Non-Linear Sea Level Variations in the Eastern Tropical Pacific

Niedzielski, Tomasz

doi:10.2478/v10018-010-0001-z

Cited by 6 publications

(5 citation statements)

References 31 publications

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“…Our study supplements the predictive analysis by Niedzielski and Kosek (2009) in the sense that it shows that low-order ARMA methods can have dissimilar performance in modelling irregular sea level fluctuations in the eastern tropical Pacific. This is also in agreement with what has been envisaged by Niedzielski (2010) who assumed linear processes to serve well the purpose of irregular sea level modelling at some sites located off the Equator in the eastern equatorial Pacific.…”

Section: Resultssupporting

confidence: 79%

An Application of Low-Order Arma and Garch Models for Sea Level Fluctuations

Niedzielski¹,

Kosek²

2010

Artificial Satellites

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ABSTRACT. The paper presents the analysis of geographically-dependent irregular sea level fluctuations, often referred to as residual terms around deterministic signals, carried out by means of stochastic low-order autoregressive moving average (ARMA) and generalised autoregressive conditional heteroscedastic (GARCH) models. The gridded sea level anomaly (SLA) time series from TOPEX/Poseidon (T/P) and Jason-1 (J-1) satellite altimetry, commencing on 10th January 1993 and finishing on 14th July 2003, has been examined. The aforementioned models, limited to low-orders being combinations of 0,1 and 2, have been fitted to the SLA data. The root mean square and the Shapiro-Wilk test for the normal distribution have been used to calculate statistics of the residuals from these models. It has been found that autoregressive (AR) models as well as ARMA ones serve well the purpose of adequate modelling irregular sea level fluctuations, with a successful fit in some patchy bits of the equatorial Pacific. In contrast, GARCH models have been shown to be rather inaccurate, specifically in the vicinity of the tropical Pacific, in the North Pacific and in the equatorial Indian Ocean. The pattern of the Tropical Instability Waves (TIWs) has been noticed in the statistics of AR and ARMA model residuals indicating that the dynamics of these waves cannot be captured by the aforementioned linear stochastic processes.

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Section: Resultssupporting

confidence: 79%

An Application of Low-Order Arma and Garch Models for Sea Level Fluctuations

Niedzielski¹,

Kosek²

2010

Artificial Satellites

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“…Journal of Geophysical Research: Oceans of SLA implies the considerable nonlinearity in its dynamics, which adds to uncertainties and difficulties of sea level prediction in the WTP (Niedzielski, 2010;Niedzielski & Kosek, 2010). On the other hand, SLAs are dynamically associated with the thermocline displacements and the upper ocean geostrophic current anomalies.…”

Section: 1029/2020jc016616mentioning

confidence: 99%

“…Statistical analysis of previous studies (Burgers & Stephenson, 1999; Niedzielski, 2010; Niedzielski & Kosek, 2010) suggested that SLAs over the tropical Pacific, resembling sea surface temperature (SST) anomalies, do not strictly conform to the normal distribution. As shown in Figure 1d, the prevailing negative skewness values in the WTP are probably linked to the predominance of El Niño over La Niña in their SLA signatures (Niedzielski & Kosek, 2010), which may be related with not only the ENSO's asymmetry but also the nonlinearity in ocean response to ENSO (An & Kim, 2017; Guan et al, 2019; Im et al, 2015; Niedzielski & Kosek, 2010; Świerczyńska et al, 2014; Wen et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…El Niño and La Niña, modulated by nonlinear processes of the tropical Pacific climate, are not perfect mirrors of each other and show asymmetries in amplitude, duration time, and occurrence frequency (e.g., An & Choi, 2009; An & Jin, 2004; Burgers & Stephenson, 1999; Gergis & Fowler, 2009; Guan et al, 2019; Hu et al, 2016; Jin et al, 2003; Ohba & Ueda, 2007; Okumura & Deser, 2010; Su et al, 2010; Yu et al, 1997). The negatively skewed distribution of SLA implies the considerable nonlinearity in its dynamics, which adds to uncertainties and difficulties of sea level prediction in the WTP (Niedzielski, 2010; Niedzielski & Kosek, 2010). On the other hand, SLAs are dynamically associated with the thermocline displacements and the upper ocean geostrophic current anomalies.…”

Section: Introductionmentioning

confidence: 99%

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Asymmetry of Interannual Sea Level Variability in the Western Tropical Pacific: Responses to El Niño and La Niña

Ren

Zheng

et al. 2020

JGR Oceans

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The western tropical Pacific (WTP) exhibits pronounced large-scale sea level anomalies (SLAs) during El Niño-Southern Oscillation (ENSO) events with amplitudes of~0.1 m, exerting potential threats to many low-lying islands. It is found that the sea level falling in El Niño condition is evidently stronger than the rising in La Niña condition. This SLA asymmetry in the WTP associated with ENSO is investigated in this study, and the underlying dynamic processes are explored. Such asymmetry is most prominent at around 160°E with the SLA response to El Niño being three times stronger than to La Niña, but it is much inconspicuous near the western boundary. Sensitivity experiments of a simplified ocean model suggest that the different structures of surface wind anomalies between El Niño and La Niña conditions are critical in generating asymmetric SLA responses of the WTP. The El Niño's westerly wind anomaly patch locates more to the east than the La Niña's easterly wind patch during the mature stage, and its upwelling effects are accumulated over a wider longitude range and cause stronger negative SLAs in the WTP. Near the western boundary, however, upwelling effects are attenuated by easterly wind anomalies during the mature stage of El Niño. Further analysis reveals that eastern Pacific-type El Niño events are more favorable for generating asymmetric SLAs in the WTP than the central Pacific-type events. Plain Language Summary El Niño-Southern Oscillation (ENSO) is the most important climate variability phenomenon in the tropical Pacific and causes strong interannual sea level anomalies (SLAs) in the western tropical Pacific (WTP). The El Niño's sea level falling is evidently stronger than the La Niña's sea level rising. This difference is most prominent near 160°E with stronger El Niño's sea level falling but becomes much less evident near the western boundary of the Pacific Basin. The different surface wind anomaly structures between El Niño and La Niña are the primary cause. El Niño's westerly wind anomaly center locates more east than La Niña's easterly wind anomaly center in their mature phase, leading to stronger sea level falling in the WTP through westerly wind anomalies over the wide longitude range. The sea level falling is weakened by easterly wind anomalies generated near the western boundary. By contrast, effect of La Niña's easterly wind anomaly strengthens monotonically from east to west, and the produced sea level rising signatures are mainly confined to the WTP. The wind forcing structure of eastern Pacific-type El Niño is more favorable for generating asymmetric SLAs in the WTP than central Pacific-type events.

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“…The stochastic low-order autoregressive moving average (ARMA) and generalized autoregressive conditional heteroscedastic (GARCH) models were used to model irregular sea level fluctuations in the least-squares residuals of the sea level anomaly data (Niedzielski and Kosek, 2011b). The authors found that AR and ARMA models are adequate, with a successful fit to these residuals in some patchy bits of the equatorial Pacific.…”

Section: Sea Level Changementioning

confidence: 99%

Earth rotation and geodynamics

Bogusz

Brzeziński

Kosek

et al. 2015

Geodesy and Cartography

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This paper presents the summary of research activities carried out in Poland in 2011-2014 in the field of Earth rotation and geodynamics by several Polish research institutions. It contains a summary of works on Earth rotation, including evaluation and prediction of its parameters and analysis of the related excitation data as well as research on associated geodynamic phenomena such as geocentre motion, global sea level change and hydrological processes. The second part of the paper deals with monitoring of geodynamic phenomena. It contains analysis of geodynamic networks of local, and regional scale using space (GNSS and SLR) techniques, Earth tides monitoring with gravimeters and water-tube hydrostatic clinometer, and the determination of secular variation of the Earth’ magnetic field.

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Non-Linear Sea Level Variations in the Eastern Tropical Pacific

Cited by 6 publications

References 31 publications

An Application of Low-Order Arma and Garch Models for Sea Level Fluctuations

An Application of Low-Order Arma and Garch Models for Sea Level Fluctuations

Asymmetry of Interannual Sea Level Variability in the Western Tropical Pacific: Responses to El Niño and La Niña

Earth rotation and geodynamics

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