Monday, 14 January 2002
Ozone and Water Vapor: Analyzing their Relationship within the Mesosphere
Relatively little is known about the mesosphere (50-90 km) as compared with other
regions in the atmosphere. The mesosphere is difficult to measure with airborne, ground-based
and in situ satellite measurements due to its height and location between the thermosphere and the
stratosphere. One element of the mesosphere that is of particular interest is the presence of ozone
and its role in the atmospheric processes at these altitudes. Most of the ozone present in the
atmosphere resides within the stratosphere, commonly referred to as the ozone layer. A lesser
distribution of ozone exists within the mesosphere. In understanding the simpler ozone chemistry
of this region, a greater understanding of the ozone chemistry in the stratosphere and throughout
the atmosphere can result, as well as a better understanding of the mesosphere. The ozone
chemistry above 50 km is controlled predominantly by hydrogen species such as the hydroxyl
radical. Reactions involving water vapor in the mesosphere determine hydroxyl distributions.
These reactions contribute to ozone destruction, making the distribution of mesospheric ozone
directly related to the distribution of water vapor. This research will present a ten-year
comparison of satellite measurements of ozone and water vapor within the mesosphere and
analyze the relationships between them. While it is generally thought that where water vapor
increases within the mesosphere, ozone should decrease at any time of day, strong anticorrelations
of the data are observed only at sunset around 80 km. These results indicate that
statistical relationships simulating ozone and water vapor within the mesosphere should be
updated to include the diurnal variation.
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