Showing papers by "Stanley A. Changnon published in 1979"

Rainfall changes in summer caused by st. Louis.

Abstract: Precipitation in and around St. Louis was investigated to study urban influences on summer precipitation conditions. Prerain winds were used to define the "downwind area" where influences would be greatest, and wind-sorted rains were combined into monthly and summer totals. Seventy-five percent of the 16 rain patterns revealed a rainfall maximization downwind of the city, and the rainfall in the downwind area was 22.7 percent more than the rainfall upwind of St. Louis where no urban influences existed. Various statistical tests of the summer rainfall distribution reveal the downwind rainfall to be significantly greater than elsewhere and supportive of other findings that St. Louis increases rainfall.

Impact of man upon local and regional weather

Abstract: The 1975–1978 period has brought new realization that considerable atmospheric modification exists in the United States as a result of man's land use change [Weather Modification Advisory Board, 1978]. Cities, power plants, and certain agricultural activities modify the weather, often dramatically, on local and regional scales. Concern over these unintentional changes has grown nationally, making study of their nature and magnitude essential in many design and policy areas. Awareness of inadvertent weather modification has only recently become a part of wise planning for hydrologic, agricultural, transportation systems, and human activities.

How a Severe Winter Impacts on Individuals

Abstract: The winter of 1977–78 was the worst, on the basis of both low temperatures and snow, on record in Illinois and many other areas of the Midwest. Representatives of 70 households in central Illinois participated in a detailed study of how the extreme cold and snow affected individuals. The average added cost was $93 per individual, largely to residences and vehicles, and extrapolation of this to all Illinois citizens results in an estimated statewide cost in excess of $1 billion. This was compounded by a wide variety of personal inconveniences, worries, extra work, and injuries. There were no deaths in the sampled group but 52 Illinoisans were killed by the 18 winter storms. For those living in rural areas beyond the city of their employment, costs and inconveniences were greater. The average individual cost was $120, and rural dwellers experienced more travel problems, move delayed services, and more absences from school and work.

What to do About Urban-generated Weather and Climate Changes

Abstract: For many years it has been recognized that urban areas alter their climate, being warmer, dryer, and less windy than nearby rural areas. In recent years evidence has grown that large urban centers also produce sizeable changes in precipitation and even storms, changes extending well beyond the urban confines. A major national project focusing on this surprising possibility has just ended. For an area of over four thousand square kilometers, about three times the size of the city in the study area, the project has found that the summer precipitation conditions are increased downcity (east) with 10 percent more clouds, up to 30 percent more rain, 50 percent more heavy rainstorms, and 100 percent more hail than rural areas. Impact analyses reveal a series of costs to the affected urban and suburban areas, particularly to their drainage and transportation systems, but a general benefit to agriculture activities. Causes of the added clouds, rain, and storms relate to a host of urban factors, most of w...

On the Need to Evaluate Operational Weather Modification Projects

Abstract: Use of weather modification by farm groups, state agencies, and power companies to perform operational projects continues to expand. Seven percent of the United States experienced cloud seeding during 1977. The major stakeholders—those paying, those performing the seeding, and the scientific community—have all converged on the need to evaluate operational projects. Major assessments of the national situation have recommended that carefully conducted operational projects can be a source of useful scientific information if designed, operated, and evaluated properly. A project has been launched to develop statistical-physical evaluation techniques for operational projects.

The Illinois Climate Center

Abstract: The State of Illinois has just established a climate center addressing a wide variety of climate-related activities. This center has evolved after 25 years of services, research, and data management addressing the climatology of Illinois and the Midwest. The products of this effort reflect state-related interests in climate information and data. The Illinois program may also help serve as a model for some states who will evolve centers as part of the federal-state cooperative effort that is to be an integral part of the National Climate Program.

Evaluation of the McLean County Rainfall Modification Projects in 1977 and 1978

Abstract: A central area of research and services of the Atmospheric Sciences Section of the Illinois State Water Survey is planned weather modification. As part of our broad program, we attempt to evaluate, when time and skilled personnel permit, the efforts of certain operational weather modification projects in Illinois (Changnon and Towery, 1977). These attempts help us develop better evaluation capabilities and help us learn whether various modification techniques may work in Illinois. The results of our limited evaluations are also useful to Illinois citizens interested or involved in weather modification. 'This report discusses the highlights of an evaluation of the McLean County Project. Although this project is as yet a very limited, in time, effort to enhance rainfall in central Illinois, it has the portent for future longer operations and thus a more meaningful evaluation. Cloud seeding occurred over McLean County in two 1-month summer periods, one in 1977 and one in 1978. According to the project permit filed with the State, all seedablc rain events (save those weather periods forbid by State law as too dangerous for modification) were to be seeded by project aircraft using one or both common seeding techniques (Agl released at cloud base or at mid-cloud levels). The written records of the operations in McLean County are adequate,