Regulation of H_2O and CO in tropical tropopause layer by the Madden-Julian oscillation

摘要

Impacts of the Madden-Julian oscillation (MJO) on the water vapor (H_2O) and carbon monoxide (CO) abundances in the tropical tropopause layer (TTL) are investigated using Aura Microwave Limb Sounder (MLS) data for November 2004 to May 2005. The effects of the eastward propagation of MJO on H_2O and CO abundances in the TTL are evident. Deep convection transports H_2O into the upper troposphere up to about the 355- to 365-K level. Around the 365- to 375-K level, a dry anomaly is collocated with a cold anomaly, which is above a warm anomaly located near the region of convection enhancement. Tropical mean H_2O at 375 K is regulated by the MJO through convection enhancement and is coherent with the local MJO-related temperature variation. The locations of dehydration follow the eastward propagation of convection enhancement, and its area extent depends on the phase of the MJO. Enhancement of deep convection associated with the MJO also injects CO from the lower troposphere to the TTL up to 375 K. However, tropical mean CO at 375 K responds instantaneously to the large injection event occurring over the African continent.