East Australian cyclones and air‐sea feedbacks

Sérazin, G., Di Luca, A., Gupta, A. Sen, Rogé, Marine, Jourdain, N. C., Argüeso, D. and Bull, Christopher (2021) East Australian cyclones and air‐sea feedbacks. Journal of Geophysical Research: Atmospheres, 126 (20). e2020JD034391. ISSN 2169-897X

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Official URL: https://doi.org/10.1029/2020jd034391

Abstract

The importance of resolving mesoscale air-sea interactions to represent cyclones impacting the East Coast of Australia, the so-called East Coast Lows (ECLs), is investigated using the Australian Regional Coupled Model based on NEMO-OASIS-WRF (NOW) at urn:x-wiley:2169897X:media:jgrd57355:jgrd57355-math-0001 resolution. The fully coupled model is shown to be capable of reproducing correctly relevant features such as the seasonality, spatial distribution and intensity of ECLs while it partially resolves mesoscale processes, such as air-sea feedbacks over ocean eddies and fronts. The mesoscale thermal feedback (TFB) and the current feedback (CFB) are shown to influence the intensity of northern ECLs (north of urn:x-wiley:2169897X:media:jgrd57355:jgrd57355-math-0002), with the TFB modulating the pre-storm sea surface temperature by shifting ECL locations eastwards and the CFB modulating the wind stress. By fully uncoupling the atmospheric model of NOW, the intensity of northern ECLs is increased due to the absence of the cold wake that provides a negative feedback to the cyclone. The number of ECLs might also be affected by the air-sea feedbacks but large interannual variability hampers significant results with short term simulations. The TFB and CFB modify the climatology of sea surface temperature (mean and variability) but no direct link is found between these changes and those noticed in ECL properties. These results show that the representation of ECLs, mainly north of urn:x-wiley:2169897X:media:jgrd57355:jgrd57355-math-0003, depend on how air-sea feedbacks are simulated. This is particularly important for atmospheric downscaling of climate projections as small-scale sea surface temperature interactions and the effects of ocean currents are not accounted for.

Item Type: Article
Additional Information: Funding information: This research was supported by the Australian Research Council (ARC) Centre of Excellence for Climate Extremes (CE110001028). The NOW and WRF simulations were run using Computational resources provided by the NCI National Facility at the Australian National University, through awards under the Merit Allocation Scheme, the Intersect allocation scheme, and the UNSW HPC at NCI Scheme. Alex Sen Gupta acknowledges funding from the Australian Research Council (DP180101251, DP180100048, DP180102357). Daniel Argüeso was supported by the European Union's REHIPRE project H2020-MSCA-IF-2016-743547) and the COASTEPS project (CGL2017-82868-R MEIC/AEI/EU FEDER) financed by the Spanish Government and the EU FEDER fund
Uncontrolled Keywords: Atmospheric lows, Air-sea feedbacks, Ocean mesoscales, Australian East Coast, Dynamical downscaling, Tropical storms
Subjects: F700 Ocean Sciences
F800 Physical and Terrestrial Geographical and Environmental Sciences
Department: Faculties > Engineering and Environment > Geography and Environmental Sciences
Depositing User: Rachel Branson
Date Deposited: 04 Oct 2021 10:27
Last Modified: 20 Oct 2021 14:00
URI: http://nrl.northumbria.ac.uk/id/eprint/47412

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