James D. Hansom

Derivative Reflectance Spectroscopy to Estimate Suspended Sediment Concentration

Remotely sensed data can be used to estimate successfully the concentration of sediment in water. Such estimation has relied on relationships between suspended sediment concentration (SSC) and radiation in one or two broad wavebands where it is assumed that the effects of environmental variability (irradiance, subpixel cloud, etc.) are either small, or can be considered as spectrally additive constants in all wavebands. Where these assumptions do not hold, an alternative and theoretically more robust relationship is proposed, t that between SSC and derivative radiation (change in radiation per unit wavelength). Measurements of spectral reflectance (Rλ), derivative spectral reflectance (DRλ) and SSC were measured in the laboratory, where the effects of environmental variability were small and at sea where the effects of environmental variability were large. There was a strong correlation between SSC and DRλ both in the laboratory (max R2 = − 0.98) and at sea (max R2 = − 0.83) and DRλ was used to estimate SSC in the laboratory to an error of less than 8 % of the mean SSC. The correlation between Rλ and SSC was weaker at sea (max R2 = 0.46) than in the laboratory (max R2 = 0.96). This was due to the presence of large and spectrally variable environmental effects. We recommend the use of derivative spectra for the estimation of SSC when continuous spectra are available.

Optically stimulated luminescence dating of large storm events in Northern Scotland.

Climate changes over the Holocene have directly impacted on both coastal processes and human use of coastal areas. This paper presents results from the dating of wind blown sand deposits collected from coastal and archaeological sites in Northern Scotland. Archaeological remains are frequently found interspersed with sand deposits and represent distinct periods of occupation of settlement sites within the local landscapes. In some cases storm events sufficiently inundate the sites with sand to result in periodic abandonment. Storm events can also have dramatic results on adjacent rock coastlines, with storm boulder ridges emplaced by large waves, burying sand deposits on cliff-top sites. Work has been undertaken using a quartz SAR protocol to date sand deposition at two archaeological sites in Orkney and a cliff-top site in Shetland. These dates provide chronological information, which help to construct regional chronologies of climatic instability and environmental change and allow the SAR-OSL method to be assessed as an accurate sediment dating tool in this context.

Holocene spit development on a regressive shoreline, Dornoch Firth, Scotland

The series of raised and modern spits and beaches which characterise the Dornoch Firth coastline are described. The beaches and spits in the inner firth are relatively small, having developed during the mid-Holocene with little-subsequent modification. In the central firth, large spit complexes developed on the northern and southern shorelines extending westwards during the mid-Holocene. However, during the later Holocene, spit growth was towards the east on the southern shore and towards the southwest on the northern shore. In the outer firth, spit and beach development mainly occurred during the later Holocene. The development of spits at the mouth of the firth changed the wave energy environment in the central section and resulted in the marked changes in spit alignment in this area. The features also indicate that during the rise and culmination of the Main Postglacial Transgression coarse clastic sediments derived from cliff erosion dominated. In contrast during the later Holocene, when relative sea level fell, sand-sized material derived from the nearshore and offshore zone predominated.

Luminescence dating of aeolian sands from archaeological sites in Northern Britain: a preliminary study ☆

Luminescence dating of aeolian sands from archaeological sites has potential to contribute to regional chronologies for sediment deposition and to provide a greater understanding of climatic influences on early communities. The Northern and Western Isles of Scotland provide important opportunities for sampling archaeologically intercalated sands for these purposes, and to provide constrained samples for method validation. A wide range of modern beaches have been sampled in the Western and Orkney Isles of Scotland to examine regional variations in luminescence sensitivity, residuals and ease of bleaching. These modern sands have negligible residuals for infra-red stimulated luminescence (IRSL), small optically stimulated luminescence (OSL) residuals and significant thermoluminescence residuals. The relationship between these signals and laboratory bleaching results may indicate the initial depositional environment, and hence lead to a means of identifying well-bleached dating samples. Both sensitivities and residuals show regional differences, reflecting local geology. Preliminary ages obtained from aeolian sands associated with archaeological sites at Amble (Northumbria) and Tofts Ness (Sanday, Orkney) using regenerative blue OSL techniques on extracted quartz are broadly consistent with external age controls from the first and third millennium BC.

Scotland's coast: Understanding past and present processes for sustainable management

Abstract The coastline of Scotland is extremely long and varied. It comprises most of the major types of coastal environment and includes machair, a sand dune system that is unique to the western seaboard of the British Isles. Such variety has its roots in the geology and sea level inheritance of Scotland and demonstrates that long‐term processes still exert a profound influence on coastal form and functioning. Understanding how these processes affect the coast and influence such diversity is essential to efficient coastal management, although it is also imperative that the vision, strategy and political will to deliver such management are also in place.

Managing lakeshore erosion: Impacts of bank protection on Loch Lomond, Scotland

Abstract The shoreline of Loch Lomond is currently undergoing erosion not only because of passive natural changes but also because of active changes produced by the interaction of shoreline protection structures and natural processes. In order to assess the influence of protection structures on different types of loch shore, the shores were classified and their total extent, including the extent of artificial shore, was quantified. The effect of structures is often felt on adjacent shores as well as on those that the structure is designed to protect. In order to assess the extent of impact of structures, sediment cells were identified along the loch shore within which the effects of a structure may produce compensatory effects but beyond which they will not. A management strategy is presented that is aimed at minimising the detrimental effects of any future intervention in the shore system.

Geodiversity In a Changing Environment

In the last decade or so, the concept of ‘geodiversity’ has provided a focus for activity linking the physical environment, people and their cultures (Gray 2004, 2008). While there has been a strong emphasis on geoconservation, a wider agenda is now developing in response to new political, social, economic and environmental policy drivers (Henriques et al. 2011; Prosser et al. 2011; Gordon et al. 2012). This is reflected in the ecosystem approach and an emphasis on delivering economic, social, cultural and environmental benefits for society. A holistic framework is fundamental to the success of such an approach, both in terms of integrating geodiversity, biodiversity and landscape conservation, and in terms of delivering benefits for society at a time of economic constraints and in the face of potentially far-reaching effects of climate change in the longer term. Understanding geodiversity is therefore a key requirement in a more sustainable future. It provides the essential underpinnings of the natural environment and thus is fundamental to the support of all biodiversity functions, landscapes, habitats and species. Geodiversity also has direct relevance to economic activities and cultural heritage, as well as to mitigation of the impact of climate change. It delivers ecosystem services in both rural and urban settings and provides the basis for truly sustainable management of the environment in the face of change. In a wider sense geodiversity exerts a basic influence on the health and well-being of Scotland’s people. However, it is clear that the concept of ‘geodiversity’ does not have the wider cachet or familiarity that ’biodiversity’ currently enjoys. Consequently, awareness of its values and benefits remains generally low and its integration in environmental policy and the developing ecosystem approach has so far been limited. In order to address these issues, the Conference, ‘Engaging with Geodiversity – Why it Matters’ was organized jointly by Scottish Natural Heritage, the British Geological Survey (BGS), the Royal Scottish Geographical Society (RSGS) and the British Society of Soil Science (BSSS). It was held at Our Dynamic Earth in Edinburgh on 1 December 2010. Opened by the Scottish Environment Minister, Roseanna Cunningham MSP, the key aim was to highlight the wider relevance of geodiversity in Scotland and to consider how geodiversity might be better integrated within the existing policy framework that influences how we work and live. This should allow a better decision making process to emerge that secures a more sustainable future for us and our Scottish Geographical Journal Vol. 128, Nos. 3–4, 173–176, September–December 2012

Beach forms and changes associated with retreating glacier ice, South Georgia

Beach forms associated with the retreat of Cook Glacier, between 1975 and 1982 are compared with those found on polar beaches. The presence of certain characteristics but the absence of man...

Extreme Waves: Causes, Characteristics, and Impact on Coastal Environments and Society

The existence of extreme waves, as observed by seafarers, has been confirmed by data recording and modeling to be more common than previously assumed. Extreme waves mainly occur during major storms at sea by means of constructive interference of wave trains or by nonlinear wave interaction, but extreme waves may also be associated with tsunami or meteotsunami events. If they arrive at the coast, most extreme waves have the potential to cause extensive remodeling and repositioning of the shoreline environment and landforms as well as causing significant damage to human infrastructure and threat to life. The impact of extreme waves on both sedimentary and rocky coasts can be substantial with sediments or rocky boulders eroded from the coastal edge being transported and deposited some distance inland. This characteristic provides clues to the nature of the extreme event and, if recorded within the recent sedimentary record, information about the periodicity of similar events. The impact of extreme waves on coastal communities and environment has prompted a range of mitigation and adaptation strategies to cope with these hazards. These include more robust coast defences, better modeling, prediction and warning systems, improved interagency liaison, improved technical assistance, and storm impact management information for the general public, as well as provision of clear evacuation routes during a wave-related emergency. However, since climate change seems likely to result in increased rates of both sea-level rise and storm-related impacts, there is an emerging consensus that adaptive management of the coastal zone may prove to be a more sustainable strategy than the alternatives.

Scottish Landform Examples 43: Glacifluvial Landforms of Strathallan, Perthshire

A wide range of landforms and sediments is created by the melting of glacier ice, and commonly constitute the most prominent evidence of former glaciation. In upland landscapes, the concentration of meltwater activity in valley settings results in the development of complex assemblages of ice-contact glacifluvial erosional and depositional forms. An excellent example of such an assemblage exists in Strathallan and the tributary River Knaik, documenting the intensity and changing nature of ice-contact glacifluvial processes during the recession of the last British–Irish Ice Sheet into the Highlands of Scotland.