title: Maximum entropy production allows a simple representation of heterogeneity in semiarid ecosystems.
abstract: Feedbacks between water use, biomass and infiltration capacity in semiarid ecosystems have been shown to lead to the spontaneous formation of vegetation patterns in a simple model. The formation of patterns permits the maintenance of larger overall biomass at low rainfall rates compared with homogeneous vegetation. This results in a bias of models run at larger scales neglecting subgrid-scale variability. In the present study, we investigate the question whether subgrid-scale heterogeneity can be parameterized as the outcome of optimal partitioning between bare soil and vegetated area. We find that a two-box model reproduces the time-averaged biomass of the patterns emerging in a 100 x 100 grid model if the vegetated fraction is optimized for maximum entropy production (MEP). This suggests that the proposed optimality-based representation of subgrid-scale heterogeneity may be generally applicable to different systems and at different scales. The implications for our understanding of self-organized behaviour and its modelling are discussed.
authors.affiliation: Max-Planck-Institut für Biogeochemie, Hans-Knöll-Strasse 10, 07745 Jena, Germany. sschym@bgc-jena.mpg.de
authors.forename: Stanislaus J
authors.initials: SJ
authors.lastname: Schymanski
authors.forename: Axel
authors.initials: A
authors.lastname: Kleidon
authors.forename: Marc
authors.initials: M
authors.lastname: Stieglitz
authors.forename: Jatin
authors.initials: J
authors.lastname: Narula
mesh_terms: D003889:Desert Climate; D017753:Ecosystem; D019277:Entropy; D005246:Feedback; D008962:Models, Theoretical; D063245:Plant Development; D011891:Rain; D013816:Thermodynamics