Trends in the Vertical Distribution of Ozone
William J. Randel,
1*
Richard S. Stolarski,
2
Derek M. Cunnold,
3
Jennifer A. Logan,
4
M. J. Newchurch,
5
Joseph M. Zawodny
6
Analyses of satellite, ground-based, and balloon measurements
allow updated estimates of trends in the vertical profile of ozone
since 1979. The results show overall consistency among several independent measurement systems, particularly for northern hemisphere midlatitudes where most balloon and ground-based measurements are made.
Combined trend estimates over these latitudes for the period 1979-96
show statistically significant negative trends at all altitudes between
10 and 45 km, with two local extremes: 
7.4 ± 2.0% per decade
at 40 km and 7.3 ± 4.6% per decade at 15 km altitude. There is
a strong seasonal variation in trends over northern midlatitudes in the
altitude range of 10 to 18 km, with the largest ozone loss during
winter and spring. The profile trends are in quantitative
agreement with independently measured trends in column ozone, the
amount of ozone in a column above the surface. The vertical profiles of
ozone trends provide a fingerprint for the mechanisms of ozone
depletion over the last two decades.
1 National Center for Atmospheric Research,
Boulder, CO 80307, USA.
2 National Aeronautics and
Space Administration (NASA), Goddard Space Flight Center, Greenbelt, MD
20771, USA.
3 Georgia Institute of Technology,
Atlanta, GA 30332, USA.
4 Harvard University,
Cambridge, MA 02138, USA.
5 University of Alabama in
Huntsville, Huntsville, AL 35899, USA.
6 NASA
Langley Research Center, Hampton, VA 23681, USA.
*
To whom correspondence should be addressed. E-mail:
randel{at}ucar.edu
