July–September rainfall in the Greater Horn of Africa: the combined influence of the Mascarene and South Atlantic highs
July-September rainfall is a key component of Ethiopia’s annual rainfall and is a source of rainfall variability throughout inland Greater Horn of Africa. In this study we investigate the relative influences of the Mascarene (MH) and South Atlantic (AH) highs on July-September rainfall in a covaryin...
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ftcgiar:oai:cgspace.cgiar.org:10568/119427 2024-01-07T09:46:49+01:00 July–September rainfall in the Greater Horn of Africa: the combined influence of the Mascarene and South Atlantic highs Dyer, E. Hirons, L. Taye, Meron Teferi 2022-04-30T22:05:38Z p. 3621-3641 https://hdl.handle.net/10568/119427 https://link.springer.com/content/pdf/10.1007/s00382-022-06287-0.pdf https://doi.org/10.1007/s00382-022-06287-0 en eng Springer Dyer, E.; Hirons, L.; Taye, Meron Teferi. 2022. July–September rainfall in the Greater Horn of Africa: the combined influence of the Mascarene and South Atlantic highs. Climate Dynamics, 59(11-12):3621-3641. [doi: https://doi.org/10.1007/s00382-022-06287-0] 0930-7575 https://hdl.handle.net/10568/119427 https://link.springer.com/content/pdf/10.1007/s00382-022-06287-0.pdf https://doi.org/10.1007/s00382-022-06287-0 H051082 CC-BY-4.0 Open Access Climate Dynamics rainfall patterns precipitation atmospheric circulation subtropical climate models datasets Journal Article 2022 ftcgiar https://doi.org/10.1007/s00382-022-06287-0 2023-12-12T23:54:38Z July-September rainfall is a key component of Ethiopia’s annual rainfall and is a source of rainfall variability throughout inland Greater Horn of Africa. In this study we investigate the relative influences of the Mascarene (MH) and South Atlantic (AH) highs on July-September rainfall in a covarying region of the Greater Horn of Africa using CHIRPS observed rainfall and the ERA5 reanalysis. We show that a mixed metric using the circulation at 850 hPa of these two subtropical anticyclones (AH-MH), is better correlated with rainfall than individual high circulations. Variations in remote circulation are translated by changes in Central African westerlies and Turkana Jet wind speeds. We apply the AH-MH mixed metric to the CMIP5 and CMIP6 ensembles and show that it is a good indicator of mean July-September rainfall across both ensembles. Biases in circulation are shown to be related to the Hadley circulation in CMIP5 atmosphere-only simulations, while causes of biases in CMIP6 are more varied. Coupled model biases are related to southern ocean warm biases in CMIP5 and western Indian Ocean warm biases in CMIP6. CMIP6 shows an improved relationship between rainfall and Turkana Jet winds and Central African westerlies across the ensemble. Article in Journal/Newspaper Southern Ocean CGIAR CGSpace (Consultative Group on International Agricultural Research) Indian Southern Ocean Climate Dynamics |
institution |
Open Polar |
collection |
CGIAR CGSpace (Consultative Group on International Agricultural Research) |
op_collection_id |
ftcgiar |
language |
English |
topic |
rainfall patterns precipitation atmospheric circulation subtropical climate models datasets |
spellingShingle |
rainfall patterns precipitation atmospheric circulation subtropical climate models datasets Dyer, E. Hirons, L. Taye, Meron Teferi July–September rainfall in the Greater Horn of Africa: the combined influence of the Mascarene and South Atlantic highs |
topic_facet |
rainfall patterns precipitation atmospheric circulation subtropical climate models datasets |
description |
July-September rainfall is a key component of Ethiopia’s annual rainfall and is a source of rainfall variability throughout inland Greater Horn of Africa. In this study we investigate the relative influences of the Mascarene (MH) and South Atlantic (AH) highs on July-September rainfall in a covarying region of the Greater Horn of Africa using CHIRPS observed rainfall and the ERA5 reanalysis. We show that a mixed metric using the circulation at 850 hPa of these two subtropical anticyclones (AH-MH), is better correlated with rainfall than individual high circulations. Variations in remote circulation are translated by changes in Central African westerlies and Turkana Jet wind speeds. We apply the AH-MH mixed metric to the CMIP5 and CMIP6 ensembles and show that it is a good indicator of mean July-September rainfall across both ensembles. Biases in circulation are shown to be related to the Hadley circulation in CMIP5 atmosphere-only simulations, while causes of biases in CMIP6 are more varied. Coupled model biases are related to southern ocean warm biases in CMIP5 and western Indian Ocean warm biases in CMIP6. CMIP6 shows an improved relationship between rainfall and Turkana Jet winds and Central African westerlies across the ensemble. |
format |
Article in Journal/Newspaper |
author |
Dyer, E. Hirons, L. Taye, Meron Teferi |
author_facet |
Dyer, E. Hirons, L. Taye, Meron Teferi |
author_sort |
Dyer, E. |
title |
July–September rainfall in the Greater Horn of Africa: the combined influence of the Mascarene and South Atlantic highs |
title_short |
July–September rainfall in the Greater Horn of Africa: the combined influence of the Mascarene and South Atlantic highs |
title_full |
July–September rainfall in the Greater Horn of Africa: the combined influence of the Mascarene and South Atlantic highs |
title_fullStr |
July–September rainfall in the Greater Horn of Africa: the combined influence of the Mascarene and South Atlantic highs |
title_full_unstemmed |
July–September rainfall in the Greater Horn of Africa: the combined influence of the Mascarene and South Atlantic highs |
title_sort |
july–september rainfall in the greater horn of africa: the combined influence of the mascarene and south atlantic highs |
publisher |
Springer |
publishDate |
2022 |
url |
https://hdl.handle.net/10568/119427 https://link.springer.com/content/pdf/10.1007/s00382-022-06287-0.pdf https://doi.org/10.1007/s00382-022-06287-0 |
geographic |
Indian Southern Ocean |
geographic_facet |
Indian Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Climate Dynamics |
op_relation |
Dyer, E.; Hirons, L.; Taye, Meron Teferi. 2022. July–September rainfall in the Greater Horn of Africa: the combined influence of the Mascarene and South Atlantic highs. Climate Dynamics, 59(11-12):3621-3641. [doi: https://doi.org/10.1007/s00382-022-06287-0] 0930-7575 https://hdl.handle.net/10568/119427 https://link.springer.com/content/pdf/10.1007/s00382-022-06287-0.pdf https://doi.org/10.1007/s00382-022-06287-0 H051082 |
op_rights |
CC-BY-4.0 Open Access |
op_doi |
https://doi.org/10.1007/s00382-022-06287-0 |
container_title |
Climate Dynamics |
_version_ |
1787428718942093312 |