Seasonal and spatial variations in spice generation in the South Indian Ocean salinity maxima

Spiciness anomalies generated in the salinity maxima region are important for several atmospheric and oceanic factors as they move along the geostrophic pathways towards the equator and resurface. Subduction and injection mechanisms are responsible for the spiciness generation in the South Indian Oc...

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Main Authors: Kaundal, Madhu, Raju, Nadimpalli Jithendra, Samanta, Dhrubajyoti, Dash, Mihir Kumar
Other Authors: Earth Observatory of Singapore
Format: Article
Language:English
Published: 2024
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Online Access:https://hdl.handle.net/10356/174098
https://publons.com/wos-op/publon/52209460/
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1740982024-03-18T04:57:04Z Seasonal and spatial variations in spice generation in the South Indian Ocean salinity maxima Kaundal, Madhu Raju, Nadimpalli Jithendra Samanta, Dhrubajyoti Dash, Mihir Kumar Earth Observatory of Singapore Earth and Environmental Sciences Spiciness Subduction Spiciness anomalies generated in the salinity maxima region are important for several atmospheric and oceanic factors as they move along the geostrophic pathways towards the equator and resurface. Subduction and injection mechanisms are responsible for the spiciness generation in the South Indian Ocean (SIO) salinity maxima region. Using ECCO data from 1992 to 2017, here we study monthly variations of spiciness associated with both of these mechanisms in the SIO salinity maxima region. Using a Lagrangian approach, we estimated the monthly evolution of the subduction rate. A maximum subduction rate of 35–38 m/mon occurs during September and consequently decreases towards the end of the year. The effective subduction rate in the salinity maxima region shows the dominance of temporal induction (mixed layer tendency) term, with a sharp gradient in total subduction rate along the 30∘S associated with large mixed layer depth variation. Further, a high Turner angle (> 66∘) to the south of 30∘S confirms the generation of spiciness by injection mechanism. We found that the decrease in mixed layer salt (MLS) coincides with the increase in salinity below the mixed layer. To explore the significance of MLS changes in spiciness generation, we further addressed the monthly evolution of spiciness through MLS budget. Our results suggest that the entrainment and meridional advection terms are key to monthly variations in MLS changes and thus the spiciness. Ministry of Education (MOE) National Research Foundation (NRF) DS was funded by the Ministry of Education Academic Research Fund MOE2019-T3-1-004, the National Research Foundation Singapore, and the Singapore Ministry of Education, under the Research Centres of Excellence initiative. This work comprises Earth Observatory of Singapore contribution no. 434. MKD was funded by the climate change project of Department of Science and Technology, Govt. of India. 2024-03-18T04:57:04Z 2024-03-18T04:57:04Z 2022 Journal Article Kaundal, M., Raju, N. J., Samanta, D. & Dash, M. K. (2022). Seasonal and spatial variations in spice generation in the South Indian Ocean salinity maxima. Ocean Dynamics, 72, 313-323. https://dx.doi.org/10.1007/S10236-022-01502-2 1616-7341 https://hdl.handle.net/10356/174098 10.1007/S10236-022-01502-2 WOS:000782166300001 https://publons.com/wos-op/publon/52209460/ 72 313 323 en MOE2019-T3-1-004 Ocean Dynamics © 2022 Springer-Verlag GmbH Germany, part of Springer Nature. All rights reserved.
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Earth and Environmental Sciences
Spiciness
Subduction
spellingShingle Earth and Environmental Sciences
Spiciness
Subduction
Kaundal, Madhu
Raju, Nadimpalli Jithendra
Samanta, Dhrubajyoti
Dash, Mihir Kumar
Seasonal and spatial variations in spice generation in the South Indian Ocean salinity maxima
description Spiciness anomalies generated in the salinity maxima region are important for several atmospheric and oceanic factors as they move along the geostrophic pathways towards the equator and resurface. Subduction and injection mechanisms are responsible for the spiciness generation in the South Indian Ocean (SIO) salinity maxima region. Using ECCO data from 1992 to 2017, here we study monthly variations of spiciness associated with both of these mechanisms in the SIO salinity maxima region. Using a Lagrangian approach, we estimated the monthly evolution of the subduction rate. A maximum subduction rate of 35–38 m/mon occurs during September and consequently decreases towards the end of the year. The effective subduction rate in the salinity maxima region shows the dominance of temporal induction (mixed layer tendency) term, with a sharp gradient in total subduction rate along the 30∘S associated with large mixed layer depth variation. Further, a high Turner angle (> 66∘) to the south of 30∘S confirms the generation of spiciness by injection mechanism. We found that the decrease in mixed layer salt (MLS) coincides with the increase in salinity below the mixed layer. To explore the significance of MLS changes in spiciness generation, we further addressed the monthly evolution of spiciness through MLS budget. Our results suggest that the entrainment and meridional advection terms are key to monthly variations in MLS changes and thus the spiciness.
author2 Earth Observatory of Singapore
author_facet Earth Observatory of Singapore
Kaundal, Madhu
Raju, Nadimpalli Jithendra
Samanta, Dhrubajyoti
Dash, Mihir Kumar
format Article
author Kaundal, Madhu
Raju, Nadimpalli Jithendra
Samanta, Dhrubajyoti
Dash, Mihir Kumar
author_sort Kaundal, Madhu
title Seasonal and spatial variations in spice generation in the South Indian Ocean salinity maxima
title_short Seasonal and spatial variations in spice generation in the South Indian Ocean salinity maxima
title_full Seasonal and spatial variations in spice generation in the South Indian Ocean salinity maxima
title_fullStr Seasonal and spatial variations in spice generation in the South Indian Ocean salinity maxima
title_full_unstemmed Seasonal and spatial variations in spice generation in the South Indian Ocean salinity maxima
title_sort seasonal and spatial variations in spice generation in the south indian ocean salinity maxima
publishDate 2024
url https://hdl.handle.net/10356/174098
https://publons.com/wos-op/publon/52209460/
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