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Regional climate modeling

4 mars 2014 ( maj : 22 avril 2015 ), par Benjamin Pohl

Three nested domains allow simulating the regional climate variability and quantify associated uncertainties and biases at high spatial resolutions. The first domain includes metropolitan France and neighboring countries at a spatial resolution of roughly 20km. The second domain zooms over the Alps, using a 4km horizontal grid. The third domain is centered over the Mont-Blanc Massif with a kilometer-scale mesh spacing. Lateral boundary conditions are provided by the ERA-Interim reanalyses, produced by ECMWF in Reading, UK, and available every 6hrs since January 1st, 1979, at a 0.75° resolution. Surface data included CORINE Land Cover (version 2006) and a digital elevation model derived from the SRTM dataset.

DOMAIN1 (“France”) includes 80 x 80 x 30 grid points (latitude x longitude x vertical levels), resulting in 192,000 voxels. In this domain, the elevation of the Mont-Blanc reaches 2600m only (which is already better than some global models, for which it does not exceed 800 or 1000m asl.).

DOMAIN2 (“Alps”) is includes the same number of voxels, but with a resolution 5 times finer. The Mont-Blanc reaches 3550m asl.

DOMAIN3 (“Mont-Blanc Massif”) is finally composed of 93 x 93 x 30 = roughly 260,000 voxels. The elevation of the virtual Mont-Blanc in our simulations is 4450m.

This domain is sensibly larger than the focus region of the VIP-Mont-Blanc project to minimize edge effects along the inner domain boundaries.

Over the 1979-2014 period, one nudged simulations will be performed to feed permafrost and glacier models, 10 free (not nudged) members will feed climate studies, and additional simulations will be performed to address the sensitivity of the simulated climate to the model’s physics.

All calculations are performed by the Centre de Recherches de Climatologie / Biogéosciences laboratory, using HPC resources from DSI-CCuB (université de Bourgogne) and ANR funding.

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