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A viral social media put up claimed to put up an actual photograph of Antarctica as seen from house. It’s not a photograph, however it makes use of NASA satellites to indicate sea ice cowl.
A Twitter account devoted to astrophotography shared an image it said was Antarctica as seen from house. The picture, which seems to depict a large ring of sea ice across the continent, has been preferred 140,000 instances because it was first posted July 15.
Probably the most fashionable replies to the photograph was from an individual who believed the photograph was proof that international warming is a hoax.
“Do not see any melting polar cap there, loads of ice,” mentioned the person in the reply. “International warming? No.”
THE QUESTION
Is that this an actual photograph of Antarctica as seen from house?
THE SOURCES
THE ANSWER
No, this isn’t an actual photograph of Antarctica as seen from house. It’s a picture a NASA scientist created utilizing actual satellite tv for pc information to depict what the continent would look in the course of the time of 12 months when it’s too darkish for any satellites to {photograph} it.
WHAT WE FOUND
The picture within the tweet, which isn’t an actual photograph, is a visualization by NASA’s Cindy Starr launched in 2007. The visualization was designed to depict the extent of the ocean ice within the Antarctic on Sept. 21, 2005.
Sea ice is frozen ocean water that kinds, grows and melts totally throughout the ocean. In distinction, glaciers and icebergs kind on land. Within the visualization that went viral, the ocean ice is the world of sunshine blue between the darkish blue of the unfrozen ocean and the white of the continent.
Starr created the picture utilizing a mixture of actual information and photographs from NASA satellites. For the ocean ice, Starr pulled from information collected by NASA’s AQUA satellite tv for pc, which measures Earth’s microwave radiation to find out how a lot sea ice surrounds Antarctica. Microwave radiation readings from land, sea ice and open ocean are all totally different, so scientists can use the readings to establish sea ice and measure it.
She then mixed that microwave radiation information with infrared radiation readings from each NASA’s AQUA satellite tv for pc and its TERRA satellite tv for pc. This type of radiation creates infrared gentle, which is invisible to the human eye however could be picked up by gear like satellites. Starr used infrared readings from September 2004 to create the Antarctic continent, and used readings from 2002 so as to add within the cloud cowl.
Why would NASA have to make use of all of this information to create this picture, as a substitute of simply utilizing satellite tv for pc photographs? It’s as a result of Antarctica is in fixed darkness throughout its winter, which happens throughout the identical months that make up American summertime. Since a lot of Antarctica can be shrouded by darkness in the course of the winter, NASA says it might solely {photograph} the continent in the course of the summer season.
Precise NASA photographs of Antarctica are all the time taken in the course of the continent’s spring or summer season. Antarctic sea ice seems white in these photographs, virtually similar to the colour of the continent itself, somewhat than gentle blue prefer it seems within the visualization. There’s little or no sea ice in these photographs, a stark distinction to the ocean ice extent depicted within the visualization.
Antarctica’s sea ice varies drastically between seasons, which is essential for understanding why the ocean ice seems prefer it covers a a lot bigger space than we’d usually see in a photograph of Antarctica.
A picture created by the Nationwide Snow and Ice Knowledge Heart (NSIDC) depicts the typical minimal and most sea ice throughout March and September for the Arctic and Antarctic from 1981 by means of 2010. It exhibits that in September, which is winter for Antarctica, sea ice usually surrounds the continent in a lot the identical means the NASA visualization depicts. However in February, a summer season month for Antarctica, virtually all the sea ice surrounding the continent melts away.
“At its winter most, Antarctic sea ice covers an space of round 11 million sq. miles: virtually twice the scale of the USA of America, and bigger than Antarctica itself,” the Antarctic and Southern Ocean Coalition says.
Not solely does Antarctic sea ice fluctuate wildly between seasons, however it additionally does so on an annual foundation, too.
Since measurements started in 1978, Antarctica’s sea ice cowl regularly elevated for about 30 years. In 2014, Antarctic sea ice cowl hit a file excessive, based on the Antarctic and Southern Ocean Coalition. In 2017, simply three years later, it hit a file low.
“Inside solely three years, 35 years of gradual beneficial properties had been misplaced,” the Antarctic and Southern Ocean Coalition mentioned.
Researchers are at present learning Antarctica’s altering sea ice to enhance the efficiency of local weather fashions and higher predict the modifications to return. The Antarctic and Southern Ocean Coalition say warming oceans, native winds, cloud cowl, meltwater from ice cabinets, the ozone gap and variable local weather patterns such because the El Niño have an effect on Antarctic sea ice dynamics. It’s at present unknown whether or not the properties of the ice, equivalent to its thickness, is altering as a consequence of international warming
NASA provides a timeline of September and February Antarctic sea ice cowl from year-to-year, and the way that 12 months’s ice compares to the median between 1981 and 2010. Sea ice cowl in September 2005, the identical month the visualization from the tweet depicts, was across the winter peak’s median, if barely much less.
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