Sediment transport patterns at Trafalgar offshore windfarm

A simple analytical model of wave propagation has been developed in order to study the potential sediment transport patterns due to the action of currents and waves in the neighborhood of cylindrical structures as well inside a group of these structures. The attention is focused on the study of Trafalgar offshore windfarm, a case in which it has been necessary to analyze the flow trough porous structures in order to model fish growing-cages planned to be installed at each aerogenerator structure. The results are obtained by averaging over one period of wave in order to evaluate the net potential sediment transport. The analysis of the results reveals how the processes of wave diffraction and reflection give rise to periodic patterns of sediment transport around and between the structures.     

Modeling bio-geomorphological influences for offshore sandwaves

The coastal environment shows a wide range of bed patterns, for which sandwaves and sandbanks are among the most common. Less known in this context is the high benthic diversity in the coastal environment, which gives rise to the question to what extend the benthos interacts with the shape of the seabed. This paper reviews field and flume experiments on bio-geomorphological influences between benthos and sediment and tests the hypothesis that both the occurrence and the dimensions of sandwaves are dependent on the benthic diversity in the North Sea. Mathematical inclusions to account for biological activity in idealized models reveal that biota is able to influence the wavelength of sandwaves significantly, compared to the default case. More importantly, the models indicate that biota is able to induce bed patterns under conditions when the physical parameters suggest a stable flat bed and vice versa. Present model explorations indicate that future research should focus on the parameterization of subtidal biological activity on sediment dynamics and thereby on seabed patterns. Such knowledge will enable process-based modeling of the spatial and temporal variation in biological activity on seabed morphodynamics and validate the proposed modeling approach with field measurements.     

Local Log-Law-of-the-Wall in Neutrally-Stratified Boundary-Layer Flows

It is well known that in a neutrally-stratified turbulent flow in a deep constant-stress layer above a flat surface,the horizontal mean velocity varies logarithmically with height (the so-called `log-law-of-the-wall').More recently, the same logarithmic law has also been foundin the presence of non-flat surfaces, where it governs thedynamics of the areally-averagedvelocity and involves renormalized effective parameters.Here, we analyze wind profiles over two-dimensional sinusoidal hillsobtained both from numerical simulations performed with a primitiveequation model and from wind-tunnel measurements. We showthat also the local velocity profiles behave to a verygood approximation logarithmically, for a distance from the surface of the order of the maximum hill height almost to the top of the boundary layer. Such alocal log-law-of-the-wall involves effective parameters smoothly depending on theposition along the underlying topography.This dependence looks very similar to the topography itself.     

Steppin' in it: postcoloniality in northern Pakistan

This paper examines the transcultural relations between researchers and research subjects in a postcolonial research setting. I draw from my experience doing dissertation research in northern Pakistan to discuss how my research subjects' effectively constructed me as a sahib, or what I saw as a colonial subject position. I examine the ways that my research subjects and I co-constructed, although unequally, my position and location as a researcher. The asymmetries of power relations in research are exacerbated by postcolonial relations in this contact zone. The contribution of those I researched is significant towards understanding our locations as postcolonial subjects in this research setting, and the location from which I produced the research. While it was difficult to do research as anyone other than a sahib during my research, the stories I tell and metaphors I employ in this paper attempt to destabilize my location as a colonial sahib, an authority. The scatological references that run throughout this paper are an attempt to write against the inherently colonial epistemologies that underpin geographic research more generally.     

Trends and variability of ocean waves under RCP8.5 emission scenario in the Mediterranean Sea

Ocean Dynamics - Wind-generated ocean waves are key inputs for several studies and applications, both near the coast (coastal vulnerability assessment, coastal structures design, harbor...     

Assessment of global wave models on regular and unstructured grids using the Unresolved Obstacles Source Term

Ocean Dynamics - The Unresolved Obstacles Source Term (UOST) is a general methodology for parameterizing the dissipative effects of subscale islands, cliffs, and other unresolved features in ocean...     

The Value of Autoethnography for Field Research in Transcultural Settings*

Mary Louise Pratt uses the term autoethnography to refer to those instances in which members of colonized groups strive to represent themselves to their colonizers in ways that engage with colonizers' terms while also remaining faithful to their own self‐understandings. This paper extends Pratt's conceptualization of autoethnography and describes how it may be used to inform field research in transcultural settings in the formerly colonized world. Drawing from research in a village in northern Pakistan, we argue that approaching fieldwork with an “autoethnographic sensibility” can yield important epistemological, methodological, and political insights into our research practices. The paper concludes by suggesting that these insights extend beyond a postcolonial, or even cross‐cultural, research context, to inform more general debates in human geography about how to achieve a critical and reflexive research practice.     

Autoethnography: A Limited Endorsement*

In this commentary, we wish to draw from Kathryn's experience in Askole to complicate the argument we developed in favor of an autoethnographic sensibility in the earlier article in this issue ( Butz and Besio 2004 ). Just as we used David's first‐person singular voice in much of that article, we use Kathryn's voice here to reflect the central influence of her research circumstances on the points that we make. We will return to the first‐person plural voice in the commentary's conclusion where we attempt to synthesize the lessons of our two sets of research experiences.