Quasi-steady circulation regimes in the Baltic Sea

Circulation plays an essential role in the creation of physical and biogeochemical fluxes in the Baltic Sea. The main aim of the work was to study the quasi-steady circulation patterns under prevailing forcing conditions. Six months of continuous vertical profiling and fixed-point measurements of currents, two monthly underwater glider surveys, and numerical modelling were applied in the central Baltic Sea. The vertical structure of currents was strongly linked to the location of the two pycnoclines: the seasonal thermocline and the halocline. The vertical movements of pycnoclines and velocity shear maxima were synchronous. The quasi-steady circulation patterns were in geostrophic balance and high-persistent. The persistent patterns included circulation features such as upwelling, downwelling, boundary current, and sub-halocline gravity current. The patterns had a prevailing zonal scale of 5–60 km and considerably higher magnitude and different direction than the long-term mean circulation pattern. Northward (southward) geostrophic boundary current in the upper layer was observed along the eastern coast of the central Baltic in the case of southwesterly (northerly) wind. The geostrophic current at the boundary was often a consequence of wind-driven, across-shore advection. The sub-halocline quasi-permanent gravity current with a width of 10–30 km from the Gotland Deep to the north over the narrow sill separating the Farö Deep and Northern Deep was detected in the simulation, and it was confirmed by an Argo float trajectory. According to the simulation, a strong flow, mostly to the north, with a zonal scale of 5 km occurred at the sill. This current is an important deeper limb of the overturning circulation of the Baltic Sea. The current is stronger with northerly winds and restricted by the southwesterly winds. The circulation regime has an annual cycle due to seasonality in the forcing. Boundary currents are stronger and more frequently northward during the winter period. The sub-halocline current towards the north is strongest in March–May and weakest in November–December.

Numerical simulation of storm surge associated with severe cyclonic storms in the Bay of Bengal during 2008-11

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Regional management of the Bay of Bengal water area. The challenges of maritime security

The Bay of Bengal is the largest bay in the world that forms the northeastern part of the Indian Ocean, bordered mostly by the Eastern Coast of India, southern coast of Bangladesh and Sri Lanka to the west and Myanmar and the Andaman and Nicobar Islands (part of India) to the east. The regional management of the Bay of Bengal water area is performed by regional organisations such as ASEAN, SAARC, BIMSTEC and IORA unifying Bay’s coastal states. Nevertheless, differences in political and economic interests of the states, separate conflicts between states and consequences of the pandemic not only challenged the integrity of the regional management but also led to rising insecurity of the Bay of Bengal and fears to navigate in that area. In this article, the authors, in a more detailed way, will disclose existing regional management systems, concerns related to maritime security and give recommendations on how to increase efficiency in collective management of maritime security issues and how the concept of due diligence may play the vital role in the regulation of not only maritime security aspects but also aspects of environmental protection and potential transition to the blue economy.

The Gulf Stream and the Californian Current as Factors Affecting the Behavior and Health of Americans

Due to the existence of the Earth's geomagnetic field, Lorentz’s forces constantly act on all sea currents. These forces distribute the charges of sea currents in both vertical and horizontal directions. In particular, this distribution manifests itself in the electric polarization of sea currents in directions perpendicular to them. So, earlier it was shown that the same Lorentz forces cause negative electrization of the Sargasso Sea. It is also shown here that the positive electrization of the western edge of the Gulf Stream and, consequently, the eastern coast of the United States is also caused by the Lorentz force arising from the interaction of this sea current with the vertical component of the geomagnetic field. It is also shown here that the positive electrization of east edge of California Current together with west coast of USA is also caused due to the similar reasons. All this allows us to conclude that an increased concentration of positive air ions is constantly retained in the air both in the east and in the west of the United States. This situation has caused the need for an analysis of how the predominantly positive electrization of the air affects both human health and their physical and mental activity. The results of this analysis are presented here. It is also shown that these results can be useful for residents of some other countries.

Modeling The Mysterious Tsunami Swirls In The Northeast Coast Of Japan During The March 2011 Tohoku Earthquake

The formation of tsunami swirls near the coast is an obvious oceanographic phenomenon during the occurrence of giant submarine earthquakes and mega-tsunamis. Several tsunami vortices were generated during the Asian tsunami of 2004 and the great Japan tsunami of March 2011 which lasted for several hours.New models of tsunami generation and propagation are hereby proposed and were used to investigate the tsunami inception, propagation and associated formation of swirls in the eastern coast of Japan. The proposed generation model assumes that the tsunami was driven by current oscillations at the seabed induced by the submarine earthquake. The major aim of this study is to develop a tsunami model to simulate the occurrence of tsunami swirls. Specifically, this study attempts to simulate and understand the formation of the mysterious tsunami swirls in the northeast coast of Japan. In addition, this study determines the vulnerability of the Philippines to destructive tsunami waves that originate near Japan. A coarse resolution model was therefore developed in a relatively large area encompassing Japan Sea and the eastern Philippine Sea. On the other hand, a fine-resolution model was implemented in a small area off Sendai coast near the epicenter. The model result was compared with the tsunami record obtained from the National Data Buoy Center with relatively good agreement as far as the height and period of the tsunami are concerned. Furthermore, the fine-resolution model was able to simulate the occurrence of tsunami vortices off Sendai coast with various sizes that lasted for several hours.