Harmattan, Saharan heat low, and West African monsoon circulation: modulations on the Saharan dust outflow towards the North Atlantic
The outflow of dust from the northern African continent towards the North Atlantic is stimulated by the atmospheric circulation over North Africa, which modulates the spatio-temporal distribution of dust source activation and consequently the entrainment of mineral dust into the boundary layer, as w...
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ftdoajarticles:oai:doaj.org/article:3f7dd1127a2e48dc8e933af5e609c643 2023-05-15T17:30:10+02:00 Harmattan, Saharan heat low, and West African monsoon circulation: modulations on the Saharan dust outflow towards the North Atlantic K. Schepanski B. Heinold I. Tegen 2017-09-01T00:00:00Z https://doi.org/10.5194/acp-17-10223-2017 https://doaj.org/article/3f7dd1127a2e48dc8e933af5e609c643 EN eng Copernicus Publications https://www.atmos-chem-phys.net/17/10223/2017/acp-17-10223-2017.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-17-10223-2017 1680-7316 1680-7324 https://doaj.org/article/3f7dd1127a2e48dc8e933af5e609c643 Atmospheric Chemistry and Physics, Vol 17, Pp 10223-10243 (2017) Physics QC1-999 Chemistry QD1-999 article 2017 ftdoajarticles https://doi.org/10.5194/acp-17-10223-2017 2022-12-31T13:35:56Z The outflow of dust from the northern African continent towards the North Atlantic is stimulated by the atmospheric circulation over North Africa, which modulates the spatio-temporal distribution of dust source activation and consequently the entrainment of mineral dust into the boundary layer, as well as the transport of dust out of the source regions. The atmospheric circulation over the North African dust source regions, predominantly the Sahara and the Sahel, is characterized by three major circulation regimes: (1) the harmattan (trade winds), (2) the Saharan heat low (SHL), and (3) the West African monsoon circulation. The strength of the individual regimes controls the Saharan dust outflow by affecting the spatio-temporal distribution of dust emission, transport pathways, and deposition fluxes. This study aims at investigating the atmospheric circulation pattern over North Africa with regard to its role favouring dust emission and dust export towards the tropical North Atlantic. The focus of the study is on summer 2013 (June to August), during which the SALTRACE (Saharan Aerosol Long-range TRansport and Aerosol-Cloud interaction Experiment) field campaign also took place. It involves satellite observations by the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) flying on board the geostationary Meteosat Second Generation (MSG) satellite, which are analysed and used to infer a data set of active dust sources. The spatio-temporal distribution of dust source activation frequencies (DSAFs) allows for linking the diurnal cycle of dust source activations to dominant meteorological controls on dust emission. In summer, Saharan dust source activations clearly differ from dust source activations over the Sahel regarding the time of day when dust emission begins. The Sahara is dominated by morning dust source activations predominantly driven by the breakdown of the nocturnal low-level jet. In contrast, dust source activations in the Sahel are predominantly activated during the second half of the day, when ... Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Atmospheric Chemistry and Physics 17 17 10223 10243 |
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topic |
Physics QC1-999 Chemistry QD1-999 |
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Physics QC1-999 Chemistry QD1-999 K. Schepanski B. Heinold I. Tegen Harmattan, Saharan heat low, and West African monsoon circulation: modulations on the Saharan dust outflow towards the North Atlantic |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
The outflow of dust from the northern African continent towards the North Atlantic is stimulated by the atmospheric circulation over North Africa, which modulates the spatio-temporal distribution of dust source activation and consequently the entrainment of mineral dust into the boundary layer, as well as the transport of dust out of the source regions. The atmospheric circulation over the North African dust source regions, predominantly the Sahara and the Sahel, is characterized by three major circulation regimes: (1) the harmattan (trade winds), (2) the Saharan heat low (SHL), and (3) the West African monsoon circulation. The strength of the individual regimes controls the Saharan dust outflow by affecting the spatio-temporal distribution of dust emission, transport pathways, and deposition fluxes. This study aims at investigating the atmospheric circulation pattern over North Africa with regard to its role favouring dust emission and dust export towards the tropical North Atlantic. The focus of the study is on summer 2013 (June to August), during which the SALTRACE (Saharan Aerosol Long-range TRansport and Aerosol-Cloud interaction Experiment) field campaign also took place. It involves satellite observations by the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) flying on board the geostationary Meteosat Second Generation (MSG) satellite, which are analysed and used to infer a data set of active dust sources. The spatio-temporal distribution of dust source activation frequencies (DSAFs) allows for linking the diurnal cycle of dust source activations to dominant meteorological controls on dust emission. In summer, Saharan dust source activations clearly differ from dust source activations over the Sahel regarding the time of day when dust emission begins. The Sahara is dominated by morning dust source activations predominantly driven by the breakdown of the nocturnal low-level jet. In contrast, dust source activations in the Sahel are predominantly activated during the second half of the day, when ... |
format |
Article in Journal/Newspaper |
author |
K. Schepanski B. Heinold I. Tegen |
author_facet |
K. Schepanski B. Heinold I. Tegen |
author_sort |
K. Schepanski |
title |
Harmattan, Saharan heat low, and West African monsoon circulation: modulations on the Saharan dust outflow towards the North Atlantic |
title_short |
Harmattan, Saharan heat low, and West African monsoon circulation: modulations on the Saharan dust outflow towards the North Atlantic |
title_full |
Harmattan, Saharan heat low, and West African monsoon circulation: modulations on the Saharan dust outflow towards the North Atlantic |
title_fullStr |
Harmattan, Saharan heat low, and West African monsoon circulation: modulations on the Saharan dust outflow towards the North Atlantic |
title_full_unstemmed |
Harmattan, Saharan heat low, and West African monsoon circulation: modulations on the Saharan dust outflow towards the North Atlantic |
title_sort |
harmattan, saharan heat low, and west african monsoon circulation: modulations on the saharan dust outflow towards the north atlantic |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/acp-17-10223-2017 https://doaj.org/article/3f7dd1127a2e48dc8e933af5e609c643 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Atmospheric Chemistry and Physics, Vol 17, Pp 10223-10243 (2017) |
op_relation |
https://www.atmos-chem-phys.net/17/10223/2017/acp-17-10223-2017.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-17-10223-2017 1680-7316 1680-7324 https://doaj.org/article/3f7dd1127a2e48dc8e933af5e609c643 |
op_doi |
https://doi.org/10.5194/acp-17-10223-2017 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
17 |
container_issue |
17 |
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10223 |
op_container_end_page |
10243 |
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1766125990826737664 |