EOS MLS and GEOS-CHEM: Observed and Modelled Carbon Monoxide and Ozone in the Upper Troposphere During the First Year of the Aura Mission.

Since August 2004, the EOS Microwave Limb Sounder (MLS) has been measuring carbon monoxide (CO) and ozone in the upper troposphere (as well as in the stratosphere and mesosphere). To complement these observations, the GEOS-CHEM global 3-D chemical transport model has been run for the same period to simulate the CO and ozone distribution in the upper troposphere. The observations and model simulations are compared and salient features discussed, including the trapping of CO in the Tibetan anticyclone, and possible transport of ozone from the sub-tropical stratosphere to the tropical troposphere.