Tuesday, 11 January 2000: 9:15 AM
The University of Virginia has participated in a number of research
programs focussed on identifying the origin and fate of ozone in the
non-urban troposphere, and its transport on a hemispheric scale. Our
ability to forecast and diagnose the significant contribution of
natural ozone has improved with our use of multispectral satellite
imagery along with derived dynamical tracers. In particular, we have
used the analytic expression relating GOES-8/9 water vapor radiances
to relative humidity in combination with regional-scale model
temperature grids to derive relatively high horizontal resolution
(8km) images of upper-tropospheric specific humidity. The accuracy
of these images increases with dryness of the atmosphere; consequently,
the images provide new insight into the dynamics of events such as
tropopause folds, cut-off lows, and shear lines. Using in-situ chemical
observations from recent field campaigns, we will show that in the
wake of stratosphere/troposphere exchange events, the distribution
of dry air in the mid-to-upper troposphere is an effective tracer for
ozone of stratospheric origin. The availability of Unidata internet
data feeds and supported applications have enabled the development
of this research and have fostered interdisciplinary education on tropospheric
dynamics as they impact chemistry. In addition to the traditional
GOES data available to the Unidata community, we have recently expanded
our ability to interpret variations in ozone by importing into McIDAS
gridded fields of total column ozone from the Total Ozone Mapping
Spectrometer (TOMS) on the polar orbiting NASA Earth Probe. We use this
information as an independent corroboration of our interpretation of the
dynamically driven variations in the tropospheric ozone.
Previous atmospheric chemistry investigations relied upon trajectory models, and modelled tracers, such as isentropic potential vorticity as primary tools for diagnosing Lagrangian transport and airparcel origin of balloon and aircraft data. Our ability to visualize atmospheric flow and the evolution of tracer fields like specific humidity provides a context for evaluating traditional diagnostic tools like Lagrangian trajectory models, and regional-scale chemical transport models. Results to date show promise for advancing our understanding of the global oxidant budget.
![](images/flag.png)
![](images/blue_ribbon.png)