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CO as a Precursor of Ozone and a Tracer of Transport: Evidence from MOPITT Data. J. Kar (UT), H. Bremer (UB), James R. Drummond (UT), F. Nichitiu (UT), J. Zou (UT), J. Liu (UT), Y. Rochon (MSC), J. C. Gille (NCAR), M. N. Deeter(NCAR), G. Francis (NCAR), D. Ziskin (NCAR), J. Warner (NCAR).
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CO as a Precursor of Ozone and a Tracer of Transport: Evidence from MOPITT Data J. Kar (UT),H. Bremer (UB), James R. Drummond (UT), F. Nichitiu (UT), J. Zou (UT), J. Liu (UT), Y. Rochon (MSC), J. C. Gille (NCAR), M. N. Deeter(NCAR), G. Francis (NCAR), D. Ziskin (NCAR), J. Warner (NCAR)
Carbon Monoxide (CO) Tracer of Transport ( ~ few mths) Precursor of Ozone Sink of OH • Use MOPITT CO data to address: • Correlation between CO and O3 in the context of biomass • burning in the tropics (Delineate the causes of ozone variation) • Signature of transport phenomena (Convection, STE?!)
MOPITT measures upwelling radiation by gas • correlation radiometry in thermal IR near 4.7 m • and reflected solar radiation near 2.3 m • CO mixing ratio profiles and total columns are retrieved • by Optimal Estimation Technique. Mixing ratios reported at • surface, 850, 700,500,350,250,150 hPa • a Priori Single and constant over time (variations in • retrievals reflect geophysical variations). • Retrievals on different levels are not independent • • Averaging Kernel (Vertical resolution) • Validation of MOPITT data– MOPITT CO biased by < 8%
Bremer et al.,2004 JGR (In press)
10 Year Climatology of 10 day Back Trajectories Courtesy: Sam Oltmans
Convection Signature in MOPITT CO Data Near Calcutta(22.3N, 88.2E)
Back Trajectories, OLR and SST Indicate Convective Activity
Locations of CO Profiles with Possible Signature of Convection(2002) x x 30-50 x x Pressure(hPa) x x CO m.r.(ppbv)
STE as seen in MOPITT CO Data near Wallops Island (37.8N, 75.5W)
Conclusions: • Distinct seasonal patterns of CO at several SHADOZ • stations indicate strong influence of African and South • American biomass burning. • Enhanced CO columns are consistent with corresponding • enhancement in tropospheric ozone content from sonde • data except at San Cristobal and Paramaribo. • Signatures of Convection and Stratosphere Troposphere • Exchange events can be detected in MOPITT CO data. • Zonal mean height latitude cross sections of CO indicate • convective transport in the southern tropics, possible • signature of downward branch of Hadley cell (NH) and a • seasonal migration of the boundary between the polluted • northern hemisphere and relatively clean southern • hemisphere.