McCormick Observatory Astronomer Collects Climate Data for Weather Service

Listen to the UVA Today Radio Show report on this story by Fariss Samarrai:

March 3, 2010 — When Charlottesville broke a 116-year-old record Feb. 10 with the winter's 55th inch of snow, Ricky Patterson was there to record it.

He is Charlottesville's official volunteer weather observer for the National Weather Service.

"We got 3.8 inches that day, which put us over the previous record of 54.7 inches set during the winter of 1995-96," he said.

As of March 3, the total stands at 56.8 inches. This is also the 10th-coldest winter on record.

Nearly every morning at 8 o'clock for the past eight years, Patterson, a University of Virginia astronomer by profession, has "trudged" from his University-owned house on Observatory Hill to the McCormick weather station to record the day's minimum and maximum temperatures and the precipitation – snowfall, rainfall, or any mix between.

"News reporters tend to describe me as 'trudging'" he said, "but it's really just a hundred-yard walk. I don't think I've ever trudged."

Patterson records the data and e-mails it to the weather service. The service then merges that information with data from about 11,000 other sites around the country to create a big-picture view of the nation's climate. Over the span of time, years and decades and, ultimately, centuries, clear patterns emerge, indicating warming or cooling trends and seasonal averages.

"I collect and send the data," Patterson said. "The climatologists interpret it."

This winter's temperatures in Charlottesville have been well below average, Patterson said, and, obviously, much more snowy than usual. The typical winter here produces about 18 inches. 

Patterson is the latest in a long line of volunteer climate observers who have performed this function at McCormick Observatory since 1894. A back room there contains dozens of leather-bound ledgers, each containing hundreds of entries, written and signed in fountain pen ink by long-gone observers.

Some of them actually may have trudged to the observatory in rough weather from their homes below the hill. 

"For decades the data was mailed to the weather service," Patterson said. "Then it was sent by telegram, and then by phone. We've been using the Internet for quite a while now."

Certain observations, such as temperature, are taken by automated instruments and streamed in near-real time to the weather Web site Weather Underground.

Patterson has walked to the station in "all kinds of weather" – in the heat and humidity of summer, during snowstorms, windstorms, hail and rain and sleet and freezing rain. And on nice days, too.

He's seen all kinds of wildlife: deer, bears, turtles, snakes, raccoons, possums, skunks and other forms of varmint. He's seen red-shouldered hawks and barred owls, and a family of pileated woodpeckers.

"It's a pleasant way to start a day," he said.

On the days when he's out of town, he has backup volunteers to observe for him, including Jerry Stenger, the state climatologist at U.Va.

On a typical day, Patterson spends about 15 minutes collecting, recording and transmitting data. On snow days, he has more to do.

"What the climatologists are really interested in is precipitation," he said. "They want to know how much water an area got."

With snow it's a little tricky. Some snowfalls are very "wet," and may not get deep in inches but are made up of relatively large amounts of water. "Dry" snows tend to be light and fluffy, measuring more in depth, but not so much in water.

Patterson recorded 20.5 inches of snow on Dec. 18 and 19, a very large amount for this area, but it contained only 1.71 inches of water. From Feb. 5 through 7, a very wet 14.7 inches of snow fell that produced 2.96 inches of water. Patterson said typically 30 inches of snow would be needed to produce that much water.

"This winter has been snowy and wet," he said. Total precipitation over the last three months is 17.83 inches of water, while the average is 12.45 inches.

Patterson determines how much water a snowfall contains by melting it. He does this by adding a measured amount of hot water to the measured snow, and then he deducts the added water from the total water to get the original snowfall amount.

When he's done recording and sending his data, he heads down hill to the astronomy department, where he puts in a day's work, researching heavenly bodies far beyond the climate of the earth.

— By Fariss Samarrai