@article{fdi:010061171,
  title = {{R}ecent changes in air temperature, heat waves occurrences, and atmospheric circulation in {N}orthern {A}frica},
  author = {{F}ontaine, {B}. and {J}anicot, {S}erge and {M}onerie, {P}. {A}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}his study documents the time evolution of air temperature and heat waves occurrences over {N}orthern {A}frica for the period 1979-2011. {A} significant warming (1 degrees-3 degrees {C}), appearing by the mid-1960s over {S}ahara and {S}ahel, is associated with higher/lesser frequency of warm/cold temperatures, as with longer duration and higher occurrences of heat waves. {H}eat waves episodes of at least 4 day duration have been examined after removing the long-term evolution. {T}hese episodes are associated with specific anomalies: (i) in spring, positive low-level temperature anomalies over the {S}ahel and {S}ahara; low and midlevel cyclonic rotation over {M}orocco associated with a {R}ossby wave pattern, lessening the {H}armattan; more/less atmospheric moisture westward/eastward to 0 degrees; upward/downward anomalies above the western/eastern regions associated with the {R}ossby wave pattern; (ii) in summer, a similar but weaker positive low-level temperature anomaly (up to 3 degrees {C}); less moisture westward to 10 degrees {W}, a cyclonic anomaly in central {S}ahel favoring the monsoon eastward to 0 degrees and a midlevel anticyclonic anomaly over the {W}estern {S}ahara, increasing southward the flux divergence associated with the {A}frican {E}asterly {J}et. {I}n {M}arch-{M}ay, two to three heat waves propagate eastward. {T}hey are preceded by an abnormal warm cell over {L}ibya and southwesterlies over the {W}est {S}ahara. {A} large trough stands over {N}orth {A}tlantic while midtropospheric subsidence and anticyclonic rotation reinforce over the continent, then migrates toward the {A}rabian peninsula in breaking up. {T}hese signals are spatially coherent and might suggest the role of short {R}ossby waves with an eastward group velocity and a baroclinic mode, possibly associated with jet stream deformation.},
  keywords = {{C}limate {C}hange ; {H}eat waves ; {A}frican monsoon ; {AFRIQUE} {DU} {NORD}},
  booktitle = {},
  journal = {{J}ournal of {G}eophysical {R}esearch.{A}tmospheres},
  volume = {118},
  numero = {15},
  pages = {8536--8552},
  ISSN = {2169-897{X}},
  year = {2013},
  DOI = {10.1002/jgrd.50667},
  URL = {https://www.documentation.ird.fr/hor/fdi:010061171},
}