Abrupt termination of the 1997–98 El Niño in response to a Madden–Julian oscillation

Takayabu, Yukari N.; Iguchi, Toshio; Kachi, Misako; Shibata, Akira; Kanzawa, Hiroshi

doi:10.1038/46254

Cited by 255 publications

(138 citation statements)

References 16 publications

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“…Results during pre-La Ni na are more ambiguous than those of the rest of the events, suggesting that the MJO during pre-La Ni na does not significantly prepare La Ni na conditions, but may trigger La Ni na onset through abrupt upwelling in the eastern Pacific as indicated in Takayabu et al (1999).…”

Section: Resultsmentioning

confidence: 99%

“…In contrast to the WWBs, strengthening of surface easterly winds associated with intraseasonal variations that propagate faster than the MJO, sometimes called convectively coupled Kelvin waves, triggered El Ni no termination (Takayabu et al 1999;McPhaden 2008). Thus, intraseasonal variations may not have unified behaviors or impacts on ENSO.…”

Section: Introductionmentioning

confidence: 99%

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The Oceanic Response to the Madden-Julian Oscillation and ENSO

Seiki

Takayabu

Yoneyama

et al. 2009

SOLA

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Oceanic responses to relatively strong MaddenJulian Oscillations (MJOs) and background winds controlled by El Ni no-Southern Oscillation (ENSO) are examined. The MJO's arrival excites dominant downwelling and upwelling Kelvin waves during El Ni no developing (pre-El Ni no: PEN) and other (non-PEN) phases, respectively. These opposite signals come from background wind directions under different ENSO phases and exert opposite impacts on SST. In addition, MJO convection itself develops accompanied by larger surface wind variations during PEN phases, which can be related to the interactive amplifications of synopticand planetary-scale disturbances when westerly wind bursts occur. Consequently, the strength of westerly forcing and its oceanic response during PEN phases are larger than that of the corresponding easterly forcing and its response during non-PEN phases. These results suggest that modulations of MJO amplitude and structure under the background westerly and easterly winds associated with ENSO phases exert opposite but asymmetric impacts on the ocean.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Oceanic Response to the Madden-Julian Oscillation and ENSO

Seiki

Takayabu

Yoneyama

et al. 2009

SOLA

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“…The effects of the zonal flow vertical shears on large-scale equatorial waves also have long histories as one of the key elements in understanding tropical dynamics (e.g., Lindzen 1970; Kasahara and Silva Dias 1986;Wang and Xie 1996). The recent work of Takayabu et al (1999) that showed the role of the MJO in the abrupt termination of the 1997-98 El Niñ o, emphasized the importance of zonal wind vertical shear in the MJO structure itself.…”

Section: Categorization Of Sounding Datamentioning

confidence: 99%

Moisture Variability over the Tropical Western Pacific Ocean

Yoneyama

2003

Journal of the Meteorological Society of Japan

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In this paper, we study the characteristics of moisture variability over the tropical western Pacific warm pool region using sounding data obtained through the use of research vessels. Data used here were collected in both boreal summer and winter seasons over a nine-year period from 1993 through 2001. Sounding data are categorized into five zonal wind vertical shear modes, and then examined for common and singular features of moisture variability.The results show frequent occurrences of high relative humidity centered around 945 hPa, and 560 hPa, for any wind shear conditions, as previously found in the Tropical Ocean and Global Atmosphere/Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) studies. We also found another small peak at 845 hPa in low-level easterly conditions. The degree of these features is modulated by wind shear mode differences. An interesting feature is that the variation of total precipitable water is well represented by the synoptic scale mid-tropospheric moisture variation. However, a close relation between the total moisture budget and the moisture variation in the boundary layer is also obtained for a time scale of less than a few days (especially the diurnal cycle).We investigated extremely dry air conditions as one factor modulating mid-tropospheric moisture. Backward air parcel trajectories show that there are two major routes for the intrusion of dry air over the warm pool. In the first, the air parcel could be traced back to higher latitudes and the upper troposphere. For this type, anticyclonic equatorward flow associated with developing mid-latitude baroclinic waves, such as Rossby wave breaking, is responsible for injecting subtropical dry air into the Tropics-as proposed by Yoneyama and Parsons for TOGA COARE dry events. In the second type, the air parcel could be traced back to the upper troposphere, but within lower latitudes in the central-eastern Pacific. For this case, the air parcel originates from the trade winds that passed over the region where dry air was injected by the anticyclonic equatorward flow associated with the baroclinic wave development in the subtropical region.The relationship between dry air conditions and large-scale features is also discussed.

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“…On the one hand, pronounced MJO events produce westerly wind passage in the western Pacific, a key factor for the onset and development of ENSO (Harrison and Schopf, 1984;Kessler et al, 1995;Belamari et al, 2003;Wang et al, 2013). On the other hand, ENSO may impact the evolution of the MJO in space and time through changing the background convection in the tropical Pacific (Hendon et al, 1998;Takayabu et al, 1999;Tam and Lau, 2005;Pohl and Matthews, 2007;Roundy and Kravitz, 2009). …”

Section: Introductionmentioning

confidence: 99%

Contrasting Madden–Julian Oscillation activity during various stages of EP and CP El Niños

Feng

Liu

Chen

et al. 2014

Atmospheric Science Letters

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This study revisits the relations between Madden-Julian Oscillation (MJO) and El Niño that is classified as eastern Pacific (EP) and central Pacific (CP) types. During an EP-type event that produces lasting dry conditions in the Maritime Continent and western Pacific, the MJO activity is weak especially in its 4th-6th phases as a strong response. In contrast during CP-type episodes, the MJO exhibits notably enhanced and suppressed amplitudes in its different phases. The low-level westerly wind anomalies of enhanced MJO impact the CP-type El Niño more than vice versa.

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Abrupt termination of the 1997–98 El Niño in response to a Madden–Julian oscillation

Cited by 255 publications

References 16 publications

The Oceanic Response to the Madden-Julian Oscillation and ENSO

The Oceanic Response to the Madden-Julian Oscillation and ENSO

Moisture Variability over the Tropical Western Pacific Ocean

Contrasting Madden–Julian Oscillation activity during various stages of EP and CP El Niños

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