气候变化领域集成服务门户(CCPortal): Indian Ocean Dipole Changes During the Last Interglacial Modulated by the Mean Oceanic Climatology

CCPortal

DOI	10.1029/2023GL106153
	Indian Ocean Dipole Changes During the Last Interglacial Modulated by the Mean Oceanic Climatology
	Liu, Shanshan; Yuan, Chaoxia; Behera, Swadhin; Luo, Jing-Jia; Yamagata, Toshio
发表日期	2024
ISSN	0094-8276
EISSN	1944-8007
起始页码	51
结束页码	1
卷号	51 期号:1
英文摘要	Investigating the Indian Ocean Dipole (IOD) during the Last Interglacial (LIG) can advance knowledge of IOD behaviors in orbitally-induced warmer-than-present scenarios. Based on multiple model outputs from the Paleoclimate Modeling Intercomparison Project Phase 4, the analysis suggests reduced frequencies of the IOD compared to the preindustrial period. Spatially, the whole growing and mature stages of the IOD feature suppressed variability over the west and westward expansions of eastern anomalies, while the eastern perturbation enhances only at the initial phase. The overall amplitude assessed by the dipole mode index shows only minor reductions. These changes are attributed to orbitally-induced enhancement in mean-state westward currents along the equator, which transport more anomalous cold water westward. In addition, the subdued El Nino-Southern Oscillation (ENSO) during the LIG is unlikely to cause a weakening of the IOD, in association with a less important role of ENSO in the formation of the IOD. The IOD is one of the leading modes of interannual climate variability in the tropical Indian Ocean, characterized by west-east contrasted sea surface temperature (SST) anomalies. The connection between changes in the IOD and mean states is an important issue to be addressed. This study examines IOD behaviors during an orbitally-induced warm scenario, the LIG (similar to 127 ka BP), using the preindustrial period as the baseline. The results suggest significant reductions in IOD frequencies and structural changes, with westward extended eastern cooling and spatially uniform suppression in western warming throughout the growing and mature stages, accompanied by intensified eastern cooling at the initial phase. The overall amplitude of the IOD, as measured by the dipole mode index, exhibits only minor reductions. The main mechanism behind the change lies in enhanced equatorial easterlies over the Indian Ocean, which are triggered by orbitally-induced amplifications in Pacific subtropical anticyclones and increases in northern Africa-South Asia summer monsoon precipitation. Subsequently, equatorial westward currents enhance, modulating the mean advection of SST anomalies during IOD events. Further composite analyses show that the concurrently subdued ENSO is unlikely to induce an IOD attenuation since the ENSO-IOD connections are diminished as indicated by decreased correlation coefficients. Spatial structural change and less frequency of Indian Ocean Dipole in Last Interglacial compared to preindustrial periodMain causes are that orbitally-induced enhancement of equatorial westward currents intensifies mean advection of anomalous cold waterThe concurrent suppression in El Nino-Southern Oscillation is unlikely to cause a weakening in the Indian Ocean Dipole
英文关键词	Indian Ocean; atmosphere-ocean interaction; tropical variability; Last Interglacial; numerical modeling; climate change
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:001138755100005
来源期刊	GEOPHYSICAL RESEARCH LETTERS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/306327
作者单位	Nanjing University of Information Science & Technology; Japan Agency for Marine-Earth Science & Technology (JAMSTEC)
推荐引用方式 GB/T 7714	Liu, Shanshan,Yuan, Chaoxia,Behera, Swadhin,et al. Indian Ocean Dipole Changes During the Last Interglacial Modulated by the Mean Oceanic Climatology[J],2024,51(1).
APA	Liu, Shanshan,Yuan, Chaoxia,Behera, Swadhin,Luo, Jing-Jia,&Yamagata, Toshio.(2024).Indian Ocean Dipole Changes During the Last Interglacial Modulated by the Mean Oceanic Climatology.GEOPHYSICAL RESEARCH LETTERS,51(1).
MLA	Liu, Shanshan,et al."Indian Ocean Dipole Changes During the Last Interglacial Modulated by the Mean Oceanic Climatology".GEOPHYSICAL RESEARCH LETTERS 51.1(2024).