Multi-satellite ocean tide modelling—the K1 constituent

All major ocean tide constituents are aliased into signals with periods less than 90 days from TOPEX/POSEIDON altimetry, except the K₁ constituent. The aliased K₁ has a period of 173 days. Consequently, it might be confounded with height variations caused by the semiannual cycle having a period of 183 days.The correlation between K₁ and the semiannual signal has been investigated both locally and globally using combinations of T/P, ERS-1 and GEOSAT observations. Subsequently, two empirical methods have been investigated to improve the mapping of K₁ from multiple satellites.At high latitudes, where the presence of crossing tracks cannot separate K₁ from the semiannual signal from TOPEX/POSEIDON, the importance of including ERS-1 and GEOSAT observations was demonstrated. A comparison with 29 pelagic and coastal tide gauges in the Southern Ocean south of 50°S gave 5.59 (M₂), 2.27 (S₂) and 5.04 (K₁) cm RMS agreement for FES95.1 ocean tide model. The same comparison for the best empirical estimated constituents based on TOPEX/POSEIDON + ERS-1 + GEOSAT gave 4.32, 2.21, and 4.29 cm for M₂, S₂ and K₁, respectively.     

Investigating the Waterfront: The Entangled Sociomaterial Transformations of Coastal Space in Karnataka,India

Triggered by urbanization and changing land use, coastal transformation is a rapidly increasing phenomenon in the global south, driving dramatic livelihoods impacts. However, the existing literature on small-scale fisheries (SSF) has paid little attention to the way coastal transformations shape conditions for SSF livelihoods communities. This study proposes a new orientation in SSF studies by exploring the assemblage of entangled sociomaterial processes that account for coastal transformations by investigating waterfront transformation in a fishing community in Karnataka, India. Drawing on ethnographic fieldwork, we conclude that an entanglement of sociomaterial processes produces unequal outcomes among stakeholders that subsequently reinforce the political and economic marginalization of certain groups of waterfront users. Moreover, the investigated context-specific waterfront assemblage intimately connects to the broader context of national fishery policy, urbanization, and tourism, directing the way coastal space can and should be transformed. Such an analysis contributes to the understanding of changing livelihoods in SSF communities.     

Killing Animals for Recreation? A Quantitative Study of Hunters’ Motives and Their Perceived Moral Relevance

Hunters in the Western world today do not need to hunt to obtain food and other animal products. So why do they hunt? This paper examines the motives of hunters, the motives ascribed to hunters by members of the general public, and the role motives play for the moral acceptability of hunting among members of the general public. It draws on a nationally representative survey of the general public (n?=?1,001) and hunters (n?=?1,130) in Denmark. People with a negative attitude to hunting are more likely to take motives into account when they consider the acceptability of hunting. Three clusters of motives defining distinctive hunting motivational orientations were identified: action/harvest, management/care, and natural and social encounters. The general public ascribed action/harvest motives to hunters more than hunters did. In a policy perspective, if hunters’ motives are misperceived, improved dialog may be needed to protect the legitimacy of recreational hunting.     

A volume-conserving representation of cell faces in corner point grids

Corner point grids is currently the standard grid representation for use in reservoir simulation. The cell faces in corner point grids are traditionally represented as bilinear surfaces where the edges between the corner points all are straight lines. This representation has the disadvantage that along faults with varying dip the cell faces on either side will not precisely match, giving overlapping cells or gaps between cells. We propose an alternative representation for the cell faces. The four vertical cell faces are still represented as bilinear surfaces, but instead of having linear edges between the cell corners along the top and bottom faces, we propose a representation of the vertical cell faces where any horizontal intersection will give a straight line, giving column faces whose shape is independent of the corner point locations of the individual grid cells. This ensures that the grid columns match up and that there are no gaps or overlapping volumes between grid cells. This representation gives a local parameterization for the whole grid column, and the top and bottom grid cell surfaces are modeled as bilinear using this parameterization. A set of local coordinates for the grid cell permits all the common grid operations like volume calculation, area calculation for cell faces, and blocking of well traces.     

The Bothnian Sea ice stream: early Holocene retreat dynamics of the south‐central Fennoscandian Ice Sheet

The Gulf of Bothnia hosted a variety of palaeo‐glaciodynamic environments throughout the growth and decay of the last Fennoscandian Ice Sheet, from the main ice‐sheet divide to a major corridor of marine‐ and lacustrine‐based deglaciation. Ice streaming through the Bothnian and Baltic basins has been widely assumed, and the damming and drainage of the huge proglacial Baltic Ice Lake has been implicated in major regional and hemispheric climate changes. However, the dynamics of palaeo‐ice flow and retreat in this large marine sector have until now been inferred only indirectly, from terrestrial, peripheral evidence. Recent acquisition of high‐resolution multibeam bathymetry opens these basins up, for the first time, to direct investigation of their glacial footprint and palaeo‐ice sheet behaviour. Here we report on a rich glacial landform record: in particular, a palaeo‐ice stream pathway, abundant traces of high subglacial meltwater volumes, and widespread basal crevasse squeeze ridges. The Bothnian Sea ice stream is a narrow flow corridor that was directed southward through the basin to a terminal zone in the south‐central Bothnian Sea. It was activated after initial margin retreat across the Åland sill and into the Bothnian basin, and the exclusive association of the ice‐stream pathway with crevasse squeeze ridges leads us to interpret a short‐lived stream event, under high extension, followed by rapid crevasse‐triggered break‐up. We link this event with a c. 150‐year ice‐rafted debris signal in peripheral varved records, at c. 10.67 cal. ka BP. Furthermore, the extensive glacifluvial system throughout the Bothnian Sea calls for considerable input of surface meltwater. We interpret strongly atmospherically driven retreat of this marine‐based ice‐sheet sector.     

Comparisons among the five ground-motion models developed using RESORCE for the prediction of response spectral accelerations due to earthquakes in Europe and the Middle East

This article presents comparisons among the five ground-motion models described in other articles within this special issue, in terms of data selection criteria, characteristics of the models and predicted peak ground and response spectral accelerations. Comparisons are also made with predictions from the Next Generation Attenuation (NGA) models to which the models presented here have similarities (e.g. a common master database has been used) but also differences (e.g. some models in this issue are nonparametric). As a result of the differing data selection criteria and derivation techniques the predicted median ground motions show considerable differences (up to a factor of two for certain scenarios), particularly for magnitudes and distances close to or beyond the range of the available observations. The predicted influence of style-of-faulting shows much variation among models whereas site amplification factors are more similar, with peak amplification at around 1s. These differences are greater than those among predictions from the NGA models. The models for aleatory variability (sigma), however, are similar and suggest that ground-motion variability from this region is slightly higher than that predicted by the NGA models, based primarily on data from California and Taiwan.