A sub-fossil coral Sr∕Ca record documents northward shifts of the Tropical Convergence Zone in the eastern Indian Ocean
<p>Sea surface temperature (SST) variability in the south-eastern tropical Indian Ocean is crucial for rainfall variability in Indian Ocean rim countries. A large body of literature has focused on zonal variability associated with the Indian Ocean Dipole (IOD) which peaks in austral spring. In...
Saved in:
| Main Authors: | , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2025-01-01
|
| Series: | Climate of the Past |
| Online Access: | https://cp.copernicus.org/articles/21/211/2025/cp-21-211-2025.pdf |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832583755923980288 |
|---|---|
| author | M. Pfeiffer H. Takayanagi H. Takayanagi L. Reuning T. K. Watanabe T. K. Watanabe S. Ito D. Garbe-Schönberg T. Watanabe T. Watanabe T. Watanabe C.-C. Wu C.-C. Shen C.-C. Shen J. Zinke G.-J. A. Brummer S. Y. Cahyarini |
| author_facet | M. Pfeiffer H. Takayanagi H. Takayanagi L. Reuning T. K. Watanabe T. K. Watanabe S. Ito D. Garbe-Schönberg T. Watanabe T. Watanabe T. Watanabe C.-C. Wu C.-C. Shen C.-C. Shen J. Zinke G.-J. A. Brummer S. Y. Cahyarini |
| author_sort | M. Pfeiffer |
| collection | DOAJ |
| description | <p>Sea surface temperature (SST) variability in the south-eastern tropical Indian Ocean is crucial for rainfall variability in Indian Ocean rim countries. A large body of literature has focused on zonal variability associated with the Indian Ocean Dipole (IOD) which peaks in austral spring. In today's climate, northward shifts of the Tropical Convergence Zone (TCZ) co-vary with the IOD, and it is unclear whether these shifts may also occur independently. We have developed a new monthly resolved <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow><mrow class="chem"><mi mathvariant="normal">Sr</mi></mrow><mo>/</mo><mrow class="chem"><mi mathvariant="normal">Ca</mi></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="33pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="b2a006b9788c1eb325815616d85bb8f7"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cp-21-211-2025-ie00004.svg" width="33pt" height="14pt" src="cp-21-211-2025-ie00004.png"/></svg:svg></span></span> record from a sub-fossil coral cored at Enggano Island (Sumatra, Indonesia). Core sections containing diagenetic phases are omitted from the SST reconstruction. U<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="57ee8123d9c9aefcf23d9c7f6463c158"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cp-21-211-2025-ie00005.svg" width="8pt" height="14pt" src="cp-21-211-2025-ie00005.png"/></svg:svg></span></span>Th dating shows that the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow><mrow class="chem"><mi mathvariant="normal">Sr</mi></mrow><mo>/</mo><mrow class="chem"><mi mathvariant="normal">Ca</mi></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="33pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="90dc7a8a55bd37b8673bdad01c3cf421"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cp-21-211-2025-ie00006.svg" width="33pt" height="14pt" src="cp-21-211-2025-ie00006.png"/></svg:svg></span></span>-based SST record extends from 1869–1918 and from 1824–1862 with a relative age uncertainty of <span class="inline-formula">±3</span> years (<span class="inline-formula">2<i>σ</i></span>). At Enggano Island, coastal upwelling and cooling in austral spring impact SST seasonality and are coupled to the latitudinal position of the TCZ. The sub-fossil coral indicates an increase in SST seasonality between 1856 and 1918 relative to the 1930–2008 period. We attribute this to enhanced cooling due to stronger south-easterly (SE) winds driven by a northward shift in the TCZ in austral spring. A nearby sediment core indicates colder SSTs and a shallower thermocline prior to <span class="inline-formula">∼1930</span>. These results are consistent with an increase in the north–south SST gradient in the eastern Indian Ocean, calculated from historical temperature data, that is not seen in the zonal SST gradient. We conclude that the relationship between meridional and zonal variability in the eastern Indian Ocean is non-stationary and modulated by the long-term evolution of temperature gradients.</p> |
| format | Article |
| id | doaj-art-f4fb88bbb7a14a58b34e15e5a72cb03b |
| institution | Kabale University |
| issn | 1814-9324 1814-9332 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj-art-f4fb88bbb7a14a58b34e15e5a72cb03b2025-01-28T08:17:13ZengCopernicus PublicationsClimate of the Past1814-93241814-93322025-01-012121123710.5194/cp-21-211-2025A sub-fossil coral Sr∕Ca record documents northward shifts of the Tropical Convergence Zone in the eastern Indian OceanM. Pfeiffer0H. Takayanagi1H. Takayanagi2L. Reuning3T. K. Watanabe4T. K. Watanabe5S. Ito6D. Garbe-Schönberg7T. Watanabe8T. Watanabe9T. Watanabe10C.-C. Wu11C.-C. Shen12C.-C. Shen13J. Zinke14G.-J. A. Brummer15S. Y. Cahyarini16Institute of Geosciences, Kiel University, 24118 Kiel, GermanyInstitute of Geology and Paleontology, Graduate School of Science, Tohoku University, Aramaki-Aza-Aoba 6-3, Sendai, 980-8578, JapanAdvanced Institute for Marine Ecosystem Change (WPI-AIMEC), Tohoku University, Sendai, 980-8578, JapanInstitute of Geosciences, Kiel University, 24118 Kiel, GermanyInstitute of Geosciences, Kiel University, 24118 Kiel, GermanyKIKAI Institute for Coral Reef Sciences, Kikai Town, Kagoshima, 891-6151, JapanInstitute of Geosciences, Kiel University, 24118 Kiel, GermanyInstitute of Geosciences, Kiel University, 24118 Kiel, GermanyKIKAI Institute for Coral Reef Sciences, Kikai Town, Kagoshima, 891-6151, JapanDepartment of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810, JapanResearch Institute for Humanity and Nature (RIHN), Kyoto, 603-8047, JapanCollege of Marine Sciences and Engineering, Nanjing Normal University, Nanjing, 210023, ChinaDepartment of Geosciences, High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), National Taiwan University, Taipei, 10617, TaiwanResearch Center for Future Earth, National Taiwan University, Taipei, 10617, TaiwanSchool of Geography, Geology and the Environment, University of Leicester, Leicester, LE1 7RH, UKDepartment of Ocean Systems, Royal Netherlands Institute for Sea Research (NIOZ), and Utrecht University, 1790 AB Den Burg, the NetherlandsRes. Group of Paleoclimate & Paleoenvironment, Res. Centr. for Climate and Atmosphere, National Research and Innovations Agency (BRIN), Bandung, Republic of Indonesia<p>Sea surface temperature (SST) variability in the south-eastern tropical Indian Ocean is crucial for rainfall variability in Indian Ocean rim countries. A large body of literature has focused on zonal variability associated with the Indian Ocean Dipole (IOD) which peaks in austral spring. In today's climate, northward shifts of the Tropical Convergence Zone (TCZ) co-vary with the IOD, and it is unclear whether these shifts may also occur independently. We have developed a new monthly resolved <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow><mrow class="chem"><mi mathvariant="normal">Sr</mi></mrow><mo>/</mo><mrow class="chem"><mi mathvariant="normal">Ca</mi></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="33pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="b2a006b9788c1eb325815616d85bb8f7"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cp-21-211-2025-ie00004.svg" width="33pt" height="14pt" src="cp-21-211-2025-ie00004.png"/></svg:svg></span></span> record from a sub-fossil coral cored at Enggano Island (Sumatra, Indonesia). Core sections containing diagenetic phases are omitted from the SST reconstruction. U<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="57ee8123d9c9aefcf23d9c7f6463c158"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cp-21-211-2025-ie00005.svg" width="8pt" height="14pt" src="cp-21-211-2025-ie00005.png"/></svg:svg></span></span>Th dating shows that the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow><mrow class="chem"><mi mathvariant="normal">Sr</mi></mrow><mo>/</mo><mrow class="chem"><mi mathvariant="normal">Ca</mi></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="33pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="90dc7a8a55bd37b8673bdad01c3cf421"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cp-21-211-2025-ie00006.svg" width="33pt" height="14pt" src="cp-21-211-2025-ie00006.png"/></svg:svg></span></span>-based SST record extends from 1869–1918 and from 1824–1862 with a relative age uncertainty of <span class="inline-formula">±3</span> years (<span class="inline-formula">2<i>σ</i></span>). At Enggano Island, coastal upwelling and cooling in austral spring impact SST seasonality and are coupled to the latitudinal position of the TCZ. The sub-fossil coral indicates an increase in SST seasonality between 1856 and 1918 relative to the 1930–2008 period. We attribute this to enhanced cooling due to stronger south-easterly (SE) winds driven by a northward shift in the TCZ in austral spring. A nearby sediment core indicates colder SSTs and a shallower thermocline prior to <span class="inline-formula">∼1930</span>. These results are consistent with an increase in the north–south SST gradient in the eastern Indian Ocean, calculated from historical temperature data, that is not seen in the zonal SST gradient. We conclude that the relationship between meridional and zonal variability in the eastern Indian Ocean is non-stationary and modulated by the long-term evolution of temperature gradients.</p>https://cp.copernicus.org/articles/21/211/2025/cp-21-211-2025.pdf |
| spellingShingle | M. Pfeiffer H. Takayanagi H. Takayanagi L. Reuning T. K. Watanabe T. K. Watanabe S. Ito D. Garbe-Schönberg T. Watanabe T. Watanabe T. Watanabe C.-C. Wu C.-C. Shen C.-C. Shen J. Zinke G.-J. A. Brummer S. Y. Cahyarini A sub-fossil coral Sr∕Ca record documents northward shifts of the Tropical Convergence Zone in the eastern Indian Ocean Climate of the Past |
| title | A sub-fossil coral Sr∕Ca record documents northward shifts of the Tropical Convergence Zone in the eastern Indian Ocean |
| title_full | A sub-fossil coral Sr∕Ca record documents northward shifts of the Tropical Convergence Zone in the eastern Indian Ocean |
| title_fullStr | A sub-fossil coral Sr∕Ca record documents northward shifts of the Tropical Convergence Zone in the eastern Indian Ocean |
| title_full_unstemmed | A sub-fossil coral Sr∕Ca record documents northward shifts of the Tropical Convergence Zone in the eastern Indian Ocean |
| title_short | A sub-fossil coral Sr∕Ca record documents northward shifts of the Tropical Convergence Zone in the eastern Indian Ocean |
| title_sort | sub fossil coral sr ca record documents northward shifts of the tropical convergence zone in the eastern indian ocean |
| url | https://cp.copernicus.org/articles/21/211/2025/cp-21-211-2025.pdf |
| work_keys_str_mv | AT mpfeiffer asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT htakayanagi asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT htakayanagi asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT lreuning asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT tkwatanabe asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT tkwatanabe asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT sito asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT dgarbeschonberg asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT twatanabe asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT twatanabe asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT twatanabe asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT ccwu asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT ccshen asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT ccshen asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT jzinke asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT gjabrummer asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT sycahyarini asubfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT mpfeiffer subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT htakayanagi subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT htakayanagi subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT lreuning subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT tkwatanabe subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT tkwatanabe subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT sito subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT dgarbeschonberg subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT twatanabe subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT twatanabe subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT twatanabe subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT ccwu subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT ccshen subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT ccshen subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT jzinke subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT gjabrummer subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean AT sycahyarini subfossilcoralsrcarecorddocumentsnorthwardshiftsofthetropicalconvergencezoneintheeasternindianocean |