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Measurements Of Pollution In The Troposphere (MOPITT): 5 Years Of Measurements*, James Drummond ¹ , JC Gille ² , D Edwards ² , J Kar ¹ , J Liu ¹ , F Nichitiu ¹ , J Zou ¹ , ¹ University of Toronto , ² National Center for Atmospheric Research — The Measurements of Pollution In the Troposphere (MOPITT) was launched on the Terra spacecraft on 18^th December 1999 and has been retrieving vertical profiles of carbon monoxide (CO) – a major pollutant - globally since March 2000. The retrievals have been validated extensively by comparison with in-situ aircraft measurements through a regular program as well through special field campaigns. This dataset, which is still being expanded, represents the most comprehensive measurement set on any constituent of the troposphere, apart from water vapour. It is now being used effectively to study the role of CO in tropospheric chemistry, its role as a tracer of transport processes and in inverse models to better constrain the emissions. The retrievals have been shown to have sufficient vertical information to distinguish the upper troposphere from the middle troposophere. This is being exploited to study the upper tropospheric phenomena.

We shall present some of the most fascinating results from the analysis of five years of MOPITT data. These include : The first observational confirmation of the Asian summer monsoon plume of CO that is created by deep convective uplifting of boundary layer pollution during the south Asian monsoon. Evidence of “fronts” in MOPITT CO data when CO concentrations vary by 50-100% within a horizontal distance of 100 kms across a very sharp boundary. From a study of large forest fires in Northwest United States in 2000, it was found that the spatial CO plumes match remarkably well with the location and density of fires and wind direction, and the spatial and temporal variation of CO emission can be captured by MOPITT in 3-day composites. Globally, we found that for a year with normal fire activities, the CO annual cycle is closely influenced by biomass burning in South America, Africa, and Australia, while in other regions, it is more controlled by other CO source/sink terms. However, the normal cycle in different regions can be disturbed by anomalously strong fire activities in those regions in other years.

The MOPITT instrument was constructed by COMDEV of Cambridge, Ontario and the project was financed by the Canadian Space Agency and the Natural Sciences and Engineering Research Council.

* This work is being supported by CSA, NSERC