Glacial to interglacial climate variability in the southeastern African subtropics (25–20° S)
We present a continuous and well-resolved record of climatic variability for the past 100 000 years from a marine sediment core taken in Delagoa Bight, off southeastern Africa. In addition to providing a sea surface temperature reconstruction for the past ca. 100 000 years, this record also allows a...
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ftcopernicus:oai:publications.copernicus.org:cp82511 2023-05-15T13:31:40+02:00 Glacial to interglacial climate variability in the southeastern African subtropics (25–20° S) Hahn, Annette Schefuß, Enno Groeneveld, Jeroen Miller, Charlotte Zabel, Matthias 2021-01-29 application/pdf https://doi.org/10.5194/cp-17-345-2021 https://cp.copernicus.org/articles/17/345/2021/ eng eng doi:10.5194/cp-17-345-2021 https://cp.copernicus.org/articles/17/345/2021/ eISSN: 1814-9332 Text 2021 ftcopernicus https://doi.org/10.5194/cp-17-345-2021 2021-02-01T17:21:47Z We present a continuous and well-resolved record of climatic variability for the past 100 000 years from a marine sediment core taken in Delagoa Bight, off southeastern Africa. In addition to providing a sea surface temperature reconstruction for the past ca. 100 000 years, this record also allows a high-resolution continental climatic reconstruction. Climate sensitive organic proxies, like the distribution and isotopic composition of plant-wax lipids as well as elemental indicators of fluvial input and weathering type provide information on climatic changes in the adjacent catchment areas (Incomati, Matola and Lusutfu rivers). At the transition between glacials and interglacials, shifts in vegetation correlate with changes in sea surface temperature in the Agulhas Current. The local hydrology, however, does not follow these orbitally paced shifts. Instead, precipitation patterns follow millennial-scale variations with different forcing mechanisms in glacial vs. interglacial climatic states. During glacials, southward displacement of the Intertropical Convergence Zone facilitates a transmission of northern hemispheric signals (e.g., Heinrich events) to the southern hemispheric subtropics. Furthermore, the southern hemispheric westerlies become a more direct source of precipitation as they shift northward over the study site, especially during Antarctic cold phases. During interglacials, the observed short-term hydrological variability is also a function of Antarctic climate variability; however, it is driven by the indirect influence of the southern hemispheric westerlies and the associated South African high-pressure cell blocking the South Indian Ocean Convergence Zone related precipitation. As a consequence of the interplay of these effects, small-scale climatic zones exist. We propose a conceptual model describing latitudinal shifts of these zones along the southeastern African coast as tropical and temperate climate systems shift over glacial and interglacial cycles. The proposed model explains some of the apparent contradictions between several paleoclimate records in the region. Text Antarc* Antarctic Copernicus Publications: E-Journals Antarctic Indian Climate of the Past 17 1 345 360 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
We present a continuous and well-resolved record of climatic variability for the past 100 000 years from a marine sediment core taken in Delagoa Bight, off southeastern Africa. In addition to providing a sea surface temperature reconstruction for the past ca. 100 000 years, this record also allows a high-resolution continental climatic reconstruction. Climate sensitive organic proxies, like the distribution and isotopic composition of plant-wax lipids as well as elemental indicators of fluvial input and weathering type provide information on climatic changes in the adjacent catchment areas (Incomati, Matola and Lusutfu rivers). At the transition between glacials and interglacials, shifts in vegetation correlate with changes in sea surface temperature in the Agulhas Current. The local hydrology, however, does not follow these orbitally paced shifts. Instead, precipitation patterns follow millennial-scale variations with different forcing mechanisms in glacial vs. interglacial climatic states. During glacials, southward displacement of the Intertropical Convergence Zone facilitates a transmission of northern hemispheric signals (e.g., Heinrich events) to the southern hemispheric subtropics. Furthermore, the southern hemispheric westerlies become a more direct source of precipitation as they shift northward over the study site, especially during Antarctic cold phases. During interglacials, the observed short-term hydrological variability is also a function of Antarctic climate variability; however, it is driven by the indirect influence of the southern hemispheric westerlies and the associated South African high-pressure cell blocking the South Indian Ocean Convergence Zone related precipitation. As a consequence of the interplay of these effects, small-scale climatic zones exist. We propose a conceptual model describing latitudinal shifts of these zones along the southeastern African coast as tropical and temperate climate systems shift over glacial and interglacial cycles. The proposed model explains some of the apparent contradictions between several paleoclimate records in the region. |
format |
Text |
author |
Hahn, Annette Schefuß, Enno Groeneveld, Jeroen Miller, Charlotte Zabel, Matthias |
spellingShingle |
Hahn, Annette Schefuß, Enno Groeneveld, Jeroen Miller, Charlotte Zabel, Matthias Glacial to interglacial climate variability in the southeastern African subtropics (25–20° S) |
author_facet |
Hahn, Annette Schefuß, Enno Groeneveld, Jeroen Miller, Charlotte Zabel, Matthias |
author_sort |
Hahn, Annette |
title |
Glacial to interglacial climate variability in the southeastern African subtropics (25–20° S) |
title_short |
Glacial to interglacial climate variability in the southeastern African subtropics (25–20° S) |
title_full |
Glacial to interglacial climate variability in the southeastern African subtropics (25–20° S) |
title_fullStr |
Glacial to interglacial climate variability in the southeastern African subtropics (25–20° S) |
title_full_unstemmed |
Glacial to interglacial climate variability in the southeastern African subtropics (25–20° S) |
title_sort |
glacial to interglacial climate variability in the southeastern african subtropics (25–20° s) |
publishDate |
2021 |
url |
https://doi.org/10.5194/cp-17-345-2021 https://cp.copernicus.org/articles/17/345/2021/ |
geographic |
Antarctic Indian |
geographic_facet |
Antarctic Indian |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-17-345-2021 https://cp.copernicus.org/articles/17/345/2021/ |
op_doi |
https://doi.org/10.5194/cp-17-345-2021 |
container_title |
Climate of the Past |
container_volume |
17 |
container_issue |
1 |
container_start_page |
345 |
op_container_end_page |
360 |
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1766019978965811200 |