The water cycle of the Mediterranean basin ; a continental perspective

Séminaire de Jan POLCHER, LMD-IPSL, jeudi 27 février 14h30, salle 105 OSUG-B

Abstract :
The Mediterranean Sea is warming and shows a salinity increase. This trend is common to most tropical oceans and can be explained by changes in the interactions with a warming atmosphere. Particularly interesting in the Mediterranean is that not only the atmospheric water cycle plays a role but also the continental branch. Arguably, the continental branch is the better observed part of the water cycle and where trends should be most readily identifiable.

In this talk we will show that the flux from the continents to the ocean in the Mediterranean is probably not as well known as we would like. Recent studies have indicated that the contribution of un-gauged rivers and submarine groundwater discharges might have been underestimated. Furthermore, in this region of the world, the climatic trends superimposes those driven by human water usage for agriculture. This leads to a particularly difficult attribution of observed changes to either intentional or unintentional human interventions in the Earth system.

The main geographical elements of the Mediterranean water cycle (https://www.nature.com/articles/s41598-019-44293-1)

The presentation will also describe the modelling strategy followed at IPSL to try and reproduce and predict the evolutions of the water cycle of the Mediterranean in the context of climate change. The regional Earth system modelling effort underway at the institute allows us to compare predictions of the water fluxes between the Mediterranean catchment, the sea and the atmosphere with observationally based estimates. It shows that at these scales our knowledge of the processes is still insufficient to quantify the sources of discrepancies.

Par Jan POLCHER, LMD-IPSL
Séminaire animé par Clémentine JUNQUAS