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  • Author or Editor: Stanley A. Changnon Jr. x
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Stanley A. Changnon Jr.
,
Floyd A. Huff
, and
Richard G. Semonin

METROMEX, a field project designed and now in progress at St. Louis, involves 4 research groups planning and working cooperatively to study inadvertent weather modification by urban-industrial effects, and, in particular, man-made changes of precipitation. Urban areas affect most forms of weather and some, such as winds, temperature, and visibility, are obvious and their changes are easily measured. Inadvertent precipitation changes are harder to measure, and except for the well-documented La Porte anomaly, urban-related rain changes have had only limited study. Examination of historical data at St. Louis has revealed summer increases in the immediate downwind area of: 1) rainfall (10–17%); 2) moderate rain days (11–23%); 3) heavy rainstorms (80%); 4) thunderstorms (21%); and 5) hailstorms (30%). METROMEX field measurements in the summer of 1971 involved 220 raingages and hailpads, 3 radar sets, 70 rainwater collectors, 14 pibal stations, 4 meteorological aircraft, unique atmospheric tracers, and a wide variety of standard and unusual meteorological equipment. These measurement tools were used to provide information on 1) the processes of cloud and precipitation formation, 2) the chemistry of aerosols and rainwater, 3) the urban heat budget, 4) the 3-D patterns of precipitation elements, and 5) the airflow and cloud development for numerical models.

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Neil G. Towery
,
Stanley A. Changnon Jr.
, and
Griffith M. Morgan Jr.

The characteristics of commonly used surface hail instruments are reviewed and instruments evaluated. The instruments evaluated have been classified into two major categories: integrating and recording. The integrating sensors are relatively inexpensive and provide certain useful hail data. The recording sensors are much more expensive but provide more useful data including time of hail. The review includes the principles of operation, types of data obtained, operational advantages and disadvantages, and approximate cost of each type of instrument.

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Stanley A. Changnon
,
Roger A. Pielke Jr.
,
David Changnon
,
Richard T. Sylves
, and
Roger Pulwarty

Societal impacts from weather and climate extremes, and trends in those impacts, are a function of both climate and society. United States losses resulting from weather extremes have grown steadily with time. Insured property losses have trebled since 1960, but deaths from extremes have not grown except for those due to floods and heat waves. Data on losses are difficult to find and must be carefully adjusted before meaningful assessments can be made. Adjustments to historical loss data assembled since the late 1940s shows that most of the upward trends found in financial losses are due to societal shifts leading to ever-growing vulnerability to weather and climate extremes. Geographical locations of the large loss trends establish that population growth and demographic shifts are the major factors behind the increasing losses from weather–climate extremes. Most weather and climate extremes in the United States do not exhibit steady, multidecadal increases found in their loss values. Without major changes in societal responses to weather and climate extremes, it is reasonable to predict ever-increasing losses even without any detrimental climate changes. Recognition of these trends in societal vulnerability to weather-climate extremes suggests that the present focus on mitigating the greenhouse effect should be complemented by a greater emphasis on adaptation. Identifying and understanding this societal vulnerability has great importance for understanding the nation's economy, in guiding governmental policies, and for planning for future mitigative activities including ways for society to adapt to possible effects of a changing climate.

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William C. Ackermann
,
Stanley A. Changnon Jr.
, and
Ray Jay Davis

The Illinois State Water Survey, a state water resources research agency, initiated efforts in 1971 to develop and secure a law for Illinois that would permit and regulate weather modification activities. Such legislation was deemed a prime requirement, not only for the proper execution of scientific experiments on weather modification in Illinois but for the general benefit of citizens of Illinois through encouragement to properly conducted activities and protection from improperly conducted weather modification operations. (It was our intention to develop a “model law” that reflected the best aspects of weather modification legislation and experience in other states, and which would serve as a model for future legislation in other states.) The efforts began in October 1971 and were completed in September 1973 with the signing of the Illinois Weather Modification Control Bill and its accompanying appropriation bill. This paper describes the type of law desired, the activities performed to secure the law, and the primary aspects of the enacted Illinois law.

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Stanley A. Changnon Jr.
,
Howard J. Critchfield
,
Robert W. Durrenberger
,
Charles L. Hosler
, and
Thomas B. McKee

The value of climate data and the information derived from the data still seems to be an unknown to many. Five persons engaged in providing climate services in different U.S. climatic zones have assembled a few widely different examples of recent uses of climate data and information. These help demonstrate the diversity of applications, and the value of the data and of those who can interpret them.

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Gerald A. Meehl
,
Thomas Karl
,
David R. Easterling
,
Stanley Changnon
,
Roger Pielke Jr.
,
David Changnon
,
Jenni Evans
,
Pavel Ya. Groisman
,
Thomas R. Knutson
,
Kenneth E. Kunkel
,
Linda O. Mearns
,
Camille Parmesan
,
Roger Pulwarty
,
Terry Root
,
Richard T. Sylves
,
Peter Whetton
, and
Francis Zwiers

Weather and climatic extremes can have serious and damaging effects on human society and infrastructure as well as on ecosystems and wildlife. Thus, they are usually the main focus of attention of the news media in reports on climate. There are some indications from observations concerning how climatic extremes may have changed in the past. Climate models show how they could change in the future either due to natural climate fluctuations or under conditions of greenhouse gas-induced warming. These observed and modeled changes relate directly to the understanding of socioeconomic and ecological impacts related to extremes.

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