1. Figure 3. The MJO-related vertical structures of MACC CO. CO are averaged between 15ºN – 15ºS. Rainfall is averaged between 5ºN – 5ºS. ABSTRACT. We report the Madden-Julian oscillation (MJO) in carbon monoxide (CO) assimilated in ECMWF Monitoring Atmospheric Composition and Climate (MACC) products. Such signal is strongest below 700 hPa and is closely related to the sources over lands, which are closely related to biomass burning activities. This work merits the recent efforts of the implementation of tracer transports in the current ECMWF assimilations. The Madden-Julian Oscillation in Carbon Monoxide Assimilated in ECMWF King-Fai Li †,, Johannes Fleming £, Peter Bechtold £, King-Fai Li †,#, Johannes Fleming £, Peter Bechtold £, Baijun Tian $, Duane E. Waliser $ & Yuk L. Yung † † Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA $ European Centre for Medium-Range Weather Forecasts, Reading, UK £ Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA The Madden-Julian Oscillation in Carbon Monoxide Assimilated in ECMWF King-Fai Li †,, Johannes Fleming £, Peter Bechtold £, King-Fai Li †,#, Johannes Fleming £, Peter Bechtold £, Baijun Tian $, Duane E. Waliser $ & Yuk L. Yung † † Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA $ European Centre for Medium-Range Weather Forecasts, Reading, UK £ Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA # Correspondence author Email address: kfl@gps.caltech.edu YOTC 11’ Beijing, China I. MOTIVATION  The MJO in atmospheric carbon dioxide (CO 2 ) recently observed [Li et al., 2010] poses an important constraint on the simulation of the global carbon cycle. It is necessary to also investigate similar modulations in other carbon- related tracers.  A possible source of CO 2 may involve biomass burning which is highly dependent on weather patterns. To that end, a good tracer of biomass burning activities is CO.  ECMWF MACC assimilation of CO using various satellite measurements provide a high spatial-temporal resolution product for this purpose. Figure 2. The MJO of MACC CO at 700 hPa. II. DATA DESCRIPTIONS  MACC CO products are available at http://www.gmes- atmosphere.eu/.http://www.gmes- atmosphere.eu/  In this work, CO daily products during 2003 – 2005 are used. TRMM rainfall during 2002 – 2010 are also used to characterize the weather patterns.  The data has a spatial resolution of 1.25º × 1.25º and 13 levels in the troposphere. Figure 1. The MJO-modulation of MACC CO surface flux due to biomass burning. III. METHODS  Monthly averages are first removed to derive the CO anomalies.  Strong MJO events during boreal winters (April – November) are identified using the Wheeler-Hendon index [Wheeler & Hendon, 2002]. The MJO cycle is defined by 8 phases which characterize the propagation of the MJO disturbance from eastern Indian Ocean to the central Pacific Ocean.  CO anomalies during in individual MJO phases are averaged. IV. RESULTS  Figure 1 shows that during the MJO cycle, CO surface flux due to biomass burning attains a negative anomaly over a region where the rainfall anomaly is positive, and vice versa. This clearly shows the influence of weather patterns on human activities.  Figure 2 shows that the CO pattern in the mid- troposphere is closely correlated with the surface flux term, implying the role of the vertical air movements. Note that unlike the propagating MJO disturbance, the CO signal is nearly stationary because of the stationary sources over land.  Figure 3 shows that the CO anomaly below 700 hPa is anticorrelated with the rainfall anomaly, especially in the eastern hemisphere, but the anticorrelation is less apparent above, which requires further investigation. Reference. Li et al. (2010), PNAS 107, 19175; Wheeler & Hendon (2004), Mon. Wea. Rev. 132, 1917. V. FUTURE WORK  The derived MJO patterns in MACC CO may be compared with satellite measurements (e.g. MODIS).  The sink of CO can also be examined through MACC OH near the surface.