Hypsometry, Volume and Physiography of the Arctic Ocean and Their Paleoceanographic Implications

Recent analyses of the International Bathymetric Chart of the Arctic Ocean (IBCAO) grid model include: Hypsometry (the distribution of surface area at various depths); ocean volume distribution; and physiographic provinces [Jakobsson 2002; Jakobsson et al., in press]. The present paper summarizes the main results from these recent studies and expands on the paleoceanographic implications for the Arctic Ocean, which in this work is defined as the broad continental shelves of the Barents, Kara, Laptev, East Siberian and Chukchi Seas, the White Sea and the narrow continental shelves of the Beaufort Sea, the Arctic continental margins off the Canadian Arctic Archipelago and northern Greenland. This, the Worlds smallest ocean, is a virtually land-locked ocean that makes up merely 2.6 % of the area, and 1.0 % of the volume, of the entire World Ocean. The continental shelf area, from the coastline out to the shelf break, comprises as much as 52.9 % of the total area in the Arctic Ocean, which is significantly larger in comparison to the rest of the world oceans where the proportion of shelves, from the coastline out to the foot of the continental slope, only ranges between about 9.1 % and 17.7 %. In Jakobsson [2002], the seafloor area and water volume were calculated for different depths starting from the present sea level and progressing in increments of 10 m to a depth of 500 m, and in increments of 50 m from 550 m down to the deepest depth within each of the analyzed Arctic Ocean seas. Hypsometric curves expressed as simple histograms of the frequencies in different depth bins were presented, along with depth plotted against cumulative area for each of the analyzed seas. The derived hypsometric curves show that most of the Arctic Ocean shelf seas besides the Barents Sea, Beaufort Sea and the shelf off northern Greenland have a similar shape with the largest seafloor area between 0 and 50 m. The East Siberian and Laptev seas, in particular, show area distributions concentrated in this shallow depth range, and together with the Chukchi Sea they form a large flat shallow shelf province comprising as much as 22 Besides being the world’s smallest ocean with the by far largest shelf area in proportion to its size, the Arctic Ocean is unique in terms of its physiographic setting. The Fram Strait is the only real break in the barrier of vast continental shelves enclosing the Arctic Ocean. The second largest physiographic province after the continental shelves consists of ridges, which is in contrast to the rest of the World’s oceans where abyssal plains dominate. As much as 15.8 % of the area is underlain by ridges indicating the profound effect they have on ocean circulation

Arctic Ocean Physiography

The first order physiographic provinces of the Arctic Ocean has been defined using the recently updated International Bathymetric Chart of the Arctic Ocean (IBCAO) grid model as the main database and a semi-quantitative approach. The first step in our classification of physiographic provinces is an evaluation of seafloor gradients contained in a slope model that was derived from the IBCAO grid. The slope information reveals certain seafloor process-related features, which add to the bathymetric information. Using interactive 3D-visualization, the slope and bathymetric information were simultaneously analyzed and certain slope intervals of the Arctic Ocean seafloor were found to generally characterize major physiographic provinces. This information was used for the initial classification, although in certain locations gradual changes in bottom inclination made it difficult to detect transitions between some physiographic provinces, as for example, the transition between continental rise and slope, as well as between the rise and abyssal plain. In these cases some manual intervention was required guided by generated bathymetric profiles. The areas of the provinces we classified are individually calculated, and their morphologies are subsequently discussed in the context of the geologic evolution of the Arctic Ocean Basin as described in the published literature. In summary, our study: provides a physiographic classification of the Arctic Ocean sea floor according to the most up-to-date bathymetric model and addresses the geologic origin of the prominent features as well as provides areal computations of the defined first order physiographic provinces and of the most prominent second-order features

The Sunk Cost Fallacy and Risk-Taking Behaviour. Evidence from a computer game experiment

We examine whether behavioural sunk costs are related to an increased willingness to make risky decisions. Rational agents’ decisions should not be contingent on sunk costs; however, foregoing research suggests that individuals in fact do react to such costs. Few studies have examined behavioural sunk costs and risk-taking with “real stakes”, which is an important topic of research as many projects require investments in time and effort. If it is the case that behavioural sunk costs influence risk-taking decisions, it will be a particularly important finding in the field of risk-taking in avalanche terrain, as these types of activities are associated with large behavioural sunk costs. Our analysis is based on data from an experiment held at the start of 2020, with participants (N=65) from the psychology faculty at the University of Tromsø – The Arctic University of Norway. We are unable to find evidence of sunk cost effects. We do, however, find that risk-taking falls with time spent playing the game. This finding can either represent a learning effect or perhaps a reversed sunk cost effect

Deep Sound Field Reconstruction in Real Rooms:Introducing the ISOBEL Sound Field Dataset

Knowledge of loudspeaker responses are useful in a number of applications, where a sound system is located inside a room that alters the listening experience depending on position within the room. Acquisition of sound fields for sound sources located in reverberant rooms can be achieved through labor intensive measurements of impulse response functions covering the room, or alternatively by means of reconstruction methods which can potentially require significantly fewer measurements. This paper extends evaluations of sound field reconstruction at low frequencies by introducing a dataset with measurements from four real rooms. The ISOBEL Sound Field dataset is publicly available, and aims to bridge the gap between synthetic and real-world sound fields in rectangular rooms. Moreover, the paper advances on a recent deep learning-based method for sound field reconstruction using a very low number of microphones, and proposes an approach for modeling both magnitude and phase response in a U-Net-like neural network architecture. The complex-valued sound field reconstruction demonstrates that the estimated room transfer functions are of high enough accuracy to allow for personalized sound zones with contrast ratios comparable to ideal room transfer functions using 15 microphones below 150 Hz

Numerical simulations of submerged and pressurised X65 steel pipes – COMPLAS XII

While in service, pipelines may from time to time be exposed to impact loads from anchors or trawl gear. A lot of parameters influence the behaviour of the pipeline during impact, e.g. the diameter and thickness of the pipeline, the impactor’s mass and velocity, and of course the material used. Also potentially influencing the deformation pattern is the presence of surrounding water, which can be a difficult parameter to include experimentally. The pressurised contents of the pipeline can also be an influencing factor. To gain some insight into how the water and possible pressure inside the pipeline affect the global impact behaviour, numerical investigations have been carried out using FSI- techniques available in the explicit finite element code Europlexus. One case was set up for validation against available experimental data, and additional cases examined numerically the effect of including pressure and/or surrounding water. The simulations generally captured the deformation and load levels from the experiments well, and may be assumed to represent the events with reasonable accuracy. Adding internal pressure generally led to a higher peak load, and created a more localised deformation. Submerging the pipe in water seemed to be of minor importance with respect to global and local deformation, but this depended heavily on the FSI conditions. Other parameters than the surrounding water, which for design purposes may be omitted, appear to be more significant to the global and local response

Novel immersed boundary method for fluid-structure interaction of compressible flow

A 3D fluid-structure interaction (FSI) code is under development. The fluid domain (Navier-Stokes) solver will employ a sharp interface ghost node immersed boundary method (IBM) to apply the boundary conditions at fluid-solid interfaces. The Navier-Stokes (N-S) solver has been verified using a classic Poiseuille channel flow. The current version of the immersed boundary method is being tested by solving a heat conduction problem. The order of accuracy of the IBM was shown to be just above second order

Patient-reported outcome measures after hip fracture in patients with chronic cognitive impairment: results from 34.675 patients in the Norwegian Hip Fracture Register

Aims: Hip fracture patients have high morbidity and mortality. Patient-reported outcome measures (PROMs) assess the quality of care of patients with hip fracture, including those with chronic cognitive impairment (CCI). Our aim was to compare PROMs from hip fracture patients with and without CCI, using the Norwegian Hip Fracture Register (NHFR). Methods: PROM questionnaires at four months (n = 34,675) and 12 months (n = 24,510) after a hip fracture reported from 2005 to 2018 were analyzed. Pre-injury score was reported in the four-month questionnaire. The questionnaires included the EuroQol five-dimension three-level (EQ-5D-3L) questionnaire, and information about who completed the questionnaire. Results: Of the 34,675 included patients, 5,643 (16%) had CCI. Patients with CCI were older (85 years vs 81 years) (p < 0.001), and had a higher American Society of Anesthesiologists (ASA) classification compared to patients without CCI. CCI was unrelated to fracture type and treatment method. EQ-5D index scores were lower in patients with CCI after four months (0.37 vs 0.60; p < 0.001) and 12 months (0.39 vs 0.64; p < 0.001). Patients with CCI had lower scores for all dimensions of the EQ-5D-3L pre-fracture and at four and 12 months. Conclusion: Patients with CCI reported lower health-related quality of life pre-fracture, at four and 12 months after the hip fracture. PROM data from hip fracture patients with CCI are valuable in the assessment of treatment. Patients with CCI should be included in future studies.publishedVersio