Arctic Cyclones More Common Than Thought, Impacting Sea Ice

Cyclones can whip up water and wind, creating conditions that can impact local climate and conditions. Now, scientists have discovered that far more of these wind storms spin across the Arctic than previously thought. It turns out that 1,900 churned across the top of the world from 2000 to 2010, leaving warm water and air in their wakes and melting sea ice in the Arctic Ocean.

Cyclones are zones of low atmospheric pressure that have wind circulating around them. They can form over land or water, and go by different names depending on their size and where they are located. In Ohio, for example, a low-pressure system in December would simply be called a winter storm. Extreme low-pressure systems formed in the tropical waters can be called either hurricanes or typhoons.

Yet until now, cyclones have been difficult to detect. They can be small in size or short in duration and, in this case, occur in unpopulated areas. In order to get a better picture of cyclones in the Arctic, the researchers used statistics and computer algorithms to combine and re-examine diverse sources of historical weather information, such as satellite imagery, weather balloons, buoys and weather stations on the ground. The findings revealed that there are about 40 percent more cyclones than previously thought.

"We can't yet tell if the number of cyclones is increasing or decreasing, because that would take a multidecade view," said Bromwich, one of the researchers, in a news release. "We do know that, since 2000, there have been a lot of rapid changes in the Arctic--Greenland ice melting, tundra thawing--so we can say that we're capturing a good view of what's happening in the Arctic during the current time of rapid changes."

While researchers are unsure exactly whether these cyclones are increasing in number, they do know that more of them are happening that first thought. This, in turn, could lead to further ice melt, which could have implications for climate models.

"When a cyclone goes over water, it mixes the water up," said Bromwich in a news release. "In the tropical latitudes, surface water is warm, and hurricanes churn cold water from the deep up to the surface. In the Arctic, it's the exact opposite: there's warmer water below, and the cyclone churns that warm water up to the surface, so the ice melts."

The findings were presented Thursday, Dec. 12 at the American Geophysical Union meeting.