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Slower long-term coastal warming drives dampened trends in coastal marine heatwave exposure

Citation

Marin, M and Bindoff, NL and Feng, M and Phillips, HE, Slower long-term coastal warming drives dampened trends in coastal marine heatwave exposure, JGR Oceans, 126, (11) Article e2021JC017930. ISSN 2169-9275 (2021) [Refereed Article]


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2021. American Geophysical Union. All Rights Reserved.

DOI: doi:10.1029/2021JC017930

Abstract

Long-term temperature changes drive coastal Marine Heatwave (MHW) trends globally. Here, we provide a more comprehensive global analysis of cross-shore gradients of MHW and Sea Surface Temperatures (SST) changes using an ensemble of three satellite SST products during recent decades. Our analysis reveals depressed onshore SST trends in more than 2/3 of coastal pixels, including both eastern and western boundary current systems. These were well correlated with depressed trends of MHW exposure and severity, ranging from a −2 to −10 decrease in MHW days per decade and from a −2.5C to −15C.days per decade decrease in cumulative intensity. Results were consistent across all satellite products, indicating that these cross-shore gradients are a robust feature of observations. ERA reanalysis data show that neither air-sea heat fluxes nor wind driven upwelling were found to be consistent drivers. Global ocean circulation models (OFAM3 and ACCESS-OM2) have limited ability to simulate the depressed onshore trends. A heat budget analysis performed in the Chilean coast region, where models agree with observations, showed that the gradient of temperature change was controlled by an onshore increase of longwave radiative cooling, despite an increase in upwelling. This highlights the complexity of small-scale coastal ocean-atmosphere feedbacks, which coarser resolution climate models do not resolve. Here, we show that global coastal regions may act as thermal refugia for marine ecosystems from aspects of climate change and pulsative (MHW) changes. Contrary to the literature, our results suggest that driving mechanisms are region dependant, stressing the necessity to improve climate models resolution.

Item Details

Item Type:Refereed Article
Keywords:marine heatwave, coastal trends, offshore trends, heatwave refuge
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical oceanography
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Oceanic processes (excl. in the Antarctic and Southern Ocean)
UTAS Author:Marin, M (Mr Maxime Marin)
UTAS Author:Bindoff, NL (Professor Nathan Bindoff)
UTAS Author:Phillips, HE (Associate Professor Helen Phillips)
ID Code:147988
Year Published:2021
Deposited By:Oceans and Cryosphere
Deposited On:2021-11-26
Last Modified:2021-12-06
Downloads:0

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