The Indian Ocean Deep Meridional Overturning Circulation in Three Ocean Reanalysis Products

T. Jayasankar; R. Murtugudde; T.I. Eldho

doi:10.1029/2019GL084244

The Indian Ocean Deep Meridional Overturning Circulation in Three Ocean Reanalysis Products

T. Jayasankar, R. Murtugudde, T.I. Eldho^*

^*Corresponding author for this work

Research output: Contribution to journal › Letter › peer-review

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Abstract

The time mean Indian Ocean (IO) deep meridional overturning circulation (MOC) is compared across three ocean reanalysis products (ORAS4, GECCO2, and GFDL). The MOC stream functions obtained by vertically integrating the mass flux across a latitude-depth section in three products are found to be significantly different from each other. Detailed analysis suggests that ORAS4 delivers the best depiction of IO MOC. The inferred IO deep MOC consists of two deep and strong counterclockwise cells located south of 30°S and around 10°S, respectively. The geostrophic component along with the barotropic or external mode dominates the former, and a combination of Ekman and geostrophic components dominates the latter. GECCO2 depicts a steady decline in the northward meridional transport in the bottom layer and a consequent reduction in the MOC strength. The tropical thermocline in GECCO2 responds to this MOC variability leading to rapid and monotonic warming of the tropical IO.

Original language	English
Pages (from-to)	12146-12155
Number of pages	10
Journal	Geophysical Research Letters
Volume	46
Issue number	21
Early online date	3 Nov 2019
DOIs	https://doi.org/10.1029/2019GL084244
Publication status	Published - 16 Nov 2019
Externally published	Yes

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title = "The Indian Ocean Deep Meridional Overturning Circulation in Three Ocean Reanalysis Products",

abstract = "The time mean Indian Ocean (IO) deep meridional overturning circulation (MOC) is compared across three ocean reanalysis products (ORAS4, GECCO2, and GFDL). The MOC stream functions obtained by vertically integrating the mass flux across a latitude-depth section in three products are found to be significantly different from each other. Detailed analysis suggests that ORAS4 delivers the best depiction of IO MOC. The inferred IO deep MOC consists of two deep and strong counterclockwise cells located south of 30°S and around 10°S, respectively. The geostrophic component along with the barotropic or external mode dominates the former, and a combination of Ekman and geostrophic components dominates the latter. GECCO2 depicts a steady decline in the northward meridional transport in the bottom layer and a consequent reduction in the MOC strength. The tropical thermocline in GECCO2 responds to this MOC variability leading to rapid and monotonic warming of the tropical IO.",

author = "T. Jayasankar and R. Murtugudde and T.I. Eldho",

note = "Research funded by Indian Institute of Technology Bombay (TA).",

year = "2019",

month = nov,

day = "16",

doi = "10.1029/2019GL084244",

language = "English",

volume = "46",

pages = "12146--12155",

journal = "Geophysical Research Letters",

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T1 - The Indian Ocean Deep Meridional Overturning Circulation in Three Ocean Reanalysis Products

AU - Jayasankar, T.

AU - Murtugudde, R.

AU - Eldho, T.I.

N1 - Research funded by Indian Institute of Technology Bombay (TA).

PY - 2019/11/16

Y1 - 2019/11/16

N2 - The time mean Indian Ocean (IO) deep meridional overturning circulation (MOC) is compared across three ocean reanalysis products (ORAS4, GECCO2, and GFDL). The MOC stream functions obtained by vertically integrating the mass flux across a latitude-depth section in three products are found to be significantly different from each other. Detailed analysis suggests that ORAS4 delivers the best depiction of IO MOC. The inferred IO deep MOC consists of two deep and strong counterclockwise cells located south of 30°S and around 10°S, respectively. The geostrophic component along with the barotropic or external mode dominates the former, and a combination of Ekman and geostrophic components dominates the latter. GECCO2 depicts a steady decline in the northward meridional transport in the bottom layer and a consequent reduction in the MOC strength. The tropical thermocline in GECCO2 responds to this MOC variability leading to rapid and monotonic warming of the tropical IO.

AB - The time mean Indian Ocean (IO) deep meridional overturning circulation (MOC) is compared across three ocean reanalysis products (ORAS4, GECCO2, and GFDL). The MOC stream functions obtained by vertically integrating the mass flux across a latitude-depth section in three products are found to be significantly different from each other. Detailed analysis suggests that ORAS4 delivers the best depiction of IO MOC. The inferred IO deep MOC consists of two deep and strong counterclockwise cells located south of 30°S and around 10°S, respectively. The geostrophic component along with the barotropic or external mode dominates the former, and a combination of Ekman and geostrophic components dominates the latter. GECCO2 depicts a steady decline in the northward meridional transport in the bottom layer and a consequent reduction in the MOC strength. The tropical thermocline in GECCO2 responds to this MOC variability leading to rapid and monotonic warming of the tropical IO.

U2 - 10.1029/2019GL084244

DO - 10.1029/2019GL084244

M3 - Letter

SN - 0094-8276

VL - 46

SP - 12146

EP - 12155

JO - Geophysical Research Letters

JF - Geophysical Research Letters

IS - 21

ER -

The Indian Ocean Deep Meridional Overturning Circulation in Three Ocean Reanalysis Products

Abstract

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