Arctic sea ice hit its annual minimum on Sept. 17,
2014. The red line in this image shows the 1981-2010 average minimum extent.
Data provided by the Japan Aerospace Exploration Agency GCOM-W1
satellite.
Image Credit:
NASA/Goddard Scientific Visualization
Studio
Arctic sea ice coverage continued its below-average trend this year as the
ice declined to its annual minimum on Sept. 17, according to the NASA-supported
National Snow and Ice Data Center (NSIDC) at the University of Colorado,
Boulder.
Over the 2014 summer, Arctic sea ice melted back from its maximum extent
reached in March to a coverage area of 1.94 million square miles (5.02 million
square kilometers), according to analysis from NASA and NSIDC scientists. This
year’s minimum extent is similar to last year’s and below the 1981-2010 average
of 2.40 million square miles (6.22 million square km).
"Arctic sea ice coverage in 2014 is the sixth lowest recorded since 1978. The
summer started off relatively cool, and lacked the big storms or persistent
winds that can break up ice and increase melting," said Walter Meier, a research
scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Sea ice acts as an air conditioner for the planet,
reflecting energy from the sun. On Sept. 17, the Arctic sea ice reached its
minimum extent for 2014. At 1.94 million square miles (5.02 million square
kilometers), it’s the sixth lowest extent of the satellite
record.
Image Credit:
NASA's Goddard Space Flight Center/J.
Ng
“Even with a relatively cool year, the ice is so much thinner than it used to
be,” Meier said. “It’s more susceptible to melting.”
This summer, the Northwest Passage above Canada and Alaska remained
ice-bound. A finger of open water stretched north of Siberia in the Laptev Sea,
reaching beyond 85 degrees north, which is the farthest north open ocean has
reached since the late 1970s, according to Meier.
An animation of daily Arctic sea ice extent from
March 21 to Sept. 17 – when the ice appeared to reach it’s minimum extent for
the year. It’s the sixth lowest minimum sea ice extent in the satellite era. The
data was provided by the Japan Aerospace Exploration Agency.
Image Credit:
NASA/GSFC Scientific Visualization Studio/T.
Schindler
While summer sea ice has covered more of the Arctic in the last two years
than in 2012’s record low summer, this is not an indication that the Arctic is
returning to average conditions, Meier said. This year’s minimum extent remains
in line with a downward trend; the Arctic Ocean is losing about 13 percent of
its sea ice per decade.
To measure sea ice extent, scientists include areas that are at least 15
percent ice-covered. The NASA-developed computer analysis, which is one of
several methods scientists use to calculate extent, is based on data from NASA’s
Nimbus 7 satellite, which operated from 1978 to 1987, and the U.S. Department of
Defense’s Defense Meteorological Satellite Program, which has provided
information since 1987.
In addition to monitoring sea ice from space, NASA is conducting airborne
field campaigns to track changes in Arctic sea ice and its impact on climate.
Operation IceBridge flights have been measuring Arctic sea ice and ice sheets
for the past several years during the spring. A new field experiment, the Arctic
Radiation – IceBridge Sea and Ice Experiment (ARISE) started this month to
explore the relationship between retreating sea ice and the Arctic climate.
For more information on sea ice observations from space, visit:
NASA monitors Earth's vital signs from land, air and space with a fleet of
satellites and ambitious airborne and ground-based observation campaigns. NASA
develops new ways to observe and study Earth's interconnected natural systems
with long-term data records and computer analysis tools to better see how our
planet is changing. The agency shares this unique knowledge with the global
community and works with institutions in the United States and around the world
that contribute to understanding and protecting our home planet.
For more information about NASA's Earth science activities in 2014, including
the Operation IceBridge and ARISE airborne campaigns, visit:
NASA
Guillermo Gonzalo Sánchez Achutegui
Inscríbete en el Foro del blog y participa : A Vuelo De Un Quinde - El Foro!
No hay comentarios:
Publicar un comentario