ausblenden:
Schlagwörter:
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Zusammenfassung:
Tropospheric data from a number of aircraft campaigns have been gridded
onto global maps, forming "data composites" of chemical species
important in ozone photochemistry. Although these are not climatologies
in the sense of a long temporal average, these data summaries are useful
for providing a picture of the global distributions of these species and
are a start to creating observations-based climatologies. Using aircraft
measurements from a number of campaigns, we have averaged observations
of O-3, CO, NO, NOx, HNO3, PAN, H2O2, CH3OOH, HCHO, CH3COCH3, C2H6, and
C3H8 onto a 5 degrees latitude by 5 degrees longitude horizontal grid
with a 1-km vertical resolution. These maps provide information about
the distributions at various altitudes, but also clearly show that
direct observations of the global troposphere are still very limited. A
set of regions with 10 degrees-20 degrees horizontal extent has also
been chosen wherein there is sufficient data to study vertical profiles,
These profiles are particularly valuable for comparison with model
results, especially when a full suite of chemical species can be
compared simultaneously. The O-3 and NO climatologies generated from
measurements obtained during commercial aircraft flights associated with
the MOZAIC and NOXAR programs are incorporated with the data composites
at 10-11 km. As an example of the utility of these data composites,
observations are compared to results from two global chemical transport
models, MOZART and IMAGES, to help identify incorrect emission sources,
incorrect strength of convection, and missing chemistry in the models.
These comparisons suggest that in MOZART the NO, biomass burning
emissions may be too low and convection too weak and that the transport
of ozone from the stratosphere in IMAGES is too great. The ozone
profiles from the data composites are compared with ozonesonde
climatologies and show that in some cases the aircraft data agree with
the long-term averages, but in others, such as in the western Pacific
during PEM-Tropics-A, agreement is lacking. Finally, the data composites
provide temporal and spatial information, which can help identify the
locations and seasons where new measurements would be most valuable. All
of the data composites presented here are available via the Internet
(http://aoss.engin.umich.edu/SASSarchive/).
