Fiedler, Stephanie , Kaplan, M. L. and Knippertz, P. (2015) The importance of Harmattan surges for the emission of North African dust aerosol. Geophysical Research Letters, 42 (21). pp. 9495-9504. DOI 10.1002/2015GL065925.

Text Geophysical Research Letters - 2015 - Fiedler - The importance of Harmattan surges for the emission of North African dust.pdf - Published Version Restricted to Registered users only Download (2MB) | Contact

Abstract

Dust aerosol is important in the Earth system, but the relative impact of meteorological mechanisms on North African dust emission remains unclear. This study presents the first climatology of dust emission amounts associated with Harmattan surges (HSs), characterized by postfrontal strengthening of near-surface winds. A new automated identification uses their strong isallobaric winds as an indicator for HSs in 32 years of ERA-Interim reanalysis. Their impact on dust aerosol emission is estimated by combining the identified events with derived dust emissions. The estimate highlights that about one third of the total emission mass is associated with HSs. Spring shows the largest associated emissions of 30–50% of the monthly totals consistent with the largest number and duration of HSs. Regional emission contributions of up to 80% in the north coincide with the overall largest emission maxima in spring. The importance of HSs for dust emission implies that aerosol-climate models need to accurately represent synoptic-scale storms.

Key Points:
- First climatology of North African dust emission mass linked with Harmattan surges (HSs)
- One third of total emission linked to HSs annually and spatially averaged
- Regionally up to 80% of springtime maximum in emission mass is associated with HSs

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