Solar variations and their influence on trends in upper stratospheric ozone and temperature
Abstract
Over the past decade, knowledge of the magnitude and temporal structure of the variations in the sun's ultraviolet irradiance has increased steadily. A number of theoretical modeling studies have shown that changes in the solar ultraviolet flux during the 11-year solar cycle can have a significant effect on stratospheric ozone concentrations. With the exception of Brasseur et al., who examined a very broad range of solar flux variations, all of these studies assumed much larger changes in the ultraviolet flux than measurements now indicate. These studies either calculated the steady-state effect at solar maximum and solar minimum or assumed sinusoidal variations in the solar flux changes with time. It is now possible to narrow the uncertainty range of the expected effects on upper stratospheric ozone and temperature resulting from the 11-year solar cycle. A more accurate representation of the solar flux changes with time is used in this analysis, as compared to previous published studies. This study also evaluates the relative roles of solar flux variations and increasing concentrations of long-lived trace gases in determining the observed trends in upper stratospheric ozone and temperature. The Lawrence Livermore National Laboratory (LLNL) two-dimensional chemical-radiative-transport model of the global atmosphere is used to evaluate the combined effects on the stratosphere from changes in solar ultraviolet irradiances and trace gas concentrations over the last several decades. Derived trends in upper stratospheric ozone concentrations and temperature are then compared with available analyses of ground-based and satellite measurements over this time period.
- Publication:
-
Presented at the 71st Annual Meeting of American Meteorological Society
- Pub Date:
- October 1990
- Bibcode:
- 1990ams..meet...13W
- Keywords:
-
- Atmospheric Composition;
- Atmospheric Temperature;
- Ozone;
- Radiation Effects;
- Solar Cycles;
- Solar Temperature;
- Stratosphere;
- Trends;
- Variations;
- Geophysics