U.S. weather waxing cloudy.U.S. weather waxing cloudy Do you remember the weather years ago as having beensunnier than now? You may not be idealizing the past; you may be right. Two current studies, one an analysis of overall cloudiness in the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. and the other a close look at the weather of Michigan, indicate that the United States has gotten cloudier. Previous work had shown that the central United States The Central United States is sometimes conceived as between the Eastern United States and Western United States as part of a three-region model, roughly coincident with the Midwestern United States plus the western and central portions of the Southern United States; the term is has suffered the same fate. William L. Seaver of Virginia Polytechnic Institute in FallsChurch and James E. Lee of the MITRE Corp., a nonprofit systems engineering company in McLean, Va., compared the number of cloudless days in 45 U.S. cities during two periods, 1900-1936 and 1950-1982. Cloudless days were defined as those in which an average of 10 percent or less of the daytime sky was obscured clouds, haze, smoke or fog. The study used data collected by U.S. National Weather Service observers. An increase in cloudiness in the middle third of the UnitedStates has been documented by Stanley Changnon and his colleagues at the Illinois State Water Survey at the University of Illinois University of Illinois may refer to:
The two researchers report in the current (January) JOURNALOF CLIMATE AND APPLIED METEOROLOGY meteorology, branch of science that deals with the atmosphere of a planet, particularly that of the earth, the most important application of which is the analysis and prediction of weather. that the second half of the century has had fewer cloudless days than the first half. Los Angeles, for example, averaged 10 cloudless days per month in the years from 1900 to 1936; from 1950 to 1982, the number of cloudless days dropped to 7.6 per month. St. Louis went from 7.2 to 4.7 cloudless days per month, and Washington, D.C., from 5.3 to 4.4. Of the 45 cities checked, the only one to get sunnier was Ft. Worth, Texas, but the increase from 7.4 to 7.5 was barely enough to be significant, Lee says. And at the Fourth Conference on Climate Variations inBaltimore last week, Val L. Eichenlaub of Western Michigan University Western Michigan University, at Kalamazoo, Mich.; coeducational; founded in 1903 as Western State Normal School, became accredited in 1927 as a college, gained university status in 1957. in Kalamazoo presented data showing an increase in cloudiness in Michigan. Grand Rapids, for example, was 75 to 80 percent sunny in the late 1930s and early 1940s but dropped to about 65 percent in the 1970s. While the studies have shown a trend toward cloudiness,they don't explain why the change is occurring. But the researchers involved in the work have several ideas. Changnon, who collected the Midwest data, has suggested that jet contrails act as condensation "seeds' and instigate To incite, stimulate, or induce into action; goad into an unlawful or bad action, such as a crime. The term instigate is used synonymously with abet, which is the intentional encouragement or aid of another individual in committing a crime. cloud formation. For Michigan, Eichenlaub says, other data indicate that the polar weather front has been shifting southward, and this could be pulling in more storms and clouds. On the national scale, Lee suggests that pollution could be supplying particles around which water may condense con·dense v. con·densed, con·dens·ing, con·dens·es v.tr. 1. To reduce the volume or compass of. 2. To make more concise; abridge or shorten. 3. Physics a. . |
|
||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion