Sea Level Elevation Research Articles

Paleoenvironmental conditions across the Coniacian-Santonian in the Kometan Formation, northeastern Iraq: Insights from planktonic foraminifera distribution, mineralogy and geochemistry

The paleoenvironmental conditions during the Coniacian-Santonian interval within the Kometan Formation in northeastern Iraq have been analyzed through the distribution of depth-related planktonic foraminifera in the carbonate rocks (limestone and marly limestone) of the Kometan Formation using standard washing method for soft samples and thin section method for hard samples supported by mineralogical investigations, geochemical analysis and stable isotopic δ13C and δ18O data. The findings indicate that saline marine waters and a hot, dry to semi-arid climate with low to medium oxygen conditions were conducive to deposition, which was characterized by high organic productivity due to marine transgression. The study revealed that the distribution of shallow water forms (SWF) of globular-shaped foraminifera, compared to deep water forms (DWF) of keeled-shaped genera, along with δ13C data from the late Turonian-early Campanian succession, indicated a relatively low sea level throughout the Late Turonian period. The water level began to rise in the early Coniacian, continuing gradually until the late Coniacian, when a noticeable increase in sea level was observed. This elevated sea level persisted through the early and late Santonian periods, before starting to drop. A slight marine transgression was noted at the beginning of the early Campanian period, followed by a significant drop in sea level. During the late Turonian, a subtropical climate prevailed. Temperature increased during the early to middle Coniacian, decreased slightly at the beginning of the late Coniacian, and then rose again at the end of the late Coniacian, indicating a shift from tropical to subtropical climatic conditions. Similar hot climatic conditions persisted in a tropical-subtropical climate during the early to late Santonian and early Campanian, with a relative temperature drop near the end of the early Campanian. No evidence of an oceanic anoxic event (OAE3) was found in the Kometan Formation during the late Coniacian–early Santonian period. The hypothesized event, based on biostratigraphy, facies analysis, stable isotopes, geochemical evidence, and field study, was limited to demonstrating an increase in the ratio of keeled chamber planktonic foraminifera compared to globular chamber ones. This ratio increase of the keeled chamber types is believed to result from a deepening sedimentary environment due to rising sea levels, creating organic matter-rich beds with high productivity and relatively low oxygen conditions during the Coniacian-Santonian boundary.

New insights into the glacial and relative sea-level history of the western Fraser Lowland based on sediment cores from geotechnical drilling for the Evergreen Tunnel, British Columbia, Canada

Abstract Geotechnical drilling for a tunnel between Port Moody and Burnaby, BC, Canada, uncovered a buried fjord. Its sedimentary fill has a thickness of at least 130 m and extends more than 37 m below present mean sea level. Recovered sediments record cyclical growth and decay of successive Cordilleran ice sheets. The oldest sediments comprise 58 m of almost stoneless silt conformably overlying ice-proximal sediments and till, which in turn overlie bedrock. These sediments may predate Marine Isotope Stage (MIS) 4. Glacial sediments assigned to MIS 4 overlie this basal succession and, in turn, are overlain by MIS 3 interstadial sediments and sediments from two MIS 2 glacial advances. Indicators of relative sea-level elevations that bracket glacial deposits of MIS 4 and 2 indicate the cyclic existence of moat-like isostatic depressions in the front of expanding ice sheets. Compared with present sea level, these depressions were at least 160 m during the onsets of MIS 4 and MIS 2. Assuming a maximum eustatic drawdown of 120 m during MIS 2, isostatic depression may have exceeded 200 m during retreat of glacial ice from the Evergreen tunnel area. This is consistent with region-specific low mantle viscosity and rapid Cordilleran Ice Sheet buildup and wasting.

The role of wave setup on extreme water levels around Australia

Estimates of extreme sea levels have mainly been derived using atmospheric and tidal forcing only, but surface gravity waves are a key process that can cause a substantial elevation of mean sea level at the coast. In this paper a coupled wave-circulation model was used to simulate storm surge and wave setup across a broad range of coastal topographies and storm types around Australia. The main aim was a practical assessment of the benefits and limitations of using a coupled wave-surge model to determine wave effects for extreme sea level studies on the continental scale. The simulations included: tropical cyclones Yasi (2011) and George (2007) on the northeast and northwest coasts of Australia; Cyclone Alby (1978) that underwent extratropical transition in southwest Australia; and a large extratropical winter storm in the Southern Ocean (2016). Predicted wave setup was highly variable both spatially and temporally, with values up to 0.45 m, 35% of maximum storm surge height, and 9% of incident significant wave heights. In general, where storm surge heights were smaller, the relative importance of wave setup increased in the presence of large waves. The model best resolved wave setup in shallow gently sloping coastal areas, whilst unrealistically low values were predicted for steep coastlines. Predictions improved when wave setup was included for most sites and events, however, these wave effects were often secondary to other assumptions implicit in modeling extreme events. This was especially true for tropical cyclones where reliable wind forcing was not available. The results showed similar contributions from wave setup to other studies but highlighted the high temporal and spatial variability of wave setup across a wider variety of storms and coastal morphologies. The results also revealed that the maximum wave setup did not always coincide with the maximum storm surge. Overall, the coupled wave-surge model presented a useful tool to predict extreme water levels including wave setup when accurate depth and atmospheric data are available, however, significant challenges still exist to model this process at the continental scale.

New chronology of K-feldspar isochron optical dating (iIRSL) in the late Pleistocene coastal aeolian deposits of Southeast China

Old red sand (ORS), which developed during the late Pleistocene, is widely distributed along the coasts of the western Pacific and Indian Ocean.The Optically Stimulated Luminescence (OSL) dating technology have primarily determined its sedimentary age. However, in tropical and subtropical regions, chemical weathering can impact the calculation of environmental dose rates, potentially leading to age biases whose magnitude remains uncertain.Recently, advance in the OSL dating technique, the new K-feldspar isochron dating method (iIRSL), have determined its depositional age. This approach effectively enhances the accuracy of age data by accounting for variations in past dose rates caused by chemical weathering and changes in water content during sample burial. This study used the iIRSL method to conduct infrared stimulated luminescence signal tests on ORS samples from the Haitan Island, south China. Five grain sizes of K-feldspar grains were extracted from each sample during experimentation. The single aliquot regenerative dose method (SAR) was utilized to determine the equivalent dose for each grain size and calculate age using the isochron method (iIRSL). Furthermore, it compared the iIRSL ages with quartz age (SAR). The results indicate that: (1) This study obtained four iIRSL ages, which are consistent with the ages obtained from quartz (SAR) within a reasonable range, ranging from 62.13 ± 4.85 to 39.44 ± 4.85 ka BP. (2) Comparison of the simulation results of different weathering degrees using the iIRSL method and K-feldspar two-step IRIR methods indicates that the iIRSL method can effectively mitigate the impact of chemical weathering on age determination, giving more reliable iIRSL ages. (3) The ORS along the southern coast of China mainly deposited during Marine Isotope Stages 5, 4, and 3, exhibiting relatively higher deposition rates during MIS 5 and MIS 3 at approximately 30 cm/ka and 15 cm/ka respectively. This suggests that the ORS was predominantly deposited during periods of elevated sea levels. However, it is important to note that the data from MIS 5 may have been influenced by the absence of samples from this particular stage and limitations in dating methods, resulting in a lower frequency-density of deposition ages during MIS 5 and creating an “illusion” of sediment interruption.

Extracting iceberg freeboard using shadow length in high-resolution optical images

ABSTRACT Icebergs are big chunks of ice floating on the ocean surface, and melting of icebergs contributes for the major part of freshwater flux into ocean. Dynamic monitoring of the icebergs in Antarctica and accurate estimation of their volume are important for predicting the trend of freshwater budget of the Southern Ocean. The iceberg freeboard is a key parameter for measuring the thickness and volume of an iceberg and is defined as the difference between the elevation of iceberg surface and sea level. So far, freeboards of icebergs have been successfully extracted using InSAR DEM, and the laser and radar altimeter. However, uncertainties exist in these results mainly caused by missed detection of small icebergs due to the spatially sparse and temporally incomplete data coverage. In addition to the above techniques, optical images can also be used to extract the iceberg freeboard based on its geometric relationship with shadow length, which can effectively compensate for the above shortcomings. Although the feasibility has been preliminarily presented, the precision and extensive application of shadow-height method deserves further research, such as estimating the basal melting of icebergs. In this work, we tested an optical image-based freeboard extraction method over icebergs in Prydz Bay, Antarctica. A normalized shadow pixel index (NSPI) is designed to identify iceberg shadows with different shapes in HY-1C/D CZI and Sentinel-2 MSI optical images. The iceberg freeboard can be determined with an acceptable precision (2 m) in optical images compared with laser altimeter (i.e. ICESat-2) measurements. Moreover, basal melting of icebergs has been assessed according to the variation of freeboard using repeated optical observations. The results indicate that icebergs in the study area were with a mean freeboard of about 56 m in early December 2022, and experienced a decrease in freeboard of 1.9 m within two months, in correspondence with the Antarctic seasonal trend. The methodological framework, therefore, turns out to be a reliable complementary approach to studying the iceberg freeboard in polar regions.

Intermittency of Gravity Wave Potential Energy Generated by Mountains Revealed from COSMIC-2 Observations

The intermittency of gravity wave potential energy (GWPE) in the upper troposphere and stratosphere was investigated using the Constellation Observing System for Meteorology, Ionosphere, and Climate-2 (COSMIC-2) temperature data over three typical mountains (Tibetan Plateau, Rocky Mountains, and Andes). These typical mountains have high sea level elevations but different land–sea contrast. The probability density function (PDF) of GWPE has the independent variable of GWPE and dependent variable of occurrence probability of GWPE over a region. Our analysis showed that the PDFs of GWPE over these three mountains roughly followed lognormal distributions in all heights and months. But, the key parameters (mean value and standard deviation) of lognormal distribution varied with heights and months. Above each mountain, the two key parameters exhibited similar temporal and spatial distributions. They had the largest values around the tropopause region, smaller values in the lower stratosphere (~20–30 km), and larger values in the upper stratosphere (~35–45 km). The intermittency of GWs is represented as the ratio of the GWPE at 50th percentile to the GWPE at 90th percentile. The weakest intermittency was at ~20–30 km (above the zonal mean winds of zero) over the Tibetan Plateau and Rocky Mountains in all months and over the Andes from November to March, respectively. Generally, the weakest intermittency (~0.4) occurred in the region where the key parameters were the smallest around summer. The key parameters of lognormal distribution were dominated by annual variation over the Andes throughout the height range, 8–50 km. However, the semiannual variations are also significant in the lower stratosphere over the Tibetan Plateau and Rocky Mountains. The seasonal variations in the intermittency were not as obvious as those of the key parameters. The lognormal distributions and the intermittencies derived here provide an observational constraint on the tunable parameters in GW parameterization schemes.

Abnormal surges and the effects of the Seto Inland Sea circulation in Hiroshima Bay, Japan

The Seto Inland Sea (SIS) is the largest semienclosed coastal sea in Japan and has three connections with the outer seas. When a typhoon approached the SIS in September 2011, spatial variations of sea level elevation were observed across the SIS. Additionally, an unusual sea level rise (abnormal surge) occurred in Hiroshima Bay approximately 8 days after the typhoon passed, with the Itsukushima Shrine in the bay flooded by the surge. To understand the mechanism of the abnormal surge in the bay and the relationship between sea level variations and circulation in the SIS, we investigated the 2011 event by applying a high-resolution numerical ocean circulation model using SCHISM with bias correction for sea surface heights (SSHs) at the open boundary. The overall easterly throughflow due to the west-high east-low SSH pattern in the SIS and temporary SSH disturbances due to typhoons were well reproduced in the model results. Among the three connections, the Bungo Channel mainly determined the overall net flux into the SIS and contributed significantly to sea level variations within the SIS. Additionally, the Kii Channel played more crucial roles in shaping the circulation and local sea level variations. The Kanmon Strait exhibited minor impacts. The abnormal tide in Hiroshima Bay was mainly attributed to seawater flux input from the outer seas, in conjunction with the subtidal internal seiche with the bay. The results will help us to further understand the physical processes of the ocean and establish evidence-based safety plans for reducing natural hazard damage.

Influence of meteorological conditions in autumn/winter 2021–2022 on the development of storm surges and the dune erosion on the Polish Baltic coast as a result of climate . . . . 93

This paper presents details of 37 storm surges that occurred on the Polish southern Baltic Sea coast in the autumn/winter 2021–2022 season. They emerged during the passage of a larger number of low-pressure systems than usual from the SW-W direction over the Baltic Sea. Based on an assessment of meteorological and hydrological conditions during the storms, the relationship between the wind parameters, the sea level increase, and its maximum elevation was ascertained. The relationship between the sea level and the run-up elevation was ascertained. The elevation of the sea level and run-up on the onshore were compared with the beach height. Sections with a lower beach were affected by dune erosion already at a lower sea level. The dependence of dune erosion on the sea level elevation was presented. The value of the dune base retreat depended on the beach elevation and the sea level expressed by the onshore flow called run-up. The most significant erosion occurred during the storm Nadine with a sea level of 1.0–1.28 m AMSL. The average erosion varied between 1.0 and 4.5 m. The maximum erosion values reached 8–13 m.

Uncertainties and discrepancies in the representation of recent storm surges in a non-tidal semi-enclosed basin: a hindcast ensemble for the Baltic Sea

Abstract. Extreme sea level events, such as storm surges, pose a threat to coastlines around the globe. Many tide gauges have been measuring the sea level and recording these extreme events for decades, some for over a century. The data from these gauges often serve as the basis for evaluating the extreme sea level statistics, which are used to extrapolate sea levels that serve as design values for coastal protection. Hydrodynamic models often have difficulty in correctly reproducing extreme sea levels and, consequently, extreme sea level statistics and trends. In this study, we generate a 13-member hindcast ensemble for the non-tidal Baltic Sea from 1979 to 2018 using the coastal ocean model GETM (General Estuarine Transport Model). In order to cope with mean biases in maximum water levels in the simulations, we include both simulations with and those without wind-speed adjustments in the ensemble. We evaluate the uncertainties in the extreme value statistics and recent trends of annual maximum sea levels. Although the ensemble mean shows good agreement with observations regarding return levels and trends, we still find large variability and uncertainty within the ensemble (95 % confidence levels up to 60 cm for the 30-year return level). We argue that biases and uncertainties in the atmospheric reanalyses, e.g. variability in the representation of storms, translate directly into uncertainty within the ensemble. The translation of the variability of the 99th percentile wind speeds into the sea level elevation is in the order of the variability of the ensemble spread of the modelled maximum sea levels. Our results emphasise that 13 members are insufficient and that regionally large ensembles should be created to minimise uncertainties. This should improve the ability of the models to correctly reproduce the underlying extreme value statistics and thus provide robust estimates of climate change-induced changes in the future.

Estimation of Sea Surface Topography Using Jason-3 Satellite Altimetry Across the Eastern Indonesian Seas in a period of 2016 to 2021

The measurement of sea level height relative to a fixed reference point, such as the geoid or mean sea level, is known as sea surface topography. There are a number of factors that affect it, such as undulation, sea surface height, and tides. Measurement of sea surface topography is very important to understand ocean dynamics. One of the factors that influences the dynamics of the sea is the flow across Indonesia. The Indonesian traffic flow is the mass flow of water from the Pacific Ocean to the Indian Ocean. The difference in pressure between the two oceans is what causes the flow. The purpose of this study is to provide precise information about the sea surface topography in the East Indonesian Sea region during the 2016–2021 period, which is required for various marine applications. This approach involves processing and analysing Jason-3 altimetry satellite data, which provides precise sea level elevation measurements. The data is then used to determine the value of the sea surface topography, which shows the spatial and temporal variations in sea level height in the region. The average sea surface topography value every month from 2016 to 2021 ranges from 1.05m to 1.30m, with the highest value occurring in January 2021 at 1.2542m and the lowest value occurring in February 2016 at 1.0498m. For the accuracy of processing results, data for 2016–2021 is used as training data for model estimation and 2021 as test data. The root mean square error value is 0.0762m. Changes in sea surface topography values tend to increase every year, except for 2019. The decline that occurred in 2019 was caused by the ENSO phenomenon, which had an effect of -0.807 on sea surface topography with an inverse correlation. The findings of this study provide important details about sea surface topography in Eastern Indonesian waters, which can be applied to enhance our understanding of ocean dynamics.

Development of GNSS Buoy for Sea Surface Elevation Observation of Offshore Wind Farm

This study presents the development and testing of a global navigation satellite system (GNSS) buoy designed for measuring the sea surface elevation and tide level. The precision-point-positioning (PPP) technology is adopted for precise observation. The design of the buoy body is optimized by stability and hydrodynamic calculations. A high-performance embedded data acquisition system with big storage and high-frequency sampling is developed for long-term observation. The GNSS buoy is deployed in a wind farm approximately 70 km offshore of China, and undergoes a 60-day ocean test. A comparison of the sea level elevations obtained from the GNSS buoy and the pressure sensor shows that there is a strong correlation between them, with a correlation coefficient of 0.99. A harmonic analysis is applied to derive the harmonic constants for four key tidal components (M2, S2, O1, and K1). The amplitude differences are −1.2 cm, 1.4 cm, −0.6 cm, and −1.2 cm, respectively, and the phase differences are 1.8°, 2.2°, −1.3°, and −2.9°, respectively. The strong correlation between the measurements of the GNSS buoy and the pressure sensor and the relatively small differences of the amplitude and phase of the main tidal components indicate that the compact GNSS buoy demonstrates a capability to continuously measure the sea surface elevation and tide level with an elevation reference in the open sea.

Calcareous dinoflagellate blooms during the Late Cretaceous 'greenhouse' world-a case study from western Ukraine.

The Late Cretaceous was a unique period in the history of the Earth characterized by elevated sea levels, reduced land area, and significantly high concentrations of atmospheric CO2 resulting in increased temperatures across the globe-a 'Greenhouse World'. During this period, calcareous dinoflagellate cysts (c-dinocysts) flourished and became a ubiquitous constituent of calcifying plankton around the world. An acme in calcareous dinocysts during the Albian to the Turonian coincided with the highest recorded seawater surface temperatures and was possibly linked to conditions that favored calcification and a highly oligotrophic system in European shelf seas. This study examines the potential applicability of c-dinocysts as a proxy for paleoenvironmental conditions based on their assemblage changes plotted against foraminiferal occurrences and microfacies analysis. The material was extracted from the upper Turonian chalk of the Dubivtsi region in western Ukraine. An inverse correlation was observed between species diversity and the number of c-dinocyst specimens. Nutrient availability gradients apparently determined important changes in the calcareous dinocysts distribution. These trophic changes were likely caused by the interplay of eustatic sea-level fluctuations and Subhercynian tectonic activity leading to changeable nutrient inputs from the nearby land.

Sea level variability and coastal inundation over the northeastern Mediterranean Sea

ABSTRACT Sea level is a key element of global-scale climatic changes with significant coastal impacts. The northeastern Mediterranean Sea (Aegean, Ionian, and Cretan Seas: AICS) consists of extended low-lying coastal zones exposed to coastal inundation due to seawater level increases. The variability of the Sea Level Anomaly (SLA) in the AICS has been evaluated with the use of satellite-derived observations from 1993 to 2021. The general SLA trend over the AICS domain was 3.6 mm/year, which is higher than that of the overall Mediterranean Sea. The coastal inundation variability along the AICS coastline, specifically in 20 characteristic study areas, was investigated based on the long-term satellite-derived sea level observations, high-resolution land elevation data, and numerical simulations, conducted with a coastal inundation (CoastFLOOD) model. The coastal zones were categorized based on the frequency of occurrence and percentage coverage of flooding incidents during the 29-year period, while the interannual trends and the seasonality of inundated littoral and inland areas also showed intense spatial variation. High flooding levels occurred at coastal areas of either extended low-lying areas and/or high sea level elevations. The coastal zones were categorized based on a heuristic Coastal Inundation Hazard Index (CIHI: 1–5 ranking) that was determined by the occurrence frequency of severe floods (temporal component) and their impact area (spatial component). Our study findings provide vital information about the coastal inundation conditions and the respective hazard level of the AICS, useful to support enhanced coastal zone management for the improvement of coastal protection and decisions about coastal hazards’ mitigation.

Pemodelan Hidrodinamika 2-Dimensi Arus Laut Permukaan Perairan Desa Berakit Kabupaten Bintan

Information related to ocean currents is not yet available in Berakit Village waters, ocean currents are an important parameter to determine the condition of a waters. An alternative that can be used to determine the condition of ocean currents is to use hydrodynamic modeling. The purpose of the study was to analyze the distribution pattern and characteristics of surface ocean currents. This research was conducted by conducting 2-dimensional hydrodynamic modeling simulating ocean currents for 1 (one) year in December 2020-November 2021 using MIKE 21 software by sampling in 6 (six) different conditions, namely at the highest tide, lowest tide, high tide. towards the ebb and flow of the full moon, the ebb towards the negligible tide, the tide towards the ebb tide and the ebb towards the negligible tide. The model results were validated by the RMSE formula with a value of 2%, the model results were very good, so that they could be used as a reference in providing an overview of the real conditions of the pattern and current distribution at the research location. The movement of ocean currents at the time of the full moon and negligible dominant currents move towards the south of the waters, while at the time of the full tide and negligible the dominant currents move towards the north of the waters. In the north season, the current velocity ranges from 0.00006 m/s-0.125 m/s with the dominant movement towards the north. East monsoon currents move predominantly north and south with speeds ranging from 0.0000003 m/s-0.129 m/s. In the south monsoon the dominant current moves to the north and south at a speed of 0.0000007 m/s-0.13 m/s. in the west season, the dominant current moves to the north and south at a speed of 0.00001 m/s-0.12 m/s. The speed of the dominant ocean currents is greater at high tide compared to low tide, this is due to differences in sea level elevation in the opposite direction of motion.

Coastal protection challenges after heavy storms on the Polish coast

The paper presents the implications for future coastal protection and management policies at the marginal shelf sea on the Polish Baltic Sea coast. These emerged after a series of almost overlapping storms in January and February 2022, causing massive dune retreat at locations where hitherto relatively stable beaches demonstrated sediment deficits under long periods of more energetic wave climate and especially elevated sea levels. On the other hand, sand-saturated areas showed greater resilience. The potential sediment scarcity is expected to be linked to a possible interaction between local geological makeup and climate change-induced increases in storminess. Sandy beaches with pronounced organic intrusions become no longer sufficiently resilient. The culprit seems to be peat outcrops on the emerged beaches and its lenses inside dune massifs. Under such circumstances, it can be expected that in the future, initially isolated erosion hotspots will gradually transform into large erosion embayments. Consequently, future coastal protection and management will no longer be able to rely solely on pure nature-based solutions, but, respecting the building with nature paradigm, will involve more complex schemes with unnatural materials kept at the minimum volume to avoid disruption of seascape/landscape and discontinuity and disconnectivity of ecosystem services. However, it is important to realize that such more advanced protection measures will come at a higher cost, and coastal segments without vital economic or ecological value will have to be abandoned.

Outsized Turbidity Currents as a Primary Mechanism for Neoproterozoic Organic Carbon Delivery to the Deep Sea

Levees in modern deep-marine systems have been shown to sequester significant amounts of organic carbon due largely to their expanse and high rates of sedimentation. However, relatively few studies have examined organic carbon sequestration in ancient deep-marine leveed slope channel systems. Physical and geochemical analyses of well-exposed levee deposits in the Neoproterozoic Windermere Supergroup in B.C., Canada have shown that intervals of organic-rich (up to 4% TOC) strata correlate with conditions of elevated sea level and primary productivity on the shelf. Organic matter (OM) occurs primarily as micro- to nano-scale carbon adsorbed onto the surface of clay grains and notably occurs mostly in anomalously thick, mud-rich sandstone beds that are interspersed within successions of thin-bedded, comparatively organic-poor turbidites. The concentration of organic carbon in thick beds suggests that even when primary productivity is high it only becomes mobilized in significant quantities into the deep sea by uncommon, outsized turbidity currents. Although markedly more common in organic-rich intervals, thick, organic-rich beds occur also in organic-poor levee deposits, suggesting that the occurrence and frequency of outsized flows may be linked to primary productivity on the shelf. High rates of OM production and fallout would result in rapid accumulation of OM on the seafloor that then binds and provides mechanical strength to the accumulating sediment. Later this overthickened, organic-rich sediment pile becomes gravitationally unstable and ultimately remobilized downslope. These failure events create large, surge-like flows that are considerably thicker than the depth of the slope channels through which they travel. Accordingly, continuous overspill over the channel margins results in the deposition of an anomalously thick, sand- and organic-rich bed. These episodic events not only deplete the outer continental shelf of OM, but apparently also reduces the gradient slope of the local seabed, which then results in the more typical smaller, channel-confined organic-poor turbidity currents. Additionally, the abrupt and single-bed occurrence of OM-rich strata suggests that the buildup of organic-rich strata and seafloor stabilization was rapid but only of limited duration. Significantly, this study suggests that outsized turbidity currents that originate on the outer continental shelf are the primary mechanism for organic matter delivery to the deep sea, at least in pre-vegetation times, and that flow size and frequency, in addition to primary productivity, exerts an important control on the distribution of organic carbon in deep-sea sediments.

Coastal vulnerability assessment for the coast of Tamil Nadu, India-a geospatial approach.

A coastal region is a section of land that borders a significant body of water, often the sea or ocean. Despite their productivity, they are sensitive to even little alterations in the outside environment. This study aims to develop a spatial coastal vulnerability index (CVI) map for the Tamil Nadu coast of India, which has diverse coastal and marine environments that are ecologically fragile zones. Climate change is expected to increase the intensity and frequency of severe coastal hazards, such as rising sea levels, cyclones, storm surges, tsunamis, erosion, and accretion, severely impacting local environmental and socio-economic conditions. This research employed expert knowledge, weights, and scores from the analytical hierarchy process (AHP) to create vulnerability maps. The process includes the integration of various parameters such as geomorphology, Land use and land cover (LULC), significant wave height (SWH), rate of sea level rise (SLR), shoreline change (SLC), bathymetry, elevation, and coastal inundation. Based on the results, the very low, low, and moderate vulnerability regions comprise 17.26%, 30.77%, and 23.46%, respectively, whereas the high and very high vulnerability regions comprise 18.20% and 10.28%, respectively. The several locations tend to be high and very highdue to land-use patterns and coastal structures, but very few are contributed by geomorphological features. The results are validated by conducting a field survey in a few locations along the coast. Thus, this study establishes a framework for decision-makers to implement climate change adaptation and mitigation actions in coastal zones.

CoastFLOOD: A High-Resolution Model for the Simulation of Coastal Inundation Due to Storm Surges

Storm surges due to severe weather events threaten low-land littoral areas by increasing the risk of seawater inundation of coastal floodplains. In this paper, we present recent developments of a numerical modelling system for coastal inundation induced by sea level elevation due to storm surges enhanced by astronomical tides. The proposed numerical code (CoastFLOOD) performs high-resolution (5 m × 5 m) raster-based, storage-cell modelling of coastal inundation by Manning-type equations in decoupled 2-D formulation at local-scale (20 km × 20 km) lowland littoral floodplains. It is fed either by outputs of either regional-scale storm surge simulations or satellite altimetry data for the sea level anomaly. The presented case studies refer to model applications at 10 selected coastal sites of the Ionian Sea (east-central Mediterranean Sea). The implemented regular Cartesian grids (up to 5 m) are based on Digital Elevation/Surface Models (DEM/DSM) of the Hellenic Cadastre. New updated features of the model are discussed herein concerning the detailed surveying of terrain roughness and bottom friction, the expansion of Dirichlet boundary conditions for coastal currents (besides sea level), and the enhancement of wet/dry cell techniques for flood front propagation over steep water slopes. Verification of the model is performed by comparisons against satellite ocean color observations (Sentinel-2 images) and estimated flooded areas by the Normalized Difference Water Index (NDWI). The qualitative comparisons are acceptable, i.e., the modelled flooded areas contain all wet area estimations by NDWI. CoastFLOOD results are also compared to a simplified, static level, “bathtub” inundation approach with hydraulic connectivity revealing very good agreement (goodness-of-fit > 0.95). Furthermore, we show that proper treatment of bottom roughness referring to realistic Land Cover datasets provides more realistic estimations of the maximum flood extent timeframe.

A coupled wave-hydrodynamical model to assess the effect of Mediterranean storms under climate change: The Calabaia case study

Climate change will have an undeniable influence on coastal areas, resulting in increased rates of both sea level rise and storm-related impacts. In this context, it is crucial to estimate the local probable extreme sea wave conditions, to properly reproduce the sea state and the coastal hydrodynamic, and to investigate the effectiveness of sea defenses under sea level rise. This work describes the first steps towards an innovative fully coupled modeling system composed of a wind-sea wave (SWAN) and hydrodynamic model (2DEF). Numerical simulations, focusing on the shoreline of Calabaia, Cosenza, Italy, have been compared to the MIKE model outcomes in the same area. The simulations have been performed to investigate the inshore sea wave characteristics, to assess the effectiveness of the actual sea defense interventions, and to identify the impact of extreme storms, by combining sea level rise and extreme sea wave scenarios with the most recent georeferenced territorial data. The models are two-way coupled at half-hourly intervals exchanging the following fields: 2D sea level, surface currents and bottom elevation are transferred from 2DEF to SWAN; sea wave characteristics computed by SWAN is then passed to 2DEF by modifying the radiation stress.

ROB ANALYSIS ON THE COAST OF SEMARANG CITY (CENTRAL JAVA, INDONESIA) ON MAY 23, 2022 BASED ON TIDAL DATA AND INUNDATION DISTRIBUTION

The coast of Semarang City every year always faces flood and tidal problems. Flooding is generally caused by the ongoing rainy season, while tidal flows are caused by rising Java sea levels before the interseason change. This study aims to find the relationship between the tidal incident on May 23, 2022 on the coast of Semarang City with the tidal pattern at the Port of Semarang, and find out the distribution of tidal flows based on the height of inundation in the coastal area of Semarang City. The material used is daily tide data on May 23, 2022, monthly tide data April-May 2022. Data on the distribution of high inundation was obtained based on field surveys and interviews. The results showed that the peak of java sea level elevation occurred on May 23, 2022 with an altitude at the tide staff of 210 cm. Rob occurs almost evenly along the north coast of Semarang City with different heights. The largest tidal height occurred in the Semarang Port Area, which reached a puddle height of 100 cm. There are supposes that the amount of inundation at the site is related to the land subsidence at the site that continues to occur.