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In the framework of ocean-atmosphere coupling
studies in the Indian ocean and African monsoon studies in the Guinea
gulf, the LMD and the CNES (Franch Space Agency) must release
instrumented drifting balloons in the lower troposphere. These
balloons, while following the air masses displacements, give a
description of atmospheric dynamics on a broad range of scale. First of
all, one of the goals of this research project consists of simulating
trajectories of these drifting balloons in order to optimize the
launching strategy during the field phase experiment. Indeed,
scientific interpretation of experimental results depends on both
quality and quantity of measurements. However, the number of balloons
is limited because of their relatively high cost. Moreover, the use of
balloons has a lot of constraints (flights far away continents,
inhabited regions and airports). Because of these constraints,
launching decisions become difficult. From meteorological predictions,
trajectories computations of drifting balloons can help this type of
decision. That is why, an operational tool to help the launching
strategy during experiments is carried out. Besides, data obtained
during the experimental measurements will allow us to test our
numerical models and to compare observed trajectories (Fig 2) with simulated
ones. Next, the experimental results analysis can allow to obtain a
description of the flow regime and its temporal evolution (to show
evidence of small scales local circulations).
Keywords : Balloon, Trajectory, Forecasts, ECMWF.
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