Drobinski P. auteur aut IRD Sultan Benjamin auteur aut IRD Janicot Serge auteur aut IRD text journalArticle eng text/pdf reformatted digital access It has been observed that the West African monsoon onset is concomitant with the enhancement of the Saharan heat low. We show through a combined diagnostic and linear modeling study a possible interaction between northern Africa orography and the deepening of the Saharan heat low at the time of the monsoon onset. The amplification of an anticyclonic circulation above and north of the Hoggar massif leads to an increase and a southeasterly-northeasterly rotation of the wind ahead of the Hoggar which contribute to an increased leeward-trough effect enhancing the Saharan heat low. The Atlas does not play any role during the monsoon onset but contributes to the mean climatological location of the Saharan heat low. specialized CLIMATOLOGIE METEOROLOGIE GEOMORPHOLOGIE TEMPERATURE DE SURFACE DESERT CIRCULATION ATMOSPHERIQUE MODELISATION CHANGEMENT CLIMATIQUE MOUSSON ALGERIE SAHARA 021CLIMAT01 021METEO 072BCLIGE 32 1 art. no L01705 [5 ] 2005 0094-8276 https://www.documentation.ird.fr/hor/fdi:010065706 10.1029/2004GL020710 0094-8276 [F B010065706] https://www.documentation.ird.fr/hor/fdi:010065706 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers16-03/010065706.pdf IRD - Base Horizon / Pleins textes 2016-03-30 2016-04-01 fdi:010065706 fre