HR: 15:10h
AN: H13M-06    [Abstracts]
TI: Multi-Scale Entropy Analysis of Mississippi River Flow
AU: Li, Z
EM: zli@sfwmd.gov
AF: South Florida Water Management District, 3301 Gun Club Road, West Palm Beach, FL 33416-4680, United States
AU: * Zhang, Y
EM: you-kuan-zhang@uiowa.edu
AF: The University of Iowa, Department of Iowa 121 TH, Iowa City, IA 52242, United States
AB: Multiscale Entropy (MSE) analysis was applied to the long-term (131 years) daily flow rates (Q) of the Mississippi River (MR) to investigate possible change in the complexity of the MR system due to human activities since 1940s. Unlike traditional entropy-based method that calculates entropy at only one single scale, the MSE analysis provided entropies over multiple time scales and thus accounts for multi-scale structures embedded in time series. It is found that the sample entropy (SE) for Q of the MR and its two components, overland flow (OF) and base flow (BF), generally increase as time scale increases. More importantly, it is found that there have been entropy decreases in Q, OF, and BF over large time scales. In other words, the MR may have been losing its complexity since 1940s. A possible explanation for the loss in the complexity of the MR system is that the major changes in land use and land cover and soil conservation practices in the MR basin since 1940s -- these changes alter the natural system which existed before human intervention and thus reduce its complexity.
DE: 1804 Catchment
DE: 1834 Human impacts
DE: 1860 Streamflow
DE: 1872 Time series analysis (3270, 4277, 4475)
SC: Hydrology [H]
MN: 2007 Fall Meeting