An upper-branch Brewer-Dobson circulation index for attribution of stratospheric variability and improved ozone and temperature trend analysis (2016)
AuthorsBall WT, Kuchar A, Rozanov EV, Staehelin J, Tummon F, Smith AK, Sukhodolov T, Stenke A, Revell L, Coulon A, Schmutz W, Peter Tshow all
We ﬁnd that wintertime temperature anomalies near 4hPa 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 ∼5hPa and dropping to 0 at ∼50 and ∼0.5hPa, respectively, and increasing again into the mesosphere. Ozone similarly sees up to an additional 50%ofvariabilityaccountedfor,withaslightlyhighermaximum and strong altitude dependence, with zero improvement found at 10hPa. Further, the uncertainty on all equatorial multiple-linear regression coefﬁcients can be reduced byupto35and20%intemperatureandozone,respectively, and so this index is an important tool for quantifying current and future ozone recovery.
ANZSRC Fields of Research02 - Physical Sciences
37 - Earth sciences::3701 - Atmospheric sciences::370104 - Atmospheric composition, chemistry and processes