A new analysis of variability and predictability of seasonal rainfall of central southern Africa for 1950–94
Abstract Using wavelet analysis and wavelet‐based empirical orthogonal function analysis on scale‐averaged‐wavelet power and individual scale power, we identified the non‐stationary sea‐surface temperature (SST) fields of the South Atlantic and Indian Oceans that are associated with coherent regions...
Published in: | International Journal of Climatology |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2004
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1002/joc.1062 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.1062 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.1062 |
id |
crwiley:10.1002/joc.1062 |
---|---|
record_format |
openpolar |
spelling |
crwiley:10.1002/joc.1062 2024-06-23T07:56:47+00:00 A new analysis of variability and predictability of seasonal rainfall of central southern Africa for 1950–94 Mwale, Davison Yew Gan, Thian Shen, Samuel S. P. 2004 http://dx.doi.org/10.1002/joc.1062 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.1062 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.1062 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor International Journal of Climatology volume 24, issue 12, page 1509-1530 ISSN 0899-8418 1097-0088 journal-article 2004 crwiley https://doi.org/10.1002/joc.1062 2024-06-11T04:43:35Z Abstract Using wavelet analysis and wavelet‐based empirical orthogonal function analysis on scale‐averaged‐wavelet power and individual scale power, we identified the non‐stationary sea‐surface temperature (SST) fields of the South Atlantic and Indian Oceans that are associated with coherent regions of rainfall variability in central southern Africa (CSA). The dominant mode of CSA rainfall is out of phase between the coastal areas and the centre of CSA and has been decreasing consistently since 1970. The frequencies associated with this mode are between 2–2.4 and 5.6–8 years. The Benguela ocean current SSTs form the dominant spatial pattern of the South Atlantic Ocean, and the Brazil and Guinea ocean current SSTs form the second leading mode. The Benguela spatial patterns were found to migrate seasonally between Africa's west coast and South America's east coast. The northern Indian Ocean SST forms the leading mode of variability, followed by the south Indian Ocean SST. Using predictor fields identified from both oceans, we achieved encouraging results of predicted CSA rainfall using a non‐linear statistical teleconnection artificial neural network–genetic algorithm model. At 3 month lead time, correlations of between 0.8 and 0.9, root‐mean‐square errors of between 0.4 and 0.9 and Hansen Kuipers skill scores of between 0.4 and 0.8 were obtained between observed and predicted CSA rainfall. Copyright © 2004 Royal Meteorological Society Article in Journal/Newspaper South Atlantic Ocean Wiley Online Library Indian Kuipers ENVELOPE(161.400,161.400,-77.900,-77.900) International Journal of Climatology 24 12 1509 1530 |
institution |
Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
Abstract Using wavelet analysis and wavelet‐based empirical orthogonal function analysis on scale‐averaged‐wavelet power and individual scale power, we identified the non‐stationary sea‐surface temperature (SST) fields of the South Atlantic and Indian Oceans that are associated with coherent regions of rainfall variability in central southern Africa (CSA). The dominant mode of CSA rainfall is out of phase between the coastal areas and the centre of CSA and has been decreasing consistently since 1970. The frequencies associated with this mode are between 2–2.4 and 5.6–8 years. The Benguela ocean current SSTs form the dominant spatial pattern of the South Atlantic Ocean, and the Brazil and Guinea ocean current SSTs form the second leading mode. The Benguela spatial patterns were found to migrate seasonally between Africa's west coast and South America's east coast. The northern Indian Ocean SST forms the leading mode of variability, followed by the south Indian Ocean SST. Using predictor fields identified from both oceans, we achieved encouraging results of predicted CSA rainfall using a non‐linear statistical teleconnection artificial neural network–genetic algorithm model. At 3 month lead time, correlations of between 0.8 and 0.9, root‐mean‐square errors of between 0.4 and 0.9 and Hansen Kuipers skill scores of between 0.4 and 0.8 were obtained between observed and predicted CSA rainfall. Copyright © 2004 Royal Meteorological Society |
format |
Article in Journal/Newspaper |
author |
Mwale, Davison Yew Gan, Thian Shen, Samuel S. P. |
spellingShingle |
Mwale, Davison Yew Gan, Thian Shen, Samuel S. P. A new analysis of variability and predictability of seasonal rainfall of central southern Africa for 1950–94 |
author_facet |
Mwale, Davison Yew Gan, Thian Shen, Samuel S. P. |
author_sort |
Mwale, Davison |
title |
A new analysis of variability and predictability of seasonal rainfall of central southern Africa for 1950–94 |
title_short |
A new analysis of variability and predictability of seasonal rainfall of central southern Africa for 1950–94 |
title_full |
A new analysis of variability and predictability of seasonal rainfall of central southern Africa for 1950–94 |
title_fullStr |
A new analysis of variability and predictability of seasonal rainfall of central southern Africa for 1950–94 |
title_full_unstemmed |
A new analysis of variability and predictability of seasonal rainfall of central southern Africa for 1950–94 |
title_sort |
new analysis of variability and predictability of seasonal rainfall of central southern africa for 1950–94 |
publisher |
Wiley |
publishDate |
2004 |
url |
http://dx.doi.org/10.1002/joc.1062 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.1062 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.1062 |
long_lat |
ENVELOPE(161.400,161.400,-77.900,-77.900) |
geographic |
Indian Kuipers |
geographic_facet |
Indian Kuipers |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_source |
International Journal of Climatology volume 24, issue 12, page 1509-1530 ISSN 0899-8418 1097-0088 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/joc.1062 |
container_title |
International Journal of Climatology |
container_volume |
24 |
container_issue |
12 |
container_start_page |
1509 |
op_container_end_page |
1530 |
_version_ |
1802650123419779072 |