Graduate School in Physics and Astrophysics ------------------------------------------- ANNUAL REPORT ------------------------------------------- Fill with a text editor (without TAB or formatting) Repeat fields for each course as necessary. ------------------------------------------- name: Donatella D'Onofrio email: donatella.donofrio@hotmail.it ciclo: XXVIII year completed (1,2 or 3): 1 supervisor: Dott. Antonello Provenzale ------------------------------------------- SUMMER SCHOOLS, INTERNATIONAL SCHOOLS (only those attended in the current year) title: "Parametrization of subgrid physical processes" place: European Centre for Medium-Range Weather Forecasts (ECMWF), Reading, UK webpage: http://www.ecmwf.int/newsevents/training/2013/nwp/contents.html#PA days: 22 April- 2 May (42 hours of lectures) talk or poster (Y/N): N ------------------------------------------- SUMMER SCHOOLS, INTERNATIONAL SCHOOLS (only those attended in the current year) title: "Climate Change and the Mountain Environment" place: Valsavarenche, Valle D'Aosta (Italy) webpage: http://www.to.isac.cnr.it/aosta/ days: 18 - 28 June talk or poster (Y/N): N ------------------------------------------- SUMMER SCHOOLS, INTERNATIONAL SCHOOLS (only those attended in the current year) title: "The Fluid Dynamics of Climate" place: Centre International des Sciences MŽcaniques (CISM), Udine, Italy webpage: http://www.cism.it/courses/C1309/ days: 26 - 30 August poster (Y/N): Y ------------------------------------------- CONFERENCES, WORKSHOP (only those attended in the current year) title: "Eco-hydrology of Semiarid Environments: Confronting Mathematical Models with Ecosystem Complexity", International Workshop of Israel Science Foundation place: Ben-Gurion University of the Negev, Beer-Sheva, Israel webpage: http://www.geog.bgu.ac.il/eco-hyd/index.html days: 20 - 22 May talk or poster (Y/N): N ------------------------------------------- CONFERENCES, WORKSHOP (only those attended in the current year) title: "Climate change and its implications on ecosystem services and society". SISC (Societˆ Italiana per le Scienze del Clima) First Annual Conference place: Lecce, Italy webpage: http://www.sisclima.it/conferenza/conferenza/?lang=en days: 23-24 September talk (Y/N): Y ------------------------------------------- VISITS AND STAGES (only those done in the current year) institution: Laboratoire de MŽtŽorologie Dynamique, Ecole Normale Superieure place: Paris, France starting date: 4 March days: 4-29 March --------------------------------------------------- Research activity/Publications in the current year (max characters 2500) Publication (Under minor revisions): D. D'Onofrio, E. Palazzi, J. von Hardenberg, S. Calmanti and A. Provenzale, Stochastic rainfall downscaling of climate models, Journal of Hydrometeorology, Under minor revisions. Research activity: Idealized model for savanna environment with soil moisture dynamics. Savannas occupy about a fifth of the global land surface and, despite their importance for socio-economical issues (Scholes, 2003), their origin, nature and dynamics are still poorly understood. One key open question, in particular, concerns the understanding of the mechanisms potentially responsible for tree-grass coexistence in such an environment. Along a gradient of water availability, tropical grasslands and forest represent limiting cases of complete dominance in the most water-limit and in the wettest environments respectively. Another important question arises: What are the factors determining the variation in tree-grass cover across the tropical savanna spectrum? Arid and semi-arid savanna tree cover is currently thought to be determined mainly by water availability; tree growth is water-limited, and grasses can at times outcompete trees, especially when they are seedlings (Sankaran et al., 2004, 2005). One purpose of my work is studying, by using an idealized model, the interplay of tree-grass competition with soil moisture dynamics, in order to reproduce and better understand the processes which are responsible for the coexistence between the two species and for the variation in tree-grass cover along a mean annual rainfall gradient. Idealized models, despite their simplicity with respect to the complex, fully-coupled climate models, allow to understand local ecosystem dynamics and critical transitions in the large-scale climate (Rietkerk et al. 2011). During this first year, under the supervision of Dr. Antonello Provenzale, I developed a simple ecohydrological model of savanna vegetation involving competition for water through the soil moisture dynamics. The model is a simple implicit-space system described by four coupled ordinary differential equations for the dynamics of trees, tree seedlings, grasses and soil moisture in an idealized savanna environment. The tree-grass equations derive from the model described in Baudena et al. 2009, which is based on Tilman studies (1994), whereas the soil moisture dynamics is based on the model described in Laio et al. (2001). Assuming that the colonization rates of grasses and trees are water-dependent and that grasses can outcompete trees when they are seedlings, the model is able to predict grassland, savanna (tree-grass coexistence) and forest along a gradient of mean annual rainfall, as well as variations in tree-grass cover at a fixed mean precipitation value, due to precipitation intermittency. BE AWARE: research activity and Pubs are not evaluated as didactic credits, but are requested to trace the PhD students' career