Antarctic ice melting: warm ocean currents to melt the ice below

Multinational research team study concluded that warm ocean currents, flowing through Antarctic ice shelf is the main cause of the Antarctic ice ice loss, this discovery will enable scientists to make more accurate predictions of future sea level rise on the 25th.

With the U.S. Aeronautics and Space Administration (NASA) of ice, clouds, senior terrestrial satellite (Ice, Cloud, and land Elevation Satellite, ICESat) to obtain information on auxiliary accompanied by a computer model, the researchers were able to distinguish by the melting ice shelf two major forces: the warm current from the sea, under the lead under the ice to melt, and the other is due to the result of warm air above the ice shelf to melt.

Moderator of the research project, the British Antarctic Survey, (British Antarctic Survey) Hamish Pritchard said: "no melting glaciers at the top of the snow by the summer sun, warm ocean currents from the next, near a very large number of ice in order to melt away." He pointed out, "The real interesting glacier sensitivity of this phenomenon some ice shelf thinning of the year a few meters, causing glaciers year discharge billions of tons of ice to the sea this phenomenon proves the importance of the ice shelf on the slow glacial speed; Glacier ice ice bed to be able to control the loss of Antarctic ice bed. "

Researchers collected by instruments installed in ICESat laser light 4.5 million pen laser ranging data, drawn out to cover almost the entire thickness of the floating ice shelf of Antarctica change, showing the trend of the entire continent of ice shelf melting.

54 ice shelf map data the 20 ice shelf (the majority located in West Antarctica) ice beneath the warm ocean current flows through the melt, recharge these thin ice shed further accelerate the inland glaciers flow to the sea, so that accelerated sea level rise more ice into the sea.

In the last 5 years of the study period (October 2003 - October), the study found that this causes in marine ice thinning the driving force, to become the largest and most rapidly the main reason for the loss of the West Antarctic ice.

This study was conducted by belonging to the British Antarctic Survey, (located at the University of Cambridge), the Netherlands, Utrecht University, University of California, San Diego, and Oregon non-profit organization "Earth and Space Research (Earth and Space Research) scientists have jointly completed and the results published in the journal Nature.

Scientists use time series to draw 4.5 million pen space telemetry data collected by ICESat covering almost the entire Antarctic continent floating ice shelf thickness variation map. They measure the change in the height of the ice shelf over time, and the use of a computer model to remove the image of snowfall and other natural factors on changes in ice height. The researchers also used the tidal patterns to estimate the impact of tidal height variation of the ice.

"This study presents a space telemetry is a powerful tool to study Earth phenomena." Tom Wagner, NASA's cryosphere program (cryosphere program) scientist, said: "Together with other NASA gravity backtracking and Climate Experiment (GRACE ) land ice data from satellite radar and aircraft come, we change the ice bed will get more comprehensive information, this information will help to estimate sea level rise. "

The past, most of the use of satellite radar data to estimate the changes in ice shelves and glaciers, but laser ranging will be more precise detection of the thickness of the ice shelf changes over time. This will be more true rendering of the topography of the coastal area. Is difficult to the sense measured floating ice shelf and the boundaries of land ice Baseline (grounding line) because of the low resolution radar.

ICESat is the first one designed to study the Earth's polar regions, and the use of laser ranging technology satellite. Its service constitutes for 2003 to 2009; successor ICESat-2 satellite is scheduled to launch in 2016. This study uncovered ICESat-2 satellite launch an urgent need; limited knowledge we impact of global climate change in the polar, no other scientist Jay Zwally of NASA Goddard Space Flight Center (Goddard Space Flight Center) things like satellite telemetry to monitor these changes.

The study will also occur during the ice bottom, ice shelves and glaciers accelerated change caused by the operation of the regional wind, ice melting phenomenon observed link. Pritchard said, "Studies show that the Antarctic wind change due to climate change, which affects the strength and direction of ocean currents, and thus render the funnel-like warm water in the bottom of the ice floes. These studies and our findings are presented Antarctic glacier response to climate change and rapid change. "

Example of the Antarctic Peninsula to explain the impact of the wind. Antarctic Peninsula, Antarctica on a strip of land mass, a land mass orientation Chaoxiangna United States. This study shows that the Peninsula's largest ice shelf thinning snowmelt explain summer warm air through the surface of the ice shelf. To explain the change in the trend of melting ice melting ice phenomenon and summer of the Antarctic Peninsula sea-borne wind trend.

This study is part of the international community in order to further understand the interaction between ice and climate, sea level rise and more reliable sources of information.

The host David Vaughan of the EU-funded research projects of ice into the sea "(ice2sea program), the main contribution of this study is that a clear presentation of the bed of ice in Antarctica losing ice because in recent years. But more importantly, the future, the key is to understand the oceans to predict changes in the ice bed. Perhaps we should not only seek answers from the air of the Antarctic continent, should know more about surround sea.