dc.contributor.author |
Ivanciu, Ioana
|
|
dc.contributor.author |
Ndarana, Thando
|
|
dc.contributor.author |
Matthes, Katja
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|
dc.contributor.author |
Wahl, Sebastian
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|
dc.date.accessioned |
2023-04-24T12:49:47Z |
|
dc.date.available |
2023-04-24T12:49:47Z |
|
dc.date.issued |
2022-10 |
|
dc.description |
DATA AVAILABILITY STATEMENT : The model output used in this study is available at https://doi.org/10.5281/zenodo.6523956 (Ivanciu, 2022). The ERA5 hourly data on pressure levels from 1979 to present (Hersbach et al., 2018) is publicly available from the Copernicus Climate Change Service (C3S) Climate Data Store (CDS) at https://doi.org/10.24381/cds.bd0915c6 (accessed on 16.05.2020). The CPC Global Unified Gauge-Based Analysis of Daily Precipitation data is provided by the NOAA PSL, Boulder, Colorado, USA, from their Web site at https://psl.noaa.gov/data/gridded/data.cpc.globalprecip.html (accessed on 16.05.2022). |
en_US |
dc.description |
SUPPLEMENTARY MATERIAL : Text S1, S2 and S3; Figures S1, S2, S3, S4, S5, S6 and S7 |
en_US |
dc.description.abstract |
Ridging South Atlantic Anticyclones contribute an important amount of precipitation over South Africa. Here, we use a global coupled climate model and the ERA5 reanalysis to separate for the first time ridging highs (RHs) based on whether they occur together with Rossby wave breaking (RWB) or not. We show that the former type of RHs are associated with more precipitation than the latter type. The mean sea level pressure anomalies caused by the two types of RHs are characterized by distinct patterns, leading to differences in the flow of moisture-laden air onto land. We additionally find that RWB mediates the effect of climate change on RHs during the twenty-first century. Consequently, RHs occurring without RWB exhibit little change, while those occurring with RWB contribute more precipitation over the southern and less precipitation over the northeastern South Africa in the future.
KEY POINTS :
Ridging South Atlantic Anticyclones are accompanied by Rossby wave breaking (RWB) aloft in 44% of the cases.
Ridging highs that are accompanied by RWB lead to more precipitation over South Africa than those that are not.
Ridging highs bring more precipitation over the southern and less precipitation over the northeastern part of South Africa in the future. |
en_US |
dc.description.abstract |
PLAIN LANGUAGE SUMMARY : The high pressure system located above the South Atlantic Ocean occasionally extends eastward over South Africa, leading to winds that blow onshore and carry moisture from the warm waters of the Southwest Indian Ocean to the coast. These events, termed ridging highs (RHs), bring an important contribution to precipitation over the southern and eastern parts of South Africa. Their occurrence is related to the propagation and breaking of atmospheric waves at the boundary between the troposphere and the stratosphere. This study categorizes RHs based on the behavior of atmospheric waves above and shows that events that are accompanied by wave breaking result in more precipitation over South Africa. In addition, model simulations are used to investigate the impact of climate change during the twenty-first century on RHs and the associated precipitation. Although the model predicts that in total South Africa will experience drier conditions in the future, RHs contribute to this drying trend only in the northeastern part of the country. In the southern part of South Africa, the model simulates that RHs will bring more precipitation in the future. |
en_US |
dc.description.department |
Geography, Geoinformatics and Meteorology |
en_US |
dc.description.librarian |
hj2023 |
en_US |
dc.description.sponsorship |
Bundesministerium für Bildung und Forschung and Water Research Commission.
Open Access funding enabled and organized by Projekt DEAL. |
en_US |
dc.description.uri |
https://agupubs.onlinelibrary.wiley.com/journal/19448007 |
en_US |
dc.identifier.citation |
Ivanciu, I., Ndarana, T., Matthes, K.,
& Wahl, S. (2022). On the ridging
of the South Atlantic Anticyclone
over South Africa: The impact of
Rossby wave breaking and of climate
change. Geophysical Research Letters,
49, e2022GL099607. https://doi.org/10.1029/2022GL099607. |
en_US |
dc.identifier.issn |
0094-8276 (print) |
|
dc.identifier.issn |
1944-8007 (online) |
|
dc.identifier.other |
10.1029/2022GL099607 |
|
dc.identifier.uri |
http://hdl.handle.net/2263/90452 |
|
dc.language.iso |
en |
en_US |
dc.publisher |
Wiley |
en_US |
dc.rights |
© 2022 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License. |
en_US |
dc.subject |
Ridging highs |
en_US |
dc.subject |
Rossby wave breaking (RWB) |
en_US |
dc.subject |
Climate change |
en_US |
dc.subject |
Climate modeling |
en_US |
dc.subject |
South African precipitation |
en_US |
dc.title |
On the ridging of the South Atlantic Anticyclone over South Africa : the impact of Rossby wave breaking and of climate change |
en_US |
dc.type |
Article |
en_US |