Abstract
The origin of the tropical lower-stratospheric response to 11-yr solar forcing and its possible coupling to a troposphere-ocean response is investigated using multiple linear regression (MLR) analyses of stratospheric ozone and temperature data over the 1979-2009 period and tropospheric sea level pressure (SLP) data over the 1880-2009 period. Stratospheric MLR results, comparisons with simulations from a chemistry- climate model, and analyses of decadal variations of meridional eddy heat flux indicate that the tropical lowerstratospheric response is produced mainly by a solar-induced modulation of the Brewer-Dobson circulation (BDC), with a secondary contribution from the Hadley circulation in the lowermost stratosphere. MLR analyses of long-term SLP data confirm previous results indicating a distinct positive response, on average, during the northern winter season in the North Pacific. The mean response in the Northern Hemisphere resembles a positive Arctic Oscillation mode and can also be characterized as "La Niña-like," implying a reduction of Rossby wave forcing, a weakening of the BDC, and an increase in tropical lower-stratospheric ozone and temperature near solar maxima. However, MLR analyses of different time periods show that the Pacific SLP response is not always present during every cycle; it was most clearly detected mainly during the;1938-93 period when 11-yr solar variability was especially strong. During the 1979-93 period, the SLP response was strongly present when the lower-stratospheric responses were large. But during the 1994-2009 period, the SLP response was much less significant and the lower-stratospheric responses were weak, supporting the hypothesis that the lower-stratospheric and surface climate responses are dynamically coupled.
Original language | English (US) |
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Pages (from-to) | 1841-1864 |
Number of pages | 24 |
Journal | Journal of the Atmospheric Sciences |
Volume | 69 |
Issue number | 6 |
DOIs | |
State | Published - Jun 2012 |
Externally published | Yes |
Keywords
- Atmosphere-ocean interaction
- Climate change
- ENSO
- Ozone
- Solar cycle
- Stratophere-troposphere coupling
ASJC Scopus subject areas
- Atmospheric Science