Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies
The austral westerlies strongly influence precipitation and ocean circulation in the southern temperate zone, with important consequences for cultures and ecosystems. Global climate models anticipate poleward retreat of the austral westerlies with future warming, but the available paleoclimate recor...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2012-05-01
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| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/8/877/2012/cp-8-877-2012.pdf |
| _version_ | 1811288531958497280 |
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| author | J. C. Stager P. A. Mayewski J. White B. M. Chase F. H. Neumann M. E. Meadows C. D. King D. A. Dixon |
| author_facet | J. C. Stager P. A. Mayewski J. White B. M. Chase F. H. Neumann M. E. Meadows C. D. King D. A. Dixon |
| author_sort | J. C. Stager |
| collection | DOAJ |
| description | The austral westerlies strongly influence precipitation and ocean circulation in the southern temperate zone, with important consequences for cultures and ecosystems. Global climate models anticipate poleward retreat of the austral westerlies with future warming, but the available paleoclimate records that might test these models have been limited to South America and New Zealand, are not fully consistent with each other and may be complicated by influences from other climatic factors. Here we present the first high-resolution diatom and sedimentological records from the winter rainfall region of South Africa, representing precipitation in the equatorward margin of the westerly wind belt during the last 1400 yr. Inferred rainfall was relatively high ∼1400–1200 cal yr BP, decreased until ∼950 cal yr BP, and rose notably through the Little Ice Age with pulses centred on ∼600, 530, 470, 330, 200, 90, and 20 cal yr BP. Synchronous fluctuations in Antarctic ice core chemistry strongly suggest that these variations were linked to changes in the westerlies. Equatorward drift of the westerlies during the wet periods may have influenced Atlantic meridional overturning circulation by restricting marine flow around the tip of Africa. Apparent inconsistencies among some aspects of records from South America, New Zealand and South Africa warn against the simplistic application of single records to the Southern Hemisphere as a whole. Nonetheless, these findings in general do support model projections of increasing aridity in the austral winter rainfall zones with future warming. |
| first_indexed | 2024-04-13T03:38:52Z |
| format | Article |
| id | doaj.art-1c693b677bd3488cbc34c88e4132ea0e |
| institution | Directory Open Access Journal |
| issn | 1814-9324 1814-9332 |
| language | English |
| last_indexed | 2024-04-13T03:38:52Z |
| publishDate | 2012-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj.art-1c693b677bd3488cbc34c88e4132ea0e2022-12-22T03:04:14ZengCopernicus PublicationsClimate of the Past1814-93241814-93322012-05-018387788710.5194/cp-8-877-2012Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerliesJ. C. StagerP. A. MayewskiJ. WhiteB. M. ChaseF. H. NeumannM. E. MeadowsC. D. KingD. A. DixonThe austral westerlies strongly influence precipitation and ocean circulation in the southern temperate zone, with important consequences for cultures and ecosystems. Global climate models anticipate poleward retreat of the austral westerlies with future warming, but the available paleoclimate records that might test these models have been limited to South America and New Zealand, are not fully consistent with each other and may be complicated by influences from other climatic factors. Here we present the first high-resolution diatom and sedimentological records from the winter rainfall region of South Africa, representing precipitation in the equatorward margin of the westerly wind belt during the last 1400 yr. Inferred rainfall was relatively high ∼1400–1200 cal yr BP, decreased until ∼950 cal yr BP, and rose notably through the Little Ice Age with pulses centred on ∼600, 530, 470, 330, 200, 90, and 20 cal yr BP. Synchronous fluctuations in Antarctic ice core chemistry strongly suggest that these variations were linked to changes in the westerlies. Equatorward drift of the westerlies during the wet periods may have influenced Atlantic meridional overturning circulation by restricting marine flow around the tip of Africa. Apparent inconsistencies among some aspects of records from South America, New Zealand and South Africa warn against the simplistic application of single records to the Southern Hemisphere as a whole. Nonetheless, these findings in general do support model projections of increasing aridity in the austral winter rainfall zones with future warming.http://www.clim-past.net/8/877/2012/cp-8-877-2012.pdf |
| spellingShingle | J. C. Stager P. A. Mayewski J. White B. M. Chase F. H. Neumann M. E. Meadows C. D. King D. A. Dixon Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies Climate of the Past |
| title | Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies |
| title_full | Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies |
| title_fullStr | Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies |
| title_full_unstemmed | Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies |
| title_short | Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies |
| title_sort | precipitation variability in the winter rainfall zone of south africa during the last 1400 yr linked to the austral westerlies |
| url | http://www.clim-past.net/8/877/2012/cp-8-877-2012.pdf |
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