Subsurface manifestation of marine heat waves in the southwestern Indian Ocean
<p>Marine heat waves (MHWs) are extreme events of prolonged, anomalously warm ocean temperatures. Globally, marine heat waves are increasing in frequency and intensity and are responsible for long-term impacts on marine ecosystems, which have devastating socio-economic consequences. A key gap...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2025-08-01
|
| Series: | Ocean Science |
| Online Access: | https://os.copernicus.org/articles/21/1695/2025/os-21-1695-2025.pdf |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849771921129865216 |
|---|---|
| author | C. B. Welch C. B. Welch N. Malan N. Malan D. Mawren D. Mawren T. Morris J. Sprintall J. C. Hermes J. C. Hermes |
| author_facet | C. B. Welch C. B. Welch N. Malan N. Malan D. Mawren D. Mawren T. Morris J. Sprintall J. C. Hermes J. C. Hermes |
| author_sort | C. B. Welch |
| collection | DOAJ |
| description | <p>Marine heat waves (MHWs) are extreme events of prolonged, anomalously warm ocean temperatures. Globally, marine heat waves are increasing in frequency and intensity and are responsible for long-term impacts on marine ecosystems, which have devastating socio-economic consequences. A key gap in our understanding of MHWs is how they manifest in the subsurface. This paper uses satellite sea surface temperature (SST) data and in situ subsurface temperature observations from expendable bathythermographs (XBTs) to investigate the anomalous water temperature characteristics associated with surface-identified MHWs in the southwestern Indian Ocean (SWIO) and how they progress through the water column. We find that (1) regions of high eddy activity in the Mozambique Channel and southeast of Madagascar, where eddy kinetic energy is high and SST variability is low, are primarily characterised by the occurrence of abrupt and intense MHWs and that (2) the frequency, duration and intensity of these events are largely associated with mesoscale activity. In these eddy corridors, surface-detected MHW case studies demonstrate a strong, deep-reaching subsurface temperature anomaly signal with a maximum intensity below the surface. The majority of these MHWs are associated with anticyclonic eddies, which provide a possible mechanism for the deep extent of the surface MHWs. Improving our understanding of the interaction between mesoscale features and subsurface MHW characteristics will benefit the prediction of MHWs and management of the regions' biodiversity.</p> |
| format | Article |
| id | doaj-art-d06568c752804bd3b88dfeacc4d3f210 |
| institution | DOAJ |
| issn | 1812-0784 1812-0792 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Ocean Science |
| spelling | doaj-art-d06568c752804bd3b88dfeacc4d3f2102025-08-20T03:02:28ZengCopernicus PublicationsOcean Science1812-07841812-07922025-08-01211695170810.5194/os-21-1695-2025Subsurface manifestation of marine heat waves in the southwestern Indian OceanC. B. Welch0C. B. Welch1N. Malan2N. Malan3D. Mawren4D. Mawren5T. Morris6J. Sprintall7J. C. Hermes8J. C. Hermes9Department of Ocean and Atmosphere Science, University of Cape Town, Rondebosch, Cape Town, South AfricaEgagasini Node, South African Environmental Observation Network, Cape Town, South AfricaClimate Change Research Centre, University of New South Wales, Sydney, New South Wales, AustraliaCentre of Marine Science and Innovation,, University of New South Wales, Sydney, New South Wales, AustraliaDepartment of Ocean and Atmosphere Science, University of Cape Town, Rondebosch, Cape Town, South AfricaEgagasini Node, South African Environmental Observation Network, Cape Town, South AfricaEgagasini Node, South African Environmental Observation Network, Cape Town, South AfricaScripps Institution of Oceanography, University of California, San Diego, San Diego, La Jolla, CA, USADepartment of Ocean and Atmosphere Science, University of Cape Town, Rondebosch, Cape Town, South AfricaEgagasini Node, South African Environmental Observation Network, Cape Town, South Africa<p>Marine heat waves (MHWs) are extreme events of prolonged, anomalously warm ocean temperatures. Globally, marine heat waves are increasing in frequency and intensity and are responsible for long-term impacts on marine ecosystems, which have devastating socio-economic consequences. A key gap in our understanding of MHWs is how they manifest in the subsurface. This paper uses satellite sea surface temperature (SST) data and in situ subsurface temperature observations from expendable bathythermographs (XBTs) to investigate the anomalous water temperature characteristics associated with surface-identified MHWs in the southwestern Indian Ocean (SWIO) and how they progress through the water column. We find that (1) regions of high eddy activity in the Mozambique Channel and southeast of Madagascar, where eddy kinetic energy is high and SST variability is low, are primarily characterised by the occurrence of abrupt and intense MHWs and that (2) the frequency, duration and intensity of these events are largely associated with mesoscale activity. In these eddy corridors, surface-detected MHW case studies demonstrate a strong, deep-reaching subsurface temperature anomaly signal with a maximum intensity below the surface. The majority of these MHWs are associated with anticyclonic eddies, which provide a possible mechanism for the deep extent of the surface MHWs. Improving our understanding of the interaction between mesoscale features and subsurface MHW characteristics will benefit the prediction of MHWs and management of the regions' biodiversity.</p>https://os.copernicus.org/articles/21/1695/2025/os-21-1695-2025.pdf |
| spellingShingle | C. B. Welch C. B. Welch N. Malan N. Malan D. Mawren D. Mawren T. Morris J. Sprintall J. C. Hermes J. C. Hermes Subsurface manifestation of marine heat waves in the southwestern Indian Ocean Ocean Science |
| title | Subsurface manifestation of marine heat waves in the southwestern Indian Ocean |
| title_full | Subsurface manifestation of marine heat waves in the southwestern Indian Ocean |
| title_fullStr | Subsurface manifestation of marine heat waves in the southwestern Indian Ocean |
| title_full_unstemmed | Subsurface manifestation of marine heat waves in the southwestern Indian Ocean |
| title_short | Subsurface manifestation of marine heat waves in the southwestern Indian Ocean |
| title_sort | subsurface manifestation of marine heat waves in the southwestern indian ocean |
| url | https://os.copernicus.org/articles/21/1695/2025/os-21-1695-2025.pdf |
| work_keys_str_mv | AT cbwelch subsurfacemanifestationofmarineheatwavesinthesouthwesternindianocean AT cbwelch subsurfacemanifestationofmarineheatwavesinthesouthwesternindianocean AT nmalan subsurfacemanifestationofmarineheatwavesinthesouthwesternindianocean AT nmalan subsurfacemanifestationofmarineheatwavesinthesouthwesternindianocean AT dmawren subsurfacemanifestationofmarineheatwavesinthesouthwesternindianocean AT dmawren subsurfacemanifestationofmarineheatwavesinthesouthwesternindianocean AT tmorris subsurfacemanifestationofmarineheatwavesinthesouthwesternindianocean AT jsprintall subsurfacemanifestationofmarineheatwavesinthesouthwesternindianocean AT jchermes subsurfacemanifestationofmarineheatwavesinthesouthwesternindianocean AT jchermes subsurfacemanifestationofmarineheatwavesinthesouthwesternindianocean |