HR: 1340h
AN: A53A-0849    [Abstracts]
TI: Aerosols deposition in a GCM Eulerian model with variable spatial resolution
AU: Coindreau, O
EM: olivia.coindreau@cea.fr
AF: CEA/DASE/LDG, BP.12 CEA, Bruyeres-le-Chatel, 91680 France
AU: * HEINRICH, P
EM: philippe.heinrich@cea.fr
AF: CEA/DASE/LDG, BP.12 CEA, Bruyeres-le-Chatel, 91680 France
AU: Grillon, Y
EM: yves.grillon@cea.fr
AF: CEA/DASE/LDG, BP.12 CEA, Bruyeres-le-Chatel, 91680 France
AB: Transport and deposition of cosmogenic 7Be is simulated by the GCM model, LMDZ, developed at the Laboratoire de M‚t‚orologie Dynamique in Paris. The model calculates eulerian large-scale advection based upon finite-volume methods and parameterization of turbulent mixing and convection. Simulations with a 2ø horizontal resolution and 19 levels vertically, are carried out in a "nudged" mode, where horizontal velocities and temperature are relaxed towards wind analyses ECMWF, available every 6 hours. Transport is based on mass conservation of the aerosol in the atmosphere, taking into account radioactive decay, dry and wet deposition. Concentrations of 7Be are initialized in the atmosphere as a function of latitude and pressure, based on data of. Lal and Peters (1967).We show that our model reproduces with reasonable accuracy the time series of 7Be recorded over 6 months and by 20 stations distributed over the globe, which essentially validates the precipitation model. Numerical results show the respective influence of convective and stratiform precipitation. The LMDZ model allows the use of a variable mesh define by coordinate stretching or "zoom", to increase resolution over any region of interest. Sensitivity tests are carried out by varying the spatial resolution of model, with resolution as fine as 0.5ø by 0.5ø over Europe.
DE: 3337 Numerical modeling and data assimilation
DE: 3354 Precipitation (1854)
DE: 3314 Convective processes
DE: 3319 General circulation
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting