Structure of SST and Surface Wind Variability during Indian Ocean Dipole Mode Events: COADS Observations*

Saji, N. H.; Yamagata, Toshio

doi:10.1175/1520-0442(2003)016<2735:sosasw>2.0.co;2

Cited by 299 publications

(342 citation statements)

References 43 publications

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“…Put together, Figures 7 and 8 clearly reveal that the east-west SST anomalies in the IO are coupled to the atmospheric circulation (Saji et al, 1999;Webster et al, 1999;Saji and Yamagata, 2003b). These changes in the SST cause local air-sea interactions in the region.…”

Section: Sst Anomalies Associated With Active Dipole Eventsmentioning

confidence: 81%

“…The IODM is characterized by anomalous cooling of SSTs in the southeastern equatorial IO off Sumatra and an anomalous warming in the western equatorial IO (Saji et al, 1999). In response to these SST changes, cooler waters in the eastern IO give rise to easterly winds along the equator, enhancing the cooling in the eastern equatorial IO and promoting warming in the western equatorial IO (Webster et al, 1999;Saji and Yamagata, 2003b). Further, in response to this, convection over the eastern (western) tropical IO is suppressed (enhanced) as the easterly wind anomaly over the central IO is intensified (Iizuka et al, 2000).…”

Section: Iodm and Its Variabilitymentioning

confidence: 99%

See 1 more Smart Citation

Northeast monsoon rainfall variability over south peninsular India vis‐à‐vis the Indian Ocean dipole mode

Kripalani

Kumar

2004

Intl Journal of Climatology

189

141

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Whereas the June through to September southwest summer monsoon season over the Indian subcontinent has been the main focus of research, the October through to December northeast monsoon season over south peninsular India has received less attention. Hence, this study focuses on the northeast monsoon rainfall (NEMR) variability using historical data for a 131 year period and its relationship with the neighbouring Indian Ocean sea-surface temperature (SST).Based on the observed available rainfall data, a time series of NEMR over the coherent south peninsular India has been developed. Similarly, an index to quantify the Indian Ocean dipole mode (IODM), exhibiting warm (cool) waters over the equatorial western (southeastern) Indian Ocean, has been developed using GISST data for the same period. The dynamics of the NEMR-IODM relationship are examined with the National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis data.Interannual and decadal variabilities in NEMR reveal alternate epochs of above-and below-normal rainfall. The epochs tend to last for about a decade or two. Rainfall epochs near the equatorial Indian Ocean tend to last for about a decade. No long-term trends in NEMR are noted. On the other hand, the decadal variability in the IODM reveals a dominance of the negative phase during the earlier decades (1880-1920) and a positive phase during recent decades , with suppressed activity in between. Long-term variability in the IODM clearly reveals an increasing trend, which could be related to greenhouse warming. Further, the NEMR variability is enhanced during the decades when the IODM exhibits its active phase, and is suppressed during the decades when the IODM is inactive.The NEMR and the IODM are directly related, suggesting that the positive (negative) phase enhances (suppresses) the northeast monsoon activity. During the positive phase, the anomalous flow pattern shows winds converging and suggesting moisture transport from the southeast Indian Ocean and the Bay of Bengal towards south peninsular India. In contrast, the negative phase reveals winds diverging and transporting moisture away from the south Indian region. The anomalous SST and circulation features associated with the positive IOD/excess rainfall and negative IOD/deficient rainfall are consistent and clearly bring out the coupled ocean-atmosphere dynamics over the Indian Ocean. These results show the direct influence of the IODM phenomenon on the interannual and decadal NEMR variability over south India.

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Section: Sst Anomalies Associated With Active Dipole Eventsmentioning

confidence: 81%

Section: Iodm and Its Variabilitymentioning

confidence: 99%

Northeast monsoon rainfall variability over south peninsular India vis‐à‐vis the Indian Ocean dipole mode

Kripalani

Kumar

2004

Intl Journal of Climatology

189

141

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“…Hence, they concluded that the El Niñ o and Southern Oscillation are more loosely coupled than numerous past studies would suggest. The motivation of the present short article is due to the fact that the Indian Ocean Dipole (IOD) discovered recently (Saji et al 1999;Webster et al 1999;Behera et al 1999;Iizuka et al 2000;Yamagata et al 2002), has suggested a new role of the Indian Ocean in determining the sea level pressure oscillation over the Asia-Pacific sector. Since its existence has come to the light very recently, a brief description of the Indian Ocean phenomenon is provided here.…”

Section: Introductionmentioning

confidence: 96%

“…Since its existence has come to the light very recently, a brief description of the Indian Ocean phenomenon is provided here. Saji et al (1999) found that the coupled ocean-atmosphere phenomenon evolves with an east-west dipole in the SST anomaly, and named it the Indian Ocean Dipole. The Dipole Mode Index (DMI) is thus defined as the SST anomaly difference between the eastern and the western tropical Indian Ocean (see insets in Fig.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Indian Ocean Dipole on the Southern Oscillation.

Behera¹,

Yamagata²

2003

Journal of the Meteorological Society of Japan

201

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The influence of the Indian Ocean Dipole (IOD) on the interannual atmospheric pressure variability of the Indo-Pacific sector is investigated. Statistical correlation between the IOD index and the global sea level pressure anomalies demonstrates that loadings of opposite polarity occupy the western and the eastern parts of the Indian Ocean. The area of positive correlation coefficient in the eastern part even extends to the Australian region, and the IOD index has a peak correlation coefficient of about 0.4 with the Darwin pressure index, i.e. the western pole of the Southern Oscillation, when the former leads the latter by one month. The correlation analysis with seasonally stratified data further confirms the lead role of the IOD. The IOD-Darwin relation has undergone interdecadal changes; in the last 50 years the correlation is highest during the most recent decade of 1990-99, and weakest during 1980-89.

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“…An IOD event usually develops from June, and peaks at September-November (SON) (Saji et al 1999). During a positive IOD (pIOD) event, easterly wind anomalies occur over the central equatorial Indian Ocean with negative rainfall and SST anomalies off the Sumatra-Java coast, and vice versa for a negative IOD (nIOD) event (Saji and Yamagata 2003a). Due to the strong equatorial wind anomalies and SST anomalies across the Indian Ocean basin, IOD can significantly modulate the atmospheric circulation, which results in a series of climate anomalies including droughts, floods and also effects on societies and economics such as agriculture, water resources, forestry wildfires, and the spread of insects and waterborne diseases over the Indian Ocean and the surrounding areas (Ashok et al 2001;Saji and Yamagata 2003b;Behera et al 2005;Cai et al 2009, Abstract The study of Equatorial Undercurrent (EUC) has attracted a broad attention in recent years due to its strong response and feedback to the Indian Ocean Dipole.…”

Section: Introductionmentioning

confidence: 99%

Impacts of the IOD-associated temperature and salinity anomalies on the intermittent equatorial undercurrent anomalies

Liang

Tang

et al. 2017

Clim Dyn

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Structure of SST and Surface Wind Variability during Indian Ocean Dipole Mode Events: COADS Observations*

Cited by 299 publications

References 43 publications

Northeast monsoon rainfall variability over south peninsular India vis‐à‐vis the Indian Ocean dipole mode

Northeast monsoon rainfall variability over south peninsular India vis‐à‐vis the Indian Ocean dipole mode

Influence of the Indian Ocean Dipole on the Southern Oscillation.

Impacts of the IOD-associated temperature and salinity anomalies on the intermittent equatorial undercurrent anomalies

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