A review of techniques for parameter sensitivity analysis of environmental models

Mathematical models are utilized to approximate various highly complex engineering, physical, environmental, social, and economic phenomena. Model parameters exerting the most influence on model results are identified through a ‘sensitivity analysis’. A comprehensive review is presented of more than a dozen sensitivity analysis methods. This review is intended for those not intimately familiar with statistics or the techniques utilized for sensitivity analysis of computer models. The most fundamental of sensitivity techniques utilizes partial differentiation whereas the simplest approach requires varying parameter values one-at-a-time. Correlation analysis is used to determine relationships between independent and dependent variables. Regression analysis provides the most comprehensive sensitivity measure and is commonly utilized to build response surfaces that approximate complex models.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42691/1/10661_2004_Article_BF00547132.pd

Radioecology of some natural organisms and systems in Colorado. Eleventh technical progress report, May 1, 1972--April 30, 1973

The broad purpose of this research is to provide information on the behavior of radionuclides in, and radiation sensitivity of, selected organisms and natural ecosystems in Colorado. Components of alpine tundra, montane forests, shortgrass plains, and freshwater lakes and streams are currently under investigation with respect to behavior and effects of radionuclides. Data are presented from studies on the content of /sup 238/Pu and /sup 239/Pu in samples of soil, litter, vegetation, and tissues of mule deer, rodents, and birds collected in the vicinity of Rocky Flats; the content of fallout /sup 137/Cs and / sup 90/Sr in the tissues of mule deer and in forage samples; the migration of / sup 137/Cs through food chains in a lake ecosystem; tracer studies of energy flow from the dominant grass of the shortgrass plains, Bouteloua gracilis, through arthropod consumers, using /sup 32/P as the tracer and grasshoppers as the test organism; and the effects of gamma radiation from a large /sup 137/Cs source on arthropods, microorganisms, and soil chemistry of a chronic irradiation field. (CH

Radioecology of natural systems. Final report, May 1, 1962-October 31, 1979

This is the final report to the US Department of Energy and its predecessors on Contract EY-76-S-02-1156 with Colorado State University. During the first five years of the program, investigations were focused on the accumulation of fallout radionuclides in a well-studied mule deer population in north-central Colorado. In 1967, the scope of the program was enlarged to include studies on radionuclide behavior in mountain lake ecosystems, radiation effects on a shortgrass plains ecosystem, and the combined effects of radiation and intraspecific competition on the pika (Ochotona princeps). In 1971, studies on the geochemistry of lead in an alpine lake and the foraging impact of grasshoppers were added to the diverse program. The summer of 1972 marked the beginning of the research program which was to dominate the effort for the duration of the contract, namely the behavior of plutonium in the terrestrial environs of the Rocky Flats plutonium facility near Denver, Colorado. This report is a general, qualitative summary of activities and major findings over the entire tenure of the program

Contrasting cesium dynamics in neighboring deep and shallow warm-water reservoirs

cited By 7To measure the long term retention and seasonal dynamics of an initial 4 kg addition of 133Cs into an 11.4-ha, 157,000 m3 reservoir (Pond 4, near Aiken, South Carolina, USA), the concentrations and inventories of 133Cs in the water column were measured at periodical intervals for 522 days following the 1 August, 1999 release. After rapid declines in concentrations and inventories during the first 90 days, the 133Cs concentrations in the water column declined at an average proportional rate of 0.004 d-1. However, there were periods of less rapid and more rapid rates of declines, and these were correlated with periods of increasing and decreasing K concentrations in the water column. The decline rates were less and the K concentrations greater in the winter than in the summer. In the deeper, neighboring monomictic reservoirs of Par Pond and Pond B, a yearly cycle of increasing and decreasing 137Cs concentrations in the water column is driven by anoxic remobilization of Cs from the sediments into a persistent summer hypolimnion. In Pond 4, whose mean depth of 1.6 m is too shallow to support a persistent anoxic hypolimnion, the pattern of yearly dynamics for K and Cs appear to be related to the accumulation and release of these elements from the extensive, seasonal macrophyte communities. The contrasting results between Pond 4 and Pond B suggest that a full appreciation of the relative importance of 1) anoxic remobilization and 2) accumulation and release by macrophytes in these systems remains to be established. © 2010