The relative importance of ocean advection and surface heat fluxes during the Madden-Julian Oscillation in a coupled ocean-atmosphere model

Karlowska, Eliza ORCID: https://orcid.org/0000-0003-2401-0871, Matthews, Adrian ORCID: https://orcid.org/0000-0003-0492-1168, Webber, Ben ORCID: https://orcid.org/0000-0002-8812-5929, Graham, Tim and Xavier, Prince (2024) The relative importance of ocean advection and surface heat fluxes during the Madden-Julian Oscillation in a coupled ocean-atmosphere model. Journal of Geophysical Research: Oceans, 129 (11). ISSN 2169-9275

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Abstract

Intraseasonal variability of ocean surface mixed layer temperature (MLT) in the tropics can be linked to the Madden--Julian Oscillation (MJO), the main source of intraseasonal atmospheric variability in the tropics. Here we conduct a boreal winter mixed layer heat budget using 10 day forecast composites of a coupled ocean--atmosphere Numerical Weather Prediction model of the UK Met Office to reveal that ocean advection plays a major role in modulating intraseasonal anomalies of MLT over the tropical Indian Ocean and the Maritime Continent. Large scale (approximately 10 degree) intraseasonal anomalies of MLT (approximately 0.1 degC) are driven by net surface heat flux. Ocean advection dominates at smaller horizontal scales (approximately 1 degree), contributing up to 0.5 degC to the intraseasonal MLT anomaly. Prior to the development of the enhanced MJO convection in the western Indian Ocean (phases 8 and 1), ocean advection reinforces the net heat flux warming in this region. However, ocean advection opposes the net heat flux warming in the Maritime Continent prior to the development of suppressed MJO convection in this region. When the MJO convection develops over the central Indian Ocean (phase 3), ocean advection (net surface heat flux) drives the intraseasonal MLT anomalies in the western Indian Ocean (central Indian Ocean and the Maritime Continent). Our results demonstrate the importance of ocean dynamics during the initiation and growth of the MJO, and raise implications for models that do not resolve these processes.

Item Type:	Article
Additional Information:	Data Availability Statement: Daily interpolated OLR values were obtained from National Oceanic and Atmospheric Administration (Liebmann & Smith, 1996) available at https://psl.noaa.gov/data/gridded/data.olrcdr.interp.html. Observed RMM indices (Wheeler & Hendon, 2004) were retrieved from Bureau of Meteorology, available at http://www.bom.gov.au/climate/mjo/. Figures were made with Matplotlib version 3.3.4 (Caswell et al., 2021; Hunter, 2007). Data to generate the figures can be accessed at https://www.zotero.org/e.karlowska/collections/WJJ6IRGP. Funding Information: EK was supported by the Natural Environment Research Council and ARIES DTP (Grant number NE/S007334/1). AJM was partially funded by the Natural Environment Research Council TerraMaris project (Grant NE/R016704/1).
Faculty \ School:	Faculty of Science Faculty of Science > School of Environmental Sciences University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups:	Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences Faculty of Science > Research Groups > Climatic Research Unit Faculty of Science > Research Groups > Fluids & Structures Faculty of Science > Research Groups > Numerical Simulation, Statistics & Data Science
Related URLs:	http://www.scopus.com/inward/record.url?...
Depositing User:	LivePure Connector
Date Deposited:	05 Nov 2024 12:30
Last Modified:	20 Nov 2024 14:30
URI:	https://ueaeprints.uea.ac.uk/id/eprint/97506
DOI:	10.1029/2024JC021515

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