical in Antarctica until the 21st century, but it has become more common in recent years.

Antarctica Air Temperature February 9, 2020

Antarctica Air Temperature, February 9, 2020.

The warm temperatures of February 2020 were caused by a combination of meteorological elements. A ridge of high pressure was centered over Cape Horn at the beginning of the month, and it allowed warm temperatures to build. Typically, the peninsula is shielded from warm air masses by the Southern Hemisphere westerlies, a band of strong winds that circle the continent. However, the westerlies were in a weakened state, which allowed the extra-tropical warm air to cross the Southern Ocean and reach the ice sheet. Sea surface temperatures in the area were also higher than average by about 2-3°C.

Dry, warm foehn winds also could have played a part. Foehn winds are strong, gusty winds that cause downslope windstorms on mountains, often bringing warm air with them. In February 2020, westerly winds ran into the Antarctic Peninsula Cordillera. As such winds travel up the mountains, the air typically cools and condenses to form rain or snow clouds. As that water vapor condenses into liquid water or ice, heat is released into the surrounding air. This warm, dry air travels downslope on the other side of the mountains, bringing blasts of heat to parts of the peninsula. The drier air means fewer low-lying clouds and potentially more direct sunlight east of the mountain range.

“Two things that can make a foehn-induced melt event stronger are stronger winds and higher temperatures,” said Rajashree Tri Datta, an atmospheric researcher at NASA’s Goddard Space Flight Center. With warmer air in the surrounding atmosphere and ocean, the conditions were conducive this month for a foehn wind event.

This February heatwave was the third major melt event of the 2019-2020 summer, following warm spells in November 2019 and January 2020. “If you think about this one event in February, it isn’t that significant,” said Pelto. “It’s more significant that these events are coming more frequently.“

Image Credits: NASA Earth Observatory images by Joshua Stevens, using Landsat data from the U.S. Geological Survey and GEOS-5 data from the Global Modeling and Assimilation Office at NASA GSFC.

Let’s block ads! (Why?)



Source link

Continue Reading

Science

STEVE appears over Canada during 'surprise' solar storm – Livescience.com

Published

 on


In the dark of Sunday night and Monday morning (Aug. 7 and 8), a surprise solar storm slammed into Earth, showering our planet in a rapid stream of charged particles from the sun. The resulting clash of solar and terrestrial particles in Earth‘s atmosphere caused stunning auroras to appear at much lower latitudes than usual — and, in southern Canada, triggered a surprise cameo from the mysterious sky phenomenon known as STEVE.

Alan Dyer, an astronomy writer and photographer based in southern Alberta, Canada, caught the wispy ribbons of green and violet light on camera as they shot through the sky.

“STEVE lasted about 40 minutes, appearing as the … aurora to the north subsided,” Dyer wrote on Twitter (opens in new tab) on Aug. 8. “STEVE was ‘discovered’ here so he likes appearing here more than anywhere else!”

Related: Earliest documented aurora found in ancient Chinese text

As Dyer noted, the strange sky glow called STEVE was first described by citizen scientists and aurora hunters in northern Canada in 2017. STEVE is typically composed of an enormous ribbon of purplish light, which can hang in the sky for an hour or more, accompanied by a “picket fence” of green light that usually disappears within a few minutes. 

The glowing river of light may look like an aurora, but it’s actually a unique phenomenon that was considered “completely unknown” to science upon its discovery. Today, scientists have a slightly better idea of what’s going on. 

STEVE (short for “strong thermal velocity enhancement”) is a long, thin line of hot gas that slices through the sky for hundreds of miles. The hot air inside STEVE can blaze at more than 5,500 degrees Fahrenheit (3,000 degrees Celsius) and move roughly 500 times faster than the air on each side of it, satellite observations have shown.

Whereas the northern lights occur when charged solar particles bash into molecules in Earth’s upper atmosphere, STEVE appears much lower in the sky, in a region called the subauroral zone. That likely means solar particles aren’t directly responsible for STEVE, Live Science previously reported. However, STEVE almost always appears during solar storms like Sunday’s, showing up after the northern lights have already begun to fade.

One hypothesis suggests that STEVE is the result of a sudden burst of thermal and kinetic energy in the subauroral zone, somehow triggered by the clash of charged particles higher in the atmosphere during aurora-inducing solar storms. However, more research is needed to uncover the true secrets of STEVE. In the meantime, we can simply bask in its otherworldly glow and wave back at its twinkling green fingers.

Originally published on Live Science.

Adblock test (Why?)



Source link

Continue Reading

Science

Perseid meteor shower: when to catch it in Manitoba | CTV News – CTV News Winnipeg

Published

 on


The peak of a spectacular space light show is expected to happen by the end of the week.

The Perseid meteor shower is expected to be at its best and brightest the night of Aug. 12 going into the morning of Aug. 13.

Scott Young, an astronomer at the Manitoba Museum, said this is an annual event that will produce dozens of shooting stars throughout the night.

“Every meteor is a piece of dust from outer space that is crashing into the earth at tremendous speed and basically vaporizing in a poof and a flash of light, and that it is what we see as a meteor,” he said. “On certain nights of the year, the earth in its orbit around the sun actually goes through a cloud of dust, sort of like an interplanetary dust bunny, essentially, and all that dust hits on the same night … and so we are basically crashing through the dust left behind by a comet.”

The cloud of dust was left behind by the comet Swift-Tuttle, which last passed by the earth in 1992. Since then, the meteor shower has reached its peak between Aug. 11 and 13.

For those who are looking to enjoy the meteor show, Young suggests people get away from city lights, especially this year as the shower also coincides with a full moon.

“The moon can wash out those fainter meteors, and also if you are in the city, city lights will also wash out those fainter meteors. If you want to see the best show, you want to go late Friday after midnight, into the early morning hours of Saturday.”

If people can’t see the shower that night, Young says not to worry as the Perseid meteor shower is already happening right now and will continue to the end of August. As long as people are away from bright lights, Young says they should be able to see some shooting stars.

He recommends going to places like Birds Hill Provincial Park to enjoy the shower, but noted if people can find a place that is away from direct light, whether that be a park within the City of Winnipeg, or even a person’s backyard, he suggests people will be able to see something.

Once the meteor shower is over, however, Young does have a cautionary tale to share.

“We get dozens calls of people seeing an interesting rock on the ground and thinking that they’ve found a meteorite. There are no meteorites that will fall and actually land on the ground from this shower. These are little pieces of dust and they completely vaporize in the atmosphere. You might find meteorites out there, but they are very, very rare and so don’t get all excited about every rock that you find after this. The odds are it’s a meteor-wrong and not a meteorite.”

Young said weather-permitting, the Manitoba Museum will livestream the shower on its social media channels.

Adblock test (Why?)



Source link

Continue Reading

Science

NASA’s Hubble Space Telescope captured two festive-looking nebulas – Tech Explorist

Published

 on


The image shows NGC 248, about 60 light-years long and 20 light-years wide. They are two nebulas, situated to appear as one. The nebulas, together, are called NGC 248.

Initially discovered in 1834 by the astronomer Sir John Herschel, NGC 248 resides in the Small Magellanic Cloud, located approximately 200,000 light-years away in the southern constellation Tucana.

Small Magellanic Cloud is a dwarf galaxy that is a satellite of our Milky Way galaxy. The image is part of a study called Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE).

The dwarf satellite galaxy contains several brilliant hydrogen nebulas, including NGC 248. Intense radiation from the brilliant central stars is heating hydrogen in each nebula, causing them to glow red.

The study’s principal investigator, Dr. Karin Sandstrom of the University of California, San Diego, said“The Small Magellanic Cloud has between a fifth and a tenth of the amount of heavy elements that the Milky Way does. Because it is so close, astronomers can study its dust in great detail and learn about what dust was like earlier in the history of the universe.”

“It is important for understanding the history of our galaxy, too. Most of the star formation happened earlier in the universe, at a time when there was a much lower percentage of heavy elements than there is now. Dust is a critical part of how a galaxy works, how it forms stars.”

The image is part of a study called Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE). The data used in this image were taken with Hubble’s Advanced Camera for Surveys in September 2015.

Adblock test (Why?)



Source link

Continue Reading

Trending