Monday, 10 January 2000: 10:45 AM
In the Goddard Earth Observing System (GEOS) ozone data assimilation system
(DAS) ozone observations from Total Ozone Mapping Spectrometer (TOMS) and
Solar Backscatter Ultraviolet (SBUV) instruments are assimilated into a
transport and chemistry model driven by GEOS core DAS assimilated winds.
Besides global 3-dimensional analyzed ozone fields the system produces the
transport, chemistry and analysis increments, i.e. changes to the ozone
field due to advection, photochemical processes, and analysis of observations,
respectively. The amplitude and nature of these increments indicate strengths
and weaknesses of a transport and chemistry model. For a realistic model,
prediction and observations agree and analysis increments are small. In the
regions where a model has systematic errors, the analysis increments are large,
and they are consistently counteracting the transport or chemistry increments.
We compare models in which transport is driven by different winds and chemistry
is specified using different parameterizations by including them into the ozone
assimilation system. The comparison of analysis, transport and chemistry
increments reveals strengths and weaknesses of each model under study.
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