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CO 2 in the upper troposphere: Influence of stratosphere‐troposphere exchange
Author(s) -
Shia RunLie,
Liang MaoChang,
Miller Charles E.,
Yung Yuk L.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl026141
Subject(s) - troposphere , stratosphere , tropopause , atmospheric sciences , environmental science , atmosphere (unit) , climatology , altitude (triangle) , latitude , mixing ratio , quasi biennial oscillation , seasonality , geology , meteorology , geography , geometry , mathematics , geodesy , statistics
A two‐dimensional transport model constrained to measured surface CO 2 concentrations was used to simulate the spatial and temporal variation of CO 2 in the atmosphere for the period from 1975 to 2004. We find that the amplitude, phase and shape of the CO 2 seasonal cycle vary as a function of both altitude and latitude. Cross tropopause exchanges, especially the downward branch of the Brewer‐Dobson circulation, which brings stratospheric air to the upper troposphere at middle and high latitudes, change the CO 2 concentration and seasonal cycle in the extra‐tropics. The model results match recent aircraft measurements of CO 2 in the upper troposphere ( Matsueda et al. , 2002) remarkably well. We conclude that upper tropospheric CO 2 volume mixing ratios will provide a valuable tool for validating vertical transport. The implications of the CO 2 variation caused by the stratosphere‐troposphere exchange for remote sensing of CO 2 are discussed.