BrewerâDobson circulation refers to the global atmospheric circulation pattern of tropical
tropospheric air rising into the
stratosphere and then moving poleward as it descends.[1] The basics of the circulation were first proposed by
Gordon Dobson[2][3] and
Alan Brewer.[4] The term "BrewerâDobson circulation" was first introduced in 1963.[5] This circulation pattern explains observations of
ozone and
water vapor distribution, and has been accelerating in recent decades, likely due to
climate change.[6]
Circulation
BrewerâDobson circulation is driven by planetary scale
atmospheric waves, namely
Rossby waves, with results in westward drag and therefore poleward pumping action to conserve
angular momentum.[1]
Global impacts
Because it moves air into and out of the stratosphere, BrewerâDobson circulation determines the mean age and
residence time of stratospheric gases, as well as tropical
tropopause temperatures and stratospheric
water vapor.[1] BrewerâDobson circulation directly impacts the distribution and abundance of
stratospheric ozone by moving it from the tropics towards the poles.[1] This transport helps to explain why tropical air has less
ozone than polar air, even though the tropical
stratosphere is where most atmospheric
ozone is produced.[1] BrewerâDobson circulation also influences the lifetime of ozone-degrading substances and some greenhouse gases.
Acceleration due to greenhouse effect
Interest in BrewerâDobson circulation has increased in the 21st century due to predictions of
general circulation models and chemistry-climate models that the circulation will accelerate due to
greenhouse-gas induced
climate change.[1] Observations have recently confirmed that BrewerâDobson circulation has accelerated at ~2.0% per decade for the past four decades, leading to a cooling of the tropical lower
stratosphere and warming in high latitudes.[6]
^Dobson, G. M. B.; Harrison, D. N.; Lindemann, F. A. (1926). "Measurements of the amount of ozone in the Earth's atmosphere and its relation to other geophysical conditions". Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character. 110 (756): 660â693.
Bibcode:
1926RSPSA.110..660D.
doi:
10.1098/rspa.1926.0040.