Convection-driven pattern formation in grass (Invited)
Abstract
Spatial patterns of 'dead' lawn grass have often been ascribed to Turing-type reaction-diffusion processes related to water scarcity. However, morphologically-similar patterns can also result from fluid convection. Therefore, we present an alternative hypothesis: that the air within the grass canopy is unstable to a convective instability, such that chill damage caused by falling cold air is responsible for the creation of brown and green bands of grass. We model the grass as a uniform porous medium of upright cylindrical rods subject to a temperature gradient and find that the resulting patterns are consistent with several features of small-scale vegetation patterns, including their length scale, rapid onset and transient nature. Finally, the predictions are found to be consistent with measurements made for a particular instance of lawn-patterning in North Carolina. We close by discussing the implications for other plant species. Lawn grass patterning at Duke University.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMNG52A..03D
- Keywords:
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- 0439 BIOGEOSCIENCES / Ecosystems;
- structure and dynamics;
- 1813 HYDROLOGY / Eco-hydrology;
- 4460 NONLINEAR GEOPHYSICS / Pattern formation