Influence of the tropical Atlantic Ocean and its Walker circulation cell on October–December rainfall variability over Tanzania
Abstract The study investigates the influence of the tropical Atlantic Ocean and its Walker circulation cell on October–December (OND) rainfall variability over Tanzania. The first two SVD modes contribute 95.3% of the total covariance with the strongest (positive) and significant correlation ( r ≅...
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crwiley:10.1002/joc.6550 2024-06-02T08:14:30+00:00 Influence of the tropical Atlantic Ocean and its Walker circulation cell on October–December rainfall variability over Tanzania Limbu, Paul Tilwebwa Shelleph Guirong, Tan National Key Research and Development Program of China National Natural Science Foundation of China 2020 http://dx.doi.org/10.1002/joc.6550 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.6550 https://onlinelibrary.wiley.com/doi/pdf/10.1002/joc.6550 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/joc.6550 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.6550 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor International Journal of Climatology volume 40, issue 13, page 5767-5782 ISSN 0899-8418 1097-0088 journal-article 2020 crwiley https://doi.org/10.1002/joc.6550 2024-05-06T07:03:46Z Abstract The study investigates the influence of the tropical Atlantic Ocean and its Walker circulation cell on October–December (OND) rainfall variability over Tanzania. The first two SVD modes contribute 95.3% of the total covariance with the strongest (positive) and significant correlation ( r ≅ .7) at the 99% confidence level showing a close relationship between OND rainfall and MAM tropical Atlantic SST anomalies. Significant positive running correlation observed between MAM Atlantic SSTs and OND rainfall indicates the variability of rainfall observed during the OND season is influenced by variability of Atlantic Ocean SSTs anomaly. Both SVD modes captured the positive phase of the South Atlantic Ocean Dipole (SAOD) which is characterized by warm sea surface temperature (SST) anomalies in the southwest pole (SWP) and cool SST anomalies in the northeast pole (NEP). The Walker circulation cell observed is due to inhomogeneous warming over the tropical Atlantic Ocean with ascending limb where it is relatively warm in the SWP and descending limb where it is relatively cool in the NEP. Nonsignificant low correlation is observed between the Atlantic Walker circulation index and the Oceanic Indices (dipole mode index [DMI] and Niño3.4). This indicates that the Atlantic Walker circulation cell is an independent system resulting from local ocean–atmosphere interaction and does not depend on the influence of the tropical Indian or Pacific Oceans. Above average rainfall in Tanzania during the OND season is associated with the ascending limb of the Atlantic Walker circulation cell which is enhanced by convection in the western Atlantic Ocean and the latent heat released through the condensation in the mid‐level which is advected by westerly winds aloft towards the study region, enhancing warming, and ultimately enhancing rainfall over Tanzania. Article in Journal/Newspaper South Atlantic Ocean Wiley Online Library Indian Pacific International Journal of Climatology 40 13 5767 5782 |
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Open Polar |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract The study investigates the influence of the tropical Atlantic Ocean and its Walker circulation cell on October–December (OND) rainfall variability over Tanzania. The first two SVD modes contribute 95.3% of the total covariance with the strongest (positive) and significant correlation ( r ≅ .7) at the 99% confidence level showing a close relationship between OND rainfall and MAM tropical Atlantic SST anomalies. Significant positive running correlation observed between MAM Atlantic SSTs and OND rainfall indicates the variability of rainfall observed during the OND season is influenced by variability of Atlantic Ocean SSTs anomaly. Both SVD modes captured the positive phase of the South Atlantic Ocean Dipole (SAOD) which is characterized by warm sea surface temperature (SST) anomalies in the southwest pole (SWP) and cool SST anomalies in the northeast pole (NEP). The Walker circulation cell observed is due to inhomogeneous warming over the tropical Atlantic Ocean with ascending limb where it is relatively warm in the SWP and descending limb where it is relatively cool in the NEP. Nonsignificant low correlation is observed between the Atlantic Walker circulation index and the Oceanic Indices (dipole mode index [DMI] and Niño3.4). This indicates that the Atlantic Walker circulation cell is an independent system resulting from local ocean–atmosphere interaction and does not depend on the influence of the tropical Indian or Pacific Oceans. Above average rainfall in Tanzania during the OND season is associated with the ascending limb of the Atlantic Walker circulation cell which is enhanced by convection in the western Atlantic Ocean and the latent heat released through the condensation in the mid‐level which is advected by westerly winds aloft towards the study region, enhancing warming, and ultimately enhancing rainfall over Tanzania. |
author2 |
National Key Research and Development Program of China National Natural Science Foundation of China |
format |
Article in Journal/Newspaper |
author |
Limbu, Paul Tilwebwa Shelleph Guirong, Tan |
spellingShingle |
Limbu, Paul Tilwebwa Shelleph Guirong, Tan Influence of the tropical Atlantic Ocean and its Walker circulation cell on October–December rainfall variability over Tanzania |
author_facet |
Limbu, Paul Tilwebwa Shelleph Guirong, Tan |
author_sort |
Limbu, Paul Tilwebwa Shelleph |
title |
Influence of the tropical Atlantic Ocean and its Walker circulation cell on October–December rainfall variability over Tanzania |
title_short |
Influence of the tropical Atlantic Ocean and its Walker circulation cell on October–December rainfall variability over Tanzania |
title_full |
Influence of the tropical Atlantic Ocean and its Walker circulation cell on October–December rainfall variability over Tanzania |
title_fullStr |
Influence of the tropical Atlantic Ocean and its Walker circulation cell on October–December rainfall variability over Tanzania |
title_full_unstemmed |
Influence of the tropical Atlantic Ocean and its Walker circulation cell on October–December rainfall variability over Tanzania |
title_sort |
influence of the tropical atlantic ocean and its walker circulation cell on october–december rainfall variability over tanzania |
publisher |
Wiley |
publishDate |
2020 |
url |
http://dx.doi.org/10.1002/joc.6550 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.6550 https://onlinelibrary.wiley.com/doi/pdf/10.1002/joc.6550 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/joc.6550 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.6550 |
geographic |
Indian Pacific |
geographic_facet |
Indian Pacific |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_source |
International Journal of Climatology volume 40, issue 13, page 5767-5782 ISSN 0899-8418 1097-0088 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/joc.6550 |
container_title |
International Journal of Climatology |
container_volume |
40 |
container_issue |
13 |
container_start_page |
5767 |
op_container_end_page |
5782 |
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1800738384451207168 |