Showing papers by "Stanley A. Changnon published in 1989"
TL;DR: In this article, an in-depth analysis of newspaper accounts of droughts between paired cities, one in drought and one not in drought, was used to measure the differences in the types of drought impacts, and in the time of onset of impacts as related to developing precipitation deficiencies.
Abstract: Drought is an interaction between physical processes and human activities. This study quantified the impacts of precipitation deficiencies on streamflow, reservoirs, and shallow ground water supplies. An in-depth analysis of newspaper accounts of droughts between paired cities, one in drought and one not in drought, were used to measure the differences in the types of drought impacts, and in the time of onset of impacts as related to developing precipitation deficiencies. Precipitation deficiencies related to the onset and the magnitude of surface water supply adjustments, and to shallow ground water problems, were established. Thus, monitoring and prediction of the onset and magnitude of drought problems can now be done from readily available data on precipitation deficiencies. Newspapers were found to be reliable indicators for the timing of drought impacts and adjustments as precipitation deficiency develops. A review of local and state adjustments during two recent droughts revealed most decision makers lacked information and experience in dealing with drought.
66 citations
TL;DR: A notable, largely unexpected impact involved stoppages of barge traffic on the lower Mississippi River during June and July, a result of shallow areas produced by record low flows and shoaling as mentioned in this paper.
Abstract: The drought of 1988 rated as one of the nation's worst in the past 100 years, resulting in a myriad of impacts and responses. A notable, largely unexpected impact involved stoppages of barge traffic on the lower Mississippi River during June and July, a result of shallow areas produced by record low flows and shoaling. The barge industry hauls 45% of all bulk commodities (grains, coal, petroleum) shipped in the central United States. The low flows were a result of the unusually large areas extent of drought conditions across most of the Mississippi Basin, which comprises 40% of the continental United States. Most 1987 months had been relatively warm and dry, minimizing moisture in the soils and shallow ground water. Then deficient snowmelt (due to low winter snow-falls) and record low spring 1988 precipitation combined to produce the record low flows along much of the Mississippi River. Most responses to the drought came in a crisis mode and included concentrated dredging to open channels, govern...
34 citations
TL;DR: In this paper, the authors show that the variability of thunder days was very much less than that of precipitation or of frequency of extra tropical cyclones, and they also confirmed well known seasonal and regional patterns of thunder activity.
Abstract: 1901–80 data for the contiguous U.S. show that secular variability of thunder days was very much less than that of precipitation or of frequency of extra tropical cyclones. Overall, there may have been a slight decline, but more evident was an increase to the thirties followed by a falling off, broken only by a peak in the seventies. These up-and-down movements were evident in most months of the year and regions of the U.S. The general decrease, however, was clear only in the South East and replaced by an increase in the Upper Great Lakes region. Secular variation in thunder day frequency was slightly correlated positively with that of extra tropical cyclone frequency and negatively with sea level pressure. The analysis also confirmed well known seasonal and regional patterns of thunder activity.
19 citations
TL;DR: In this paper, the temporal and spatial relationships between thunderstorms and flashes were investigated using data for 1983-85 for 25 first-order stations (10 in the West and 15 along the East Coast).
Abstract: Temporal and spatial relationships between thunderstorms (events) and flashes were investigated using data for 1983–85 for 25 first-order stations (10 in the West and 15 along the East Coast). Thunder events were compared with flashes within three ranges: 5 km, 10 km, and 20 km, around each station. Cluster analysis revealed six geographic regions: Florida, Southeast (South Carolina, Georgia), Mid-Atlantic (Virginia, Maryland Pennsylvania), Northeast (New York and New England), Rocky Mountains, and an intermontane area. Periods of multiple flashes not within thunder events and within 10 km of a point (most realistic for audibility), revealed that 10% to 20% (depending upon region) of all thunderstorms were missed. Also, 13% (Rockies) to 44% (Mid-Atlantic) of all thunderstorms have recorded durations too short (missed flashes before their reported start), and the average underestimated durations were from 55% (Northeast Mid-Atlantic) to 26% (Rockies). Flashes isolated in time and space, due to loc...
11 citations
TL;DR: In this paper, historical hourly rainfall data (1950-84) were subjected to spatial and temporal analyses to provide information for developing rainfall insurance rates for the contiguous United States The dimensions of the study illustrate a balance between insurance needs, funding, and adequate climatic analyses.
Abstract: Historical hourly rainfall data (1950–84) were subjected to spatial and temporal analyses to provide information for developing rainfall insurance rates for the contiguous United States The dimensions of the study illustrate a balance between insurance needs, funding, and adequate climatic analyses Assessment of the hourly rainfall data from 2092 stations in the United States revealed that only 211 had data deemed useful to this study Seventeen regions with similar probabilities of rainfall (rate areas) were defined The average patterns of hourly rainfall closely resemble the nation's average annual precipitation pattern Separate seasonal rain-hour probabilities were defined throughout the United States because of marked differences between wetter and drier portions of the year Temporal analyses of rain hours defined the length of record to use in rate determinations, and how often new rates should be calculated Long-term trends were not present during 1950–84 in any area, and 78% of the 5
10 citations
01 Jan 1989
TL;DR: Changnon et al. as discussed by the authors studied the effects of past low lake levels and future climate-related low Lake Michigan on Lake Michigan, Chicago, and the Illinois Shoreline.
Abstract: This study concerned 1) effects and adjustments resulting from the record-low levels of Lake Michigan during 1964-1965, and 2) the potential effects of future low water levels resulting from expected climate changes. The low lake levels of the 1960s did not cause many major impacts at the time they occurred. The two major imparts discerned, damage to shoreline structures and encroachment of structures onto areas closer to the lake, resulted because of a sequence in which the low water levels were followed by high levels. Climate scenarios based on three global climate model estimates showing a doubling of carbon dioxide (CO2) in the atmosphere, and scenarios based on extreme annual precipitation values from a 133-year period on the Great Lakes basin, were used to determine potential future low lake levels. Possible economic impacts were then determined. If the lake level is reduced from current averages by 0.86 to 1.0 meter during the next 50 years, economic impacts should not be very severe and could probably be handled largely by normal maintenance and replacement costs. Illinois shoreline impacts would cost about $ 100 million. If the lake level is reduced from current averages by 1.25 or 2.52 meters, more sizable economic imparts will occur, costing up to an estimated $291 million and $545 million, respectively. Parts of these costs could be handled by normal replacement costs, particularly if a master plan for changing affected facilities is implemented. The degree of climate change and ensuing lake level will greatly affect the seriousness of the economic outcome, but the environmental and water resource effects are extremely serious under all the climate scenarios. Reference: Changnon, Stanley A., Steven M. Leffler, and Robin Shealy. Effects of Past Low Lake Levels and Future Climate-Related Low Lake Levels on Lake Michigan, Chicago, and the Illinois Shoreline. Illinois State Water Survey, Champaign, Report of Investigation 110, 1989. Indexing Terms: Chicago area, climate change, climate scenarios, economic impact, Great Lakes, Illinois shoreline, Lake Michigan, low water, policy needs, prediction, water level fluctuations, water levels.
4 citations