The hydrodynamics condition of water operating area for flight test site selection of N219 Amphibious aircraft

This research aims to assess the hydrodynamics condition of the water area for site selection of that purpose. The bathymetry data of Karimunjawa Island were obtained from the 1986 Pushidrosal bathymetric map. Furthermore, wind direction, wind speed, wave height and direction, and tidal data around the waters of Karimunjawa Island were input in hydrodynamic and spectral modelling using MIKE 21 HD-SW. West monsoon and east monsoon were applied in this model. The validation result between hydrodynamic modelling and Tidal Model Driver (TMD) data is 98.89%. The surface elevation around the domain has a range of 0.072 - 0.5 m. The average water depth at the seaplane dock plan is about 2.5 m from MSL. The hydrodynamic modeling results show that the surface elevation value at the seaplane dock plan location shows that the sea level is between -0.467 to 0.473 m (in both west and east season). The current velocity at the planned seaplane dock site in both the west and east monsoons is relatively slow (<0.185 m/s). The dominant wave direction is southeastward in the east and west monsoons. The dominant Hs is about 0.23 – 0.6 m in both seasons. At the planned water operating area, the average of Hs is 0.23 m - 0.36 m. Generally, this location fulfills the criteria of site selection for the flight test location of N219A.

THE SHIP WRECK OF THE LATE 4th / EARLY 3rd CENTURY BC NEAR KINBURN SPIT

During the campaign of 2018 the international underwater archaeological expedition has explored the waters of Tendra Spit and Kinburn Spit on the shelf of the Black Sea, in Mykolaiv and Kherson regions of Ukraine. Underwater archaeological exploration focused on the waters near the northern tip of Tendra Spit, from both the Gulf of Tendra and the sea, and north-western tip of Kinburn Spit. In addition to the visual reconnaissance, divers were using sonar, profiler and side-scan sonar. As a result, the bathymetric map has been compiled. In the initial part of research the work was limited to mapping and taking photographs of the discoveries. During these works was discovered and cleansed the ancient Shipwreck of the late 4th — early 3rd century BC. It was possible to identify the well-preserved fragment of the hull of ancient Wreck of a length of 9.45 m in situ with ballast stones, ceramic material from the cargo, lead plating and him constructions elements. After clearing of the sand from the preserved part of the ship hull with the help of a hydro injector the video and photo documentation was carried out. As a result of these works, large-scale photo mosaic of the object and its 3D-model were made. The condition of the wooden hull is excellent, the technological holes, connections, bronze and iron nails are preserved. Outside of Ukraine several shipwrecks of the same period are attested. The best studied are the following: shipwreck of the 3rd century BC at Grand Congloue, France; the Mazotos shipwreck of the 4th century BC in Cyprus; the Porticello shipwreck of the end of the 5th or beginning of the 4th century BC in Italy; the Alonnisos shipwreck from the end of the 5th century BC, Greece; the Kyrenia shipwreck from the end of the 4th — beginning of the 3rd centuries BC in Cyprus. In the Black Sea, in 2011 a shipwreck from the end of the 4th — beginning of the 3rd centuries BC near Eregli, Turkey (ancient Herakleia Pontica) was discovered by a deep-sea expedition of the research vessel «Nautilus» under the direction of Michael Brennan at a depth of 101 m. Most of the known merchant ships of this period were small, ranging from 12 to 17 m (table). Boris Peters provides a reconstruction sketch of the Lake Donuzlav ship of the late 4th — early 3rd centuries BC. It is almost identical to the reconstruction of the Kyrenia merchant ship, based on its hull which was preserved by 75 %, The replica named «Kyrenia 2» was built and made several voyages. It can be assumed that the Kinburn Spit ship found in 2018 was of similar appearance but further research will provide more detailed information.

Novel Bathymetry of Lake Afdera Reveals Fault Structures and Volcano-Tectonic Features of an Incipient Transform Zone (Afar, Ethiopia)

Lake Afdera is a hypersaline endorheic lake situated at 112 m below sea-level in the Danakil Depression. The Danakil Depression is located in the northern part of the Ethiopian Afar and features an advanced stage of continental rifting. The remoteness and inhospitable environment explain the limited scientific research and knowledge about this lake. Bathymetric data were acquired during 2 weeks expeditions in January/February 2016 and 2017 using an easily deployable echosounder system mounted on an inflatable motorized boat. This study presents the first complete bathymetric map of the lake Afdera. Bathymetric results show that the lake has an average depth of 20.9 m and a total volume of 2.4 km3. The maximum measured depth is 80 m, making Lake Afdera the deepest known lake in Afar and the lowest elevation of the Danakil Depression. Comparison with historical reports shows that the lake level did not fluctuate significantly during the last 50 years. Two distinct tectonic basins to the north and the south are recognized. Faults of different orientations control the morphology of the northern basin. In contrast, the southern basin is affected by volcano-tectonic processes, unveiling a large submerged caldera. Comparison between the orientation of faults throughout the lake with the regional fault pattern indicates that the lake is part of two transfer zones: the major Alayta–Afdera Transfer Zone and the smaller Erta Ale–Tat’Ali Transfer Zone. The interaction between these Transfer Zones and the rift axis forms the equivalent of a developing nodal basin which explains the lake’s position as the deepest point of the depression. This study provides evidence for the development of an incipient transform fault on the floor of the Afar depression.

Methodology for Bathymetric Mapping Using Open-Source Software

The modern technologies not only provide an opportunity to collect water depth data much more efficiently than in the past, but also there is a wide range of opportunities to process these data to develop bathymetric maps and perform various calculations in the computer environment. This research aims to construct a high-resolution bathymetric map by using open-source software. Lake Zebrus was selected as the study site, where fieldwork was performed to obtain the depth data and subsequently process to find optimal methodology for creating a bathymetric map. The methodology used in this research is modifiable for different purposes and is based on obtaining the best results from using open-source resources and knowledge of cartography. Lake Zebrus is an example how to perform accurate and state of the art bathymetric survey in a short time period. The area of Lake Zebrus is 417.57 ha. The lake has a small crooked coastline. Lake Zebrus has a maximum depth of 4.45 m and an average depth of 1.48 m. Results from the bathymetric survey can be used for further research based on depth data. The research tasks are accomplished as the methodology selected is repeatable in the other lakes. The research results prove that this methodology can be used for a bathymetric survey and it is possible to obtain high-definition results using open-source resources.

MORPHOLOGICAL EVOLUTION OF THE BOTTOM OF THE POTOU LAGOON OVER THE LAST TEN YEARS (COASTAL ZONE OF COTE D'IVOIRE)

This study with a morphology and hydrosedimentology character was done to carry out a with an understanding the evolution of the channels and sedimentation in Potou lagoon in Ivory Coast starting from the realization of the bathymetric map. The bathymetry of this lagoon avered that the depths are lower than 2.11 m out of 22 km2, and presente three types of channels. In fact the channels in "U" represent a balance between the agents of accumulation and erosion. Channels resulting from processes of erosion which are in "V" and channels intermediate indicating an evolution of the type "V" in "U". In particular during these fourteen last years the Potou lagoon has sudden great phenomenon of deposit is a volume of +66791000.18 m³of sediments deposed on a surface which is thus estimated at 65.2 % of chenal surface. These deposits are certainly causes of full high funds in this lagoon. The mean velocity of sedimentation on Potou lagoon is thus estimated at 26.5 cm/year. As for the erosion, it could be estimated at-8487601 m³ a volume of on a surface wich is thus estimated at 34 % of chenal surface. The sedimentary budget would be thus estimated at+58303398.68449 m³ on a surface of 12.45 m2. A surface which is thus estimated at 0.8 %hasn’t sudden phenomenon of deposit or erosion. The bathymetric chart and the sedimentary budget of Potou lagoon are tools necessary for use of the stretch of water by the users. Thus, the zones at the risks determined on the bathymetric chart, such as the high bottom and the points of swirl generated by the depressions, will be easily avoided.

Caractérisation hydrologique et morpho-sédimentaire d’une zone de dragage en lagune Ebrié et risques de contamination de la nappe d’Abidjan : cas du secteur lagunaire Abatta- Bingerville

The main objective of this study is to assess the impacts of dredging on the Abidjan aquifer in the Bingerville sector. The data acquisition campaigns take place in July 2019. They consisted in the collection of morphobathymetric, hydrological and sedimentological data in the study area where catchment fields are located at most four (4) kilometers away. The physicochemical and microbiological analysis of the waters in this sector of the Ebrié lagoon has shown that they are of poor quality and therefore unsuitable for all domestic and consumer uses. Thus, any intrusion into the Abidjan aquifer would be synonymous with pollution of the aquifer water, the treatment of which would prove to be very expensive. The conductivity levels, especially at the bottom of the water (≥ 4m deep), are therefore higher than the WHO potability standard (2006) which is <2500 µS / cm. In addition, the bathymetric surveys obtained have highlighted topographic backgrounds with depressions of 4 to 5 m in general. However in dredging areas depths of more than 15 m have been observed. To assess the speed of sedimentation in order to assess the sanding capacity of dredged areas, this bathymetric map was superimposed on that of 1975 produced by TASTET. This superimposition highlights sedimentary movements with very significant sedimentation rates ranging from 1.7 to 1.9 m / s.

Late-glacial fluctuations of two southern Patagonia outlet glaciers revealed by high-resolution seismic surveys

Lago Argentino hosts various calving glaciers, among them the famous Perito Moreno. Whereas the onland late Pleistocene–Holocene glacial history is rather well constrained, the submerged glacier-related features were until now undisclosed. Here we present a series of high-resolution seismic profiles revealing moraine bodies associated with the late-glacial glacier dynamics and the first bathymetric map of the Brazo Rico and Brazo Sur, the two southern arms of Lago Argentino. At the eastern termination of Brazo Rico, we identified at the lake floor the submerged expression of the Puerto Bandera 3 moraine mapped onshore, which represents the oldest event (12,660 ± 70 cal yr BP oldest minimum age) recognized in this lake arm, and seven other younger events expressed by a series of terminal and recessional moraines. Along the Brazo Sur, few moraine bodies have been imaged by seismic data. Here, the youngest temporal constraint comes from the Frías moraine (ca. 6000 cal yr BP), which closes off the southern end of the Brazo Sur. At the confluence of the two arms, the Perito Moreno and the former Frías glacier merged and flowed toward east during their late-glacial maximum advance (i.e., Puerto Bandera 1 moraine). The subaqueous evidence of moraine bodies testifies to the occurrence of previously undocumented pulses of the Perito Moreno and former Frías glaciers within the general phase of late Pleistocene–Holocene regression.

Tidal asymmetry in the Sylt-Romo Bight, south-eastern North Sea

&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;The study is dedicated to the tidal dynamics in the Sylt-R&amp;#248;m&amp;#248; Bight with a focus on the non-linear processes. The FESOM-C model was used as the numerical tool, which works with triangular, rectangular or mixed grids and is equipped with a wetting/drying option. As the model&amp;#8217;s success at resolving currents largely depends on the quality of the bathymetric data, we have created a new bathymetric map for an area based on recent studies of Lister Deep, Lister Ley, and the H&amp;#248;jer and R&amp;#248;m&amp;#248; Deep areas. This new bathymetric product made it feasible to work with high resolution grids (up to 2 m in the wetting/drying zone). As a result, we were able to study the tidal energy transformation and the role of higher harmonics in the domain in detail. The tidal ellipses, maximum tidally-induced velocities, energy fluxes and residual circulation maps were constructed and analysed for the entire bight. Additionally, tidal asymmetry maps were introduced and constructed. The full analysis was performed on two grids with different structures and showed a convergence of the results as well as fulfillment of the energy balance. The tidal residual circulation and asymmetric tidal cycles largely define the circulation pattern, transport and accumulation of sediment and the distribution of bedforms in the bight, therefore the results are necessary and useful benchmarks for further studies in the area, including baroclinic and sediment dynamics investigations.&lt;/p&gt;

SPECIFIC FEATURES OF THE GEODYNAMIC SETTINGS IN THE AREA OF THE SOUTHEASTERN LINK OF THE MAGELLAN MOUNTAINS, PACIFIC OCEAN

On the basis of a detailed bathymetric map of the area of the southeastern part of the Magellan Mountains constructed on the results of multi-beam echolocation, the authors performed a lineament analysis of the relief, distinguished linear relief objects, measured their azimuths, and built a rose-diagram of the direction of the area's lineaments. Models of the deep and near-surface deformation field of the area with the selection of blocks with the predominant stretching and the predominant compression are constructed. Along the lines of changing the sign of stress (block boundaries), block movements occur. The directions of the block boundaries are compared with the direction of the lineaments, and a conclusion is made about their spatial and genetic relationship. Systems of the direction of linear landforms and boundaries of deep and near-surface blocks partially correspond to four main systems of the global regmatic network indicating a significant influence of the latter on the structural plan of the area. The redistribution of stress values is associated with modern geological processes that lead to the formation of new features of the bottom relief and partial destruction of the old guyot surfaces.