HR: 0800h
AN: NG41B-0528    [Abstracts]
TI: Water Level Dynamics in the Great Lakes of North America
AU: * Smigelski, J R
EM: smigelski.3@wright.edu
AF: Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435, United States
AU: Tebbens, S F
EM: sarah.tebbens@wright.edu
AF: Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435, United States
AU: Barton, C C
EM: chris.barton@wright.edu
AF: Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435, United States
AB: Anthropogenic as well as natural fluctuations such as precipitation, runoff, snowmelt, retention time, evaporation, and outflow all contribute to water levels observed in the Great Lakes. Verified hourly water level data for five stations in Lake Michigan and four stations in Lake Superior were obtained from NOAA and examined. For each station, an hourly time series ranging from 20 to 30 years in duration was decimated to produce a time series with four hour intervals. Four distinct regions of scaling are observed with inflection points at approximately 1 day, 5 days, and 30 - 60 days. For time scales of less than one day, the power-scaling exponent (β) ranges from 0.1 to 0.5, indicating a white noise. From 1 day to 5 - 7 days, β ranges from 1.5 to 2.6, indicating moderate to strong persistence which is probably due to frontal movements of weather systems. On timescales between 5 days and 30 - 60 days, β ranges from 0.1 to 0.4, again indicating a white noise which may be due to monthly and seasonal weather variations within the Great Lakes System. Beyond 30 - 60 days, all stations exhibit strong persistence, with β between 2.1 and 2.7. Barometric pressure and precipitation data also exhibit scaling with β different from the water level data, but with breaks in slope occurring over the same period of time. The variations observed in the changing β of water levels (environmental noise) are likely to have biological impacts on population dynamics of organisms, including rates of survival or extinction (Batchhelder and Powell 2002). Understanding biological-physical coupling and the impact of water level fluctuations is fundamental to ecosystem dynamics.
DE: 3205 Fourier analysis (3255)
DE: 3235 Persistence, memory, correlations, clustering (3265, 7857)
DE: 3255 Spectral analysis (3205, 3280)
DE: 3270 Time series analysis (1872, 4277, 4475)
DE: 4430 Complex systems
SC: Nonlinear Geophysics [NG]
MN: 2007 Fall Meeting