Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, February 3, 1994 TAG: 9402030146
SECTION: VIRGINIA PAGE: C3 EDITION: NEW RIVER VALLEY
SOURCE: The Washington Post
DATELINE: LENGTH: Medium
Now, a University of Virginia scientist says that park officials' claims are bunk and that visibility at the park actually may have improved slightly over the past 30 years.
"The popular perception is somewhat different than the reality," said Patrick Michaels, a professor of environmental science and the state's climatologist. "A family poking along Skyline Drive in 1970 were seeing the same distance as people are seeing today."
His study is adding to a debate that has economic as well as recreational significance. Environmental concerns have blocked development of power plants in the area.
A Shenandoah Valley resident since 1979, Michaels said he studied the issue because his "subjective perception" was that visibility at the park had not changed.
Last month, he reviewed records on noontime visibility at two of the airports nearest the park - Elkins, W.Va., and Lynchburg - and found that it had not changed much over 30 years.
For instance, visibility at the Elkins airport in July 1970 was about 10 miles, Michaels said. It fluctuated from a low of 12.7 miles in July 1982 to a high of 16.9 miles in July 1987. The visibility in July 1990 was 14 miles.
Park officials were not shy about attacking Michaels' study. "He's misusing the data," said Julie Thomas, who manages the park's air-quality program. The visibility data "may be true for the airports, but it doesn't correlate to what's happening here." Elkins is 85 miles west of the park, and Lynchburg is 60 miles south.
But Michaels said he picked those airports because they are in the same air stream as the park and are "extremely representative."
Pulling out their research, park officials pointed to a 40 percent increase in sulfur particulates since 1983. Sulfur is a major source of visibility reduction, Thomas said.
Park officials also cited their own visibility study. It says that the percentage of days from May to October in which visibility at the park was less than 10 miles increased from 24 percent in 1991 to 36 percent last year.
Robert Eldred, a research physicist at the Crocker Nuclear Laboratory in Davis, Calif., questioned Michaels' and the park officials' conclusions. "Airport visibility figures are never really reliable," said Eldred, who is part of a team studying air quality at national parks. "The way it works is that some guy looks out the window and checks off a list of factors. It's not nearly as accurate as instruments."
As for sulfur measures, Eldred said, they do not always indicate a visibility problem.
In the end, the answer may lie in the eye of the beholder. Take Pat Butt, 65, a Loudoun County resident who has camped and hiked in and driven through the Shenandoah every year since 1958.
"I really can't say whether it's worse or not," Butt said. "I do know that the visibility is clearest when it's cold, particularly in late fall and early spring, and that it's typically hazy in the summer."
by CNB