@article{fdi:010085205,
  title = {{E}vidence for interhemispheric mercury exchange in the {P}acific ocean upper troposphere},
  author = {{K}oenig, {A}. {M}. and {S}onke, {J}. {E}. and {M}agand, {O}. and {A}ndrade, {M}. and {M}oreno, {I}. and {V}elarde, {F}. and {F}orno, {R}. and {G}utierrez, {R}. and {B}lacutt, {L}. and {L}aj, {P}. and {G}inot, {P}atrick and {B}ieser, {J}. and {Z}ahn, {A}. and {S}lemr, {F}. and {D}ommergue, {A}.},
  editor = {},
  language = {{ENG}},
  abstract = {{E}ven though anthropogenic mercury ({H}g) emissions to the atmosphere are similar to 2.5 times higher in the {N}orthern {H}emisphere ({NH}) than in the {S}outhern {H}emisphere ({SH}), atmospheric {H}g concentrations in the {NH} are only similar to 1.5 times higher than in the {SH}. {G}lobal {H}g models attribute this apparent discrepancy to large {SH} oceanic {H}g emissions or to interhemispheric exchange of {H}g through the atmosphere. {H}owever, no observational data set exists to serve as a benchmark to validate whether these coarse-resolution models adequately represent the complex dynamics of interhemispheric {H}g exchange. {D}uring the 2015-2016 {E}l {N}ino, we observed at mount {C}hacaltaya in the tropical {A}ndes a similar to 50% increase in ambient {H}g compared to the year before, coinciding with a shift in synoptic transport pathways. {U}sing this event as a case study, we investigate the impact of interhemispheric exchange on atmospheric {H}g in tropical {S}outh {A}merica. {W}e use {HYSPLIT} to link {H}g observations to long-range transport and find that the observed {H}g increase relates strongly to air masses from the tropical {P}acific upper troposphere ({UT}), a region directly impacted by interhemispheric exchange. {I}nclusion of the modeled seasonality of interhemispheric air mass exchange strengthens this relationship significantly. {W}e estimate that interhemispheric exchange drives {H}g seasonality in the {SH} tropical {P}acific {UT}, with strongly enhanced {H}g between {J}uly and {O}ctober. {W}e validate this seasonality with previously published aircraft {H}g observations. {O}ur results suggest that the transport of {NH}-influenced air masses to tropical {S}outh {A}merica via the {P}acific {UT} occurs regularly but became more detectable at {C}hacaltaya in 2015-2016 because of a westward shift in air mass origin.},
  keywords = {mercury ; interhemispheric exchange ; pollutant transport ; interhemispheric gradient ; model validation ; {PACIFIQUE} ; {AMERIQUE} {DU} {SUD} ; {ZONE} {TROPICALE} ; {ANDES} ; {CHACALTAYA} {MONT}},
  booktitle = {},
  journal = {{J}ournal of {G}eophysical {R}esearch : {A}tmospheres},
  volume = {127},
  numero = {10},
  pages = {e2021{JD}036283 [19 p.]},
  ISSN = {2169-897{X}},
  year = {2022},
  DOI = {10.1029/2021jd036283},
  URL = {https://www.documentation.ird.fr/hor/fdi:010085205},
}