An upper-branch Brewer-Dobson circulation index for attribution of stratospheric variability and improved ozone and temperature trend analysis
Ball, William T.
Rozanov, Eugene V.
Smith, Anne K.
- Journal Article
Rights / licenseCreative Commons Attribution 3.0 Unported
We find that wintertime temperature anomalies near 4 hPa and 50 N/S are related, through dynamics, to anomalies in ozone and temperature, particularly in the tropical stratosphere but also throughout the upper stratosphere and mesosphere. These mid-latitude anomalies occur on timescales of up to a month, and are related to changes in wave forcing. A change in the meridional Brewer–Dobson circulation extends from the middle stratosphere into the mesosphere and forms a temperature-change quadrupole from Equator to pole. We develop a dynamical index based on detrended, deseasonalised mid-latitude temperature. When employed in multiple linear regression, this index can account for up to 60% of the total variability of temperature, peaking at 5 hPa and dropping to 0 at 50 and 0.5 hPa, respectively, and increasing again into the mesosphere. Ozone similarly sees up to an additional 50% of variability accounted for, with a slightly higher maximum and strong altitude dependence, with zero improvement found at 10 hPa. Further, the uncertainty on all equatorial multiple-linear regression coefficients can be reduced by up to 35 and 20% in temperature and ozone, respectively, and so this index is an important tool for quantifying current and future ozone recovery Show more
Journal / seriesAtmospheric Chemistry and Physics
Organisational unit03517 - Peter, Thomas
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