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6 March 2017

New NASA Study Improves Sea Ice Forecasting in Arctic Summer

As climate change continues to do battle with the Earth, threatening global ecosystems and industries alike in the process, ensuring that we have a proper understanding of how our planet is reacting to these changing conditions is vital. Nowhere perhaps is this more crucial than the Arctic; conditions in the frozen North have a drastic impact not only on the surrounding area, but around the world, influencing weather conditions, global temperatures, ocean currents and human activity as ice levels fluctuate  and adapt to changing seasons.

However, our knowledge of the Arctic is far from complete. For one, scientists still struggle each year, as the sea ice begins its retreat following its wintertime peak, to predict the extent to which the ice will shrink. A new NASA forecasting model now aims to use satellite data gathered since 1979 to refine and improve upon current systems, thereby allowing for much more accurate predictions.

Currently, there are a couple of accepted methods when it comes to gathering data on sea ice extent in the Arctic summer. The first, and simplest, is to assume a continuation of long-terms trends; while accurate to some extent, this approach does not account for outlying seasons or years when the ice may be present at higher levels than such trends indicate. The second relies more heavily on real-time data, analysing the physical characteristics of the sea ice as the year goes on and incorporating this into estimations concerning how September sea ice levels may differ from the expected long-term trend. The new forecasting model is essentially a high-tech combination of these two approaches, as the team behind its development found that forecasts based on melt onset were most reliable in early spring, whilst sea ice coverage-based predictions were more reliable from June onwards.

NASA claims that, by implementing the new forecasting model, they can predict the extent of September sea ice coverage as early as March of the given year. Making use of real-time satellite data allows the predictions to improve as the year goes on as they are able to incorporate more information about that year’s sea ice melt and open water distribution into their algorithms.

“What we have shown is that we can use information collected in the spring and onwards to determine if we should see more or less ice come the end of summer than expected from the long-term decline,” said Alek Petty, lead author of the new paper, which was published on February 27th in the journal Earth’s Future.

The team tested the model by making predictions for each year of the satellite record up to the current date, evaluating these results against both predictions made on the basis of long-term trends, and historical records of the actual minimum extent of the sea ice for that given year.

“We found that our forecast model does much better than the linear trend at capturing what actually happened to the sea ice in any specific year,” Petty said.

“Our model is very good at catching the highs and the lows. The absolute values? Not exactly, but it tends to do very well at seeing when the sea ice extent is going to go up and when it’s going to go down compared to what we might be expecting for that year.”

Another benefit of the new forecasting model is its ability to make predictions for specific areas, such as the Beaufort and Chukchi seas to the north of Alaska, rather than just the Arctic as a whole.

“The state of sea ice has a large impact on the Alaskan hunting communities,” Petty said. “If they know ahead of time what the sea ice cover is going to be like that year, they might be able to infer the availability of the species they hunt.”

The model is scheduled to start making predictions in the coming weeks.

Sam Bonson

Sam is an aspiring novelist with a passion for fantasy and crime thrillers. He is currently working as a content writer, journalist & editor in an attempt to expand his horizons.