Across the US, this winter has been unusually balmy, with precious little snow, or even rain, and with trees taking the warmth as a cue to send out new leaves in January. Temperature data support those impressions: in the first week of the year, temperatures were 40 degrees F higher than average in some parts of the Midwest, Discovery News reports, and snow cover is at 19 percent across the country, compared to an average of 50 percent at this time of year. In notoriously chilly Fargo, North Dakota, the January 4 high temperature of 55 broke the record for the warmest January day on record, and the country has seen close to no rain or snow in this first week of 2012, writes Wunderground meteorologist Jeff Masters. “It has been remarkable to look at the radar display day after day and see virtually no echoes,” he writes, referring to the radar echoes reflected back by storms. “It is very likely that this has been the driest first week of January in U.S. recorded history.”
Why this freaky weather? The answer is, basically, an extremely unusual jet stream over the last few months, Masters explains. The jet stream that defines weather in North America is controlled by the North Atlantic Oscillation and the Arctic Oscillation, climate patterns that reflect differences in sea-level pressure across certain stretches of the globe. And the pressure differences this year have been tremendous—for the North Atlantic Oscillation (NAO), this year saw the most extreme difference ever recorded in December, and the second most extreme for the Arctic Oscillation (AO).
The Eastern Seaboard is warily watching the progress of Hurricane Irene, wondering what course the storm will take and just how ferocious it will be. Predicting the path of a hurricane still involves some guesswork—but thanks to rapidly improving computer models and data-gathering abilities, Tekla Perry reports in IEEE Spectrum, scientists are able to make more accurate forecasts farther in advance than they were even five or ten years ago. In fact, the predicted track of a hurricane over the next 48 hours today is as accurate as a prediction for the next 24 hours was 10 years ago—a day that can make a big difference for people deciding whether to evacuate and how to prepare before the storm. Boosts in computing power mean scientists can run more, faster, and more detailed simulations of the storm, and technologies like Dopper radar provide detailed data on wind speed, air pressure, and temperature as storms progress.
In the realm of meteorology, bats, birds, and insects are usually considered “animalas non grata,” since they create unwanted noise in the Doppler radar readouts used to study storms. But now, thanks to better radar station networking and the sharing of unfiltered data, ecologists have realized that these radar systems can be used as powerful animal tracking tools.
At last week’s American Association for the Advancement of Science meeting, researchers Thomas Kunz, Winifred Frick, and Phillip Chilson explained how Dopplar data can be used by ecologists. They call their new discipline aeroecology.
This melding of meteorology and ecology started with an “Aha!” moment:
“Dr Kunz and I were meeting Dr Chilson about a year ago over breakfast and they kept talking about the ‘QPE’, and finally I asked what it is,” Dr Frick told the meeting. It stands for quantitative precipitation estimator — a numerical method to measure how much rain there is in a storm front. “I paused and said, ‘you can estimate the number of raindrops in a raincloud? Do you think we could estimate the number of bats in a bat cloud?’” To calibrate their experiment, the team took a bat into a chamber where the degree to which it reflects radio waves could be measured. “From those measurements and using radar, we’ve been able to adapt those QPE measurements to a ‘QBE’ – a quantitative bat estimator,” Dr Frick said. [BBC News]