From the 1960s to the early 90s, the westerly phase of the Quasi-Biennial Oscillation (QBO) was observed to have a longer period during the solar minima [Salby and Callaghan, 2000]. During the same period, the stratosphere was contaminated by volcanic aerosols. For the two solar cycles before and after this interval, the QBO period exhibited the opposite behavior. To determine the true dependence of the QBO period on the solar cycle in the absence of volcanic aerosols, we performed an 82-year model simulation of the QBO using a two- and-a-half-dimension model. Analysis of the model simulation indicates a positive correlation between the QBO period and the solar flux. Above 30 hPa, the easterly phase QBO duration increases more rapidly with solar flux than that of the westerly phase. However, below 50 hPa the westerly QBO duration increases faster. The mechanism for these changes is discussed.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- 1610 Atmosphere (0315;
- 1650 Solar variability (7537);
- 3334 Middle atmosphere dynamics (0341;
- 7538 Solar irradiance