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Roger A. Pielke Jr

Abstract

The role of cumulus clouds in local, regional, and global weather and climate that is understood today is based to a large extent on the pioneering work of Joanne Simpson. Her involvement in this work is illustrated through the experiences as my career developed. She also was, and is, an ideal model of mentorship. This paper illustrates this model using my interactions during the 1970s and early 1980s, and how they have influenced research articles up to the present.

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Roger A. Pielke Jr.

In recent years, those who conduct federally funded research in the United States have been asked by their patrons, the public and their elected representatives, to demonstrate more efficacy with respect to societal needs. Although there is a long record of efforts to improve connections of research with societal needs, a problem exists in that in recent decades the production of scientific knowledge seems to have outrun its effective use by society. Current debate asks questions such as the following: In what different ways has society understood the connections of research with societal needs? What are the implications of such understandings for the structure and conduct of atmospheric sciences research? How can society (and especially sponsors of science) accurately and meaningfully assess the contributions of the atmospheric sciences to societal needs? This paper seeks to shed light on dimensions of these questions through discussion of the relationship of atmospheric sciences research with societal problems. Because the atmospheric sciences have an extended record of experience in connecting research with practical problems, the lessons of that experience have significance for current efforts to improve the relation of the atmospheric sciences with society's needs. In addition, these lessons have broader relevance for more general understandings of the evolving relationship of science and society.

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BAD WEATHER? THEN SUE THE WEATHERMAN!

PART I: LEGAL LIABILITY FOR PUBLIC SECTOR FORECASTS

Roberta Klein and Roger A. Pielke Jr.

Weather forecasts have become demonstrably more accurate in recent decades due to increasingly sophisticated computer technology and models. Yet scientists cannot predict the future with 100% certainty. Relying on inaccurate or inadequate forecasts can result in great financial or even bodily harm. In such situations, what liability, if any, arises under the U.S. legal system?

This article is the first of a two-part review. Part I discusses several court decisions resolving law-suits against the federal or state government based on inaccurate or inadequate weather-related forecasts or failure to issue weather warnings that led to injury or loss. In general, most claims against the federal government based on weather forecasting or failure to warn about weather conditions have been (and likely will continue to be) resolved in favor of the government on the basis of immunity under the Federal Tort Claims Act (FTCA). State government immunity will depend on the provisions of a state's immunity statute and how the state interprets its immunity statute. Part II of the review will address claims against private sector weather forecasters. These articles aim to familiarize the reader with some of the legal issues involved when forecasts are the subject of a lawsuit, rather than provide a comprehensive, law-review-style legal analysis. The authors conclude with some forecasts of their own about liability for weather forecasters.

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Roger A. Pielke Jr. and Christopher N. Landsea

Hurricanes result in considerable damage in the United States. Previous work has shown that Atlantic hurricane landfalls in the United States have a strong relationship with the El Niño–Southern Oscillation phenomena. This paper compares the historical record of La Niña and El Niño events defined by eastern Pacific sea surface temperature with a dataset of hurricane losses normalized to 1997 values. A significant relationship is found between the ENSO cycle and U.S. hurricane losses, with La Niña years exhibiting much more damage. Used appropriately, this relationship is of potential value to decision makers who are able to manage risk based on probabilistic information.

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Roger A. Pielke Jr. and Christopher W. Landsea

Abstract

Hurricanes are the costliest natural disasters in the United States. Understanding how both hurricane frequencies and intensities vary from year to year as well as how this is manifested in changes in damages that occur is a topic of great interest to meteorologists, public and private decision makers, and the general public alike. Previous research into long-term trends in hurricane-caused damage along the U.S. coast has suggested that damage has been quickly increasing within the last two decades, even after considering inflation. However, to best capture the year-to-year variability in tropical cyclone damage, consideration must also be given toward two additional factors: coastal population changes and changes in wealth. Both population and wealth have increased dramatically over the last several decades and act to enhance the recent hurricane damages preferentially over those occurring previously. More appropriate trends in the United States hurricane damages can be calculated when a normalization of the damages are done to take into account inflation and changes in coastal population and wealth.

With this normalization, the trend of increasing damage amounts in recent decades disappears. Instead, substantial multidecadal variations in normalized damages are observed: the 1970s and 1980s actually incurred less damages than in the preceding few decades. Only during the early 1990s does damage approach the high level of impact seen back in the 1940s through the 1960s, showing that what has been observed recently is not unprecedented. Over the long term, the average annual impact of damages in the continental United States is about $4.8 billion (1995 $), substantially more than previous estimates. Of these damages, over 83% are accounted for by the intense hurricanes (Saffir–Simpson categories 3, 4, and 5), yet these make up only 21% of the U.S.-landfalling tropical cyclones.

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Roger A. Pielke Jr. and Mary W. Downton

Abstract

The poor relationship between what climatologists, hydrologists, and other physical scientists call floods, and those floods that actually cause damage to life or property, has limited what can be reliably said about the causes of observed trends in damaging floods. It further limits what can be said about future impacts of floods on society based on predicted changes in the global hydrological cycle. This paper presents a conceptual framework for the systematic assessment of the factors that condition observed trends in flood damage. Using the framework, it assesses the role that variability in precipitation has in damaging flooding in the United States at national and regional levels. Three different measures of flood damage—absolute, per capita, and per unit wealth—each lead to different conclusions about the nature of the flood problem. At a national level, of the 10 precipitation measures examined in this study, the ones most closely related to flood damage are the number of 2-day heavy rainfall events and the number of wet days. Heavy rainfall events are defined relative to a measure of average rainfall in each area, not as absolute thresholds. The study indicates that the growth in recent decades in total damage is related to both climate factors and societal factors: increased damage is associated with increased precipitation and with increasing population and wealth. At the regional level, this study reports a stronger relationship between precipitation measures and flood damage, and indicates that different measures of precipitation are most closely related to damage in different regions. This study suggests that climate plays an important, but by no means determining, role in the growth in damaging floods in the United States in recent decades.

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BAD WEATHER? THEN SUE THE WEATHERMAN!

PART II: LEGAL LIABILITY FOR PRIVATE SECTOR FORECASTS

Roberta Klein and Roger A . Pielke Jr.

Weather forecasts have become demonstrably more accurate in recent decades due to increasingly sophisticated computer technology and models. Yet scientists cannot predict the future with 100% certainty. Relying on inaccurate or inadequate forecasts can result in great financial or even bodily harm. In such situations, what liability, if any, arises under the U.S. legal system?

This article is the first of a two-part review. Part I discusses several court decisions resolving law-suits against the federal or state government based on inaccurate or inadequate weather-related forecasts or failure to issue weather warnings that led to injury or loss. In general, most claims against the federal government based on weather forecasting or failure to warn about weather conditions have been (and likely will continue to be) resolved in favor of the government on the basis of immunity under the Federal Tort Claims Act (FTCA). State government immunity will depend on the provisions of a state's immunity statute and how the state interprets its immunity statute. Part II of the review will address claims against private sector weather forecasters. These articles aim to familiarize the reader with some of the legal issues involved when forecasts are the subject of a lawsuit, rather than provide a comprehensive, law-review-style legal analysis. The authors conclude with some forecasts of their own about liability for weather forecasters.

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Kenneth E. Kunkel, Roger A. Pielke Jr., and Stanley A. Changnon

This paper reviews recent work on trends during this century in societal impacts (direct economic losses and fatalities) in the United States from extreme weather conditions and compares those with trends of associated atmospheric phenomena. Most measures of the economic impacts of weather and climate extremes over the past several decades reveal increasing losses. But trends in most related weather and climate extremes do not show comparable increases with time. This suggests that increasing losses are primarily due to increasing vulnerability arising from a variety of societal changes, including a growing population in higher risk coastal areas and large cities, more property subject to damage, and lifestyle and demographic changes subjecting lives and property to greater exposure.

Flood damages and fatalities have generally increased in the last 25 years. While some have speculated that this may be due in part to a corresponding increase in the frequency of heavy rain events, the climate contribution to the observed impacts trends remains to be quantified. There has been a steady increase in hurricane losses. However, when changes in population, inflation, and wealth are considered, there is instead a downward trend. This is consistent with observations of trends in hurricane frequency and intensity. Increasing property losses due to thunderstorm-related phenomena (winds, hail, tornadoes) are explained entirely by changes in societal factors, consistent with the observed trends in the thunderstorm phenomena. Winter storm damages have increased in the last 10–15 years and this appears to be partially due to increases in the frequency of intense nor'easters. There is no evidence of changes in drought-related losses (although data are poor) and no apparent trend in climatic drought frequency. There is also no evidence of changes in the frequency of intense heat or cold waves.

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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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David A. Schecter, Melville E. Nicholls, John Persing, Alfred J. Bedard Jr., and Roger A. Pielke Sr.

Abstract

This paper addresses the physics and numerical simulation of the adiabatic generation of infrasound by tornadoes. Classical analytical results regarding the production of infrasound by vortex Rossby waves and by corotating “suction vortices” are reviewed. Conditions are derived for which critical layers damp vortex Rossby waves that would otherwise grow and continually produce acoustic radiation. These conditions are similar to those that theoretically suppress gravity wave radiation from larger mesoscale cyclones, such as hurricanes. To gain perspective, the Regional Atmospheric Modeling System (RAMS) is used to simulate the infrasound that radiates from a single-cell thunderstorm in a shear-free environment. In this simulation, the dominant infrasound in the 0.1–10-Hz frequency band appears to radiate from the vicinity of the melting level, where diabatic processes involving hail are active. It is shown that the 3D Rossby waves of a tornado-like vortex (simulated with RAMS) can generate stronger infrasound if the maximum wind speed of the vortex exceeds a modest threshold. Technical issues regarding the numerical simulation of tornado infrasound are also addressed. Most importantly, it is shown that simulating tornado infrasound likely requires a spatial resolution that is an order of magnitude finer than the current practical limit (10-m grid spacing) for modeling thunderstorms.

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