Heat Content Variability Related to ENSO Events in the Pacific

Hasegawa, Takuya; Hanawa, Kimio

doi:10.1175/1520-0485(2003)033<0407:hcvrte>2.0.co;2

Cited by 56 publications

(60 citation statements)

References 42 publications

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“…Recent progresses obtained from the richer subsurface observations, GCM simulations, and theoretical works have suggested the importance of upper ocean heat content anomaly (UOHCA) in the tropical Pacific Ocean, which reflects the change of thermocline depth, as the precursor of forthcoming ENSO event. Indeed, the prior establishment of the zonal-mean UOHCA within the Pacific sector was found in diagnostic studies (Wyrtki 1985;Meinen and McPhaden 2000;Hasegawa and Hanawa 2003;McPhaden 2003) and coupled model simulations (Zebiak and Cane 1987;Zebiak 1989;Li 1997;An and Kang 2000) to be crucial for the onset/demise of ENSO events. These results support the hypotheses of delayed oscillator Suarez and Schopf 1988;Battisti and Hirst 1989) and recharge oscillator (Jin 1996(Jin , 1997 paradigms in explaining the ENSO phase transition mechanism.…”

Section: Introductionsupporting

confidence: 87%

“…Data cover a domain from 30 S to 40 N and from 30 E to 60 W, and are gridded on a 1 (latitude) by 2 (longitude) regular mesh at 14 NODC (National Oceanographic Data Center) standard levels between the sea surface and 500-m depth. The UOHC is calculated as the vertically averaged temperature between the sea surface and 300-m depth (Zhang and Levitus 1997;Hasegawa and Hanawa 2003).…”

Section: Datasetsmentioning

confidence: 99%

“…Although the data length is quite short, it covers the period when the relationship between the UOHC and SST variability becomes more significant after the 1976/77 Pacific climate regime shift (Hasegawa and Hanawa 2003;Terray and Dominiak 2005).…”

Section: Datasetsmentioning

confidence: 99%

See 2 more Smart Citations

Propagating Coupled Modes between the Tropical Indo-Pacific Ocean Heat Content and SST Anomalies in the Interannual Timescale

Weng

2009

Journal of the Meteorological Society of Japan

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This study uses a time-mode extended singular value decomposition (TESVD) analysis to identify the propagating coupled modes between the upper ocean heat content (UOHC) and sea surface temperature (SST) anomalies in the tropical Indo-Pacific. Four dominant TESVD modes stand out in the interannual timescale. The TESVD1 and TESVD2 depict the thermocline-SST feedback process during ENSO's persistence period and its turnabout, respectively. With an intrinsic 42-month periodicity, both modes together form an UOHCA pattern propagating counterclockwise around the circuit of equatorial-to-northern tropical Pacific followed by the SSTA propagating eastward in the equatorial waveguide. The leading role of UOHCA is mainly associated with El Niñ o occurrence. In contrast, the TESVD3 depicts the onset stage of ENSO that has the westward propagating SSTA lead the UOHCA in the cold tongue region. Suppressed equatorial upwelling directly through the positive feedback between the warmer SSTs and anomalous wind convergence from the northwestern Pacific and Caribbean Sea is another factor to trigger El Niñ o over the NINO3 region, in addition to the thermocline-SST feedback. The TESVD4 depicts the low-frequency evolution of SSTA when ENSO signal is absent. It has the westward migrating SSTA lead the UOHCA 4-month in the equatorial East Pacific. However, the pace of coupled UOHCA is nearly stagnant elsewhere due to the lack of thermocline adjustment mechanism when the zonal wind anomalies largely disappear over the equatorial Indian and West Pacific Oceans. In the Indian Ocean, while the ENSO-related SSTA evolution mainly displays an eastward basin-scale change in the first two TESVD modes, SSTA pattern depicted by the TESVD3 (TESVD4) resembles the double (single) polarity of the Indian Ocean dipole (IOD) event. It is mainly in its east pole region of southeastern Indian Ocean that the SSTA evolution tends to decouple with the underlying UOHCA.

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Section: Introductionsupporting

confidence: 87%

Section: Datasetsmentioning

confidence: 99%

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Propagating Coupled Modes between the Tropical Indo-Pacific Ocean Heat Content and SST Anomalies in the Interannual Timescale

Weng

2009

Journal of the Meteorological Society of Japan

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“…Generally, the predictability of ENSO mainly comes from the oceanic memory associated with subsurface temperature anomalies along the equatorial thermocline (Zebiak 1989). Variations in the equatorial WWV anomalies or the heat content anomalies of the equatorial Pacific precede ENSO SSTA variability by two to three seasons, so that they can serve as reliable predictors of Niño-3 SST (Meinen and Mcphaden 2000;Hasegawa and Hanawa 2003). Consistent with the phase relationship, there is a winter prediction barrier for the WWV (or OHC) anomalies, rather than a spring barrier.…”

Section: Introductionmentioning

confidence: 86%

The initial errors that induce a significant “spring predictability barrier” for El Niño events and their implications for target observation: results from an earth system model

Duan

2015

Clim Dyn

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“…Regarding the tropical-extratropical oceanic interactions there are number of competing hypotheses. It is still open question whether propagation of sub-surface thermal anomalies from the extratropics are effective (Hasegawa and Hanawa 2003) or not (Schneider et al 1999) in modifying the tropical Pacific mean state. The issue of whether the origin of decadal signals comes from the North Pacific (Zhang et al 1998) or the South Pacific (Luo and Yamagata 2001) has also been explored.…”

Section: Introductionmentioning

confidence: 99%

Source of low frequency modulation of ENSO amplitude in a CGCM

et al. 2007

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We study the relationship between changes in equatorial stratification and low frequency El Niñ o/ Southern Oscillation (ENSO) amplitude modulation in a coupled general circulation model (CGCM) that uses an anomaly coupling strategy to prevent climate drifts in the mean state. The stratification is intensified at upper levels in the western and central equatorial Pacific during periods of high ENSO amplitude. Furthermore, changes in equatorial stratification are connected with subsurface temperature anomalies originating from the central south tropical Pacific. The correlation analysis of ocean temperature anomalies against an index for the ENSO modulation supports the hypothesis of the existence of an oceanic ''tunnel'' that connects the south tropical Pacific to the equatorial wave guide. Further analysis of the wind stress projection coefficient onto the oceanic baroclinic modes suggests that the low frequency modulation of ENSO amplitude is associated with a significant contribution of higher-order modes in the western and central equatorial Pacific. In the light of these results, we suggest that, in the CGCM, change in the baroclinic mode energy distribution associated with low frequency ENSO amplitude modulation have its source in the central south tropical Pacific.

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Heat Content Variability Related to ENSO Events in the Pacific

Cited by 56 publications

References 42 publications

Propagating Coupled Modes between the Tropical Indo-Pacific Ocean Heat Content and SST Anomalies in the Interannual Timescale

Propagating Coupled Modes between the Tropical Indo-Pacific Ocean Heat Content and SST Anomalies in the Interannual Timescale

The initial errors that induce a significant “spring predictability barrier” for El Niño events and their implications for target observation: results from an earth system model

Source of low frequency modulation of ENSO amplitude in a CGCM

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