Lexington, MA., September 12, 2013 — Atmospheric and Environmental Research (AER), a Verisk Analytics (Nasdaq:VRSK) company, reports some of the strongest evidence to date that Arctic sea ice loss, which contributes to an overall warmer Arctic, has links to colder winters and related extreme weather events across northern Eurasia and much of the U.S. and Canada.
In research published yesterday in Oceanography magazine, AER scientists investigate the cause for a recent string of cold winters. The findings present a previously missing piece in the quest to understand if declining sea ice is influencing more extreme weather, including colder, snowier winters. The research may also lead to more accurate forecasts of temperatures and storms that are used by the private and public sectors in preparation for the winter season.
The research shows that the "Warm Arctic/Cold Continents" temperature pattern follows autumns with less Arctic sea ice and increased Siberian snowfall. The pattern is also associated with the negative phase of the Arctic Oscillation, which is the dominant atmospheric pattern observed during severe winters and comprises a weakened jet stream and more cold air intrusions southward from the Arctic into North America and Eurasia.
"This research shows for the first time how both sea ice melt and rapid snow advance are related to more severe winter weather," Judah Cohen, Ph.D. principal scientist and director of seasonal forecasting at AER, who is lead author of the study. "The results suggest that record sea ice melt last autumn contributed to the individual extreme weather events of last winter. Using a statistical rather than dynamical model, we established the relationship between declining sea ice, more extensive snow cover in northern Eurasia, and a weakened polar vortex, which allows cold air normally confined to the northern latitudes to spread southward."
"During this time of rapid change in the Arctic climate system and our understanding of it, the scientific community must look closely at the observational record, be open-minded in considering alternative hypotheses, and not be too quick in dismissing hypotheses that do not conform with the expectations of existing models," said Charles H. Greene, associate editor of Oceanography and director of the Ocean Resources and Ecosystems Program at Cornell University. "This paper takes that perspective, and that is why it's valuable and timely. The AER scientists took a different approach to reframe the question and, as a result, they demonstrate that snow cover in Asia and Arctic sea ice are related and key to understanding our recent streak of colder winters."
"We applied the same analytical tools to sea ice that were used to demonstrate the link between Siberian snow cover, the Arctic Oscillation, and mid-latitude weather," said Jason C. Furtado, Ph.D., staff scientist at AER and co-author of the paper. "These preliminary findings provide an additional framework to understand the important connection between the Arctic and the mid-latitudes, which subsequently can be used for predictions of the fall and winter months."
The invited paper published online in Oceanography and funded by NSF and NOAA is titled "Warm Arctic - Cold Continents, a Common Pattern Related to Arctic Sea Ice Melt, Snow Advance and Extreme Winter Weather." Cohen will present the research results today at the National Academy of Sciences workshop on arctic linkages titled "Linkages between Arctic Sea Ice Loss and Mid?Latitude Weather Patterns" in College Park, Maryland.
A Track Record of Climate Forecast Innovations
Two years ago, AER scientists developed the landmark Snow Advance Index (SAI) as part of AER's continuing efforts to provide the most accurate seasonal forecasts in the public and private sectors. Last year, AER's winter prediction model demonstrated a new and successful approach to forecast the Arctic Oscillation, which is the primary influence on weather patterns in the northeastern U.S. As a result, AER scientists predicted correctly the cold and snowy winter of 2012 to 2013 — in contrast, all the dynamical climate models predicted a warm winter.
"Now we're building on that foundation to explain how another component in the climate system — arctic sea ice — contributes to winter weather patterns across the Northern Hemisphere," said Ron Isaacs, AER president and chief executive officer. "AER scientists have pioneered the idea that autumn conditions in the Arctic can influence winter weather in the mid-latitudes, and we continue to advance our understanding of this complex relationship."
About Atmospheric and Environmental Research
Atmospheric and Environmental Research helps businesses and the government anticipate and manage climate- and weather-related risks. Government agencies such as NOAA, NASA, and the Departments of Defense and Energy rely on AER's scientists to help solve weather- and climate-related problems of vital national importance in energy, environment, national security, and climate change. Energy, insurance, and manufacturing firms count on AER to help decrease their weather-related losses and improve productivity by integrating state-of-the-art climate science and weather information into their planning and decision processes. Established in 1977 and headquartered in Lexington, Massachusetts, AER is a Verisk Analytics (Nasdaq:VRSK) company. Please visit www.aer.com.