HR: 13:40h
AN: NG12A-01 INVITED     [PDF]
TI: Order without a cause
AU: * Werner, B
EM: bwerner@ucsd.edu
AF: Complex Systems Laboratory, Cecil and Ida Green Institute of Geophysics and Planetary Physics University of California - San Diego, La Jolla, CA 92093-0225
AU: Kitluk, A
EM: akitluk@ucsd.edu
AF: Complex Systems Laboratory, Cecil and Ida Green Institute of Geophysics and Planetary Physics University of California - San Diego, La Jolla, CA 92093-0225
AU: Plug, L J
EM: lplug@dal.ca
AF: Surface Process and Pattern Laboratory, Department of Earth Sciences Dalhousie University, Halifax, NS B3H4H6 Canada
AB: The pervasiveness of order in landscapes, from striking patterns such as fields of sand dunes to less eye-catching examples such as tussock tundra, motivates efforts to find its cause. However, studying order as an abstract, overarching structure common to many similar systems or as emerging from fundamental physical processes reveals little about the dynamics of specific landscapes, because order is an irreducible property of the dynamics of a system and not a product of causal relations between different aspects of the system. This hypothesis is based on the view that the order of a landscape is the extent to which it is organized into a hierarchy of scale-separated behaviors. With increasing level in the hierarchy, time scale increases and the number of degrees of freedom decreases. The lone relations between adjacent levels connect only the fast-scale variables of the lower level with the slow-scale dynamics of the upper level (through self-organization/slaving). The dynamics at each level is an independent property of the system, not an effect caused by dynamics at any other level. Order is quantified using the number and time scales of levels in the hierarchy. Ice-rich permafrost terrain of the Kitluk drainage basin in Bering Land Bridge National Preserve, Alaska, illustrates a highly developed hierarchical order without a cause. The terrain has numerous levels, ranging from soil particle motion (~ seconds) to integrated lake drainage networks (10 ka). Using our concept of order, measurements over a range of locations reveal that this seemingly unpatterned landscape contrasts with many patterned systems, such as fields of sorted patterned ground in Western Spitsbergen, where order is less developed. Supported by the Andrew W. Mellon Foundation.
DE: 1625 Geomorphology and weathering (1824, 1886)
SC: Nonlinear Geophysics [NG]
MN: 2003 Fall Meeting