An 11-year validation of wave-surge modelling in the Irish Sea, using a nested POLCOMS-WAM modelling system

In the future it is believed that extreme coastal flooding events will increase (in frequency and intensity) as a result of climate change. We are investigating the flood risks in the eastern Irish Sea posed by extreme storm events. Here, an 11-year simulation (01/01/1996–01/01/2007) including wave–current interaction has been validated. These data can then be used to investigate the potential for coastal flooding in the study area. To accurately model a storm event in the eastern Irish Sea both wave effects and the influence of the external surge need to be considered. To simulate the waves, we have set up a one-way nested approach from a 1° North Atlantic model, to a 1.85 km Irish Sea model, using the state-of-the-art 3rd-generation spectral WAve Model (WAM). This allows the influence of swell to be correctly represented. The Proudman Oceanographic Laboratory Coastal-Ocean Modelling System (POLCOMS) has been used to model the tide–surge interaction. To include the external surge we have set up a one-way nested approach from the 1/9° by 1/6° operational Continental Shelf surge model, to a 1.85 km Irish Sea model. For the high resolution Irish Sea model we use a POLCOMS–WAM coupled model, to allow for the effects of wave–current interaction on the prediction of surges at the coast. Using two classification schemes the coupled model is shown to be good and often very good at predicting the surge, total water elevation and wave conditions. We also find the number of low level surge events has increased in the study area over the past decade. However, this time period is too short to determine any long-term trends in the wave and surge levels

Transitions in parenting among Somali refugee and immigrant families : acculturation in the U.S. and the preservation of traditional culture and values : a project based upon an independent investigation

This qualitative study explores the changing experience of family life, acculturation, and preservation of traditional collectivist culture among Somali refugee and immigrant parents raising children in the United States. Resettlement in the U.S. forced many Somali refugees to transition to a new individualistic culture of family values markedly different from their own. Nine Somali refugee and immigrant mothers and fathers residing in Connecticut and western Massachusetts participated in the research. They answered open-ended interview questions focusing on the following topics: 1) Somali parenting styles and values, 2) the preservation of Somali language, identity, and Islam, 3) changes in family systems, regarding gender roles and extended family and 4) familial conflict resolution. The findings demonstrated that the greatest challenges to parenting centered on loneliness, social isolation, and lack of support from extended family and neighbors. All participants focused on children\u27s lack of respect for elders and diminishing parental authority as fundamental differences between American and Somali values. Most regretted their limitations in passing along Somali language and Islamic study. The findings also showed that many participants transitioned to a new acceptance of their children\u27s autonomy and identity as American, thereby meaningfully integrating American and Somali values. Many affirmed that a traditional Somali council of elders functioned in their current community as a model for familial conflict mediation more familiar than therapy. These findings help build cultural competency and trust by informing social workers, educators, and other service providers of the strengths and challenges that Somali refugee and immigrant families may face in the process of acculturation

Bayesian joint models with INLA exploring marine mobile predator-prey and competitor species habitat overlap

EPSRC grant Ecowatt 2050 EP/K012851/1 ACKNOWLEDGMENTS We would like to thank the associate editor and the anonymous reviewers for their useful and constructive suggestions which led to a considerable improvement of the manuscript. The authors would also like to thank the following people/organizations for making large datasets available for use in this paper: Mark Lewis (Joint Nature Conservation Committee), Philip Hammond (Scottish Oceans Institute, University of St. Andrews), Susan Lusseau (Marine Scotland Science), Darren Stevens (The Sir Alister Hardy Foundation for Ocean Science, PML), and Yuri Artioli (Plymouth Marine Laboratory). This work was supported by the Engineering and Physical Sciences Research Council (EcoWatt250; EPSRC EP/K012851/1).Peer reviewedPublisher PD

Tidal intrusion within a mega delta: an unstructured grid modelling approach

The finite volume community ocean model (FVCOM) has been applied to the Ganges-Brahmaputra-Meghna (GBM) delta in the northern part of the Bay of Bengal in order to simulate tidal hydrodynamics and freshwater flow in a complex river system. The delta region is data-poor in observations of both bathymetry and water level; making it a challenge for accurate hydrodynamic models be configured for and validated in this area. This is the first 3D baroclinic model covering the whole GBM delta from deep water beyond the shelf break to 250 km inland, the limit of tidal penetration. This paper examines what controls tidal penetration from the open coast into an intricate system of river channels. A modelling approach is used to improve understanding of the hydrodynamics of the GBM delta system. Tidal penetration is controlled by a combination of bathymetry, channel geometry, bottom friction, and river flow. The simulated tides must be validated before this delta model is used further to investigate baroclinic processes, river salinity and future change in this area. The performance of FVCOM tidal model configuration is evaluated at a range of sites in order to assess its ability to capture water levels which vary over both a tidal and seasonal cycle. FVCOM is seen to capture the leading tidal constituents well at coastal tide gauge stations, with small root-mean-squared errors of 10 cm on average. Inland, the model compares favourably with twice daily observed water levels at thirteen stations where it is able to capture both tidal and annual timescales in the estuarine system. When the river discharge is particularly strong, the tidal range can be reduced as the tide and river are in direct competition. The bathymetry is found to be the most influential control on water levels within the delta, though tidal penetration can be significantly affected by the model's bottom roughness, and the inclusion of large river discharge. We discuss the generic problem of implementing a model in a data-poor region and the challenge of validating a hydrodynamic model from the open coast to narrow river channels

Distribution of natural disturbance due to wave and tidal bed currents around the UK

The UK continental shelf experiences large tidal ranges and winter storm events, which can both generate strong near-bed currents. The regular tidal bottom currents from tides plus wind driven ‘benthic storms’ (dominated by wave-driven oscillatory currents in shallow water) are a major source of disturbance to benthic communities, particularly in shallow waters. We aim to identify and map the relative impact of the tides and storm events on the shallower parts of the North West European continental shelf. A ten-year simulation of waves, tides and surges on the continental shelf was performed. The shelf model was validated against current meter observations and the Centre for Environmental, Fisheries and Aquaculture Science (CEFAS) network of SmartBuoys. Next, the model performance was assessed against seabed lander data from two sites in the Southern North Sea; one in deep water and another shallow water site at Sea Palling, and a third in Liverpool Bay. Both waves and currents are well simulated at the offshore Southern North Sea site. A large storm event was also well captured, though the model tends to underpredict bottom orbital velocity. Poorer results were achieved at the Sea Palling site, thought to be due to an overly deep model water depth, and missing wave-current interactions. In Liverpool Bay tides were well modelled and good correlations (average R–squared=0.89) observed for significant wave height, with acceptable values (average R–squared=0.79) for bottom orbital velocity. Using the full ten-year dataset, return periods can be calculated for extreme waves and currents. Mapping these return periods presents a spatial picture of extreme bed disturbance, highlighting the importance of rare wave disturbances (e.g. with a return period of 1 in 10 years). Annual maximum currents change little in their magnitude and distribution from year to year, with mean speeds around 0.04 ms−1, and maximums exceeding 3 ms−1. Wave conditions however are widely variable throughout the year, depending largely on storm events. Typical significant wave heights (Hs) lie between 0.5–2 m, but storm events in shallow water can bring with them large waves of 5 m and above and up to 18 m in North West Approaches/North West Scotland ( Sterl and Caires, 2005). The benthic disturbance generated by waves and currents is then estimated by calculating the combined force on an idealised object at the bed. The patterns of this disturbance reflect both regular tidal disturbance and rare wave events. Mean forces are typically 0.05–0.1 N, and are seen largely in areas of fast currents (View the MathML source>1ms−1). The pattern of maximum force however is more dependent on water depth and exposure to long-fetches (View the MathML source>1000km) suggesting it is dominated by wave events

Wachstumsmodelle mit GeoGebra 3.2

Diese Arbeit gibt Anregungen zum Einsatz von GeoGebra 3.2 bei der Behandlung von Wachstumsmodellen