Multiple equilibria on planet Dune: climate-vegetation dynamics on a sandy planet

作者：Aleina Fabio Cresto^*; Baudena Mara; D' Andrea Fabio; Provenzale Antonello

来源：TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY, 2013, 65(1): 17662.

DOI：10.3402/tellusb.v65i0.17662

• climate-vegetation interactions
• multiple stable states
• water cycle
• zero-dimensional models
• evapotranspiration

We study the interaction between climate and vegetation on an ideal water-limited planet, focussing on the influence of vegetation on the global water cycle. We introduce a simple mechanistic box model consisting in a two-layer representation of the atmosphere and a two-layer soil scheme. The model includes the dynamics of vegetation cover, and the main physical processes of energy and water exchange among the different components. With a realistic choice of parameters, this model displays three stable equilibria, depending on the initial conditions of soil water and vegetation cover. The system reaches a hot and dry state for low values of initial water content and/or vegetation cover, while we observe a wet, vegetated state with mild surface temperature when the system starts from larger initial values of both variables. The third state is a cold desert, where plants transfer enough water to the atmosphere to start a weaker, evaporation-dominated water cycle before they wilt. These results indicate that in this system vegetation plays a central role in transferring water from the soil to the atmosphere and trigger a hydrologic cycle. The model adopted here can also be used to conceptually illustrate processes and feedbacks affecting the water cycle in water-limited continental areas on Earth.

• 出版日期2013