Search

Ocean Salinity Science Conference, 6-9 November 2018, Paris.-- 1 page, We present here a sea surface salinity (SSS) and temperature (SST) dataset collected on board the S.A. Agulhas-I and S.A. Agulhas-II research vessels, in the framework of the South African National Antarctic Programme (SANAP). This dataset, available through an unrestricted repository at https://doi.org/10.7289/V56M3545, contributes to improving the knowledge of surface water features in one of the most important regions for global climate. The dataset will be highly valuable for studies focusing on climate variability in the Atlantic sector of the Southern Ocean, especially across the Antarctic Circumpolar Current and its fronts. Furthermore, we expect that the collected SSS data will represent a valuable tool for the calibration and validation of recent satellite observations provided by SMOS and Aquarius missions

Waves propagating below drift ice were observed in the North-West Barents Sea. In-situ measurements of ice and water characteristics were performed with the equipment deployed on the ice and in the water below the ice during 16 hours from 16:00, May 1, to 08:00, May 2, 2016. Peak frequencies of the observed waves were around 0.35 rad/s, 0.5 rad/s, 0.6 rad/s and 0.8 rad/s. It is found that the eddy viscosity in the boundary layer below the ice has a mean value of 140 cm2 /s with significant variations correlated with the floe acceleration. Spectral properties of the observed waves are compared with the results of the WaveWatch III model. The origin of the observed waves is discussed in the paper.

IPY2012 Conference Montréal. From Knowledge to Action, 22-27 April 2012, Montréal, Canada, The marine environment of the Arctic Ocean is under profound transformation, as clearly shown by observations and model predictions across a range of disciplines. The rapid decline in sea ice extent and volume during the boreal summers is a prime example. To improve our understanding of the key physical processes that drive change in this region, it is crucial to monitor the complex ocean-cryosphere-atmosphere system. This presentation explores how sea ice is changing in this region by using a combined observational and modeling approach that builds heavily on the latest technological advances in Space Geodesy. We have developed a high-precision (i.e., few cm position accuracy), GPS-based autonomous platform suited to the challenging Arctic Ocean environment that enables determination of sea ice motions in three-dimensions with hightemporal sampling and, when deployed as a network, also high-spatial density. The platform includes a sea ice freeboard sensor and two-way communications, thus also enabling near-real time monitoring and remote data retrieval. We have deployed several prototypes of such platform for limited durations both in the Arctic Ocean and the Southern Ocean since 2009, and two full-blown, long-term systems, on the Chukchi Sea, during the boreal summer of 2011. Although monitoring of sea ice motions in this fast changing region goes back to the early days of satellite observations, these systems bring out a level of spatio-temporal detail that has never been seen before, which in turn allows us to question our present understanding of sea ice dynamics. We will describe the technology behind this novel platform, which could also be adapted to other applications that require sustained operations and observations in the Arctic environment, and present results pertaining to sea ice dynamics, Arctic Ocean tides, ocean dynamic topography, ocean currents, and sea ice freeboard, thickness, and mass balance, from the analysis of the GPS and freeboard data collected by those systems

This document describes a plan for a mesoscalel experimen to study the physical processes by which ice, water and atmosphere interact in the outermost parts of a polar icefield, the region known as the marginal ice zone (MIZ). During the last two decades a series of large projects culminating in the Arctic lee Dynamics Joint Experiment (AIDJEX, Pritchard 1980) yielded considerable understanding of the growth, motion and decay of sea ice in the interior of the Arctic Ocean. With these experiments concluded, and coupled nonlinear sea ice dynamic- thermodynamic models in hand (Hibler 1979, Coon 1980), attention shifted to the problem of understanding the processes which occur near the open ocean boundaries of polar icefields, and which determine the advance and retreat of the sea ice edge. The exchanges which take place in this zone affect hemispheric climate and have a significant effect on naval operation and commercial fisheries.

We review the sampling and results of the radiocarbon dating of the archaeological cloth known as the Shroud of Turin, in the light of recent statistical analyses of both published and raw data. The statistical analyses highlight an inter-laboratory heterogeneity of the means and a monotone spatial variation of the ages of subsamples that suggest the presence of contaminants unevenly removed by the cleaning pretreatments. We consider the significance and overall impact of the statistical analyses on assessing the reliability of the dating results and the design of correct sampling. These analyses suggest that the 1988 radiocarbon dating does not match the current accuracy requirements. Should this be the case, it would be interesting to know the accurate age of the Shroud of Turin. Taking into account the whole body of scientific data, we discuss whether it makes sense to date the Shroud again.

Although there have been few collisions between ships and offshore installations, the grave consequences of such a collision has provoked the study of the probability of collision worldwide. A theoretical study is undertaken on the assessment of risk of collision in this paper. The causes of collision and the models of evaluating the risk collision are reviewed, which are then followed by some discussions on modelling human error and mariners' behaviour of collision avoidance decision making briefly. Finally, some suggestions on reducing such a risk are proposed.