Farmers' interest in growing GM crops in the UK, in the context of a range of on-farm coexistence issues

Although no GM crops currently are licensed for commercial production in the UK, as opposition to GM crops by consumers softens, this could change quickly. Although past studies have examined attitudes of UK farmers toward GM technologies in general, there has been little work on the impact of possible coexistence measures on their attitudes toward GM crop production. This could be because the UK Government has not engaged in any public dialogue on the coexistence measures that might be applied on farms. Based on a farm survey, this article examines farmers’ attitudes toward GM technologies and planting intentions for three crops (maize, oilseed rape, and sugar beet) based on a GM availability scenario. The article then nuances this analysis with a review of farmer perceptions of the level of constraint associated with a suite of notional farm-level coexistence measures and issues, based on current European Commission guidelines and practice in other EU Member States.

Variability of dayside convection and motions of the cusp/cleft aurora

We present measurements of the ionospheric plasma flow over the range of invariant latitudes 71–76°, observed at 10-second resolution using both the EISCAT radars, with simultaneous observations of the 630 nm cusp/cleft aurora made by a meridian-scanning photometer at Ny Ålesund, Svalbard. A major increase in the trans-auroral voltage from 5 to 40 kV (associated with sunward convection in the early afternoon sector) is found to follow a southward motion of the aurora and coincide with the onset of regular transient auroral breakup events. It is shown that these observations are consistent with recent theoretical work on how ionospheric flows are excited by time-dependent reconnection at the dayside magnetopause.

Ionospheric signatures of pulsed reconnection at the Earth's magnetopause

THE plasma precipitating into the Earth's dayside auroral atmosphere has characteristics which show that it originates from the shocked solar-wind plasma of the magnetosheath1'2. The particles of the magnetosheath plasma precipitate down a funnel-shaped region (cusp) of open field lines resulting from reconnection of the geomagnetic field with the interplanetary magnetic field3. Although the cusp has long been considered a well defined spatial structure maintained by continuous reconnection, it has recently been suggested4–6 that reconnection instead may take place in a series of discontinuous events; this is the ‘pulsating cusp model’. Here we present coordinated radar and satellite observations of a series of discrete, poleward-moving plasma structures that are consistent with the pulsating-cusp model.

Auroral bright spot sequence near 1400 MLT: Coordinated optical and ion drift observations

Optical observations of a dayside auroral brightening sequence, by means of all-sky TV cameras and meridian scanning photometers, have been combined with EISCAT ion drift observations within the same invariant latitude-MLT sector. The observations were made during a January 1989 campaign by utilizing the high F region ion densities during the maximum phase of the solar cycle. The characteristic intermittent optical events, covering ∼300 km in east-west extent, move eastward (antisunward) along the poleward boundary of the persistent background aurora at velocities of ∼1.5 km s−1 and are associated with ion flows which swing from eastward to westward, with a subsequent return to eastward, during the interval of a few minutes when there is enhanced auroral emission within the radar field of view. The breakup of discrete auroral forms occurs at the reversal (negative potential) that forms between eastward plasma flow, maximizing near the persistent arc poleward boundary, and strong transient westward flow to the south. The reported events, covering a 35 min interval around 1400 MLT, are embedded within a longer period of similar auroral activity between 0830 (1200 MLT) and 1300 UT (1600 MLT). These observations are discussed in relation to recent models of boundary layer plasma dynamics and the associated magnetosphere-ionosphere coupling. The ionospheric events may correspond to large-scale wave like motions of the low-latitude boundary layer (LLBL)/plasma sheet (PS) boundary. On the basis of this interpretation the observed spot size, speed and repetition period (∼10 min) give a wavelength (the distance between spots) of ∼900 km in the present case. The events can also be explained as ionospheric signatures of newly opened flux tubes associated with reconnection bursts at the magnetopause near 1400 MLT. We also discuss these data in relation to random, patchy reconnection (as has recently been invoked to explain the presence of the sheathlike plasma on closed field lines in the LLBL). In view of the lack of IMF data, and the existing uncertainty on the location of the open-closed field line boundary relative to the optical events, an unambiguous discrimination between the different alternatives is not easily obtained.

Auroral and plasma flow transients at magnetic noon

We present observations of a transient event in the dayside auroral ionosphere at magnetic noon. F-region plasma convection measurements were made by the EISCAT radar, operating in the beamswinging “Polar” experiment mode, and simultaneous observations of the dayside auroral emissions were made by optical meridian-scanning photometers and all-sky TV cameras at Ny Ålesund, Spitzbergen. The data were recorded on 9 January 1989, and a sequence of bursts of flow, with associated transient aurora, were observed between 08:45 and 11:00 U.T. In this paper we concentrate on an event around 09:05 U.T. because that is very close to local magnetic noon. The optical data show a transient intensification and widening (in latitude) of the cusp/cleft region, as seen in red line auroral emissions. Over an interval of about 10 min, the band of 630 nm aurora widened from about 1.5° of invariant latitude to over 5° and returned to its original width. Embedded within the widening band of 630 nm emissions were two intense, active 557.7 nm arc fragments with rays which persisted for about 2 min each. The flow data before and after the optical transient show eastward flows, with speeds increasing markedly with latitude across the band of 630 nm aurora. Strong, apparently westward, flows appeared inside the band while it was widening, but these rotated round to eastward, through northward, as the band shrunk to its original width. The observed ion temperatures verify that the flow speeds during the transient were, to a large extent, as derived using the beamswinging technique; but they also show that the flow increase initially occurred in the western azimuth only. This spatial gradient in the flow introduces ambiguity in the direction of these initial flows and they could have been north-eastward rather than westward. However, the westward direction derived by the beamswinging is consistent with the motion of the colocated and coincident active 557.7 nm arc fragment, A more stable transient 557.7 nm aurora was found close to the shear between the inferred westward flows and the persisting eastward flows to the North. Throughout the transient, northward flow was observed across the equatorward boundary of the 630 nm aurora. Interpretation of the data is made difficult by lack of IMF data, problems in distinguishing the cusp and cleft aurora and uncertainty over which field lines are open and which are closed. However, at magnetic noon there is a 50% probability that we were observing the cusp, in which case from its southerly location we infer that the IMF was southward and many features are suggestive of time-varying reconnection at a single X-line on the dayside magnetopause. This IMF orientation is also consistent with the polar rain precipitation observed simultaneously by the DMSP-F9 satellite in the southern polar cap. There is also a 25% chance that we were observing the cleft (or the mantle poleward of the cleft). In this case we infer that the IMF was northward and the transient is well explained by reconnection which is not only transient in time but occurs at various sites located randomly on the dayside magnetopause (i.e. patchy in space). Lastly, there is a 25% chance that we were observing the cusp poleward of the cleft, in which case we infer that IMF Bz was near zero and the transient is explained by a mixture of the previous two interpretations.

Analysis of incoherent scatter radar data from non-thermal F-region plasma

A procedure is presented for fitting incoherent scatter radar data from non-thermal F-region ionospheric plasma, using theoretical spectra previously predicted. It is found that values of the shape distortion factor D∗, associated with deviations of the ion velocity distribution from a Maxwellian distribution, and ion temperatures can be deduced (the results being independent of the path of iteration) if the angle between the line-of-sight and the geomagnetic field is larger than about 15–20°. The procedure can be used with one or both of two sets of assumptions. These concern the validity of the adopted model for the line-of-sight ion velocity distribution in the one case or for the full three-dimensional ion velocity distribution function in the other. The distribution function employed was developed to describe the line-of-sight velocity distribution for large aspect angles, but both experimental data and Monte Carlo simulations indicate that the form of the field-perpendicular distribution can also describe the distribution at more general aspect angles. The assumption of this form for the line-of-sight velocity distribution at a general aspect angle enables rigorous derivation of values of the one-dimensional, line-of-sight ion temperature. With some additional assumptions (principally that the field-parallel distribution is always Maxwellian and there is a simple relationship between the ion temperature anisotropy and the distortion of the field-perpendicular distribution from a Maxwellian), fits to data for large aspect angles enable determination of line-of-sight temperatures at all aspect angles and hence, of the average ion temperature and the ion temperature anisotropy. For small aspect angles, the analysis is restricted to the determination of the line-of-sight ion temperature because the theoretical spectrum is insensitive to non-thermal effects when the plasma is viewed along directions almost parallel to the magnetic field. This limitation is expected to apply to any realistic model of the ion velocity distribution function and its consequences are discussed. Fit strategies which allow for mixed ion composition are also considered. Examples of fits to data from various EISCAT observing programmes are presented.

Analysis of incoherent scatter spectra from non-Maxwellian plasma

Incoherent scatter data from non-thermal F-region ionospheric plasma are analysed, using theoretical spectra predicted by Raman et al. It is found that values of the semi-empirical drift parameter D∗, associated with deviations of the ion velocity distribution from a Maxwellian, and the plasma temperatures can be rigorously deduced (the results being independent of the path of iteration) if the angle between the line-of-sight and the geomagnetic field is larger than about 15–20 degrees. For small aspect angles, the deduced value of the average (or 3-D) ion temperature remains ambiguous and the analysis is restricted to the determination of the line-of-sight temperature because the theoretical spectrum is insensitive to non-thermal effects when the plasma is viewed along directions almost parallel to the magnetic field. This limitation is expected to apply to any realistic model of the ion velocity distribution, and its consequences are discussed. Fit strategies which allow for mixed ion composition are also considered. Examples of fits to data from various EISCAT observing programmes are presented.

Model predictions of the occurrence of non-Maxwellian plasmas, and analysis of their effects on EISCAT data

The recent identification of non-thermal plasmas using EISCAT data has been made possible by their occurrence during large, short-lived flow bursts. For steady, yet rapid, ion convection the only available signature is the shape of the spectrum, which is unreliable because it is open to distortion by noise and sampling uncertainty and can be mimicked by other phenomena. Nevertheless, spectral shape does give an indication of the presence of non-thermal plasma, and the characteristic shape has been observed for long periods (of the order of an hour or more) in some experiments. To evaluate this type of event properly one needs to compare it to what would be expected theoretically. Predictions have been made using the coupled thermosphere-ionosphere model developed at University College London and the University of Sheffield to show where and when non-Maxwellian plasmas would be expected in the auroral zone. Geometrical and other factors then govern whether these are detectable by radar. The results are applicable to any incoherent scatter radar in this area, but the work presented here concentrates on predictions with regard to experiments on the EISCAT facility.

EISCAT observations of plasma convection and the high-latitude, winter F-region during substorm activity

A 24 h period of observations by the EISCAT radar and other ground-based instrumentation is used to study the role of plasma convection in determining the morphology of the high-latitude F-region during winter. It is suggested that, in the afternoon sector of the polar convection pattern, rapid zonal (westward) flows caused low F-region electron densities due to an extension of the mid-latitude trough far into the sunlit hemisphere. Low densities on the dawn side prior to 0600 UT may also have been due to a trough-like feature. Although the generation mechanism is unclear, the trough may be the fossil remnant of a substorm. Around midnight, high F-region densities were seen, probably due to plasma flow emerging from the cap through soft particle precipitation in the auroral oval. Two substorms occurred at times when the radar was south of the auroral oval. Both caused enhanced convection speeds, a swing to equatorward flow, enhanced E-region densities and a depleted F-region. The first was seen as a Westward Travelling Surge, and the swing to purely southward flow which followed the surge front did not return to westward flows until 80–110 min later. The Harang discontinuity was observed co-rotating eastwards between the substorms, 65 ± 30 min before the separatrix between the dawn and dusk convection cells.

Field-perpendicular and field-aligned plasma flows observed by EISCAT during a prolonged period of northward IMF

The effect of a prolonged period of strongly northward Interplanetary Magnetic Field (IMF) on the high-latitude F-region is studied using data from the EISCAT Common Programme Zero mode of operation on 11–12 August 1982. The analysis of the raw autocorrelation functions is kept to the directly derived parameters Ne, Te, Ti and velocity, and limits are defined for the errors introduced by assumptions about ion composition and by changes in the transmitted power and system constant. Simple data-cleaning criteria are employed to eliminate problems due to coherent signals and large background noise levels. The observed variations in plasma densities, temperatures and velocities are interpreted in terms of supporting data from ISEE-3 and local riometers and magnetometers. Both field-aligned and field-perpendicular plasma flows at Tromsø showed effects of the northward IMF: convection was slow and irregular and field-aligned flow profiles were characteristic of steady-state polar wind outflow with flux of order 1012 m−2 s−1. This period followed a strongly southward IMF which had triggered a substorm. The substorm gave enhanced convection, with a swing to equatorward flow and large (5 × 1012 m−2 s−1), steady-state field-aligned fluxes, leading to the possibility of O+ escape into the magnetosphere. The apparent influence of the IMF over both field-perpendicular and field-aligned flows is explained in terms of the cross-cap potential difference and the location of the auroral oval.

A novel transport assimilation method for the Atlantic meridional overturning circulation at 26°N

One of the prerequisites for achieving skill in decadal climate prediction is to initialize and predict the circulation in the Atlantic Ocean successfully. The RAPID array measures the Atlantic Meridional Overturning Circulation (MOC) at 26°N. Here we develop a method to include these observations in the Met Office Decadal Prediction System (DePreSys). The proposed method uses covariances of overturning transport anomalies at 26°N with ocean temperature and salinity anomalies throughout the ocean to create the density structure necessary to reproduce the observed transport anomaly. Assimilating transport alone in this way effectively reproduces the observed transport anomalies at 26°N and is better than using basin-wide temperature and salinity observations alone. However, when the transport observations are combined with in situ temperature and salinity observations in the analysis, the transport is not currently reproduced so well. The reasons for this are investigated using pseudo-observations in a twin experiment framework. Sensitivity experiments show that the MOC on monthly time-scales, at least in the HadCM3 model, is modulated by a mechanism where non-local density anomalies appear to be more important for transport variability at 26°N than local density gradients.

Earth's energy imbalance since 1960 in observations and CMIP5 models

Observational analyses of running 5-year ocean heat content trends (Ht) and net downward top of atmosphere radiation (N) are significantly correlated (r~0.6) from 1960 to 1999, but a spike in Ht in the early 2000s is likely spurious since it is inconsistent with estimates of N from both satellite observations and climate model simulations. Variations in N between 1960 and 2000 were dominated by volcanic eruptions, and are well simulated by the ensemble mean of coupled models from the Fifth Coupled Model Intercomparison Project (CMIP5). We find an observation-based reduction in N of -0.31±0.21 Wm-2 between 1999 and 2005 that potentially contributed to the recent warming slowdown, but the relative roles of external forcing and internal variability remain unclear. While present-day anomalies of N in the CMIP5 ensemble mean and observations agree, this may be due to a cancellation of errors in outgoing longwave and absorbed solar radiation.

Investigating preferences for dynamic electricity tariffs: the effect of environmental and system benefit disclosure

Dynamic electricity pricing can produce efficiency gains in the electricity sector and help achieve energy policy goals such as increasing electric system reliability and supporting renewable energy deployment. Retail electric companies can offer dynamic pricing to residential electricity customers via smart meter-enabled tariffs that proxy the cost to procure electricity on the wholesale market. Current investments in the smart metering necessary to implement dynamic tariffs show policy makers’ resolve for enabling responsive demand and realizing its benefits. However, despite these benefits and the potential bill savings these tariffs can offer, adoption among residential customers remains at low levels. Using a choice experiment approach, this paper seeks to determine whether disclosing the environmental and system benefits of dynamic tariffs to residential customers can increase adoption. Although sampling and design issues preclude wide generalization, we found that our environmentally conscious respondents reduced their required discount to switch to dynamic tariffs around 10% in response to higher awareness of environmental and system benefits. The perception that shifting usage is easy to do also had a significant impact, indicating the potential importance of enabling technology. Perhaps the targeted communication strategy employed by this study is one way to increase adoption and achieve policy goals.

Method for exploratory cluster analysis and visualisation of single-trial ERP ensembles

Background: The validity of ensemble averaging on event-related potential (ERP) data has been questioned, due to its assumption that the ERP is identical across trials. Thus, there is a need for preliminary testing for cluster structure in the data. New method: We propose a complete pipeline for the cluster analysis of ERP data. To increase the signalto-noise (SNR) ratio of the raw single-trials, we used a denoising method based on Empirical Mode Decomposition (EMD). Next, we used a bootstrap-based method to determine the number of clusters, through a measure called the Stability Index (SI). We then used a clustering algorithm based on a Genetic Algorithm (GA)to define initial cluster centroids for subsequent k-means clustering. Finally, we visualised the clustering results through a scheme based on Principal Component Analysis (PCA). Results: After validating the pipeline on simulated data, we tested it on data from two experiments – a P300 speller paradigm on a single subject and a language processing study on 25 subjects. Results revealed evidence for the existence of 6 clusters in one experimental condition from the language processing study. Further, a two-way chi-square test revealed an influence of subject on cluster membership.