Clotilde Dubois

Post Doctoral Resarch Assistant at the Centre National de Recherches Météorologiques (CNRM, Météo-France) Groupe de Modélisation Grande Echelle et Climat (GMGEC), Unité dynamique du climat (UDC) email: clotilde.dubois AT cnrm.meteo.fr tel: +33 561079863 bureau 287 : bâtiment Navier (CNRM) page last modified : February 2007

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Scientific Interests

Projets

Publications

Curriculum Vitae

Scientific Interests

Thermohaline Circulation and vertical mixing:

Part of my PhD. work revolved around modelling the role of the ocean in the global climate system. I focussed in particular, the issue of vertical mixing (Kv) in which is not currently resolved in a satisfactory manner in global climate model. The value of ocean diapycnal mixing sets the rate at which dense bottom water can be mixed up through the stratified water column abd thus plays an important role in the meridional overturning circulation (MOC). The mixing in the ocean occurs on a range of scales though many are smaller than model resolution and need to be parameterised. The processes responsible for the small scale mixing in the ocean are numerous and occur at different locations and depths. Observation programs showed very little mixing in the thermocline (0.1 cm2/s) while values of 1 cm2/s and higher are found near rough topography. Previous idealised experiments and simplified theory suggest that the strength of the MOC and the ocean heat transport scale with the Kv. My PhD work investigated the dependence of the MOC and othe parameters on Kv using atmosphere-ocean general circulation models such as FORTE and MPI-OM/ECHAM5.

Arctic varibility and climate change :

The main focus of my Post-doctoral research consists of analysing climate changes scenarios in the Arctic region. Numerous climate simulations using global coupled climate models have been produced for the IPCC-AR4 over the 21th century and under different greenhouse gases forcings. Current analyses show that most of these global coupled models correctly simulate the Arctic climate system and several aspects of its variability over the 20th century. Furthermore, a recent study has showed that abrupt reductions of sea-ice are common features in the IPPC-AR4 projections (Holland, M.M. et al. ,2006) and are linked rapid increase in ocean heat transport in the Arctic. As a firts step, I will investigate existing IPCC-AR4 simulations performed by CNRM-CM3 (Climate GCM from Meteo-France) and other models used for the IPCC-AR4 during transient climate change simulations over the 21th century in the Arctic region. CNRM-CM3 was used to provide climate simulation data for IPCC-AR4 analysis projects, it consists of the ARPEGE-Climat model for the atmosphere, the OPA model for the ocean and GELATO for the sea-ice model (Salas-Melia, D. et al., 2005). I will also examine which other coupled processes (ocean-sea ice-atmospheric feedbacks) could explain the sudden sea ice depletion events that have been identified. The strong natural variability in the Arctic region makes it difficult to separate individual processes. Therefore, to identify the impact of different physical parameterisations of the sea ice model on the Arctic variability and abrupt depletion, sensitivity experiments will be performed, using the CNRM-CM3 climate GCM, and will include changes in the parameterisations of thermodynamics processes of the sea-ice model. The sensitivity experiments will investigate the role of the atmosphere on the radiative budget in the Arctic region. Its sensitivity to stratospheric variability will be investigated by looking at the role of volcanic aerosols and ozone feedbacks via the Arctic Oscillation on sea ice formation.

Projects

Throughout my research, I have been involved and implicated in the following projects:

ENSEMBLES, here

COAPEC (Coupled Ocean Atmosphere Processes and European Climate), here

Rapid Climate Change, here

Publications

Please click here for a copy of my thesis's abstract.

Curriculum Vitae

Please click here for a copy of my CV.