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...
| Main Authors: | , , |
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| Format: | Journal Article |
| Language: | Inglés |
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Springer
2022
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10568/119427 |
| _version_ | 1855513617007378432 |
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| author | Dyer, E. Hirons, L. Taye, Meron Teferi |
| author_browse | Dyer, E. Hirons, L. Taye, Meron Teferi |
| author_facet | Dyer, E. Hirons, L. Taye, Meron Teferi |
| author_sort | Dyer, E. |
| collection | Repository of Agricultural Research Outputs (CGSpace) |
| 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 | Journal Article |
| id | CGSpace119427 |
| institution | CGIAR Consortium |
| language | Inglés |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | Springer |
| publisherStr | Springer |
| record_format | dspace |
| spelling | CGSpace1194272025-10-26T12:54:49Z 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 rainfall patterns precipitation atmospheric circulation subtropical climate models datasets 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. 2022-12 2022-04-30T22:05:38Z 2022-04-30T22:05:38Z Journal Article https://hdl.handle.net/10568/119427 en Open Access 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] |
| 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 |
| title | 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_short | 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 |
| topic | rainfall patterns precipitation atmospheric circulation subtropical climate models datasets |
| url | https://hdl.handle.net/10568/119427 |
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