Divergent future change in South Atlantic Ocean Dipole impacts on regional rainfall in CMIP6 models
The South Atlantic Ocean Dipole (SAOD) exerts strong influence on climate variability in parts of Africa and South America. Here we assess the ability of an ensemble of 35 state-of-the-art coupled global climate models to simulate the SAOD impacts on regional rainfall for the historical period (1950...
Published in: | Environmental Research: Climate |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
IOPScience
2024
|
Subjects: | |
Online Access: | https://oceanrep.geomar.de/id/eprint/60374/ https://oceanrep.geomar.de/id/eprint/60374/1/Nworgu_2024_Environ._Res.%20_Climate_3_035002.pdf https://iopscience.iop.org/article/10.1088/2752-5295/ad3a0e https://doi.org/10.1088/2752-5295/ad3a0e |
id |
ftoceanrep:oai:oceanrep.geomar.de:60374 |
---|---|
record_format |
openpolar |
spelling |
ftoceanrep:oai:oceanrep.geomar.de:60374 2024-06-23T07:56:47+00:00 Divergent future change in South Atlantic Ocean Dipole impacts on regional rainfall in CMIP6 models Nworgu, Uzoma C. Nnamchi, Hyacinth C. Rosario, Nilton E. 2024-05-15 text https://oceanrep.geomar.de/id/eprint/60374/ https://oceanrep.geomar.de/id/eprint/60374/1/Nworgu_2024_Environ._Res.%20_Climate_3_035002.pdf https://iopscience.iop.org/article/10.1088/2752-5295/ad3a0e https://doi.org/10.1088/2752-5295/ad3a0e en eng IOPScience https://oceanrep.geomar.de/id/eprint/60374/1/Nworgu_2024_Environ._Res.%20_Climate_3_035002.pdf Nworgu, U. C., Nnamchi, H. C. and Rosario, N. E. (2024) Divergent future change in South Atlantic Ocean Dipole impacts on regional rainfall in CMIP6 models. Open Access Environmental Research: Climate, 3 (3). Art.Nr. 035002. DOI 10.1088/2752-5295/ad3a0e <https://doi.org/10.1088/2752-5295%2Fad3a0e>. doi:10.1088/2752-5295/ad3a0e cc_by_4.0 info:eu-repo/semantics/openAccess Article PeerReviewed info:eu-repo/semantics/article 2024 ftoceanrep https://doi.org/10.1088/2752-5295/ad3a0e 2024-06-11T14:18:41Z The South Atlantic Ocean Dipole (SAOD) exerts strong influence on climate variability in parts of Africa and South America. Here we assess the ability of an ensemble of 35 state-of-the-art coupled global climate models to simulate the SAOD impacts on regional rainfall for the historical period (1950–2014), and their future projections (2015–2079). For both periods we consider the peak phase of the dipole in austral winter. Observational analysis reveals four regions with spatially coherent SAOD impacts on rainfall; Northern Amazon, Guinea Coast, Central Africa, and Southeast Brazil. The observed rainfall response to the SAOD over Northern Amazon (0.31 mm d−1), Guinea Coast (0.38 mm d−1), and Southeast Brazil (0.12 mm d−1) are significantly underestimated by the modeled ensemble-mean response of 0.10 ± 0.15 mm d−1, 0.05 ± 0.15 mm d−1, −0.01 ± 0.04 mm d−1, respectively. A too southerly rain belt in the ensemble, associated with warmer-than-observed Atlantic cold tongue, leads to better performance of models over Central Africa (46% simulate observations-consistent SAOD-rainfall correlations) and poor performance over the Guinea Coast (only 5.7% simulate observations-consistent SAOD-rainfall correlations). We also find divergent responses among the projections of ensemble members precluding a categorical statement on the future strength of the SAOD-rainfall relationship in a high-emissions scenario. Our results highlight key uncertainties that must be addressed to enhance the value of SAOD-rainfall projections for the affected African and South American countries. Article in Journal/Newspaper South Atlantic Ocean OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Austral Environmental Research: Climate 3 3 035002 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
The South Atlantic Ocean Dipole (SAOD) exerts strong influence on climate variability in parts of Africa and South America. Here we assess the ability of an ensemble of 35 state-of-the-art coupled global climate models to simulate the SAOD impacts on regional rainfall for the historical period (1950–2014), and their future projections (2015–2079). For both periods we consider the peak phase of the dipole in austral winter. Observational analysis reveals four regions with spatially coherent SAOD impacts on rainfall; Northern Amazon, Guinea Coast, Central Africa, and Southeast Brazil. The observed rainfall response to the SAOD over Northern Amazon (0.31 mm d−1), Guinea Coast (0.38 mm d−1), and Southeast Brazil (0.12 mm d−1) are significantly underestimated by the modeled ensemble-mean response of 0.10 ± 0.15 mm d−1, 0.05 ± 0.15 mm d−1, −0.01 ± 0.04 mm d−1, respectively. A too southerly rain belt in the ensemble, associated with warmer-than-observed Atlantic cold tongue, leads to better performance of models over Central Africa (46% simulate observations-consistent SAOD-rainfall correlations) and poor performance over the Guinea Coast (only 5.7% simulate observations-consistent SAOD-rainfall correlations). We also find divergent responses among the projections of ensemble members precluding a categorical statement on the future strength of the SAOD-rainfall relationship in a high-emissions scenario. Our results highlight key uncertainties that must be addressed to enhance the value of SAOD-rainfall projections for the affected African and South American countries. |
format |
Article in Journal/Newspaper |
author |
Nworgu, Uzoma C. Nnamchi, Hyacinth C. Rosario, Nilton E. |
spellingShingle |
Nworgu, Uzoma C. Nnamchi, Hyacinth C. Rosario, Nilton E. Divergent future change in South Atlantic Ocean Dipole impacts on regional rainfall in CMIP6 models |
author_facet |
Nworgu, Uzoma C. Nnamchi, Hyacinth C. Rosario, Nilton E. |
author_sort |
Nworgu, Uzoma C. |
title |
Divergent future change in South Atlantic Ocean Dipole impacts on regional rainfall in CMIP6 models |
title_short |
Divergent future change in South Atlantic Ocean Dipole impacts on regional rainfall in CMIP6 models |
title_full |
Divergent future change in South Atlantic Ocean Dipole impacts on regional rainfall in CMIP6 models |
title_fullStr |
Divergent future change in South Atlantic Ocean Dipole impacts on regional rainfall in CMIP6 models |
title_full_unstemmed |
Divergent future change in South Atlantic Ocean Dipole impacts on regional rainfall in CMIP6 models |
title_sort |
divergent future change in south atlantic ocean dipole impacts on regional rainfall in cmip6 models |
publisher |
IOPScience |
publishDate |
2024 |
url |
https://oceanrep.geomar.de/id/eprint/60374/ https://oceanrep.geomar.de/id/eprint/60374/1/Nworgu_2024_Environ._Res.%20_Climate_3_035002.pdf https://iopscience.iop.org/article/10.1088/2752-5295/ad3a0e https://doi.org/10.1088/2752-5295/ad3a0e |
geographic |
Austral |
geographic_facet |
Austral |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_relation |
https://oceanrep.geomar.de/id/eprint/60374/1/Nworgu_2024_Environ._Res.%20_Climate_3_035002.pdf Nworgu, U. C., Nnamchi, H. C. and Rosario, N. E. (2024) Divergent future change in South Atlantic Ocean Dipole impacts on regional rainfall in CMIP6 models. Open Access Environmental Research: Climate, 3 (3). Art.Nr. 035002. DOI 10.1088/2752-5295/ad3a0e <https://doi.org/10.1088/2752-5295%2Fad3a0e>. doi:10.1088/2752-5295/ad3a0e |
op_rights |
cc_by_4.0 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1088/2752-5295/ad3a0e |
container_title |
Environmental Research: Climate |
container_volume |
3 |
container_issue |
3 |
container_start_page |
035002 |
_version_ |
1802650105812090880 |