NASA: Arctic sea ice narrowed significantly

How long will we see a Arctic without ice in the summer? Studies based on NASA's ICESat satellite will reveal that.

The Arctic sea ice is considerably thinner because the thin ice changes seasonally to replace the permanent ice record. The new results observed by NASA satellites provide clear evidence of a change in the Arctic ice cover.

So far, NASA and Washington University scientists in Seattle have conducted the most comprehensive survey to estimate the volume and thickness of the ice covering the Arctic Ocean using the ICESat satellite. Ron Kwoh, of NASA's Jet Propulsion Laboratory in Pasadena, California, who led the research team presented new findings in Geophysical Research-Oceans last July 7.

Ice melting phenomenon in the North Pole (Photo: VNN)

The Arctic ice cap expands every winter when the sun sets for a few months and severe cold occurs. In the summer, Arctic ice melts or gets wind and ocean currents swept away. However, the permanent tape still exists, it has an average thickness of nearly 9 feet (~ 3 m) and a seasonal tape about 6 feet thick (~ 2m).

From ICESat's measurements, scientists found that Arctic sea ice is usually thinned by 7 inches (~ 18cm) each year and over four winters (2004-2008), sea ice has thinned 2.2 feet ( ~ 67cm). The area of ​​permanent ice over the years has decreased by 42% .

Ron Kwok said even in the past years when the size of the sea ice has remained stable, but the thickness and volume of ice covered continue to decrease, making the sea ice continue to shrink. The data provided by ICESat will help scientists know how fast the Arctic ice is falling and how long it will take to see a Arctic that has no ice in the summer.

In recent years, the amount of replacement ice in winter is no longer enough to compensate for the loss of ice in the summer. As a result, in the summer, the increased freezing water absorbs heat and heats the oceans, the ice will melt more. Between 2004 and 2008, permanent ice shrinks more than 595,000 square miles (~ 957,000 km ² ) - roughly the size of Alaska.

During the study period, the relationship of the two layers of ice (ice changes in season and ice storage) in the total volume of Arctic ice cover has reversed. In 2003, 62% of Arctic ice volume was background tape and 38% was seasonal change. By 2008, 68% were bandages that changed seasonally and 32% were bandages.

The sea ice area in 2005 was significantly reduced compared to 1979 (Photo: NASA).

The team believes that the change in ice thickness and volume in the Arctic Ocean is generally due to warming and anomalies in the flow of ice. Kwoh said that there was almost no additional supply of permanent ice, along with the unusually high ice separation from the North Pole after the summer of 2005 and 2007, causing ice volumes in the Arctic to drop to record levels.

Jay Zwally, co-researcher and scientist at the ICESat project at NASA's Goddard Center for Astronautics in Greenbelt, said one of the major problems has been overlooked when information about what's happening to the sea. The tape is comprehensive information about the thickness of the tape . The US Navy submarine provided specific data on the thickness of the ice. These figures match exactly with ICESat's measurement information so we are completely confident about the ability to monitor the thickness of ice across the Arctic region via satellites.