Spatiotemporal variation of surface eddy kinetic energy in the South Australian Basin

doi:10.3969/j.issn.1001-909X.2023.03.003

Abstract

Abstract:

The spatiotemporal variation of surface eddy kinetic energy (EKE) in the South Australian Basin was studied using sea level anomaly during 1993-2019. The results show that in spatial scale there are two regions of high EKE: one to the west, and one to the east. On the seasonal scale, surface EKE is the strongest in austral winter with a maximum (57±9 cm²/s²) in July and the weakest in autumn with a minimum (40±5 cm²/s²) in March. On the interannual scale, surface EKE is related to El Niño-Southern Oscillation (ENSO) and Southern Annular Mode (SAM). Partial correlation analysis indicates that surface EKE shows negative correlations with ENSO, lagging the Niño3.4 index by 9 months, and EKE is significantly weakened (strengthened) in the decaying year of El Niño (La Niña). Meanwhile, surface EKE shows positive correlations with SAM, lagging SAM index by 14 months, and EKE is significantly strengthened (weakened) in the next year of the positive (negative) SAM phases.

Key words: eddy kinetic energy, spatiotemporal variation, El Niño-Southern Oscillation (ENSO), Southern Annular Mode (SAM), South Australian Basin

CLC Number:

P731.2

LIU Jia, ZHENG Shaojun, YAN Li, CHEN Hangbiao, LIU Tingzhen. Spatiotemporal variation of surface eddy kinetic energy in the South Australian Basin[J]. Journal of Marine Sciences, 2023, 41(3): 22-33.

Figures/Tables 13

Fig.1 Schematic circulation in the South Australian Basin and adjacent regions (Figure was modified from reference[4].)

Fig.2 Multi-year average distribution of surface eddy kinetic energy calculated from AVISO in the South Australian Basin

Fig.3 Monthly mean surface EKE anomaly distribution calculated from AVISO in the South Australian Basin during 1993-2019

Fig.4 Monthly mean variation of surface EKE calculated from AVISO in the South Australian Basin during 1993-2019

Fig.5 Monthly mean geostrophic currents and geostrophic speed distribution in the South Australian Basin

Fig.6 Time series of surface EKE (a), EKE anomaly (b), and one year low-pass filtered EKE anomaly (c), respectively in the South Australian Basin

Fig.7 Time series of one year low-pass filtered EKE anomaly and Ni?o3.4 index (a), IOB index (b), IOD index (c) and SAM index (d) in the South Australian Basin (The red indicates positive EKE anomaly and blue indicates negative EKE anomaly.)

Fig.8 The correlations between one year low-pass filtered EKE anomaly and Ni?o3.4 index (a), IOB index (b), IOD index (c), and SAM index (d) (The positive value of lag time indicates that EKE anomaly lags the index and a negative value indicates that EKE anomaly leads the index, and dash lines represent 95% confidence level.)

Fig.9 The partial correlations between one year low-pass filtered EKE anomaly and Ni?o3.4 index, after removing the SAM (a), between one year low-pass filtered EKE anomaly and SAM index, after removing the ENSO (b) (The positive value of lag time indicates that EKE anomaly lags the index and a negative value indicates that EKE anomaly leads the index, and dash lines represent 95% confidence level.)

Fig.10 Spatial distribution of surface EKE anomaly during El Ni?o periods

Fig.11 Spatial distribution of surface EKE anomaly during La Ni?a periods

Fig.12 Spatial distribution of surface EKE anomaly during positive SAM phases

Fig.13 Spatial distribution of surface EKE anomaly during negative SAM phases

References 29

[1]	SCHILLER A, OKE P R, BRASSINGTON G, et al. Eddy-resolving ocean circulation in the Asian-Australian region inferred from an ocean reanalysis effort[J]. Progress in Oceanography, 2008, 76(3): 334-365. DOI URL
[2]	MIDDLETON J F, CIRANO M. A northern boundary current along Australia’s southern shelves: The Flinders Current[J]. Journal of Geophysical Research, 2002, 107(C9): 3129.
[3]	FU L L. Pattern and velocity of propagation of the global ocean eddy variability[J]. Journal of Geophysical Research, 2009, 114(C11): C11017.
[4]	OKE P R, GRIFFIN D A, RYKOVA T, et al. Ocean circulation in the Great Australian Bight in an eddy-resolving ocean reanalysis: The eddy field, seasonal and interannual variability[J]. Deep Sea Research Part II: Topical Studies in Oceanography, 2018, 157/158: 11-26. DOI URL
[5]	RIDGWAY K R, CONDIE S A. The 5500-km-long boundary flow off western and southern Australia[J]. Journal of Geophysical Research, 2004, 109(C4): C04017.
[6]	MIDDLETON J F, BYE J A T. A review of the shelf-slope circulation along Australia’s southern shelves: Cape Leeuwin to Portland[J]. Progress in Oceanography, 2007, 75(1): 1-41. DOI URL
[7]	GODFREY J S, VAUDREY D J, HAHN S D. Observations of the shelf-edge current south of Australia, winter 1982[J]. Journal of Physical Oceanography, 1986, 16(4): 668-679. DOI URL
[8]	CRESSWELL G R, GRIFFIN D A. The Leeuwin Current, eddies and sub-Antarctic waters off south-western Australia[J]. Marine and Freshwater Research, 2004, 55(3): 267. DOI URL
[9]	SEBILLE E V, ENGLAND M H, ZIKA J D, et al. Tasman leakage in a fine-resolution ocean model[J]. Geophysical Research Letters, 2012, 39(6): L06601.
[10]	PILO G S, MATA M M, AZEVEDO J L L. Eddy surface properties and propagation at Southern Hemisphere western boundary current systems[J]. Ocean Science, 2015, 11(4): 629-641. DOI URL
[11]	EDEN C, BÖNING C. Sources of eddy kinetic energy in the Labrador Sea[J]. Journal of Physical Oceanography, 2002, 32(12): 3346-3363. DOI URL
[12]	CHEN X A, QIU B, CHEN S M, et al. Seasonal eddy kinetic energy modulations along the North Equatorial Countercurrent in the western Pacific[J]. Journal of Geophysical Research: Oceans, 2015, 120(9): 6351-6362. DOI URL
[13]	ZHENG S J, FENG M, DU Y, et al. Interannual variability of eddy kinetic energy in the subtropical southeast Indian Ocean associated with the El Niño-Southern Oscillation[J]. Journal of Geophysical Research: Oceans, 2018, 123(2): 1048-1061. DOI URL
[14]	ZHANG N N, LIU G Q, LIU Q Y, et al. Spatiotemporal variations of mesoscale eddies in the southeast Indian Ocean[J]. Journal of Geophysical Research: Oceans, 2020, 125(8): e2019JC015712.
[15]	CHU X Q, DONG C M, QI Y Q. The influence of ENSO on an oceanic eddy pair in the South China Sea[J]. Journal of Geophysical Research: Oceans, 2017, 122(3): 1643-1652. DOI URL
[16]	ZHENG S J, FENG M, DU Y, et al. Annual and interannual variability of the tropical instability vortices in the equatorial eastern Pacific observed from Lagrangian surface drifters[J]. Journal of Climate, 2016, 29(24): 9163-9177. DOI URL
[17]	曾伟强, 张书文, 马永贵, 等. 1993—2017年南海中尺度涡特征分析[J]. 广东海洋大学学报, 2019, 39(5):96-106.
	ZENG W Q, ZHANG S W, MA Y G, et al. Analysis of mesoscale eddy characteristics in the South China Sea from 1993 to 2017[J]. Journal of Guangdong Ocean University, 2019, 39(5): 96-106.
[18]	FENG M, MCPHADEN M J, XIE S P, et al. La Niña forces unprecedented Leeuwin Current warming in 2011[J]. Scientific Reports, 2013, 3: 1277. DOI PMID
[19]	WIJFFELS S, MEYERS G. An intersection of oceanic waveguides: Variability in the Indonesian throughflow region[J]. Journal of Physical Oceanography, 2004, 34(5): 1232-1253. DOI URL
[20]	FAN L L, XU J J, HAN L G. Impacts of onset time of El Niño events on summer rainfall over southeastern Australia during 1980-2017[J]. Atmosphere, 2019, 10(3): 139. DOI URL
[21]	茅威. ENSO与IOD对澳大利亚南半球冬春季干旱的影响[D]. 南京: 南京信息工程大学, 2021.
	MAO W. Effects of ENSO and IOD on drought in austral winter and spring of Australia[D]. Nanjing: Nanjing University of Information Science & Technology, 2021.
[22]	王忠鹏. 南半球热带外气候变量与两种形态ENSO的联系及ENSO与SAM相关关系研究[D]. 上海: 上海交通大学, 2019.
	WANG Z P. Study on the linkage of the southern hemisphere extratropical climate variability to two types of ENSO and the relationship between ENSO and SAM[D]. Shanghai: Shanghai Jiao Tong University, 2019.
[23]	PEPLER A, TIMBAL B, RAKICH C, et al. Indian Ocean dipole overrides ENSO’s influence on cool season rainfall across the eastern seaboard of Australia[J]. Journal of Climate, 2014, 27(10): 3816-3826. DOI URL
[24]	CAI W J, VAN RENSCH P. Austral summer teleconnections of Indo-Pacific variability: Their nonlinearity and impacts on Australian climate[J]. Journal of Climate, 2013, 26(9): 2796-2810. DOI URL
[25]	TRENBERTH K E, CARON J M, STEPANIAK D P, et al. Evolution of El Niño-Southern Oscillation and global atmospheric surface temperatures[J]. Journal of Geophysical Research: Atmospheres, 2002, 107(D8): 4065.
[26]	杨丽娜, 吴奇儒, 陈旺, 等. 太平洋南赤道流体积输运的年际变异[J]. 广东海洋大学学报, 2021, 41(6):36-43.
	YANG L N, WU Q R, CHEN W, et al. Interannual variability of the volume transport of the Pacific south equatorial current[J]. Journal of Guangdong Ocean University, 2021, 41(6): 36-43.
[27]	REN H L, LU B, WAN J H, et al. Identification standard for ENSO events and its application to climate monitoring and prediction in China[J]. Journal of Meteorological Research, 2018, 32(6): 923-936. DOI
[28]	郭飞燕. 热带印度洋海温年际变化主模态的分类及其与ENSO的联系[D]. 青岛: 中国海洋大学, 2015.
	GUO F Y. Classfication of the SST interannual variability major modes of tropical Indian Ocean and their relations with ENSO[D]. Qingdao: Ocean University of China, 2015.
[29]	殷鑫, 吴小飞. 前冬印度洋海盆一致模对ENSO衰减期华南春季降水的影响[J]. 高原山地气象研究, 2022, 42(4):49-59.
	YIN X, WU X F. Influence of Indian Ocean Basin on South China spring rainfall during the decaying phase of ENSO in preceding winter[J]. Plateau and Mountain Meteorology Research, 2022, 42(4): 49-59.