Zonal Structure of Tropical Pacific Surface Salinity Anomalies Affects the Eastern and Central Pacific El Ni&ntilde;os Differently

doi:10.1029/2023GL105554

IOCAS-IR > 海洋环流与波动重点实验室

	Zonal Structure of Tropical Pacific Surface Salinity Anomalies Affects the Eastern and Central Pacific El Niños Differently
	Guan, Cong1,2 ; Tian, Feng 1,2; McPhaden, Michael J.3; Hu, Shijian 1,2; Wang, Fan1,2
	2023-11-16
发表期刊	GEOPHYSICAL RESEARCH LETTERS
ISSN	0094-8276
卷号	50 期号:21 页码:10
通讯作者	Wang, Fan(fwang@qdio.ac.cn)
摘要	Maximum sea surface salinity (SSS) anomalies are found in the central Pacific during the eastern Pacific El Nino (EPEN) and located further westward during the central Pacific El Nino (CPEN), but whether these differences affect event strengths is unclear. By performing ocean general circulation model experiments via modifying freshwater flux anomalies, we find salinity effects on surface warming during both types are highly sensitive to zonal locations of SSS anomalies, with the strongest warming induced by the SSS anomalies near the international dateline. Further analysis reveals that vertical mixing and entrainment dominate this temperature sensitivity, with the strongest response to SSS anomalies occurring in the central Pacific. The central-Pacific SSS anomalies increase EPEN warming by 0.15 degrees C while the westward-located SSS anomalies make little contribution to CPEN warming. Therefore, the distinct zonal structures of SSS anomalies facilitate stronger EPEN than the CPEN, increasing their difference in intensity by about 10%. The El Nino-Southern Oscillation (ENSO) is the strongest year-to-year climate variability in the planet. The central Pacific El Nino (CPEN) have been recognized in recent decades, with weaker surface warming located more westward, in contrast to the traditional eastern Pacific El Nino (EPEN). Previous studies have underscored various air-sea processes in shaping these differences, however, the impact of salinity remains unknown. Here based on ocean model experiments, we found the salinity effect on El Nino warming is very sensitive to zonal locations of salinity anomalies. The salinity anomalies located in the central Pacific are more effective in modulating local ocean vertical stratification, weakening the colder subsurface water into the mixed layer and further enhancing the surface warming. Therefore, the central equatorial Pacific-located salinity anomalies during EPEN contributes to its stronger warming than those west-located salinity anomalies during CPEN, enhancing the sea surface temperature difference between the two events by about 10%. Our results provide new insight in understanding the ENSO diversity and also its low-frequency variability, which may be helpful for interpreting more complex model simulations and for and predicting ENSO variations. Salinity anomalies in the central Pacific induce the strongest surface warming during both types of El Nino, tapering off to the east and westThe distinct sea surface salinity zonal structures between the two El Ninos amplify their difference in sea surface temperature magnitude by about 10%Salinity effects on vertical mixing and entrainment account for the different eastern Pacific and central Pacific El Nino responses
关键词	ENSO salinity tropical Pacific El Nino ENSO diversity
DOI	10.1029/2023GL105554
收录类别	SCI
语种	英语
资助项目	The authors thank the two anonymous reviewers for their constructive comments on the original version of this manuscript. This work was supported by the National Natural Science Foundation of China (Grants 42176008) and the Youth Innovation Promotion Assoc[42176008] ; National Natural Science Foundation of China[2023214] ; Youth Innovation Promotion Association of CAS[42221005] ; NSFC Innovative Group Grant[2022YFF0801401] ; NSFC Innovative Group Grant[5541] ; National Key Ramp;D program
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:001090432900001
出版者	AMER GEOPHYSICAL UNION
WOS关键词	HYBRID COUPLED MODEL ; FRESH-WATER FLUX ; BARRIER-LAYER ; TOGA DECADE ; PART I ; ENSO ; VARIABILITY ; NINO ; TEMPERATURE ; FEEDBACKS
引用统计
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/181541
专题	海洋环流与波动重点实验室
通讯作者	Wang, Fan
作者单位	1.Chinese Acad Sci, Inst Oceanol, Key Lab Ocean Circulat & Waves, Qingdao, Peoples R China 2.Laoshan Lab, Qingdao, Peoples R China 3.NOAA Pacific Marine Environm Lab, Seattle, WA USA
第一作者单位	海洋环流与波动重点实验室
通讯作者单位	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	Guan, Cong,Tian, Feng,McPhaden, Michael J.,et al. Zonal Structure of Tropical Pacific Surface Salinity Anomalies Affects the Eastern and Central Pacific El Niños Differently[J]. GEOPHYSICAL RESEARCH LETTERS,2023,50(21):10.
APA	Guan, Cong,Tian, Feng,McPhaden, Michael J.,Hu, Shijian,&Wang, Fan.(2023).Zonal Structure of Tropical Pacific Surface Salinity Anomalies Affects the Eastern and Central Pacific El Niños Differently.GEOPHYSICAL RESEARCH LETTERS,50(21),10.
MLA	Guan, Cong,et al."Zonal Structure of Tropical Pacific Surface Salinity Anomalies Affects the Eastern and Central Pacific El Niños Differently".GEOPHYSICAL RESEARCH LETTERS 50.21(2023):10.

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