Roles of Geospatial Technologies in Hydrographic Practice

Any seafarer or mariner that uses the sea knows that navigation without correct charts is impossible and hazardous because nautical charts are the most essential and indispensable tools for vessels to sail safely at sea. For vessels to safely sail at sea, the seas and the oceans ought to be charted and this falls within the domain of hydrography. However, the seas cannot be charted effectively in the absence of the deployment of human resources and adequate tools like satellite and aerial imagery, survey boats and other equipment that will facilitate the hydrographic operations. The acquisition of data and information about the sea depths, nature of sea bed, waterways, navigational hazards and navigational objects among others, basically falls within the sphere of hydrography which is primarily known as survey at sea. The paper offers a review of geospatial technologies in hydrographic practice for enhanced safety of navigation at sea. The review is important to both the mariners, shipping industry and the government in order to explore the potentials provided by Geographic Information System, Remote Sensing, cloud GIS, big data GIS and Global Positioning System to enhance the practice of hydrography. The data and materials used for the review were obtained from literature in the internet and other published works. The paper looked at hydrography as a profession, roles of geospatial technologies in hydrographic practice, benefits of hydrography to national development and finally, the weaknesses of geospatial technologies in hydrographic practice were equally examined.

Algorithmic Design of an FPGA-Based Calculator for Fast Evaluation of Tsunami Wave Danger

Events of a seismic nature followed by catastrophic floods caused by tsunami waves (the incidence of which has increased in recent decades) have an important impact on the populations of littoral regions. On the coast of Japan and Kamchatka, it takes nearly 20 min for tsunami waves to approach the nearest dry land after an offshore seismic event. This paper addresses an important question of fast simulation of tsunami wave propagation by mapping the algorithms in use in field-programmable gate arrays (FPGAs) with the help of high-level synthesis (HLS). Wave propagation is described by the shallow water system, and for numerical treatment the MacCormack scheme is used. The MacCormack algorithm is a direct difference scheme at a three-point stencil of a “cross” type; it happens to be appropriate for FPGA-based parallel implementation. A specialized calculator was designed. The developed software was tested for precision and performance. Numerical tests computing wave fronts show very good agreement with the available exact solutions (for two particular cases of the sea bed topography) and with the reference code. As the result, it takes just 17.06 s to simulate 1600 s (3200 time steps) of the wave propagation using a 3000 × 3200 computation grid with a VC709 board. The step length of the computational grid was chosen to display the simulation results in sufficient detail along the coastline. At the same time, the size of data arrays should provide their free placement in the memory of FPGA chips. The rather high performance achieved shows that tsunami danger could be correctly evaluated in a few minutes after seismic events.

Late Quaternary Geology of the Canterbury Continental Terrace

<p>The Late Quaternary stratigraphy and sedimentary processes are interpreted for an area of continental shelf and slope on the eastern side of the South Island, New Zealand, between latitudes 43°00's and 44°50's. Two formations are recognised in the Late Quaternary stratigraphy of the shelf: the Canterbury Bight Formation of mainly Last Glacia1 age and, locally overlying it, the Pegasus Formation of mainly Holocene age. The formations are distinguished by shelf-wide unconformities (visib1e in seismic profiles), by geomorphology, by grain-size modes, and by macrofauna. Ridge-and-swa1e topography occurs on two scales on the shelf. Very large ridges and troughs are interpreted from microbathymetry, stratigraphy, sediments and macrofauna to be the remains of Pleistocene barrier/lagoon complexes. With the aid of radiocarbon dates, four well developed shorelines between 28,000 yr and 15,000 yr old are recognised. The smaller ridges are submarine features, formed by strong currents. Those ridges that are in a zone of constricted and accelerated currents near Banks Peninsula are active, while those well removed from the peninsula constriction are fossil and date from times of lower sea level. Sedimentation on the continental shelf has reached a state of equilibrium with the modern hydraulic regime. Relict sediments of the deglacial transgressive sand/gravel sheet are being reworked in zones of high energy, principally in the region of constricted flow around Banks Peninsula. Modern-input sand (distinguished by its grain-size mode) is restricted by currents mainly to an active belt near shore, but locally it has replaced palimpsest sand on the middle shelf. The modern mud facies, being confined by zones of higher energy, has reached its maximum areal extent; its greatest thickness is in Pegasus Bay. Sea-bed drifter studies, and studies of sediment texture and provenance show that net sediment movement on the shelf and along shore during both Pleistocene and modern times has been northwards. The continental slope is dissected by submarine slide scars in the south and by submarine canyons in the north. Streams of fine sand, transported from the continental shelf to the upper slope by north-flowing currents during Pleistocene lowered sea levels, initiated the erosion of submarine canyons. Interception of littoral-drifted gravel by established canyons reaching Pleistocene strand lines probably accelerated. canyon erosion. The canyons are thought to be now effectively dormant. Deposition of fine sediment from suspension has dominated the development of the southern slope. This slope is consequently free of deeply corrasional features like submarine canyons but is prone to failure by gravity sliding. The youngest slides are less than 18,000 yr old. The history of growth of Pegasus Submarine Canyon is investigated in detail. The course of the canyon across the shelf is not fault controlled. As well as growing landwards, the canyon and its tributaries have, during Pleistocene sea level stillstands, grown southwards along shore towards the supply of littoral drifted gravel and sand. A buried tributary, of Penultimate Glacial age or older, on the canyon's west side, once brought the canyon 7 km closer to the present shore. The relative ages of the south-trending arms of the canyon are inferred from their relationship to known Last Glacial shorelines that are preserved on the shelf, and by their position with respect to a regional subsurface unconformity of Penultimate Glacial age. Canyon erosion was concentrated in the largest arm during the last deglacial rise of sea level, and shallow channels, interpreted as feeders are common around its rim.</p>

Late Quaternary Geology of the Canterbury Continental Terrace

<p>The Late Quaternary stratigraphy and sedimentary processes are interpreted for an area of continental shelf and slope on the eastern side of the South Island, New Zealand, between latitudes 43°00's and 44°50's. Two formations are recognised in the Late Quaternary stratigraphy of the shelf: the Canterbury Bight Formation of mainly Last Glacia1 age and, locally overlying it, the Pegasus Formation of mainly Holocene age. The formations are distinguished by shelf-wide unconformities (visib1e in seismic profiles), by geomorphology, by grain-size modes, and by macrofauna. Ridge-and-swa1e topography occurs on two scales on the shelf. Very large ridges and troughs are interpreted from microbathymetry, stratigraphy, sediments and macrofauna to be the remains of Pleistocene barrier/lagoon complexes. With the aid of radiocarbon dates, four well developed shorelines between 28,000 yr and 15,000 yr old are recognised. The smaller ridges are submarine features, formed by strong currents. Those ridges that are in a zone of constricted and accelerated currents near Banks Peninsula are active, while those well removed from the peninsula constriction are fossil and date from times of lower sea level. Sedimentation on the continental shelf has reached a state of equilibrium with the modern hydraulic regime. Relict sediments of the deglacial transgressive sand/gravel sheet are being reworked in zones of high energy, principally in the region of constricted flow around Banks Peninsula. Modern-input sand (distinguished by its grain-size mode) is restricted by currents mainly to an active belt near shore, but locally it has replaced palimpsest sand on the middle shelf. The modern mud facies, being confined by zones of higher energy, has reached its maximum areal extent; its greatest thickness is in Pegasus Bay. Sea-bed drifter studies, and studies of sediment texture and provenance show that net sediment movement on the shelf and along shore during both Pleistocene and modern times has been northwards. The continental slope is dissected by submarine slide scars in the south and by submarine canyons in the north. Streams of fine sand, transported from the continental shelf to the upper slope by north-flowing currents during Pleistocene lowered sea levels, initiated the erosion of submarine canyons. Interception of littoral-drifted gravel by established canyons reaching Pleistocene strand lines probably accelerated. canyon erosion. The canyons are thought to be now effectively dormant. Deposition of fine sediment from suspension has dominated the development of the southern slope. This slope is consequently free of deeply corrasional features like submarine canyons but is prone to failure by gravity sliding. The youngest slides are less than 18,000 yr old. The history of growth of Pegasus Submarine Canyon is investigated in detail. The course of the canyon across the shelf is not fault controlled. As well as growing landwards, the canyon and its tributaries have, during Pleistocene sea level stillstands, grown southwards along shore towards the supply of littoral drifted gravel and sand. A buried tributary, of Penultimate Glacial age or older, on the canyon's west side, once brought the canyon 7 km closer to the present shore. The relative ages of the south-trending arms of the canyon are inferred from their relationship to known Last Glacial shorelines that are preserved on the shelf, and by their position with respect to a regional subsurface unconformity of Penultimate Glacial age. Canyon erosion was concentrated in the largest arm during the last deglacial rise of sea level, and shallow channels, interpreted as feeders are common around its rim.</p>

Sedimentary Processes and the Holocene Development of Palmyra Atoll, Equatorial Pacific Ocean

<p>Coral atolls are unique landforms in that they are the physical manifestations of the interplay between both biological and geological processes. Prominent amongst these processes is the ability of the reef organisms to produce CaCO3 and its subsequent erosion and dispersal as sediment. Overriding controls on this process are organic productivity, wave energy, and relative sea level. The development and stability of atolls are thus critically dependent on the balance between several processes which may change over time. Atolls are regarded as being particularly vulnerable to environmental change. This study investigates the Holocene geological history of Palmyra atoll, at 5°52’N 162°04’W, in the northern Line Islands. Beachrock is used as an indicator of (a) paleo-sea level and (b) paleo-shoreline conditions from clasts trapped within the beachrock matrix. The study also models annual CaCO3 production and hydrodynamic conditions at the sea bed to provide an integrated assessment of the past and present sedimentary processes and reef island development at Palmyra Atoll. The atoll is currently the focus of intensive scientific study by the Palmyra Atoll Research Consortium and is particularly suited to this study because of the reduced human presence. This allows the examination of the relationship between beachrock, islet development and other processes, in an environment lacking ongoing anthropogenic development. Beachrock was found at 10 locations at Palmyra Atoll and yielded 14C ages ranging from 1249 to 105 cal. yrs BP. Typically, the beachrock contains mostly coral and algal clasts and is thought to form in the intertidal zone. Continual wetting and drying throughout a tidal cycle results in the precipitation of marine phreatic cements, which thus, indicate paleo-shorelines and sea level elevation. The production of CaCO3 sediment at Palmyra was estimated using reef habitat zones from Hopley (1996) and suggests that the most productive areas are reef terraces and the reef edge. An estimate total of 91,500 tonnes of CaCO3 is produced annually on the reefs, although only approximately 9 % of this becomes sediment that remains on the reef islands. Hydrodynamic processes were modelled using the SWAN model, a bathymetric grid from NOAA, and bottom conditions estimated from other studies. Input parameters were determined using a 13 year WAVEWATCHIII hindcast model of the wave climate for the central Pacific, as well as estimations of extreme wave events. Sediment transport was inferred from the modelled bed shear stress and these results show that to form most of the beachrock outcrops on Palmyra extremely strong wave action must be coupled with a higher sea level in order to allow the propagation of wave energy across the reef to some of the island shorelines. Integration of all results suggests that growth of the reef islands at Palmyra Atoll was initiated as the sea level fell from the mid-Holocene Highstand, 1-2 m above present mean sea level. The islands subsequently grew progressively eastward, forming 3-4 island chains which strike north or northeast. The beachrock that formed on these island provided protection from later wave erosion. Despite limitations caused by lack of climatic and other environmental data due to the isolation of the study area, results are reliable and highlight the application of beachrock as a proxy for past climates and sea levels.</p>

Sedimentary Processes and the Holocene Development of Palmyra Atoll, Equatorial Pacific Ocean

<p>Coral atolls are unique landforms in that they are the physical manifestations of the interplay between both biological and geological processes. Prominent amongst these processes is the ability of the reef organisms to produce CaCO3 and its subsequent erosion and dispersal as sediment. Overriding controls on this process are organic productivity, wave energy, and relative sea level. The development and stability of atolls are thus critically dependent on the balance between several processes which may change over time. Atolls are regarded as being particularly vulnerable to environmental change. This study investigates the Holocene geological history of Palmyra atoll, at 5°52’N 162°04’W, in the northern Line Islands. Beachrock is used as an indicator of (a) paleo-sea level and (b) paleo-shoreline conditions from clasts trapped within the beachrock matrix. The study also models annual CaCO3 production and hydrodynamic conditions at the sea bed to provide an integrated assessment of the past and present sedimentary processes and reef island development at Palmyra Atoll. The atoll is currently the focus of intensive scientific study by the Palmyra Atoll Research Consortium and is particularly suited to this study because of the reduced human presence. This allows the examination of the relationship between beachrock, islet development and other processes, in an environment lacking ongoing anthropogenic development. Beachrock was found at 10 locations at Palmyra Atoll and yielded 14C ages ranging from 1249 to 105 cal. yrs BP. Typically, the beachrock contains mostly coral and algal clasts and is thought to form in the intertidal zone. Continual wetting and drying throughout a tidal cycle results in the precipitation of marine phreatic cements, which thus, indicate paleo-shorelines and sea level elevation. The production of CaCO3 sediment at Palmyra was estimated using reef habitat zones from Hopley (1996) and suggests that the most productive areas are reef terraces and the reef edge. An estimate total of 91,500 tonnes of CaCO3 is produced annually on the reefs, although only approximately 9 % of this becomes sediment that remains on the reef islands. Hydrodynamic processes were modelled using the SWAN model, a bathymetric grid from NOAA, and bottom conditions estimated from other studies. Input parameters were determined using a 13 year WAVEWATCHIII hindcast model of the wave climate for the central Pacific, as well as estimations of extreme wave events. Sediment transport was inferred from the modelled bed shear stress and these results show that to form most of the beachrock outcrops on Palmyra extremely strong wave action must be coupled with a higher sea level in order to allow the propagation of wave energy across the reef to some of the island shorelines. Integration of all results suggests that growth of the reef islands at Palmyra Atoll was initiated as the sea level fell from the mid-Holocene Highstand, 1-2 m above present mean sea level. The islands subsequently grew progressively eastward, forming 3-4 island chains which strike north or northeast. The beachrock that formed on these island provided protection from later wave erosion. Despite limitations caused by lack of climatic and other environmental data due to the isolation of the study area, results are reliable and highlight the application of beachrock as a proxy for past climates and sea levels.</p>

Sedimentological data-driven bottom friction parameter estimation in modelling Bristol Channel tidal dynamics

Accurately representing the bottom friction effect is a significant challenge in numerical tidal models. Bottom friction effects are commonly defined via parameter estimation techniques. However, the bottom friction coefficient (BFC) can be related to the roughness of the sea bed. Therefore, sedimentological data can be beneficial in estimating BFCs. Taking the Bristol Channel and Severn Estuary as a case study, we perform a number of BFC parameter estimation experiments, utilising sedimentological data in a variety of ways. Model performance is explored through the results of each parameter estimation experiment, including applications to tidal range and tidal stream resource assessment. We find that theoretically derived sediment-based BFCs are in most cases detrimental to model performance. However, good performance is obtained by retaining the spatial information provided by the sedimentological data in the formulation of the parameter estimation experiment; the spatially varying BFC can be represented as a piecewise-constant field following the spatial distribution of the observed sediment types. By solving the resulting low-dimensional parameter estimation problem, we obtain good model performance as measured against tide gauge data. This approach appears well suited to modelling tidal range energy resource, which is of particular interest in the case study region. However, the applicability of this approach for tidal stream resource assessment is limited, since modelled tidal currents exhibit a strong localised response to the BFC; the use of piecewise-constant (and therefore discontinuous) BFCs is found to be detrimental to model performance for tidal currents.

Rules on Decarbonization and Humans Rights Law

In the 21st-century pandemic world faces, the challenge of global climate change in the form of temperature increase resulting in global warming, extremely crucial for small Iceland states. States from the South Pacific region are the biggest emitters of GHG. Rules of International Environmental Law are being called upon to address the protection and preservation of each environmental media including atmospheric air as substantial media for livelihood on the planet earth. Covid 19 disease strikes human’s breathing system and it is possible, that somehow this is reasoned from changes in the climate system. Thus, the rights of humans proclaimed and established on an international scale under ECHR and 1966 Covenants on separate rights of Humans are correlated with rules of environmental law, likewise, sedentary rocks on the sea bed are connected with the deep seabed, for the sustainability of their lifecycle. If the rights to life, to private and family life are protected and respected for the enjoyment by human beings, the Rules of International Environmental law on climate change mitigation are respected and implemented simultaneously because UNFCC, Paris Agreement, and Kyoto Protocol aim to protect the global atmosphere from GHG emissions ultimately to keep life on the earth, which includes Human’s opportunity to live in a healthy environment under rights to life, private life, and family living standards. The present article tries, briefly to describe how rules of IEL on Climate Change (Hard Laws) and Human Rights Norms interrelate with each other.

Accuracy Assessment of Satellite Derived Bathymetry Model for Depth Extraction in Sorong Shallow Water Area

Marine research has continuously improved the methods in obtaining the related bathymetric data; not only relying on the conventional methods for i.e. echosounder-based methods, but also by incorporating satellite technology for i.e. passive remote sensing technology, in this case, satellite derived bathymetry (SDB). Regarding the SDB method, as we know, variation of sea bed cover can influence the relation between the spectral reflection of shallow water area and the depth of the sea. In this situation, normalization of the sea bed variation is needed. Previous studies have mentioned that the band ratio can help to normalize the variation of sea bed cover. This research is intended to compare the accuracy of satellite derived bathymetry by using single band and band ratio. Four bands of Sentinel 2A (blue, green, red, and NIR bands) are used along with a single beam echosounder (SBES) measurement data published in 2015 used as training and testing data for the SDB model. Furthermore, the influence of sun glint correction to the results was evaluated and the accuracy of the model was estimated. In total there are four single bands and six combinations of band ratio that are used for this research. The results show that green band outperformed band ratio in term of RMSE value. However, visually, only band ratio of blue/green band that provided a much more representative depth spatial distribution especially for shallow water area below 3 m. In this case, band ratio is effective in normalizing the variation of sea bed cover. Furthermore, the use of sun glint correction in the process is also increase accuracies of the SDB model. The highest accuracy was obtained when using green band after sun glint correction with RMSE value 2.999 m while when using band ratio of the blue band to the green band (blue/green), the accuracy was 3.624 m. In conclusion, SDB model to extend methods in obtaining bathymetry data is promising as more images become available free of charge and in various resolutions.