• 010505 oceanography close

The modern approach for wind wave climate estimation is presented. The input for wave calculation by numerical models is reanalysis data. For extreme wave estimation in severe storms the reanalysis data has to be corrected (by regression model as an example). For calculations of wind waves in Caspian Sea SWAN model was used. 40 years continues calculations were made. At the first stage calculations performed for whole the sea, and then these data were used as the first input for detailed calculations for shallow the Northern Caspian Sea. The estimates of extreme wave heights were presented for different depths.

The Earth system models have been actively developed during recent decades. They integrate the blocks describing the dynamics of the atmosphere, the ocean and the cryosphere. The Antarctic ice sheet (AIS) is one of the most important components of the Earth’s cryosphere. Therefore, the incorporation of the AIS model into the Earth system model will significantly improve the accuracy of reconstructions of climate parameters for paleoclimate studies and for climate predictions. This paper presents a description of the energy balance block of the AIS model. This is a continuation of our recent work on integration of the cryosphere block to the climate model. The testing of the block (the EWBM-A buffer model) was carried out using the climate data generated by the INMCM model developed in the Institute of Numerical Mathematics of RAS. The results of the calculations of the surface mass balance components of the Antarctic ice sheet are presented for the 30-year pre-industrial period and are compared with the recent results obtained in the literature.

This paper describes an experimental study carried out in a laboratory water tunnel to examine the mean, periodic and turbulent components of the velocities in combined oscillatory and steady flow boundary layer over a fixed bed of vortex ripples. The fluid velocities, both the horizontal and the vertical components, were measured simultaneously with a laser Doppler anemometer. The measurements indicate that the addition of a steady current causes a significant effect on the near-bed ensemble velocity field of the oscillatory motion, owing primarily to the asymmetry of the lee-vortices that are formed during each half cycle of the oscillation. On the other hand, the effect of adding an oscillatory motion on the time-mean velocity field of a steady current is also significant in that the current experiences a considerably enhanced roughness due to the additional turbulence produced by the wave motion. The measurements also indicate that, depending on the spatial position over a ripple wave length, the turbulent intensities in combined flows are either increased or decreased with respect to the same in oscillatory flow alone. However, peak values of the spatially averaged turbulence quantities in the near-bed interaction layer of combined flows do not show a significant change with respect to the pure oscillatory flow components. The decay of turbulence as well as the near-bed momentum transfer in combined flows have also been examined.

South Indian Ocean Rossby waves (SIO-RW) are identified in the Global Ocean Data Assimilation System (GODAS) 1.5–7 yr filtered sea surface height (SSH) time series. There is a persistent three-year...

ABSTRACT Kim, Y.-J.; Itoh, S.; Oya, Y., and Yoon, J.-S., 2018. Study on storm surge prediction model considering typhoon characteristics for largest scale. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 736–740. Coconut Creek (Florida), ISSN 0749-0208. The coastal area of Japan has been damaged yearly with many storm surges and flooding disasters in the past, including those associated with tropical cyclones (TCs). Also, the scale of damage is increasing rapidly due to the changing global climate and environment. As the disasters due to storm surges become unpredictable, more measures should be taken to prevent serious damage and casualties. Therefore, in this study, the aim is to mitigate the unpredictable damage by assuming storm surges of the largest scale and to propose a storm surge model that considers the characteristics of TCs. The main objectives of ...

In the course of studies of hydrochemical monitoring data for the period from 2017 to 2019, we found that the Gelendzhik bay, which belongs to semi-closed water areas, has an increased background of mineral and organic nitrogen forms compared to the background in the Golubaya bay corresponding to the open coast. Increased concentrations of mineral forms of nitrogen in the Gelendzhik bay we detected, probably due to anthropogenic impact.

Abstract Two oppositely rotating mesoscale eddies, originating from the Leeuwin Current, were captured during a research cruise in the interior southeast Indian Ocean in August 2012, a few hundred kilometers off the west coast of Australia. The two eddies had different vertical structures: the anticyclonic eddy had stronger vertical shear above 200 m and a less stratified thermocline below the mixed layer, while the cyclonic eddy had a more barotropic structure in the upper 500 m. Compared with the same types of eddies sampled in 2003 close to the Australian coast, the 2012 anticyclonic eddy had a larger radius, deeper isothermal depths, and higher peak velocity; whereas the 2012 cyclonic eddy had a similar structure with the 2003 survey. We use an Argo float and three surface drifters deployed and trapped in the anticyclonic eddy to track its evolution over a 4-month period. The eddy was observed to propagate 1000 km further to the west, indicating that the Leeuwin Current properties of the eddy may be preserved for over 2000 km off the west coast of Australia. The eddy appeared to have experienced radial excursions relative to the eddy center, with periodicity of 4–6 days and 15 days, during their anticlockwise motions. The radial movements of the drifters appeared to be constrained by the radial momentum balance within the eddy. The importance of eddy distortions to ocean primary production in anticyclonic eddies in the southeast Indian Ocean warrants further studies.

International audience; This paper aims to analyze the shoreline changes of coastal accumulations (sandy and gravel beaches/barriers) of Brittany (Western France). Three long, medium, and short term spatio-temporal scale observations are taken into consideration for the assessment of shoreline dynamics at this regional scale. Firstly, the long-term shoreline position evolution is based on a comparison of two sets of aerial orthophotos (1949-1952 and (2006-2009). A total of 652 beaches were analyzed in order to map and quantify erosion (35% of the total studied coastline), stability (38%), and accretion (27%) over the last 60 years. In detail, these percentages vary significantly according to the beach/barrier morphologies (spits vs pocket beaches), sediment composition (sandy vs gravelly), and hydrodynamic context (exposed vs sheltered). Secondly, a pluri-annual (i.e., medium-term) shoreline change analysis based on five representative beaches was conducted. This analysis was also based on image processing using sets of aerial photos taken every five years over the last 60 years (1948-2013). Results show an alternation of significant erosion- and accretion-dominated periods (respectively EDP and ADP), with six main EDP (i.e., periods 1962-1968, 1977-1978, 1980-1985, 1987-1990, 1993-1997, and 2013-2014) related to an increase in the frequency of extreme water levels associated with storm events. Finally, the short-term change analysis based on high-frequency monitoring of 11 sites was carried out over the period 1998-2017. These surveys, based on field topo-morphological measurements, highlight the impact of five morphogenetic events associated with significant storm events: 1998-2000 (storms Lothar and Martin in December 1999), 2008 (storm Johanna on March 10, 2008), the winter of 2013-2014 (a cluster of storms in January, February, and March 2014), 2016 (storm Ruzica/Imogen on February 8, 2016) and 2018 (storm Eleanor on January 2, 2018). A relevant recovery phase, which took place between 2008 and 2012 due to the calm and cold winters, was also recognized. The identification of parameters involved in shoreline variations at these three timescales is important for future management options of the Brittany coast.

We provide a mean-value theorem for a class of positive linear functionals. As an application, we improve the classical First Mean-value Theorem for Integrals and obtain other related results.

Divers need proper communication techniques as sound waves cannot propagate through water. Research fraternity has designed several underwater communication systems to overcome this intriguing factor of communication. Researchers have opted several approaches for audio signal communication through water. Designed communication systems vary in complex circuitry, audio signal quality, system components and cost. In this present study, we seek to experimentally demonstrate the feasibility of laser diodes and solar cell receiver for audio signal transmission through water. Audio signals were transmitted through water by imposing over blue, green and red LDs. We have examined light scattering and our findings validate laser diode with shorter wavelength gives less scattering. This paper also outlines an approach for out-of-sight communication. In our experimental trials, the maximum propagation distance is 62 cm by using 450 nm blue laser diode. This study also includes discussion of collimating lens effect on audio signal transmission.