Improving global chemical simulations of the upper troposphere-lower troposphere with sequential assimilation of MOZAIC data
Cathala, M.-L. ; Pailleux, J. ; Peuch, V.-H.
Année de publication
2003
The quantity and variety of atmospheric measurements of chemical
constituents are strongly increasing, both for in situ and
remote-sensing observing systems. This is an incentive to develop data
assimilation schemes for atmospheric chemistry models, in the
perspective of building realistic three-dimensional time-dependent
distributions of observed and chemically related non-observed compounds.
Sequential data assimilation experiments within the global Chemistry
and Transport Model MOCAGE have been conducted, in the perspective of
using the MOZAIC database and meteorological analyses to drive a global
simulation of ozone and related tracers, focussing specially on the
upper tropospherelower stratosphere; the chemistry and dynamics in this
region of the atmosphere are of great environmental interest, yet they
are currently very difficult to model. Assimilation of subsonic
flight-level observations of ozone is anticipated to provide a
significant contribution to improve numerical simulations. Results
obtained with two different sequential data assimilation schemes are
presented. The experiments have been set up on an 8-d period in February
1997. The non-local data assimilation technique appears preferable to
the local technique tested, since the benefits of assimilation for
the former appear to remain for longer, possibly up to 34 d in the
model integration after the data assimilation phase.</div>
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