TY - JOUR
T1 - Gravitational separation in the stratosphere - A new indicator of atmospheric circulation
AU - Ishidoya, S.
AU - Sugawara, S.
AU - Morimoto, S.
AU - Aoki, S.
AU - Nakazawa, T.
AU - Honda, H.
AU - Murayama, S.
PY - 2013
Y1 - 2013
N2 - As a basic understanding of the dynamics of the atmospheric circulation, it has been believed that gravitational separation of atmospheric components is observable only in the atmosphere above the turbopause. However, we found, from our high-precision measurements of not only the isotopic ratios of N2, O2 and Ar but also the mole fraction of Ar, that gravitational separation occurs even in the stratosphere below the turbopause; their observed vertical profiles are in good agreement with those expected theoretically from molecular mass differences. The O2/N2 ratio observed in the middle stratosphere, corrected for gravitational separation, showed the same mean air age as estimated from the CO2 mole fraction. Simulations with a 2-dimensional model of the middle atmosphere indicated that a relationship between gravitational separation and the age of air in the stratosphere would be significantly affected if the Brewer-Dobson circulation was enhanced due to global warming. Therefore, gravitational separation is usable as a new indicator of changes in the atmospheric circulation in the stratosphere.
AB - As a basic understanding of the dynamics of the atmospheric circulation, it has been believed that gravitational separation of atmospheric components is observable only in the atmosphere above the turbopause. However, we found, from our high-precision measurements of not only the isotopic ratios of N2, O2 and Ar but also the mole fraction of Ar, that gravitational separation occurs even in the stratosphere below the turbopause; their observed vertical profiles are in good agreement with those expected theoretically from molecular mass differences. The O2/N2 ratio observed in the middle stratosphere, corrected for gravitational separation, showed the same mean air age as estimated from the CO2 mole fraction. Simulations with a 2-dimensional model of the middle atmosphere indicated that a relationship between gravitational separation and the age of air in the stratosphere would be significantly affected if the Brewer-Dobson circulation was enhanced due to global warming. Therefore, gravitational separation is usable as a new indicator of changes in the atmospheric circulation in the stratosphere.
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U2 - 10.5194/acp-13-8787-2013
DO - 10.5194/acp-13-8787-2013
M3 - Article
AN - SCOPUS:84883750674
SN - 1680-7316
VL - 13
SP - 8787
EP - 8796
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
IS - 17
ER -