Classification of Northern Hemisphere stratospheric ozone and water vapor profiles by meteorological regime

The extratropical upper troposphere/lower stratosphere region is characterized by complex interactions between dynamics, chemistry, microphysics, and radiation. Ozone and water vapor are two essential chemical species affected by all of these processes. Quantification of stratosphere troposphere exchange of these species is made difficult, not only by the many processes involved, but also by the varying definitions of what separates these two regions, the tropopause. This work will utilize the concept of meteorological regimes, as defined by Hudson et al. (2003, 2006), to isolate these two regions. It has been shown that these regimes are characterized by relatively constant total ozone and thermal tropopause heights despite large overlaps in latitude (Hudson et al. 2003).

In this work, mid-latitude (25-60N) ozone and water profiles from HALOE and SAGE II are used to show that each regime is characterized by a unique ozonepause and hygropause height. Therefore, at certain altitudes in the extratropical UT/LS region, a zonal average will be a combination of both tropospheric and stratospheric air, and interannual variability within a given latitude band will be the result of both changes within the regimes, and changes in the relative contribution of the regimes to the given zonal band over time. Seven-year climatologies for both species, and both instruments were also calculated and compared. Excellent agreement was obtained for the ozone climatologies. The agreement for water vapor was not as good, but the calculated climatologies agreed within experimental error. In addition, data from HALOE, SAGE II, and POAM III will be used to examine the seasonal and interannual variability of both ozone and water vapor in the lowermost stratosphere.