@article{fdi:010049458,
  title = {{L}inks between {A}frican easterly waves, midlatitude circulation and intraseasonal pulsations of the {W}est {A}frican heat low},
  author = {{L}avaysse, {C}. and {F}lamant, {C}. and {J}anicot, {S}erge and {K}nippertz, {P}.},
  editor = {},
  language = {{ENG}},
  abstract = {{D}uring summer 2006. the intensity of the thermal depression over the {S}ahara. derived from {E}uropean {C}entre for {M}edium-range {W}eather {F}orecast analyses. exhibited a strong decrease during the first couple of weeks of {S}eptember {S}imultaneously. widespread convective activity over the {S}ahel was detected. {T}he aims of this study are to identify the reasons for this decrease of the {W}est {A}frican {H}eat {L}ow ({WAHL}) activity, to discuss the possible relationship with convection and to assess the representativity of such an event at the climatological tune-scale. {F}rom spectral analysis of the daily {WAHL} thickness during summer 2006. two period bands of significant intraseasonal pulsations were identified. and confirmed using the {ERA}-40 reanalysis. namely 3-10d and 10-30d {I}n both the 2006 case-study and the climatological composite study. we find that detrimental conditions in the 3-10d period band are associated with moist and cool advections in the lower troposphere linked to the southerly sector of {A}frican easterly waves ({AEW}s) which increase convective activity over the {S}ahel {T}hese humid and cold advections from the south are more pronounced when the {AEW} interacts with a midlatitude depression {I}n the 10-30d period band. the impact of midlatitude circulation is demonstrated {D}uring the collapsing period of the 10-30d pulsations of the {WAHL} thickness, an upper-level trough is seen over northern {W}est {A}frica {T}his situation generates a surge of 700 h{P}a cold air from {L}ibya into the {S}ahara. an increase of the 925 h{P}a anticyclonic circulation and a significant increase of convective activity over the {S}ahel {C}opyright ({C}) 2010 {R}oyal {M}eteorological {S}ociety},
  keywords = {{W}est {A}frican monsoon ; tropical convection ; {AMMA} ; {ECMWF} {ERA}-40 ; reanalyses ; satellite-derived brightness temperature},
  booktitle = {},
  journal = {{Q}uarterly {J}ournal of the {R}oyal {M}eteorological {S}ociety},
  volume = {136},
  numero = {s1},
  pages = {141--158},
  ISSN = {0035-9009},
  year = {2010},
  DOI = {10.1002/qj.555},
  URL = {https://www.documentation.ird.fr/hor/fdi:010049458},
}