Main TWP2 results

TWP2 Toward integrated modelling of the Mediterranean systems

Ecosystem and climate modelling

For land ecosystems, considerable progress with respect to OT-Med objectives has been made through the work of a PhD student (S Decock) and a post-doc (M Fader) working on the agroecosystem model LPJmL (Fader et al. 2014). One post-doc has been developing the Mediterranean Sea biogeochemical/physical model ECO3M (Alekseenko et al. 2014). The LOVECLIM climate model (of intermediate complexity) has been obtained from H. Goosse (Louvain-la-Neuve) and our modelling engineer has been trained to work on it. Gea-Izquierdo et al. (2015) extended an existing mechanistic model to analyse photosynthesis and variability in carbon allocation in two evergreen species in two Mediterranean forests. The proposed model has a great potential with using abundant dendrochronological data and analysing forest performance in a context of climate change. This would help to understand how different interfering environmental factors produce instability in the climatic signal expressed in tree-rings.

Approaching the integrated model

In order to develop these activities in an interdisciplinary framework, a first dedicated OT-Med modelling workshop was held in June 2013. It provided an overview of the different modelling activities in the partner laboratories of OT-Med, and significantly broadened the discussion about model integration.

OT-Med partners then adapted modules of the respective land and ocean models upstream of a land-ocean linkage : downscaling from a global to a regional Mediterranean scale (LJPml, agroecosystem model), land use and food supply scenarios (economists), integration of permanent cultures and agricultural practice (LPJml, agroecosystem model), nutrient transfer processes, biogeochemical module of the Nemo model adjusted to match the Eco3M model requirement (to reprensent the marine carbon flux).

Efforts now focus on model coupling between land and ocean ecosystem models by developing an integrated process-based model of the key elements of the coupled system: the dynamics of agro-ecosystems under different management scenarios, and the dynamics of the first levels of the marine food web (from nutrients to jellyfishes) driven by ocean physics and rivers nutrients inputs from the land model. Land-sea interactions primarily deal with the nutrient flow, which is significantly affected by management decisions on land and which has a notable impact on the marine ecosystem and the services it provides.

In the long term, options for enhanced management of the Mediterranean region will be assessed, as well as consequences of environmental change on socio-economic vulnerability.