Exchange grid: implementation of a test configuration to evaluate fluxes modification

The goal of this study is to evaluate the impact of a new flux calculation location, performed on each ocean/atmosphere grids intersection instead of on the coarse atmosphere grid. This document describes the implementation and validation of an intermediate complexity coupled model including NEMO and various instances of the SURFEX surface module of ARPEGE, where flux calculations are performed. Major impacts affect non solar heat flux, particularly in the marginal zone, during ice production phase, which is increased.