Showing papers by "Stanley A. Changnon published in 1995"

Climate-Related Fluctuations in Midwestern Floods during 1921–1985

Abstract: Historical records of warm- and cold-season floods and associated heavy-precipitation events during 1921–1985 in the Midwest were examined for temporal fluctuations and trends. Floods in basins in the northern Midwest exhibited upward trends in both seasons but no statistically significant temporal changes existed elsewhere. The incidence of heavy-precipitation events also increased in this same area, a region where thunderstorm incidences and cyclone frequencies have also been on the increase since 1920. Pentads of high flood incidences all occurred in major wet periods (generally the 1970s and 1980s), and pentads of lowest flood incidences occurred in notable droughts (1930s and 1951–1965). The times of these droughts (early) and wet periods (late) further help explain the tendency for floods to increase during the 1921–1985 study period. When precipitation over 5-year periods decreased 8% or more below average, or increased by 7% above average, the number of floods was greatly reduced or increased. This suggests that future significantly drier climate conditions in the Midwest could have few floods, and significantly wetter conditions could have increased flood activity.

Uses and Applications of Climate Forecasts for Power Utilities

Abstract: The uses and potential applications of climate forecasts for electric and gas utilities were assessed 1) to discern needs for improving climate forecasts and guiding future research, and 2) to assist utilities in making wise use of forecasts In-depth structured interviews were conducted with 56 decision makers in six utilities to assess existing and potential uses of climate forecasts Only 3 of the 56 use forecasts Eighty percent of those sampled envisioned applications of climate forecasts, given certain changes and additional information Primary applications exist in power trading, load forecasting, fuel acquisition, and systems planning, with slight differences in interests between utilities Utility staff understand probability-based forecasts but desire climatological information related to forecasted outcomes, including analogs similar to the forecasts, and explanations of the forecasts Desired lead times vary from a week to three months, along with forecasts of up to four seasons ahea

Exploratory Analysis of Seeding Effects on Rainfall: Illinois 1989

Abstract: Radar-indicated rainfall characteristics from six experimental units randomly selected for AgI treatment were compared with those from six experimental units treated with sand during the summer of 1989 in an exploratory analysis. No differences were found between AgI and sand cell frequencies before and after treatment. The areal extent of rain in all AgI-treated units grew during treatment, whereas four of the sand units decreased, but the differences were not significant. Rainfall amounts were determined for the units and for the extended areas around them. AgI units had higher median rainfall values by the end of the treatment and thereafter for 90 min than did the sand units, whereas extended area rainfall was less in AgI than sand cases. The unit rainfalls, adjusted to account for the unit-extended area relationships, showed a systematic difference with AgI rain higher at the end of treatment (and statistically significant) and for 90 min thereafter. Comparisons based on 20 relevant meteorol...

Responses of Warm-Based, Midwestern Cumulus Congestus to Dynamic Seeding Trials

Abstract: Findings are reported from an analysis of AgI seeding effects on individual cumulus congestus clouds in the 1989 Illinois Exploratory Cloud Seeding Experiment. The experiment was designed around a dynamic seeding hypothesis. Randomized treatments of individual clouds were based on “floating” experimental units, initially cantered on the first treated cloud. The analysis was based on 12 experimental units having a total of 67 treated echo core—32 treated with sand and 35 with AgI. Prior to any analysis for seeding effects, a check of many of the physical conditions at the time of treatment that would govern future cloud growth showed a bias for the sand-treated clouds to be expected to ultimately grow larger than the AgI-treated clouds. Thus, even though randomization produced numerical balance, direct comparison between the posttreatment behavior of the entire sample of sand- and AgI-treated echoes could not be expected to provide a true impression of possible seeding effects. In an attempt to ov...

A regional response to climate information needs during the 1993 flood

Abstract: Effective responses by government agencies, businesses, and private industry to climate disasters such as the disastrous Mississippi River flood of 1993 hinge on the regional availability of diverse up-to-date weather, climate, and water information. In addition to the obvious need for accurate forecasts and warnings of severe weather and floods, other types of meteorologically based information can contribute to effective responses. Some examples of information requested during and after the 1993 flood include 1) hydroclimatic assessments of the magnitude of the event, 2) agricultural assessments of the impacts of heavy rains and flooding on corn and soybean production, and 3) probabilistic outlooks of the recurrence of flooding based on soil moisture conditions. Quick responses to these climate information needs necessitate 1) a real-time climate monitoring system, 2) physical models to assess effects and impacts, and 3) scientific expertise to address complex issues.

State Roles in the Global Climate Change Issue

Abstract: Events in 1988 helped focus the attention of several states on the global climate change issue. Consequently, the National Governors’ Association conducted an assessment in 1989 and recommended various actions. By 1994, 22 states have enacted laws or regulations and/or established research programs addressing climate change. Most of these “no regrets” actions are set up to conserve energy or improve energy efficiency and also to reduce greenhouse gas emissions. Illinois has adopted an even broader program by 1) establishing a Global Climate Change Office to foster research and provide information and 2) forming a task force to address a wide array of issues including state input to federal policies such as the Clinton administration's 1993 Climate Change Action Plan and to the research dimensions of the U.S. Global Climate Change Research Program. The Illinois program calls for increased attention to studies of regional impacts, including integrated assessments, and to research addressing means t...