Sahelian Heat Wave Characterization From Observational Data Sets. Issue 11 (3rd June 2021)

• Record Type: Journal Article
• Authors: Bouniol, D.; Guichard, F.; Barbier, J.; Couvreux, F.; Roehrig, R.
• Is Part Of: Journal of geophysical research. Volume 126:Issue 11(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-06-03
• Subjects: heat wave -- West Africa -- radiation budget -- observations; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2020JD034465
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: This paper makes use of spaceborne observational data sets in order to characterize radiative processes involved in spring time heat waves in the Sahel. Spring corresponds to the hottest period of the year, with a high aerosol load, a gradual moistening, and the presence of clouds contributing to greenhouse effect. Heat waves are defined as synoptic events that have a large spatial extent and a duration longer than 3 days. Two types of heat waves are studied: daytime heat waves, detected with the daily maximum temperature and nighttime heat waves, detected with the daily minimum temperature. Daytime heat waves correspond to situations where cloud optical thickness is lower than the climatology and a large number of these situations are also associated with a lower aerosol load and a drier atmosphere. Nighttime heat waves correspond to a moister atmosphere compared to the climatology. In a large fraction of them, an increase in aerosol loading is also observed. This study, only based on observational data sets, highlights the subtle but different radiative balance at play in both types of events. Key Points: Observational data sets are used to statistically document processes involved in spring time heat waves in the Sahel Nighttime heat waves are linked to an increase in precipitable water as well as a frequent high aerosol load Daytime heat waves are generally associated with cleaner skies; more intense events show in addition a higher amount of precipitable water