HR: 1340h
AN: NG23E-0125    [Abstracts]
TI: Scaling Analysis of Water Level Records from the North American Great Lakes
AU: * Smigelski, J
EM: smigelski.3@wright.edu
AF: Wright State University, Environmental Sciences, 3640 Colonel Glenn Hwy, Dayton, OH 45435
AU: Tebbens, S F
EM: sarah.tebbens@wright.edu
AF: Wright State University, Department of Physics, 3640 Colonel Glenn Hwy, Dayton, OH 45435
AU: Barton, C C
EM: chris.barton@wright.edu
AF: Wright State University, Department of Geological Sciences, 3640 Colonel Glenn Hwy, Dayton, OH 45435
AB: The Great Lakes hydrologic cycle is responsible for the water levels in the Great Lakes. 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, the data was decimated, and time series ranging from 20 to 30 years in duration were created with one record every four hours. Power spectral density functions for each station reveal the expected lunar, seasonal, and annual periodicities. In addition, plots of power versus period exhibit power law scaling, with the scaling exponent, Beta, changing as a function of period. For the Great Lakes stations analyzed, four distinct regions of scaling are generally observed with inflection points at approximately 1 day, 5 days, and 30-60 days. For time scales of less than one day, the Beta values range from 0.1 to 0.5, indicative of a white noise signal. Timescales from 1 day to roughly 5 days exhibit Beta values from 1.5 to 2.6, indicative of moderate to strong persistence. This persistance may be due to frontal movements of weather systems moving over the Great Lakes watershed. On timescales between 5 days and 30-60 days, Beta values range from 0.1 to 0.4, indicative of white noise to weak persistance which may be due to monthly or seasonal variations within the Great Lakes System. Above 30-60 days all stations exhibit strong persistance, with Beta values between 2.1 and 2.7.
DE: 4400 NONLINEAR GEOPHYSICS (3200, 6944, 7839)
DE: 4475 Scaling: spatial and temporal (1872, 3270, 4277)
DE: 4560 Surface waves and tides (1222)
DE: 9345 Large bodies of water (e.g., lakes and inland seas) (0746)
SC: Nonlinear Geophysics [NG]
MN: Fall Meeting 2005