Satellite sees through Arctic ice for signs of climate change

High resolution radar documents ice growth during the Arctic winter in the Beaufort Sea off the northern coast of Alaska

By Environmental News Network staff

The inhospitable environment and persistent cloud cover over the Arctic Ocean succeeded in keeping scientists at bay from any intimate knowledge of the region.

Now, Ronald Kwok and colleagues at the Jet Propulsion Laboratory in Pasadena, California, have a new tool in their science kit to understand the role the Arctic plays in Earth's weather systems. Sensors on a Canadian satellite called Radarsat can peer though clouds and the darkness of night.

These sensors allow scientists to see, for the first time, the complete ice cover of the Arctic and to track any shifts and changes over the course of an entire winter in resolutions of up to 328 feet - 100 times better than those taken by previous satellites.

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"The role of the polar regions in the global climate is not well known," said Kwok, a senior research scientist at JPL. "Yet all the storms in the winter are from the Arctic."

The previous tracking system consisted of passive-microwave technology that could only examine Arctic ice to resolutions of 15.5 miles. The system was often hampered by cloud cover. Radarsat gives researchers a high-resolution picture of the Arctic every three days.

"Before we knew only the extent of the ice cover," said Kwok. "We also knew that the sea ice extent had decreased over the last 20 years, but we knew very little about ice thickness."

Instead of measuring ice with submarines, researchers now use advanced radar that sees through the ice and tracks changes over the course of an entire winter

Since the 1950s, submarines have measured the thickness of Arctic ice in specific places but never for the entire region. While Radarsat sensors cannot measure the thickness of ice already present, it is able to measure seasonal ice that is produced or lost each year.

"We can't compare that with the submarine measurements of the '50s and '60s, but eventually we will have a hard data set to compare with itself," said Kwok. "The data we will be collecting will be used to improve climate models."

Current models show that Earth is getting warmer and warmer due to increased emissions of carbon dioxide from the burning of fossil fuels and other human-induced emissions of greenhouse gases.

As the Earth warms, researchers believe the Arctic ice will thaw and become thinner. As the ice thins, more solar radiation can enter the ocean and warm the sea water, which will cause icecaps to melt more quickly.

Radarsat will supply scientists with hard data on how much ice is lost or gained each year. These figures can be added to climate models, providing a better understanding of Earth's climate.

"It is important to improve the climate models, so we have higher confidence in the results," said Kwok. "A lot of change is going on in the climate and our weather is definitely affected by polar climate."

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Radarsat
Jet Propulsion Laboratory
National Snow and Ice Data Center

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