Climate change and increasing population growth are accelerating the need for new clean renewable energy generation. One such proposed type of renewable energy is offshore floating wind, which has yet to reach a convergence as to the optimum type of floating platform to support a wind turbine. To date there has been numerous proposals of novel floating platforms with unique hull characteristics. One such type is the advanced spar, which has a large area of sharp edges and therefore considerably different hydrodynamic viscous effects than typical cylindrical platforms. Prediction of a floating body’s low frequency drag damping is crucial to successfully predicting the horizontal motions. Calculation of the viscous effects have been seen to have the most uncertainty. Published literature shows that the viscous drag effects of floating bodies either increase or decrease with increasing wave severity as compared to still water decay tests. In this paper a combined experimental and numerical method for identifying low frequency viscous damping effects on the hull of a moored platform is introduced. An initial offset is applied to the platform, which is then released in still water and regular sinusoidal waves. The experimental results will then be compared to a weakly nonlinear time domain model in order to identify how the drag coefficients vary with wave conditions. Discussions on Keulegan–Carpenter (KC) number dependent damping are given. Finally simulations using results from these experiments are compared against a full scale deployed floating platform in multi-directional waves, current and wind.

As the offshore wind industry moves into deeper waters, the number of different floating wind platform concepts continues to expand. Accurately predicting the motion characteristics of these novel platforms is crucial to the safe and economic conversion of wind energy into electricity. A challenge in the currently used numerical simulation methods involves successfully predicting the slow drift motions and damping, especially in complex realistic environmental conditions which include multi-directional spectral waves, current and wind loading. Of most uncertainty to these predictions is determining the low frequency viscous damping which dominates the resonant surge and sway motions. In this paper, full-scale motion observations of the Fukushima FORWARD's floating wind substation are used to determine the platforms viscous drag forces. These drag coefficients are used in a combined potential flow and Morison's equation model to capture the observed behaviour. This validated numerical model is then used to describe the required fidelity of mooring line models, in order to aid platform developers in the early stages of design.

Global population growth and climate change are driving a need for increased clean renewable energy generation. One such resource is wind energy and while the onshore and fixed offshore wind energy industries are mature, the floating offshore wind energy industry is still at a demonstration phase. Floating wind turbine platforms are generally of a much smaller displacement than the typical offshore structures that have been used in the oil and gas industry. This difference results in changes to the platform dynamics, especially those resulting from second order wave forces. Existing research into low frequency drift motions of small body platforms has been mainly confined to numerical modelling with some experimental work. This work expands on this knowledge by validating numerical modelling with full scale observational data. In this paper, a numerical time-domain model of a relatively small displacement platform is developed. The platform is installed in a relatively shallow water depth of about 110 m and station keeping is provided by four equally spaced catenary mooring chains. The required fidelity for the low frequency response is compared using first order forces only and either a full QTF (quadratic transfer equation) or Newman's approximation. The model is compared with observation data from the Fukushima FORWARD project's floating substation, an advanced spar type, which is composed of measurements of multidirectional wave spectra, wind and current as model inputs and six DOF platform motions as outputs. In addition to this the model computational expense is reduced by decreasing the number of wave directions simulated. The accuracy of such reductions is then described. Observation data is grouped according to sea-state data. An empirical drag coefficient formula is proposed. The 50 year return period design sea-state is also modelled using a JONSWAP spectrum and the various numerical models.

Understanding how bird populations respond to changes in waterbody availability in the climatically variable Prairie Pothole Region (PPR) of North America hinges on being able to couple hydrological and climate modeling to represent potential future landscapes. Model experiments run with the Pothole Complex Hydrologic Model using downscaled climate data (variables relating to precipitation, temperature, and potential evapotranspiration at 1/8 degrees spatial resolution under four general circulation climate models and two gas emissions scenarios) were used to forecast the abundances of six focal wetland-dependent bird species in the Missouri Coteau portion of the PPR, providing ensemble scenarios at a spatial scale relevant to resource management. Although the projected number of May ponds (waterbodies present during bird breeding season) fluctuated through time with some decadal periodicity (and with the number present in a given year reflecting abundance over the previous three years), the ensemble model average indicated an increase in the average number of waterbodies present by the turn of the next century. Overall, the model experiments conservatively projected an 11.75% increase in the number of waterbodies present by 2090-2099 compared to a baseline period from 1967 to 2005 in the PPR. Wetland-dependent bird occurrence and abundance were significantly associated with temporal patterns and decadal periodicity in waterbody dynamics. Because of the strong associations between wetland-dependent bird occurrence and abundance and the number of prairie potholes, projected waterbody increases are forecasted to result in an 11.97% overall increase in occurrence and 8.63% increase in abundance of the six focal species by the end of the 21st century; these results contrast with forecasted drought-associated declines in waterbodies and birds in the PPR. This integrated hydrological-climatological approach offers a means of assessing how wetland-dependent bird populations may respond to changes in wetland habitat availability due to a changing dimate. Our results provide information that can help managers decide how to mitigate the effects of climate shifts on the distribution of wetland habitat and biota.

Although the United States has pursued rapid development of corn ethanol as a matter of national biofuel policy, relatively little is known about this policy's widespread impacts on agricultural land conversion surrounding ethanol refineries. This knowledge gap impedes policy makers' ability to identify and mitigate potentially negative environmental impacts of ethanol production. We assessed changes to the landscape during initial implementation of the Renewable Fuel Standard v2 (RFS2) from 2008 to 2012 and found nearly 4.2 million acres of arable non-cropland converted to crops within 100 miles of refinery locations, including 3.6 million acres of converted grassland. Aggregated across all ethanol refineries, the rate of grassland conversion to cropland increased linearly with proximity to a refinery location. Despite this widespread conversion of the landscape, recent cropland expansion could have made only modest contributions to mandated increases in conventional biofuel capacity required by RFS2. Collectively, these findings demonstrate a shortcoming in the existing 'aggregate compliance' method for enforcing land protections in the RFS2 and suggest an alternative monitoring mechanism would be needed to appropriately capture the scale of observed land use changes.

For water depths greater than 60m floating wind turbines will become the most economical option for generating offshore wind energy. Tension mooring stabilised units are one type of platform being considered by the offshore wind energy industry. The complex mooring arrangement used by this type of platform means that the dynamics are greatly effected by offsets in the positioning of the anchors. This paper examines the issue of tendon anchor position tolerances. The dynamic effects of three positional tolerances are analysed in survival state using the time domain FASTLink. The severe impact of worst case anchor positional offsets on platform and turbine survivability is shown. The worst anchor misposition combinations are highlighted and should be strongly avoided. Novel methods to mitigate this issue are presented.

As the offshore wind industry moves to water depths greater that 50m floating platforms will become the only cost effective solution for mounting turbines. Such platforms will be susceptible to bio foulingover their design life with marine growth capable of altering the hydrodynamic loading. Marine growth causes member effective diameter, mass, drag coefficients, force and hydrodynamic added mass to increase. In this paper, marine growth of various thickness and surface roughness is numerically modelled on a tension moored floating wind turbineunder survival conditions using combined potential flow boundary element method and Morison equation viscous drag. The influence of time variant Reynolds number dependent drag coefficients is compared against time invariant drag coefficients. Marine growth thickness and surface roughness have a notable effect on the platform hydrodynamic forces. Surge, pitch motions, and nacelle accelerations decrease as surface roughness increases. Minimum tendon forces decrease. This increases the probability of a catastrophic tendon snap or slack event. The authors calculate the increase in displacement required to avoid this loss in tension. Detailed limits on the quantity of marine growth are suggested by the authors, above which the platform must be cleaned. The time invariant drag coefficient method has been found to give sufficiently consistent results to the time variant Reynolds number drag coefficient method.

Links between climatic forcing and wetland habitats can be conceptualized using a graph-theoretical approach, which treats wetlands as nodes to map habitat connectivity and to define habitat networks for ecological analysis. The first and most crucial step in creating a network model, however, is to characterize the dynamic behaviors of the nodes, i.e., the occurrence of wetlands with ponded water, or water bodies. For the first time, this study applies a 3-D, fully integrated surface and subsurface flow model, HydroGeoSphere (HGS), to simulate the hydrologic dynamics of wetlands in the Prairie Pothole Region (PPR) and to characterize the resulting habitat networks as a function of climate variability. Results show HGS is able to simulate water movement in both surface and subsurface domains and capture “fill-spill” and coalescence/disaggregation behaviors of wetlands as they respond to wet and dry climatic conditions. Our simulations for a small representative subarea of the PPR show wetland networks in the PPR could easily shrink, degrade, or even collapse when the climate becomes drier. This study demonstrates the potential in applying sophisticated hydrologic models to solve critical ecological problems and the practical implications for water-resources management, conservation planning and decision-making in the PPR.

The offshore wind industry is rapidly maturing and is now expanding to more extreme. environments in deeper water and farther from shore. To date fixed foundation types (i.e.. monopoles, jackets) have been primarily used but become uneconomical in water depths greater than 50m. Floating foundations have more complex dynamics but at the moment no design has reached commercialization, although a number of devices are being tested at prototype stage. The development of concepts is carried out through physical model testing of scaled devices such that to better understand the dynamics of the system and validate numerical models. This paper investigates the testing of a scale model of a tension moored wind turbine at two different scales and in the presence and absence of a spring damper controlling its dynamic response. The models were tested under combined wave and wind thrust loading conditions. The analysis compares the motions of the platform at different scales and structural conditions through RAO, testing a mooring spring damper for load reductions.

Tuned liquid column dampers have been proved to be successful in mitigating the dynamic responses of civil infrastructure. There have been some recent applications of this concept on wind turbines and this passive control system can help to mitigate responses of offshore floating platforms and wave devices. The control of dynamic responses of these. devices is important for reducing loads on structural elements and facilitating operations and maintenance (O&M) activities. This paper outlines the use of a tuned single liquid column damper for the control of a tension leg platform supported wind turbine. Theoretical studies were carried out and a scaled model was tested in a wave basin to assess the performance of the damper. The tests on the model presented in this paper correspond to a platform with a very low natural frequency for surge, sway and yaw motions. For practical purposes, it was not possible to tune the liquid damper exactly to this frequency. The consequent approach taken and the efficiency of such approach are presented in this paper. Responses to waves of a single frequency are investigated along with responses obtained from wave spectra characterising typical sea states. The extent of control is quantified using peak and root mean squared dynamic responses respectively. The tests present some guidelines and challenges for testing scaled devices in relation to including response control mechanisms. Additionally, the results provide a basis for dictating future research on tuned liquid column damper based control on floating platforms.

Lark et al (2015 Environ. Res. Lett. 10 044003), analyze recent shifts in US agricultural land use (2008-2012) using newly-available, high-resolution geospatial information, the Cropland Data Layer. Cropland expansion documented by Lark et al suggests the need to reform national agricultural policies in the wake of an emerging, new era of US agriculture characterized by rapid land cover/land use change.

Although aspects of power generation of many offshore renewable devices are well understood, their dynamic responses under high wind and wave conditions are still to he investigated to a great detail. Output only statistical markers are important for these offshore. devices, since access to the device is limited and information about the exposure conditions and the true behaviour of the devices are generally partial, limited, and vague or even absent. The markers can summarise and characterise the behaviour of these devices from their dynamic response available as time series data. The behaviour may be linear or nonlinear and consequently a marker that can track the changes in structural situations can be quite important. These markers can then be helpful in assessing the current condition of the structure and can indicate possible intervention, monitoring or assessment. This paper considers a Delay Vector Variance based marker for changes in a tension leg platform tested in an ocean wave basin for structural changes brought about by single column dampers. The approach is based on dynamic outputs of the device alone and is based on the estimation of the non:linearity of the output signal. The advantages of the selected marker and its response with changing structural properties are discussed. The marker is observed to be important for monitoring the as-deployed structural condition and is sensitive to changes in such conditions. Influence of exposure conditions of wave loading is also discussed in this study based only on experimental data.

Background Juvenile Idiopathic Arthritis (JIA) is a common form of chronic arthritis in children, diagnosed under the age of 16.1 It is a long-term condition (LTC) characterised by several clinical and humanistic features, and is recognised in contributing to a reduction in quality of life amongst children and young people (CYP).2 Previous research has identified parental concerns about JIA; however, it is important to identify the concerns of CYP in order to address unmet needs in healthcare provision and support. Objectives To identify the top concerns of CYP with JIA. The results of the survey will inform future research to address any issues raised. There will also be a comparison to previous research conducted by Douglas et al. regarding the top concerns of parents of CYP with JIA. The project was lead by two patients with JIA who are now consumer representatives. Methods The study sample included CYP with JIA (aged 8 to 24, based on World Health Organisation definitions). Qualitative research was carried out in the form of electronic and paper-based surveys distribted via charity group workshops and social media. The top concerns and the healthcare experience of CYP with JIA was identified. Insights analysis was ongoing at the time of submission. Results In addition to responses from patients aged 8 to 24, insights were generated from younger and older patients, as well as parents. These will be reported as supplementary findings. Most CYP identified the survey via social media. Approximately three-times as many female patients responded, compared to males. The top concerns generated were grouped into overarching themes, including: long-term disease effects, a fear of being labelled as “different”, isolation from others, pain and fatigue, restriction from “normal” activities, medication and school/working life. There were also some key themes about the hospital experience of CYP, including: transition, continuity of care, the clinical environment, ineffective treatments, transparency, disease awareness and lack of support groups. There were also responses from England, Scotland, Northern Ireland and the United States of America, demonstrating some of the differences in care provision across different healthcare services. Conclusions It is evident that CYP have meaningful experience of the day-to-day burden of living with JIA, providing an essential understanding of what patients identify as priorities. The results from the survey will help to suggest further research, with an aim of developing interventions to address these concerns. Following a full analysis of the survey, this research will continue to work with CYP, families and professionals to improve the experience of CYP living with JIA. References Weiss JE, Luca NJC, Boneparth A, Stinson J. (2014). Assessment and Management of Pain in Juvenile Idiopathic Arthritis. Pediatric Drugs. 16(6): 473-481. Haverman L, Grootenhuis MA, van den Berg JM, van Veenendaal M, Dolman KM, Swart JF, Kuijpers TW, van Rossum MAJ. (2012). Predictors of health-related quality of life in children and adolescents with juvenile idiopathic arthritis: Results from a web-based survey. Arthritis Care & Research. 64(5): 694-703. Acknowledgements JIA Facebook groups, Arthritis Care Northern Ireland, Scottish Network for Arthritis in Children, Children9s Chronic Arthritis Association, all other JIA charities in the UK and Ireland. Disclosure of Interest None declared

Habitat connectivity is a landscape attribute critical to the long‐term viability of many wildlife species, including migratory birds. Climate change has the potential to affect habitat connectivity within and across the three main wetland complexes in the Great Plains of North America: the prairie potholes of the northern plains, the Rainwater Basin of Nebraska, and the playas of the southern plains. Here, we use these wetlands as model systems in a graph‐theory‐based approach to establish links between climatic drivers and habitat connectivity for wildlife in current and projected wetland landscapes and to discern how that capacity can vary as a function of climatic forcing. We also provide a case study of macrosystems ecology to examine how the patterns and processes that determine habitat connectivity fluctuate across landscapes, regions, and continents.

We quantified fluctuations in the status of individual patches (wetlands) in supporting connectivity within a network of playas, temporary wetlands of the southern Great Plains of North America that are loci for regional biodiversity. We used remote sensing imagery to delineate the location of surface waters in >8,000 playa basins in a ~31,900 km2 portion of Texas and quantified connectivity in this region from 2007 to 2011. We ranked playas as stepping-stones, cutpoints, and hubs at different levels of environmental conditions (regionally wet, dry, and average periods of precipitation) for dispersal distances ranging from 0.5 to 34 km, representing a range of species’ vagilities, to provide baseline dynamics within an area likely to experience disrupted connectivity due to anthropogenic activities. An individual playa’s status as a stepping-stone, cutpoint, or hub was highly variable over time (only a single playa was a top 20 stepping-stone, cutpoint, or hub in >50 % of all of the dates examined). Coalescence of the inundated playa network usually occurred at ≥10 km dispersal distance and depended on wetland density, indicating that critical thresholds in connectivity arose from synergistic effects of dispersal ability (spatial scale) and wet playa occurrence (a function of precipitation). Organisms with dispersal capabilities limited to <10 km routinely experienced effective isolation during our study. Connectivity is thus a dynamic emergent landscape property, so management to maintain connectivity for wildlife within ephemeral habitats like inundated playas will need to move beyond a patch-based focus to a network focus by including connectivity as a dynamic landscape property.

The Eurasian wheat belt (EWB) spans a region across Eastern Ukraine, Southern Russia, and Northern Kazakhstan; accounting for nearly 15% of global wheat production. We assessed land surface conditions across the EWB during the early growing season (April-May-June; AMJ) leading up to the 2010 Russian heat wave, and over a longer-term period from 2000 to 2010. A substantial reduction in early season values of the normalized difference vegetation index occurred prior to the Russian heat wave, continuing a decadal decline in early season primary production in the region. In 2010, an anomalously cold winter followed by an abrupt shift to a warmer-than-normal early growing season was consistent with a persistently negative phase of the North Atlantic oscillation (NAO). Regression analyses showed that early season vegetation productivity in the EWB is a function of both the winter (December-January-February; DJF) and AMJ phases of the NAO. Land surface anomalies preceding the heat wave were thus consistent with highly negative values of both the DJF NAO and AMJ NAO in 2010.

Habitat connectivity is a landscape attribute critical to the long-term viability of many wildlife species, including migratory birds. Climate change has the potential to affect habitat connectivity within and across the three main wetland complexes in the Great Plains of North America: the prairie potholes of the northern plains, the Rainwater Basin of Nebraska, and the playas of the southern plains. Here, we use these wetlands as model systems in a graph-theory-based approach to establish links between climatic drivers and habitat connectivity for wildlife in current and projected wetland landscapes and to discern how that capacity can vary as a function of climatic forcing. We also provide a case study of macrosystems ecology to examine how the patterns and processes that determine habitat connectivity fluctuate across landscapes, regions, and continents.

In the US Corn Belt, a recent doubling in commodity prices has created incentives for landowners to convert grassland to corn and soybean cropping. Here, we use land cover data from the National Agricultural Statistics Service Cropland Data Layer to assess grassland conversion from 2006 to 2011 in the Western Corn Belt (WCB): five states including North Dakota, South Dakota, Nebraska, Minnesota, and Iowa. Our analysis identifies areas with elevated rates of grass-to-corn/soy conversion (1.0–5.4% annually). Across the WCB, we found a net decline in grass-dominated land cover totaling nearly 530,000 ha. With respect to agronomic attributes of lands undergoing grassland conversion, corn/soy production is expanding onto marginal lands characterized by high erosion risk and vulnerability to drought. Grassland conversion is also concentrated in close proximity to wetlands, posing a threat to waterfowl breeding in the Prairie Pothole Region. Longer-term land cover trends from North Dakota and Iowa indicate that recent grassland conversion represents a persistent shift in land use rather than short-term variability in crop rotation patterns. Our results show that the WCB is rapidly moving down a pathway of increased corn and soybean cultivation. As a result, the window of opportunity for realizing the benefits of a biofuel industry based on perennial bioenergy crops, rather than corn ethanol and soy biodiesel, may be closing in the WCB.