scholarly journals Sea level trend and variability around Peninsular Malaysia

Ocean Science ◽  
2015 ◽  
Vol 11 (4) ◽  
pp. 617-628 ◽  
Author(s):  
Q. H. Luu ◽  
P. Tkalich ◽  
T. W. Tay
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Peninsular Malaysia ◽  
Tide Gauges ◽  
Tide Gauge Records ◽  
Regional Sea Level ◽  
Malacca Strait ◽  
Singapore Strait

Abstract. Sea level rise due to climate change is non-uniform globally, necessitating regional estimates. Peninsular Malaysia is located in the middle of Southeast Asia, bounded from the west by the Malacca Strait, from the east by the South China Sea (SCS), and from the south by the Singapore Strait. The sea level along the peninsula may be influenced by various regional phenomena native to the adjacent parts of the Indian and Pacific oceans. To examine the variability and trend of sea level around the peninsula, tide gauge records and satellite altimetry are analyzed taking into account vertical land movements (VLMs). At annual scale, sea level anomalies (SLAs) around Peninsular Malaysia on the order of 5–25 cm are mainly monsoon driven. Sea levels at eastern and western coasts respond differently to the Asian monsoon: two peaks per year in the Malacca Strait due to South Asian–Indian monsoon; an annual cycle in the remaining region mostly due to the East Asian–western Pacific monsoon. At interannual scale, regional sea level variability in the range of ±6 cm is correlated with El Niño–Southern Oscillation (ENSO). SLAs in the Malacca Strait side are further correlated with the Indian Ocean Dipole (IOD) in the range of ±5 cm. Interannual regional sea level falls are associated with El Niño events and positive phases of IOD, whilst rises are correlated with La Niña episodes and negative values of the IOD index. At seasonal to interannual scales, we observe the separation of the sea level patterns in the Singapore Strait, between the Raffles Lighthouse and Tanjong Pagar tide stations, likely caused by a dynamic constriction in the narrowest part. During the observation period 1986–2013, average relative rates of sea level rise derived from tide gauges in Malacca Strait and along the east coast of the peninsula are 3.6±1.6 and 3.7±1.1 mm yr−1, respectively. Correcting for respective VLMs (0.8±2.6 and 0.9±2.2 mm yr−1), their corresponding geocentric sea level rise rates are estimated at 4.4±3.1 and 4.6±2.5 mm yr−1. The geocentric rates are about 25 % faster than those measured at tide gauges around the peninsula; however, the level of uncertainty associated with VLM data is relatively high. For the common period between 1993 and 2009, geocentric sea level rise values along the Malaysian coast are similar from tide gauge records and satellite altimetry (3.1 and 2.7 mm yr−1, respectively), and arguably correspond to the global trend.

scholarly journals Sinking Tide Gauge Revealed by Space-borne InSAR: Implications for Sea Level Acceleration at Pohang, South Korea

2019 ◽  
Vol 11 (3) ◽  
pp. 277 ◽  
Author(s):  
Suresh Palanisamy Vadivel ◽  
Duk-jin Kim ◽  
Jungkyo Jung ◽  
Yang-Ki Cho ◽  
Ki-Jong Han ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tide Gauge ◽  
Tide Gauges ◽  
Tide Gauge Records ◽  
Relative Sea Level ◽  
Tide Gauge Station ◽  
Sea Level Acceleration ◽  
Vertical Land Motion ◽  
Gauge Station

Vertical land motion at tide gauges influences sea level rise acceleration; this must be addressed for interpreting reliable sea level projections. In recent years, tide gauge records for the Eastern coast of Korea have revealed rapid increases in sea level rise compared with the global mean. Pohang Tide Gauge Station has shown a +3.1 cm/year sea level rise since 2013. This study aims to estimate the vertical land motion that influences relative sea level rise observations at Pohang by applying a multi-track Persistent Scatter Interferometric Synthetic Aperture Radar (PS-InSAR) time-series analysis to Sentinel-1 SAR data acquired during 2015–2017. The results, which were obtained at a high spatial resolution (10 m), indicate vertical ground motion of −2.55 cm/year at the Pohang Tide Gauge Station; this was validated by data from a collocated global positioning system (GPS) station. The subtraction of InSAR-derived subsidence rates from sea level rise at the Pohang Tide Gauge Station is 6 mm/year; thus, vertical land motion significantly dominates the sea level acceleration. Natural hazards related to the sea level rise are primarily assessed by relative sea level changes obtained from tide gauges; therefore, tide gauge records should be reviewed for rapid vertical land motion along the vulnerable coastal areas.

scholarly journals Tide Gauge Records May Underestimate 20th Century Sea Level Rise

Eos ◽  
2016 ◽  
Vol 97 ◽  
Author(s):  
Leah Crane
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
20Th Century ◽  
Tide Gauge ◽  
Sea Level Change ◽  
Tide Gauges ◽  
Tide Gauge Records ◽  
Level Change

Tide gauges can help measure sea level change, but their limited locations and short records make it hard to pinpoint trends. Now researchers are evaluating the instruments' limitations.

scholarly journals Impacts of Future Sea-Level Rise under Global Warming Assessed from Tide Gauge Records: A Case Study of the East Coast Economic Region of Peninsular Malaysia

Land ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1382
Author(s):  
Milad Bagheri ◽  
Zelina Z. Ibrahim ◽  
Mohd Fadzil Akhir ◽  
Bahareh Oryani ◽  
Shahabaldin Rezania ◽  
...  
Keyword(s):  
Neural Network ◽  
Global Warming ◽  
Sea Level Rise ◽  
Sea Level ◽  
East Coast ◽  
Tide Gauge ◽  
Sea Level Change ◽  
Peninsular Malaysia ◽  
Tide Gauge Records ◽  
Level Change

The effects of global warming are putting the world’s coasts at risk. Coastal planners need relatively accurate projections of the rate of sea-level rise and its possible consequences, such as extreme sea-level changes, flooding, and coastal erosion. The east coast of Peninsular Malaysia is vulnerable to sea-level change. The purpose of this study is to present an Artificial Neural Network (ANN) model to analyse sea-level change based on observed data of tide gauge, rainfall, sea level pressure, sea surface temperature, and wind. A Feed-forward Neural Network (FNN) approach was used on observed data from 1991 to 2012 to simulate and predict the sea level change until 2020 from five tide gauge stations in Kuala Terengganu along the East Coast of Malaysia. From 1991 to 2020, predictions estimate that sea level would increase at a pace of roughly 4.60 mm/year on average, with a rate of 2.05 ± 7.16 mm on the East Coast of Peninsular Malaysia. This study shows that Peninsular Malaysia’s East Coast is vulnerable to sea-level rise, particularly at Kula Terengganu, Terengganu state, with a rate of 1.38 ± 7.59 mm/year, and Tanjung Gelang, Pahang state, with a rate of 1.87 ± 7.33 mm/year. As a result, strategies and planning for long-term adaptation are needed to control potential consequences. Our research provides crucial information for decision-makers seeking to protect coastal cities from the risks of rising sea levels.

Vertical land motion in the Iberian Atlantic coast and its implications for sea level change evaluation

2020 ◽  
Vol 14 (3) ◽  
pp. 361-378
Author(s):  
V. B. Mendes ◽  
S. M. Barbosa ◽  
D. Carinhas
Keyword(s):  
Time Series ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Atlantic Coast ◽  
Sea Level Change ◽  
Tide Gauges ◽  
Tide Gauge Records ◽  
Level Change ◽  
Vertical Land Motion

AbstractIn this study, we estimate vertical land motion for 35 stations primarily located along the coastline of Portugal and Spain, using GPS time series with at least eight years of observations. Based on this set of GPS stations, our results show that vertical land motion along the Iberian coastline is characterized, in general, by a low to moderate subsidence, ranging from −2.2 mm yr−1 to 0.4 mm yr−1, partially explained by the glacial isostatic adjustment geophysical signal. The estimates of vertical land motion are subsequently applied in the analysis of tide gauge records and compared with geocentric estimates of sea level change. Geocentric sea level for the Iberian Atlantic coast determined from satellite altimetry for the last three decades has a mean of 2.5 ± 0.6 mm yr−1, with a significant range, as seen for a subset of grid points located in the vicinity of tide gauge stations, which present trends varying from 1.5 mm yr−1 to 3.2 mm yr−1. Relative sea level determined from tide gauges for this region shows a high degree of spatial variability, that can be partially explained not only by the difference in length and quality of the time series, but also for possible undocumented datum shifts, turning some trends unreliable. In general, tide gauges corrected for vertical land motion produce smaller trends than satellite altimetry. Tide gauge trends for the last three decades not corrected for vertical land motion range from 0.3 mm yr−1 to 5.0 mm yr−1 with a mean of 2.6 ± 1.4 mm yr−1, similar to that obtained from satellite altimetry. When corrected for vertical land motion, we observe a reduction of the mean to ∼1.9 ± 1.4 mm yr−1. Actions to improve our knowledge of vertical land motion using space geodesy, such as establishing stations in co-location with tide gauges, will contribute to better evaluate sea level change and its impacts on coastal regions.

scholarly journals Sea level trend and variability around the Peninsular Malaysia

2014 ◽  
Vol 11 (3) ◽  
pp. 1519-1541 ◽  
Author(s):  
Q. H. Luu ◽  
P. Tkalich ◽  
T. W. Tay
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Peninsular Malaysia ◽  
Sea Level Anomalies ◽  
The Indian Ocean ◽  
Sea Level Trend ◽  
Malacca Strait

Abstract. Peninsular Malaysia is bounded from the west by Malacca Strait and the Andaman Sea both connected to the Indian Ocean, and from the east by South China Sea being largest marginal sea in the Pacific Basin. Resulting sea level along Peninsular Malaysia coast is assumed to be governed by various regional phenomena associated with the adjacent parts of the Indian and Pacific Oceans. At annual scale, sea level anomalies (SLAs) are generated by the Asian monsoon; interannual sea level variability is determined by the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD); while long-term sea level trend is related to global climate change. To quantify the relative impacts of these multi-scale phenomena on sea level trend and variability around the Peninsular Malaysia, long-term tide gauge record and satellite altimetry are used. During 1984–2011, relative sea level rise (SLR) rates in waters of Malacca Strait and eastern Peninsular Malaysia are found to be 2.4 ± 1.6 mm yr−1 and 2.7 ± 1.0 mm yr−1, respectively. Allowing for corresponding vertical land movements (VLM; 0.8 ± 2.6 mm yr−1 and 0.9 ± 2.2 mm yr−1), their absolute SLR rates are 3.2 ± 4.2 mm yr−1 and 3.6 ± 3.2 mm yr−1, respectively. For the common period 1993–2009, absolute SLR rates obtained from both tide gauge and satellite altimetry in Peninsular Malaysia are similar; and they are slightly higher than the global tendency. It further underlines that VLM should be taken into account to get better estimates of SLR observations. At interannual scale, ENSO affects sea level over the Malaysian coast in the range of ±5 cm with a very high correlation. Meanwhile, IOD modulates sea level anomalies mainly in the Malacca Strait in the range of ±2 cm with a high correlation coefficient. Interannual regional sea level drops are associated with El Niño events and positive phases of the IOD index; while the rises are correlated with La Niña episodes and the negative periods of the IOD index. Seasonally, SLAs are mainly monsoon-driven, in the order of 10–25 cm. Geographically, sea level responds differently to the monsoon: two cycles per year are observed in the Malacca Strait, presumably due to South Asian-Indian Monsoon; whereas single annual cycle is noted along east coast of Peninsular Malaysia, mostly due to East Asian-Western Pacific Monsoon. These results imply that a narrow topographic constriction in Singapore Strait may separate different modes of annual and interannual sea level variability along coastline of Peninsular Malaysia.

Sea Level Rise and Land Subsidence Contributions to the Signals from the Tide Gauges of China

2016 ◽  
Vol 5 (2) ◽  
Author(s):  
Albert Parker
Keyword(s):  
Sea Level Rise ◽  
Linear Model ◽  
Sea Level ◽  
Land Subsidence ◽  
Tide Gauge ◽  
Tide Gauges ◽  
Tide Gauge Records ◽  
Tide Gauge Record ◽  
Term Trend ◽  
Non Linear

AbstractThe tide gauges measure the local oscillations of the sea level vs. the tide gauge instrument. The tide gauge instrument is generally subjected to the general subsidence or uplift of the nearby inland, plus some additional subsidence for land compaction and other localised phenomena. The paper proposes a non-linear model of the relative sea level oscillations including a long term trend for the absolute sea level rise, another term for the subsidence of the instrument, and finally a sinusoidal approximation for the cyclic oscillations of periodicities up to decades. This non-linear model is applied to the tide gauges of China. The paper shows that the limited information available for China does not permit to infer any proper trend for the relative rates of rise, as the tide gauge records are all short or incomplete and the vertical movement of the tide gauge instruments is unassessed. The only tide gauge record of sufficient length that may be assembled for China is obtained by combining the North Point and Quarry Bay tide gauges in Hong Kong (NPQB). This NQPB composite tide gauge record is shown to have similarities with the tide gauge records of Sydney, equally in the West pacific, and San Diego, in the east Pacific, oscillating about the longer term trend mostly determined by the local subsidence. As it is very well known that China generally suffers of land subsidence, and the tide gauge installations may suffer of additional subsidence vs. the inland, it may be concluded from the analysis of the other worldwide tide gauges that the sea levels of China are very likely rising about the same amount of the subsidence of the tide gauges, with the sea level acceleration component still negligible.

scholarly journals Effects of the basin dynamics on sea level rise in the Black Sea

2016 ◽  
Author(s):  
A. A. Kubryakov ◽  
S. V. Stanichny ◽  
D. L. Volkov
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Black Sea ◽  
Tide Gauge ◽  
The Black Sea ◽  
Tide Gauges ◽  
Tide Gauge Records ◽  
Sea Levels ◽  
The Difference

Abstract. Satellite altimetry measurements show that magnitude of the Black Sea level trends is spatially uneven. While the basin-averaged sea level was increasing at a rate of 3.15 mm/year from 1993 to 2014, the sea level rise varied from 0.15–2.5 mm/year in the central part to 3.5–3.8 mm/year in coastal areas and 5 mm/year in the southwestern part of the sea. These differences are caused by changes in the large- and mesoscale circulation of the Black Sea. A long-term increase of the cyclonic wind curl over the basin from 1979 to 2014 strengthened divergence in the center of the Black Sea that led to an increase of sea level near the coast and a decrease in the center of the basin. Changes in the distribution and intensity of mesoscale eddies caused the formation of the local extremes of sea level trend. The variability of the dynamic sea level (DSL) – the difference between the local and the basin-averaged sea levels – contributes significantly (up to ~ 50 % of the total variance) to the seasonal and interannual variability of sea level in the basin. The DSL variability in the Black Sea depends strongly on the basin-averaged wind curl and is well reconstructed using the ERA-Interim winds from 1979 to present, including the time when altimetry data was unavailable. The reconstruction can be used to correct historical tide gauges data for dynamic effects, which are usually neglected in the analysis of the Black Sea tide gauge records.

The sources of sea-level rise in the Mediterranean Sea since 1960

2021 ◽  
Author(s):  
Francisco Mir Calafat ◽  
Thomas Frederikse ◽  
Kevin Horsburgh ◽  
Nadim Dayoub
Keyword(s):  
Sea Level Rise ◽  
Mediterranean Sea ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Sea Level Changes ◽  
Tide Gauge Records ◽  
Land Mass ◽  
The Mediterranean ◽  
Dynamic Sea Level

<p>Sea-level change is geographically non-uniform, with regional departures that can reach several times the global average. Characterizing this spatial variability and understanding its causes is crucial to the design of adaptation strategies for sea-level rise. This, as it turns out, is no easy feat, primarily due to the sparseness of the observational sea-level record in time and space. Long tide gauge records are restricted to a few locations along the coast. Satellite altimetry offers a better spatial coverage but only since 1992. In the Mediterranean Sea, the tide gauge network is heavily biased towards the European shorelines, with only one record with at least 35 years of data on the African coasts. Past studies have attempted to address the difficulties related to this data sparseness in the Mediterranean Sea by combining the available tide gauge records with satellite altimetry observations. The vast majority of such studies represent sea level through a combination of altimetry-derived empirical orthogonal functions whose temporal amplitudes are then inferred from the tide gauge data. Such methods, however, have tremendous difficulty in separating trends and variability, make no distinction between relative and geocentric sea level, and tell us nothing about the causes of sea level changes. Here, we combine observational data from tide gauges and altimetry with sea-level fingerprints of land-mass changes through a Bayesian hierarchical model to quanify the sources of sea-level rise since 1960 at any arbitrary location in the Mediterranean Sea. We find that Mediterranean sea level rose at a relatively low rate from 1960 to 1990, primarily due to dynamic sea-level changes in the nearby Atlantic, at which point it started rising significantly faster with comparable contributions from dynamic sea level and land-mass changes.</p>

scholarly journals An Update on the Status of Mean Sea Level Rise around the Korean Peninsula

Atmosphere ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1153 ◽  
Author(s):  
Phil J. Watson ◽  
Hak-Soo Lim
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Korean Peninsula ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Republic Of Korea ◽  
The Yellow Sea ◽  
Tide Gauge Records ◽  
Mean Sea Level ◽  
The Republic

The threat of sea level rise to the heavily populated Korean Peninsula, which contains around 15,000 km of coastline bordering open sea margins, has profound and far reaching implications. This study updates and extends previous detailed studies with the addition of a further 2 years of data to the end of 2019, providing renewed robustness to the identification of emerging threats associated with sea level rise within the warming sea margins around the Korean Peninsula. The study analyzes tide gauge records and satellite altimetry around the Republic of Korea using enhanced time series analysis techniques to detect coastal vertical land motion and current rates of rise in mean sea level to augment planning, design and risk management activities. Despite fluctuations over time at each site, the highest “relative” mean sea level at each of the seven longest tide gauge records occurs in 2019, with weak evidence of an acceleration in the increase in mean sea level around the Republic of Korea. Trends in sea surface height from satellite altimetry across this region note two discreet areas east and west of the Korean Peninsula around 37.5° N (around Ulleungdo Island and in the Gyeonggi Bay region of the Yellow Sea), where rates of rise are well above the global average trend.

scholarly journals Status of Mean Sea Level Rise around the USA (2020)

GeoHazards ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 80-100
Author(s):  
Phil J. Watson
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Gulf Coast ◽  
Tide Gauge ◽  
Tide Gauge Records ◽  
Mean Sea Level ◽  
Sea Levels ◽  
Vertical Land Motion ◽  
The Usa

The potential threats to the USA from current and projected sea level rise are significant, with profound environmental, social and economic consequences. This current study continues the refinement and improvement in analysis techniques for sea level research beyond the Fourth US National Climate Assessment (NCA4) report by incorporating further advancements in the time series analysis of long tide gauge records integrated with an improved vertical land motion (VLM) assessment. This analysis has also been synthesised with an updated regional assessment of satellite altimetry trends in the sea margins fringing the USA. Coastal margins more vulnerable to the threats posed by rising sea levels are those in which subsidence is prevalent, higher satellite altimetry trends are evident and higher ‘geocentric’ velocities in mean sea level are being observed. The evidence from this study highlights key spatial features emerging in 2020, which highlight the northern foreshore of the Gulf Coast and along the east coast of the USA south of the Chesapeake Bay region being more exposed to the range of factors exacerbating threats from sea level rise than other coastlines at present. The findings in this study complement and extend sea level research beyond NCA4 to 2020.

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