Abstract:    Just by inspection of Earth’s surface using Google Earth, vegetation patterns of different type can be found in semi-arid climates such as in Mali and Niger. These patterns range from nearly complete vegetation coverage with small gaps of bare ground, via labyrinth patterns, to islands of vegetation in bare ground, the so-called spot patterns. In this presentation, I will present results on the bifurcation behavior of solutions in a (reaction-diffusion) type model of vegetation pattern formation using precipitation as a control parameter. Focus will be on early warning signals of the transition to desertification.

Biography:  Henk A. Dijkstra is professor of Dynamical Oceanography at the Institute for Marine and Atmospheric research Utrecht (IMAU) within the Department of Physics of Utrecht University, The Netherlands. After graduating in applied mathematics at the University of Groningen in 1984, he worked during his PhD (in Groningen) on a Spacelab experiment involving Marangoni convection under microgravity conditions. He continued with this research at the Department of Chemical Engineering at Cornell University during the period 1988-1990. Since 1990 he works at Utrecht University mainly on the stability of the ocean circulation and on the physics of climate variability. He is author of the books “Nonlinear Physical Oceanography” (Springer, 2e edition 2005), “Dynamical Oceanography” (Springer, 2008) and “Nonlinear Climate Dynamics” (Cambridge University Press, 2013). Since 2002, he is a member of the Dutch Royal Academy of Arts and Sciences (KNAW). In 2005, he received the Lewis Fry Richardson medal from the European Geosciences Union and in 2009 he was elected a Fellow of the Society for Industrial and Applied Mathematics (SIAM).