Will climate change impact on wind power development in the UK?

Partly in response to concerns about anthropogenic climate change, renewable energy production is growing rapidly in the United Kingdom (UK). The wind power industry takes advantage of the country having some of the highest mean wind speeds in Europe. Future climate change, however, has the potential to alter the characteristics of the UK wind climate. Small changes in mean wind speed could produce much greater changes in wind energy output as the power generated is related to the cube of wind speed. This paper aims to use a simple method to provide insight into projected future UK wind climate and how this might differ from current patterns. A discussion of the scale of the projected impacts on the wind energy industry follows.     

New Zealand xenophyophores: Upper bathyal distribution,photographs of growth position,and a new species

Xenophyophores are a group of giant, but extremely fragile, rhizopod protozoans generally found at lower bathyal or abyssal depths. Recent dredge samples and photographs suggest that there is a largely endemic fauna of xenophyophores with anastomosing branches living at upper bathyal depths around New Zealand. Their distribution may be related to the layer of Antarctic Intermediate water that bathes the upper slope of the New Zealand Plateau.

Photographs of the seafloor at depths of 800–1300 m on the Lord Howe Rise show hemispherical masses, 5 cm across, of which the majority appear to be Syringammina tasmanensis Lewis, 1966 and at least one specimen may be Reticulammina lamellata Tendal, 1972. The photographs indicate that these species live on the seabed, not beneath it, that they are probably filter feeders and that they can reach a density of about one specimen per square metre.

A new species, Reticulammina maini, is described from the continental slope east of Auckland. A key to the New Zealand species of xenophyophore is presented.     

Enteroviruses in mussels and marine sediments and depuration of naturally accumulated viruses by green lipped mussels (Perna canaliculus)

Surveys were carried out over 16 months to assess the distribution of enteroviruses of human origin in sediments and mussels near two sewage outfalls on the North Taranaki Coast, New Zealand. Enteroviruses were present in high numbers in both sediments and shellfish near the New Plymouth sewage outfall with maximum virus levels of 32 000 pfu 100 g^‐1 of wet mussel tissue and 59 pfu 100 g^‐1 of wet sediment material. Viruses were recovered occasionally from sediments and mussels near the Waitara Borough outfall. Coxsackievirus B4 was the predominant virus type isolated but CB5 and Poliovirus types 1, 2, and 3 were also recovered. Attempts to depurate virus‐contaminated New Plymouth mussels, by keeping them in water for 8 days with daily water replacement, did not achieve a significant reduction in virus numbers.     

Modification of the polyethylene glycol 6000 precipitation method for recovering human and indicator viruses from oysters and mussels

Human viruses are a common contaminant of shellfish affected by human sewage wastes. They are difficult to detect as they are not easily separated from shellfish tissue. This paper describes a modification of the polyethylene glycol (PEG) precipitation technique for recovery of enteroviruses and F‐specific bacteriophages from the Pacific oyster (Crassostrea gigas) and the green‐lipped mussel (Perna canaliculus). Modifications adopted were the use of only the digestive gland tissue for virus extraction, resuspension of the primary PEG pellet in 4 volumes of eluent, and the introduction of a secondary PEG precipitation to reconcentrate the virus containing extract. The recovery rate of the virus extraction process was not affected by introduction of the secondary concentration step (overall recovery remained at 60–70% of the virus input). The advantages of reduction of tissue residue in the extract, smaller final volume, and the ability to process 2–3 times the number of individual shellfish for the same effort, improve the practicality of the method.     

Preservation of Late Amazonian Mars ice and water-related deposits in a unique crater environment in Noachis Terra: Age relationships between lobate debris tongues and gullies

The Amazonian period of Mars has been described as static, cold, and dry. Recent analysis of high-resolution imagery of equatorial and mid-latitude regions has revealed an array of young landforms produced in association with ice and liquid water; because near-surface ice in these regions is currently unstable, these ice-and-water-related landforms suggest one or more episodes of martian climate change during the Amazonian. Here we report on the origin and evolution of valley systems within a degraded crater in Noachis Terra, Asimov Crater. The valleys have produced a unique environment in which to study the geomorphic signals of Amazonian climate change. New high-resolution images reveal Hesperian-aged layered basalt with distinctive columnar jointing capping interior crater fill and providing debris, via mass wasting, for the surrounding annular valleys. The occurrence of steep slopes (>20°), relatively narrow (sheltered) valleys, and a source of debris have provided favorable conditions for the preservation of shallow-ice deposits. Detailed mapping reveals morphological evidence for viscous ice flow, in the form of several lobate debris tongues (LDT). Superimposed on LDT are a series of fresh-appearing gullies, with typical alcove, channel, and fan morphologies. The shift from ice-rich viscous-flow formation to gully erosion is best explained as a shift in martian climate, from one compatible with excess snowfall and flow of ice-rich deposits, to one consistent with minor snow and gully formation. Available dating suggests that the climate transition occurred >8 Ma, prior to the formation of other small-scale ice-rich flow features identified elsewhere on Mars that have been interpreted to have formed during the most recent phases of high obliquity. Taken together, these older deposits suggest that multiple climatic shifts have occurred over the last tens of millions of years of martian history.     

Negative diffusion in planetary rings with a nearby moon

This paper analyzes a process that has been observed in simulations of numerous systems where ring material is strongly perturbed by a nearby moon. If the ring particles can be imparted with a forced eccentricity on the order of 10⁻⁵ in a single pass by the moon, particle orbits are observed to move towards regions of higher density as a result of the organized collisions that occur in the dense peaks of the satellite wake. The width of the ring can decrease by as much as 90% if the forced eccentricity is greater than 3 × 10⁻⁵ and the unperturbed geometric optical depth is greater than 0.03. The fractional change in ring width is relatively insensitive to the particle size so long as the particle radius is much less than the product of the semimajor axis and the forced eccentricity. Including a power law particle size distribution with slope of −2.8 spanning a decade in particle radius reduces the fractional width change by about 10% compared to the uniform particle-size case. Adding gravitational interactions between ring particles only has a significant effect on ring confinement if the unperturbed geometric optical depth exceeds .03, but a 40% reduction in ring width is still achieved in a self-gravitating ring of geometric optical depth 0.3 if the forced eccentricity exceeds 3 × 10⁻⁵. This process does not require the material to be in resonance with the moon, nor does it have any minimum mass constraints because particle self-gravity is not required. The collisional damping of satellite wakes therefore provides a simple mechanism by which a single moon can reduce the radial extent of any ringlet that is close to it and has sufficient optical depth for collisions to be significant.     

Response to “Comment on “Slow-mode shock candidate in the Jovian magnetosheath” by Bebesi et al.”

Hubert and Samsonov addressed our paper published in early 2010 (Bebesi et al., 2010) about a plasma event detected in the magnetosheath of Jupiter by the plasma instruments of the Cassini spacecraft. We proposed that the characteristics of the plasma parameter variations were consistent with a slow mode shock (SMS). As our title indicated, we claimed only that the event was a possible “candidate” for an SMS according to our data, which had some restrictions as discussed in the paper. As to the origin, we proposed the following: since there was a crossing of the then highly tilted Heliospheric Current Sheet in less than two days before the event, it might have played a role in initiating the shock front.We highly appreciate the opinion of the authors, but they do not point out any hard fact that would exclude the possibility of the scenario we suggested.     

Bounding the time delay between high-energy neutrinos and gravitational-wave transients from gamma-ray bursts

We derive a conservative coincidence time window for joint searches of gravitational-wave (GW) transients and high-energy neutrinos (HENs, with energies ?100 GeV), emitted by gamma-ray bursts (GRBs). The last are among the most interesting astrophysical sources for coincident detections with current and near-future detectors. We take into account a broad range of emission mechanisms. We take the upper limit of GRB durations as the 95% quantile of the T₉₀’s of GRBs observed by BATSE, obtaining a GRB duration upper limit of ∼150 s. Using published results on high-energy (>100 MeV) photon light curves for 8 GRBs detected by Fermi LAT, we verify that most high-energy photons are expected to be observed within the first ∼150 s of the GRB. Taking into account the breakout-time of the relativistic jet produced by the central engine, we allow GW and HEN emission to begin up to 100 s before the onset of observable gamma photon production. Using published precursor time differences, we calculate a time upper bound for precursor activity, obtaining that 95% of precursors occur within ∼250 s prior to the onset of the GRB. Taking the above different processes into account, we arrive at a time window of t_HEN − t_GW ∈ [−500 s, +500 s]. Considering the above processes, an upper bound can also be determined for the expected time window of GW and/or HEN signals coincident with a detected GRB, t_GW − t_GRB ≈ t_HEN − t_GRB ∈ [−350 s, +150 s]. These upper bounds can be used to limit the coincidence time window in multimessenger searches, as well as aiding the interpretation of the times of arrival of measured signals.