Two such scientists are cyclone experts Tilinina and Gulev, who worked with Bromwich to look for evidence of telltale changes in wind direction and air pressure in the ASR data. They compared the results to three other data re-analysis groups, all of which combine global weather data.
"We found that ASR provides a new vision of the cyclone activity in high latitudes, showing that the Arctic is much more densely populated with cyclones than was suggested by the global re-analyses," Tilinina said.
One global data set used for comparison was ERA-Interim, which is generated by the European Centre for Medium-Range Weather Forecasts. Focusing on ERA-Interim data for latitudes north of 55 degrees, Tilinina and Gulev identified more than 1,200 cyclones per year between 2000 and 2010. For the same time period, ASR data yielded more than 1,900 cyclones per year.
When they narrowed their search to cyclones that occurred directly over the Arctic Ocean, they found more than 200 per year in ERA-Interim, and a little more than 300 per year in ASR.
There was good agreement between all the data sets when it came to big cyclones, the researchers found, but the Arctic-centered ASR appeared to catch smaller, shorter-lived cyclones that escaped detection in the larger, global data sets. The ASR data also provided more detail on the biggest cyclones, capturing the very beginning of the storms earlier and tracking their decay longer.
Extreme Arctic cyclones are of special concern to climate scientists because they melt sea ice, Bromwich said.
"When a cyclone goes over water, it mixes the water up. 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 u
|Contact: Jamie Abel|
Ohio Supercomputer Center