Reconstruction of Local Sea Levels at South West Pacific Islands—A Multiple Linear Regression Approach (1988–2014)

Kumar, Vandhna; Melet, Angélique; Meyssignac, Benoît; Ganachaud, Alexandre; Kessler, William S.; Singh, Awnesh; Aucan, Jérôme

doi:10.1002/2017jc013053

Cited by 11 publications

(10 citation statements)

References 74 publications

(114 reference statements)

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“…Using MLR statistics, the targeted variable (observed daily SLA) could be described by the linear combination of explanatory variables. Previous studies analyzed the linear relationship between sea level and explanatory variables of sea level pressure (SLP), precipitation, air temperature, winds, and climate variability indices [18,[48][49][50]. Here, we selected four explanatory variables: precipitation, SLP, zonal wind (U), and meridional wind (V), and we evaluated their influences on sea level vari-ations.…”

Section: Empirical Methodsmentioning

confidence: 99%

Influence of Terrestrial Precipitation on the Variability of Extreme Sea Levels along the Coast of Bangladesh

Islam

Sato

2021

Water

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The coastal area of Bangladesh is highly vulnerable to extreme sea levels because of high population exposure in the low-lying deltaic coast. Since the area lies in the monsoon region, abundant precipitation and the resultant increase in river discharge have raised a flood risk for the coastal area. Although the effects of atmospheric forces have been investigated intensively, the influence of precipitation on extreme sea levels in this area remains unknown. In this study, the influence of precipitation on extreme sea levels for three different stations were investigated by multivariate regression using the meteorological drivers of precipitation, sea level pressure, and wind. The prediction of sea levels considering precipitation effects outperformed predictions without precipitation. The benefit of incorporating precipitation was greater at Cox’s Bazar than at Charchanga and Khepupara, reflecting the hilly landscape at Cox’s Bazar. The improved prediction skill was mainly confirmed during the monsoon season, when strong precipitation events occur. It was also revealed that the precipitation over the Bangladesh area is insensitive to the El Niño-Southern Oscillation and Indian Ocean Dipole mode. The precipitation over northern Bangladesh tended to be high in the year of a high sea surface temperature over the Bay of Bengal, which may have contributed to the variation in sea level. The findings suggest that the effect of precipitation plays an essential role in enhancing sea levels during many extreme events. Therefore, incorporating the effect of terrestrial precipitation is essential for the better prediction of extreme sea levels, which helps coastal management and reduction of hazards.

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Section: Empirical Methodsmentioning

confidence: 99%

Influence of Terrestrial Precipitation on the Variability of Extreme Sea Levels along the Coast of Bangladesh

Islam

Sato

2021

Water

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“…Interannual and interdecadal sea level variability is of the order ±0.1 m in the Western South Pacific Ocean, and is determined by large-scale ocean dynamics (Kumar et al, 2018). As such, changes in current speeds and residual circulation caused by interannual sea level variability are likely to be relatively small, given the limited response seen under +1 m SLR (Figures 3b, 10b).…”

Section: Discussionmentioning

confidence: 99%

Investigations Exploring the Use of an Unstructured-Grid, Finite-Volume Modelling Approach to Simulate Coastal Circulation in Remote Island Settings—Case Study Region, Vanuatu/New Caledonia

et al. 2021

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Understanding coastal circulation and how it may alter in the future is important in island settings, especially in the South West Pacific, where communities rely heavily upon marine resources, and where sea level rise (SLR) is higher than the global average. In this study we explore the use of an unstructured-mesh finite-volume modelling approach to assist in filling the knowledge gaps with respect to coastal circulation in remote island locations—selecting the Vanuatu and New Caledonia archipelagos as our example study site. Past limited observations and modelling studies are leveraged to construct and verify a regional/coastal ocean model based on the Finite-Volume Community Ocean Model (FVCOM). Following verification with respect to tidal behaviour, we investigate how changes in wind speed and direction, and SLR, alter coastal water levels and coastal currents. Results showed tidal residual circulation was typically associated with flow separation at headlands and islands. Trade winds had negligible effect on water levels at the coast, however, wind-residual circulation was sensitive to both wind speed and direction. Wind-residual currents were typically strongest close to coastlines. Wind residual circulation patterns were strongly influenced by Ekman flow, while island blocking, topographic steering and geostrophic currents also appear to influence current patterns. Tidal amplitudes and phases were unchanged due to SLR of up to 2 m, while maximum current speeds altered by as much as 20 cm/s within some coastal embayments. Non-linear relationships between SLR and maximum current speeds were seen at some coastal reef platform sites. Under higher sea levels, tidal residual currents altered by less than ±2 cm/s which is relatively significant given maximum tidal residual current speeds are typically below 10 cm/s. Our findings indicate that under higher sea levels, coastal processes governing sediment transport, pollutant dispersal and larval transport are likely to alter, which may have implications for coastal environments and ecosystems. Given winds influence coastal circulation and subsequent coastal processes, changes in trade winds due to climate change may act to further alter coastal processes. It is felt that the current modelling approach can be applied to other regions to help fill critical knowledge gaps.

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“…Superimposed on the GMSL rise, several regions experience changes in sea level with rates greater than the GMSL rise, as a response to changes in ocean circulation and atmospheric forcing over different time scales, exerting extensive stress on low-lying coastal zones (e.g., [7]). This is notably the case in the South Pacific Ocean, where several coastal communities are facing accelerated sea level rise at rates that are 3 to 4 times higher than the GMSL rise (e.g., [9,10]). Moreover, this region (hosting small islands) has been identified as vulnerable to coastal flooding 2 of 20 in response to future sea level rise (e.g., [11]).…”

Section: Introductionmentioning

confidence: 99%

Forcing Mechanisms of the Interannual Sea Level Variability in the Midlatitude South Pacific during 2004–2020

et al. 2023

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Over the past few decades, the global mean sea level rise and superimposed regional fluctuations of sea level have exerted considerable stress on coastal communities, especially in low-elevation regions such as the Pacific Islands in the western South Pacific Ocean. This made it necessary to have the most comprehensive understanding of the forcing mechanisms that are responsible for the increasing rates of extreme sea level events. In this study, we explore the causes of the observed sea level variability in the midlatitude South Pacific on interannual time scales using observations and atmospheric reanalyses combined with a 1.5 layer reduced-gravity model. We focus on the 2004–2020 period, during which the Argo’s global array allowed us to assess year-to-year changes in steric sea level caused by thermohaline changes in different depth ranges (from the surface down to 2000 m). We find that during the 2015–2016 El Niño and the following 2017–2018 La Niña, large variations in thermosteric sea level occurred due to temperature changes within the 100–500 dbar layer in the midlatitude southwest Pacific. In the western boundary region (from 30°S to 40°S), the variations in halosteric sea level between 100 and 500 dbar were significant and could have partially balanced the corresponding changes in thermosteric sea level. We show that around 35°S, baroclinic Rossby waves forced by the open-ocean wind-stress forcing account for 40 to 75% of the interannual sea level variance between 100°W and 180°, while the influence of remote sea level signals generated near the Chilean coast is limited to the region east of 100°W. The contribution of surface heat fluxes on interannual time scales is also considered and shown to be negligible.

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Reconstruction of Local Sea Levels at South West Pacific Islands—A Multiple Linear Regression Approach (1988–2014)

Cited by 11 publications

References 74 publications

Influence of Terrestrial Precipitation on the Variability of Extreme Sea Levels along the Coast of Bangladesh

Influence of Terrestrial Precipitation on the Variability of Extreme Sea Levels along the Coast of Bangladesh

Investigations Exploring the Use of an Unstructured-Grid, Finite-Volume Modelling Approach to Simulate Coastal Circulation in Remote Island Settings—Case Study Region, Vanuatu/New Caledonia

Forcing Mechanisms of the Interannual Sea Level Variability in the Midlatitude South Pacific during 2004–2020

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