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How does the indian ocean subtropical dipole trigger the tropical indian ocean dipole via the Mascarene high?

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Acta oceanologica Sinica 2014年第1期33卷 64-76页

作者： FENG Junqiao HU Dunxin YU Lejiang Institute of oceanology Chinese Academy of Sciences Key Laboratory of ocean Circulation and Wave Chinese Academy of Sciences Applied Hydrometeorological Research Institute Nanjing University of Information Science and Technology

The variation in the indian ocean is investigated using Hadley center sea surface temperature（SST） data during the period 1958–*** the first empirical orthogonal function（EOF） modes of the SST anomalies（SSTA） in different domains represent the basin-wide warming and are closely related to the Pacific El Ni o– Southern Oscillation（ENSO） *** examination suggests that the impact of ENSO on the tropical indian ocean is stronger than that on the southern indian *** second EOF modes in different domains show different *** shows a clear east-west SSTA dipole pattern in the tropical indian ocean（indian ocean dipole,IOD）,and a southwest-northeast SSTA dipole in the southern indian ocean（indian ocean subtropical dipole,IOSD）.It is further revealed that the IOSD is also the main structure of the second EOF mode on the whole basin-scale,in which the IOD pattern does not appear.A correlation analysis indicates that an IOSD event observed during the austral summer is highly correlated to the IOD event peaking about 9 months *** of the possible physical mechanisms underlying this highly significant statistical relationship is *** IOSD and the IOD can occur in sequence with the help of the Mascarene *** SSTA in the southwestern indian ocean persists for several seasons after the mature phase of the IOSD event,likely due to the positive wind–evaporation–SST feedback *** Mascarene high will be weakened or intensified by this SSTA,which can affect the atmosphere in the tropical region by *** pressure gradient between the Mascarene high and the monsoon trough in the tropical indian ocean increases（decreases）.Hence,an anticyclone（cyclone） circulation appears over the Arabian Sea-India *** easterly or westerly anomalies appear in the equatorial indian ocean,inducing the onset stage of the *** study shows that the SSTA associated with the IOSD can lead to the onset of IOD with the aid of atmosphe

关键词： indian ocean dipole indian ocean subtropical dipole Mascarene high

Revisiting the Seasonal Evolution of the indian ocean dipole from the Perspective of Process-Based Decomposition

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Journal of ocean University of China 2023年第6期22卷 1453-1463页

作者： ZHANG Guangli FAN Hanjie HUANG Ke LONG Tong SONG Wei XIE Qiang School of Marine Sciences Sun-Yat Sen UniversitySouthern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Institute of Deep-Sea Sciences and Engineering Chinese Academy of SciencesSanya 572000China State Key Laboratory of Tropical oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Laboratory for Regional oceanography and Numerical Modeling Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China

The seasonal phase-locking feature of the indian ocean dipole(IOD)is well ***,the seasonality ten-dency of sea surface temperature anomalies(SSTAs)during the development of the IOD has not been widely *** SSTA tendencies over the two centers of the IOD peak in September-October-November are of different monthly *** SSTA tendency over the west pole is small before June-July-August but dramatically increases in ***,the SSTA tendency over the east pole gradually increases before June-July-August and decreases since *** growth rate attribution of the SSTAs is achieved by examining the roles of radiative and non-radiative air-sea coupled thermodynamic processes through the climate feedback-response analysis method(CFRAM).The CFRAM results indicate that oceanic dynamic processes largely contribute to the total SSTA tendency for initiating and fueling the IOD SSTAs,similar to previous ***,these results cannot ex-plain the monthly amplitudes of SSTA *** negative feedback processes(cloud radiative feedback,atmospheric dynamic processes,surface sensible,and latent heat flux)together play a damping role opposite to the SSTA ***,the sea surface temperature-water vapor feedback shows positive ***,variations in SSTAs can change water vapor con-centrations through evaporation,resulting in anomalous longwave radiation that amplifies the initial SSTAs through positive *** effect of water vapor feedback is well in-phase with the monthly amplitudes of SSTA tendency,suggesting that the water vapor feedback might modulate the seasonally dependent SSTA tendency during the development of the IOD.

关键词： indian ocean dipole climate feedback-response analysis method growth rate of the sea surface temperature anomaly seasonally dependent sea surface temperature anomaly water vapor feedback

Asymmetry of upper ocean salinity response to the indian ocean dipole events as seen from ECCO simulation

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Acta oceanologica Sinica 2016年第7期35卷 42-49页

作者： ZHANG Ying DU Yan ZHANG Yuhong GAO Shan State Key Laboratory of Tropical oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory of ocean Circulation and Waves Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China

The interannual variability of salinity and associated ocean dynamics in the equatorial indian ocean is analyzed using observations and numerical simulations by the Estimating the Circulation and Climate of the ocean （ECCO） model. The results show that salinity anomalies in the upper ocean are asymmetrically associated with the indian ocean dipole （IOD） events, with stronger response during their positive phases. Further investigations reveal that zonal currents along the equator, the Wyrtki jets, dominate the salinity transport. During the positive IOD events, the Wyrtld jets have stronger westward anomalies. The positive skewness of the IOD explains that the amplitude of the anomalous Wyrtld jets is stronger in the positive IOD events than that in the negative events.

关键词： Wyrtld jets salinity transport indian ocean dipole asymmetry

The Positive indian ocean dipole–like Response in the Tropical indian ocean to Global Warming

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Advances in Atmospheric Sciences 2016年第4期33卷 476-488页

作者： Yiyong LUO Jian LU Fukai LIU Xiuquan WAN Physical oceanography Laboratory Ocean University of China Atmospheric Sciences & Global Change Division Pacific Northwest National Laboratory

Climate models project a positive indian ocean dipole （plOD）-like SST response in the tropical indian ocean to global warming, By employing the Community Earth System Model and applying an overriding technique to its ocean component （version 2 of the Parallel ocean Program）, this study investigates the similarities and differences of the formation mechanisms for the changes in the tropical indian ocean during the plOD versus global warming. Results show that their formation processes and related seasonality are quite similar; in particular, wind-thermocline-SST feedback is the leading mechanism in producing the anomalous cooling over the eastern tropics in both cases. Some differences are also fbund, including the fact that the cooling effect of the vertical advection over the eastern tropical indian ocean is dominated by the anomalous vertical velocity during the plOD but by the anomalous upper-ocean stratification under global warming. These findings are lhrther examined through an analysis of the mixed layer heat budget.

关键词： indian ocean dipole positive indian ocean dipole-like response global warming Bjerknes feedback

Relationship between indian ocean dipole and ENSO and their connection with the onset of South China Sea summer monsoon

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Acta oceanologica Sinica 2006年第6期25卷 22-32页

作者： LIANG Zhaoning WEN Zhiping LIANG Jieyi WU Liji WU Naigeng Research Center for Monsoon and Environment/Department of Atmospheric Sciences Sun Yat-sen University Guangzhou 510275 China

Using Reynolds and Smith 1950 - 1998 re-constructed monthly-mean SST to discuss the relationship between the ENSO and indian ocean dipole （IOD） and their possible connection with the onset of South China Sea summer monsoon（ SCSSM）, the results are obtained as follows ： Most of IOD events have a closely positive relation to simultaneous ENSO events in summer and autumn. IOD events in autumn （ mature phase） are also closely related to ENSO events in winter （ mature phase）. When these two kinds of events happen in phase, i.e. , positive （negative） IOD events are coupled with E1 Nifío （La Nifía） events, they are always followed by late （ or early） onsets of SCSSM. On the contrary, when these two kinds of events happen out of phase, i.e. positive （negative） IOD events are coupled with La Nifia （ E1 Nifío） events, they are followed by normal onsets of SCSSM. In addition, single IOD events or single ENSO events cannot correspond well to the abnormal onset of SCSSM.

关键词： indian ocean dipole ENSO South China Sea summer monsoon early or late onset

ENSO and indian ocean dipole mode in three coupled GCMs

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Acta oceanologica Sinica 2004年第4期23卷 581-595页

作者： YUYongqiang LIUXiying LASG InstituteofAtmosphericPhysicsChineseAcademyofSciencesBeijing100029China

The simulated ENSO and indian ocean dipole (IOD) mode events from three coupled GCMs with the same oceaniccomponent model, CPM0, CPM1 and FGCM0, are compared. The only difference between the CPM0 and theCPM1 comes from the coupling scheme at the airsea interface, e.g., flux anomaly coupling scheme for the former anddirect coupling scheme for the latter. The FGCM0 is also a directly coupled GCM, but its atmospheric componentmodel is the NCAR CCM3 rather than the NCC T63AGCM as in the other two coupled GCMs CPM0 and *** three coupled models show El Nio-like interannual variability in the tropic Pacific, but the FGCM0 shows a bitstronger amplitude of El Nio events and both the CPM0 and the CPM1 show much weaker amplitude than theobserved one. In the meanwhile, the quasi-biennial variability dominates in the FGCM0 simulations, and 4 a andlonger periods are significant in both the CPM0 and CPM1 models. As the El Nio events simulated by the threecoupled GCMs, the simulated indian ocean dipole mode events are stronger from the coupled model FGCM0 andweaker from both the CPM0 and CPM1 models than those from observation.

关键词： ENSO indian ocean dipole coupled models

VARIABILITY OF THE INTER-ANNUAL RELATIONSHIP BETWEEN THE indian ocean dipole AND THE HUAXI REGION’S AUTUMN PRECIPITATION

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Journal of Tropical Meteorology 2019年第4期25卷 498-518页

作者： LIU Jia ZHAO Pcng-guo MA Zhen-feng GE Fei XIAO Hui WANG Chun-xue XU Yuan-xin Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province Chengdu 610072 China Climate Center of Sichuan Province Chengdu 610072 China Plateau Atmosphere and Environment Key Laboratory of Sichuan Province College of Atmospheric ScienceChengdu University of Information TechnologyChengdu 610225 China Guangzhou Institute of Tropical and Marine Meteorology CMAGuangzhou 510641 China

The moving-window correlation analysis was applied to investigate the relationship between autumn indian ocean dipole(IOD) events and the synchronous autumn precipitation in the Huaxi region(western China), China,based on daily precipitation, sea surface temperature(SST), and atmospheric circulation data from 1960 to 2012. The correlation curves of IOD and the early modulation of the Huaxi region's autumn precipitation indicated a behavioral change in the 1970 s. Between 1960 and 1979, when the IOD was in a positive phase during autumn, circulations changed from a "W"shape to an "M"shape at 500 hPa in the middle-high latitude region in Asia. A northwest flow allowed a cold flux to reach Sichuan province. The positive anomaly of water vapor flux transported from the western Pacific to Huaxi region strengthened, causing a precipitation increase in the east Huaxi region. Between 1980 and 1999,when the IOD in autumn was also in the positive phase, the atmospheric circulation was a "W"shape at 500 hPa. In this scenario, the positive anomaly of the water vapor flux transported from the Bay of Bengal to Huaxi region strengthened, causing a precipitation increase in the west Huaxi region. In summary, the indian ocean switched from a cold phase to a warm phase during the 1970 s, causing the instability of the inter-annual relationship between IOD and the autumn rainfall in Huaxi region.

关键词： Huaxi region's autumn precipitation indian ocean dipole Multiple-Taper Method-Singular Value Decomposition phase water vapor flux transported

THE WARMING MECHANISM IN THE SOUTHERN ARABIAN SEA DURING THE DEVELOPMENT OF indian ocean dipole EVENTS

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Journal of Tropical Meteorology 2016年第2期22卷 159-171页

作者：桂发银李崇银谭言科黎鑫夏淋淋 College of Meteorology and oceanography PLA University of Science and Technology LASG Institute of Atmospheric PhysicsChinese Academy of Sciences

This study aims to explore the relative role of oceanic dynamics and surface heat fluxes in the warming of southern Arabian Sea and southwest indian ocean during the development of indian ocean dipole(IOD) events by using National Center for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR) daily reanalysis data and Global ocean Data Assimilation System(GODAS) monthly mean ocean reanalysis data from 1982 to2013,based on regression analysis,Empirical Orthogonal Function(EOF) analysis and combined with a 21/2layer dynamic upper-ocean *** results show that during the initial stage of IOD events,warm downwelling Rossby waves excited by an anomalous anticyclone over the west indian Peninsula,southwest indian ocean and southeast indian ocean lead to the warming of the mixed layer by reducing entrainment *** anomalous anticyclone over the west indian Peninsula weakens the wind over the Arabian Sea and Somali coast,which helps decrease the sea surface heat loss and shallow the surface mixed layer,and also contributes to the sea surface temperature(SST) warming in the southern Arabian Sea by inhibiting *** weakened winds increase the SST along the Somali coast by inhibiting upwelling and zonal *** wind and net sea surface heat flux anomalies are not significant over the southwest indian *** the antecedent stage of IOD events,the warming of the southern Arabian Sea is closely connected with the reduction of entrainment cooling caused by the Rossby waves and the weakened *** the appearance of an equatorial easterly wind anomaly,the warming of the southwest indian ocean is not only driven by weaker entrainment cooling caused by the Rossby waves,but also by the meridional heat transport carried by Ekman *** anomalous sea surface heat flux plays a key role to damp the warming of the west pole of the IOD.

关键词： Arabian Sea summer monsoon indian ocean dipole 21/2layer dynamic upper-ocean model

The Connection between the Sea Surface Height Anomaly Preceding the indian ocean dipole and Summer Rainfall in China

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Atmospheric and oceanic Science Letters 2015年第4期8卷 238-243页

作者： DUAN Xin-Yu LIU Na LI Shuanglin College of Atmospheric Science Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technology Nansen-Zhu International Research Centre Institute of Atmospheric Physics Chinese Academy of Sciences Climate Change Research Center Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

The sea surface height anomaly(SSHA) signals leading the fall indian ocean dipole(IOD) are investigated. The results suggest that, prior to the IOD by one year, a positive SSHA emerges over the western-central tropical Pacific(WCTP), which peaks during winter(January-February-March, JFM), persists into late spring and early summer(April-May-June, AMJ), and becomes weakened later on. An SSHA index, referred as to SSHA_WCTP, is defined as the averaged SSHA over the WCTP during JFM. The index is not only significantly positively correlated with the following-fall(September-October-November, SON) IOD index, but also is higher than the autocorrelation of the IOD index crossing the two different seasons. The connection of SSHA_ WCTP with following-summer rainfall in China is then explored. The results suggest that higher(lower) SSHA_ WCTP corresponds to increased(reduced) rainfall over southern coastal China, along with suppressed(increased) rainfall over the middle–lower reaches of the Yangtze River, North China, and the Xinjiang region of northwestern China. Mechanistically, following the preceding-winter higher(lower) SSHA_WCTP, the South Asia High and the Western Pacific Subtropical High are weakened(intensified), which results in the East Asian summer monsoon weakening(intensifying). Finally, the connection between SSHA_WCTP and El Ni?o-Southern Oscillation(ENSO) is analyzed. Despite a significant correlation, SSHA_WCTP is more closely connected with summer rainfall. This implies that the SSHA_WCTP index in the preceding winter is a more effective predictor of summer rainfall in comparison with ENSO.

关键词： sea surface height indian ocean dipole summer rainfall in China ENSO