Tropical mid-tropospheric CO2 variability driven by the Madden-Julian oscillation.
Carbon dioxide (CO(2)) is the most important anthropogenic greenhouse gas in the present-day climate. Most of the community focuses on its long-term (decadal to centennial) behaviors that are relevant to climate change, but there are relatively few discussions of its higher-frequency forms of variability, and none regarding its subseasonal distribution. In this work, we report a large-scale intraseasonal variation in the Atmospheric Infrared Sounder CO(2) data in the global tropical region associated with the Madden-Julian oscillation (MJO). The peak-to-peak amplitude of the composite MJO modulation is ∼1 ppmv, with a standard error of the composite mean < 0.1 ppmv. The correlation structure between CO(2) and rainfall and vertical velocity indicate positive (negative) anomalies in CO(2) arise due to upward (downward) large-scale vertical motions in the lower troposphere associated with the MJO. These findings can help elucidate how faster processes can organize, transport, and mix CO(2) and provide a robustness test for coupled carbon-climate models.
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
King-Fai
KF
Li
Baijun
B
Tian
Duane E
DE
Waliser
Yuk L
YL
Yung
D001272:Atmosphere / Q000032:analysis*; D002245:Carbon Dioxide / Q000032:analysis*; D005740:Gases; D017752:Greenhouse Effect; D012621:Seasons; D014329:Tropical Climate
D005740:Gases; D002245:Carbon Dioxide