% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Lannuque:902297,
      author       = {Lannuque, Victor and Sauvage, Bastien and Barret, Brice and
                      Clark, Hannah and Athier, Gilles and Boulanger, Damien and
                      Cammas, Jean-Pierre and Cousin, Jean-Marc and Fontaine,
                      Alain and Le Flochmoën, Eric and Nédélec, Philippe and
                      Petetin, Hervé and Pfaffenzeller, Isabelle and Rohs,
                      Susanne and Smit, Herman G. J. and Wolff, Pawel and Thouret,
                      Valérie},
      title        = {{O}rigins and characterization of {CO} and
                      ${O}\<sub\>3\</sub\>$ in the {A}frican upper troposphere},
      journal      = {Atmospheric chemistry and physics},
      volume       = {21},
      number       = {19},
      issn         = {1680-7324},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2021-04160},
      pages        = {14535 - 14555},
      year         = {2021},
      abstract     = {Between December 2005 and 2013, the In-service Aircraft for
                      a Global Observing System (IAGOS) program produced almost
                      daily in situ measurements of CO and O3 between Europe and
                      southern Africa. IAGOS data combined with measurements from
                      the Infrared Atmospheric Sounding Interferometer (IASI)
                      instrument aboard the Metop-A satellite (2008–2013) are
                      used to characterize meridional distributions and
                      seasonality of CO and O3 in the African upper troposphere
                      (UT). The FLEXPART particle dispersion model and the SOFT-IO
                      model which combines the FLEXPART model with CO emission
                      inventories are used to explore the sources and origins of
                      the observed transects of CO and O3.We focus our analysis on
                      two main seasons: December to March (DJFM) and June to
                      October (JJASO). These seasons have been defined according
                      to the position of Intertropical Convergence Zone (ITCZ),
                      determined using in situ measurements from IAGOS. During
                      both seasons, the UT CO meridional transects are
                      characterized by maximum mixing ratios located 10∘ from
                      the position of the ITCZ above the dry regions inside the
                      hemisphere of the strongest Hadley cell (132 to 165 ppb at
                      0–5∘ N in DJFM and 128 to 149 ppb at 3–7∘ S in
                      JJASO) and decreasing values southward and northward. The O3
                      meridional transects are characterized by mixing ratio
                      minima of ∼42–54 ppb at the ITCZ (10–16∘ S in
                      DJFM and 5–8∘ N in JJASO) framed by local maxima
                      (∼53–71 ppb) coincident with the wind shear zones
                      north and south of the ITCZ. O3 gradients are strongest in
                      the hemisphere of the strongest Hadley cell. IASI UT O3
                      distributions in DJFM have revealed that the maxima are a
                      part of a crescent-shaped O3 plume above the Atlantic Ocean
                      around the Gulf of Guinea.CO emitted at the surface is
                      transported towards the ITCZ by the trade winds and then
                      convectively uplifted. Once in the upper troposphere,
                      CO-enriched air masses are transported away from the ITCZ by
                      the upper branches of the Hadley cells and accumulate within
                      the zonal wind shear zones where the maximum CO mixing
                      ratios are found. Anthropogenic and fires both contribute,
                      by the same order of magnitude, to the CO budget of the
                      African upper troposphere.Local fires have the highest
                      contribution and drive the location of the observed UT CO
                      maxima. Anthropogenic CO contribution is mostly from Africa
                      during the entire year, with a low seasonal variability.
                      There is also a large contribution from Asia in JJASO
                      related to the fast convective uplift of polluted air masses
                      in the Asian monsoon region which are further westward
                      transported by the tropical easterly jet (TEJ) and the Asian
                      monsoon anticyclone (AMA).O3 minima correspond to air masses
                      that were recently uplifted from the surface where mixing
                      ratios are low at the ITCZ. The O3 maxima correspond to old
                      high-altitude air masses uplifted from either local or
                      long-distance area of high O3 precursor emissions (Africa
                      and South America during all the year, South Asia mainly in
                      JJASO) and must be created during transport by
                      photochemistry.},
      cin          = {IEK-8},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IEK-8-20101013},
      pnm          = {2111 - Air Quality (POF4-211)},
      pid          = {G:(DE-HGF)POF4-2111},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000703889100001},
      doi          = {10.5194/acp-21-14535-2021},
      url          = {https://juser.fz-juelich.de/record/902297},
}