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Analyzing four decades of winter climate data, beginning in 1965, University of New Hampshire scientists found that regional temperatures are rising at a rate of 0.8 degrees per decade. Meanwhile, the number of days with snow on the ground is decreasing at the rate of 3.6 days per decade, the study found.
Both trends have intensified with time and were strongest in the heart of winter - January and February. "A lot of people who have lived in the Northeast for 30 to 40 years have witnessed a distinct change in the character of their Northeast winter," said Elizabeth Burakowski, lead author of the study and a climate researcher at UNH. "Climate has changed in the past, and it will change in the future, but what makes this period distinct is we're witnessing this change in a human lifetime."
The study, published in October in the Journal of Geophysical Research-Atmospheres, covered a region that stretches from New Jersey to Maine. Researchers analyzed data from 123 monitoring stations that reported the presence of snow on the ground, 88 stations monitoring snowfall, and 138 stations monitoring temperature.
Other studies have shown that winters in the Northeast are warming faster than other seasons, but this work used a more rigorous analysis and also suggested a possible way in which changes in snow cover may amplify warming effects.
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http://www.boston.com/news/local/massachusetts/articles/2008/12/11/winter_easing_its_grip_on_northeast/