Communicating geomorphology: an empirical evaluation of the discipline's impact and visibility

Concern among geomorphologists that the discipline's visibility and impact are becoming suppressed are reflected in a series of recent Earth Surface Exchanges (ESEX) commentaries by Tooth et al. This paper from the British Society for Geomorphology (BSG) Communicating Geomorphology Fixed‐Term Working Group (FTWG) reports initial findings from an online survey of BSG members alongside an empirical assessment of the term's prominence in academic output: international peer‐reviewed journals, undergraduate Geoscience degrees in world‐leading institutions and the UK Research Excellence Framework (REF) impact statements. Our observations indicate the scientific standing of the discipline has been retained but the term itself is less widely utilised and we offer a series of suggestions actionable by the geomorphology community. Copyright © 2017 John Wiley & Sons, Ltd.     

Using geographically weighted regression to explore the spatially heterogeneous spread of bovine tuberculosis in England and Wales

An understanding of the factors that affect the spread of endemic bovine tuberculosis (bTB) is critical for the development of measures to stop and reverse this spread. Analyses of spatial data need to account for the inherent spatial heterogeneity within the data, or else spatial autocorrelation can lead to an overestimate of the significance of variables. This study used three methods of analysis—least-squares linear regression with a spatial autocorrelation term, geographically weighted regression (GWR) and boosted regression tree (BRT) analysis—to identify the factors that influence the spread of endemic bTB at a local level in England and Wales. The linear regression and GWR methods demonstrated the importance of accounting for spatial differences in risk factors for bTB, and showed some consistency in the identification of certain factors related to flooding, disease history and the presence of multiple genotypes of bTB. This is the first attempt to explore the factors associated with the spread of endemic bTB in England and Wales using GWR. This technique improves on least-squares linear regression approaches by identifying regional differences in the factors associated with bTB spread. However, interpretation of these complex regional differences is difficult and the approach does not lend itself to predictive models which are likely to be of more value to policy makers. Methods such as BRT may be more suited to such a task. Here we have demonstrated that GWR and BRT can produce comparable outputs.     

Submarine platform development by erosion of a Surtseyan cone at Capelinhos,Faial Island,Azores

Erosion of volcanic islands ultimately creates shallow banks and guyots, but the ways in which erosion proceeds to create them over time and how the coastline retreat rate relates to wave conditions, rock mass strength and other factors are unclear. The Capelinhos volcano was formed in 1957/58 during a Surtseyan and partly effusive eruption that added an ~2.5 km² tephra and lava promontory to the western end of Faial Island (Azores, central North Atlantic). Subsequent coastal and submarine erosion has reduced the subaerial area of the promontory and created a submarine platform. This study uses historical information, photos and marine geophysical data collected around the promontory to characterize how the submarine platform developed following the eruption. Historical coastline positions are supplemented with coastlines interpreted from 2004 and 2014 Google Earth images in order to work out the progression of coastline retreat rate and retreat distance for lava- and tephra-dominated cliffs. Data from swath mapping sonars are used to characterize the submarine geometry of the resulting platform (position of the platform edge, gradient and morphology of the platform surface). Photographs collected during SCUBA and ROV dives on the submarine platform reveal a rugged surface now covered with boulders. The results show that coastal retreat rates decreased rapidly with time after the eruption and approximately follow an inverse power-law relationship with coastal retreat distance. We develop a finite-difference model for wave attenuation over dipping surfaces to predict how increasing wave attenuation contributed to this trend. The model is verified by reproducing the wave height variation over dipping rock platforms in the UK (platform gradient 1.2° to 1.8°) and Ireland (1.8°). Applying the model to the dipping platform around Capelinhos, using a diversity of cliff resistance predicted from known lithologies, we are able to predict erosion rate trends for some sectors of the edifice. We also explore wider implications of these results, such as how erosion creates shallow banks and guyots in reef-less mid-oceanic archipelagos like the Azores. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.     

Cumulative spatial impact layers: A novel multivariate spatio‐temporal analytical summarization tool

Scientific inquiry often requires analysis of multiple spatio‐temporal datasets, ranging in type and size, using complex multi‐step processes demanding an understanding of GIS theory and software. Cumulative spatial impact layers (CSIL) is a GIS‐based tool that summarizes spatio‐temporal datasets based on overlapping features and attributes. Leveraging a recursive quadtree method, and applying multiple additive frameworks, the CSIL tool allows users to analyze raster and vector datasets by calculating data, record, or attribute density. Providing an efficient and robust method for summarizing disparate, multi‐format, multi‐source geospatial data, CSIL addresses the need for a new integration approach and resulting geospatial product. The built‐in flexibility of the CSIL tool allows users to answer a range of spatially driven questions. Example applications are provided in this article to illustrate the versatility and variety of uses for this CSIL tool and method. Use cases include addressing regulatory decision‐making needs, economic modeling, and resource management. Performance reviews for each use case are also presented, demonstrating how CSIL provides a more efficient and robust approach to assess a range of multivariate spatial data for a variety of uses.     

Methods for intercomparison of wave measurements

The paper reviews methods for quality assessment and intercomparison of ocean wave data. The sampling variability for conventional time series recordings is summarized and compared to less common area measuring measurements. The sampling variability affects the scatter seen in simultaneous observations, and variability in excess of the sampling variability signifies real differences between the instruments. Various means of intercomparing wave parameters and spectra are discussed and two somewhat unconventional ways of deriving regression and calibration relationships are also shown. The methods are illustrated using data from SCAWVEX, focusing mainly on wave data from the HF radars and Directional Waveriders.     

Use of marine controlled-source electromagnetic sounding for sub-basalt exploration

The problem of imaging sedimentary structure obscured by high-velocity layers, such as carbonate, basalt or salt, using conventional seismic techniques is well known. When this problem is encountered in offshore areas, marine electromagnetic data can provide valuable, alternative and complementary constraints on the structure. We concentrate on the use of marine controlled-source electromagnetic (CSEM) sounding in the frequency domain. The feasibility of mapping sub-basalt sedimentary structure using this technique is explored by means of modelling studies which mimic a type of survey which could readily be employed in practice. As a starting point the problem is addressed in terms of 1D resistivity structure. We show that sub-basalt sediments can be detected and their depth of burial quantified to within 200 m in the examples shown. The presence of small-scale inhomogeneities in the basalt (which cause much of the scattering in seismic data) is shown to have no appreciable effect on the ability of the CSEM data to detect the sediments. The modelling is then extended to 2.5 dimensions. Again the presence of sub-basalt sediments can be readily detected and their properties and geometry quantified, especially if the electromagnetic data are combined with constraints from complementary geophysical techniques.     

Skills development in tourism: South Africa's tourism-led development strategy

Skills development for tourism has attracted only a limited scholarship in the developing world. In this paper the role of skills development in advancing South Africa's tourism-led development strategy is investigated. Skills development has a central role to play in ensuring the effective and sustainable transformation and development of the tourism industry in developing countries and, in the case of South Africa, in ensuring that poorer South Africans begin to benefit from this industry. It is argued that the current lack of an integrated and co-ordinated approach to tourism skills development seriously limits the potential of skills development to impact positively on tourism transformation and development in South Africa. This revised version was published online in August 2006 with corrections to the Cover Date.     

The use of live vegetation in geomorphological experiments: how to create optimal growing conditions

There has been increasing use of live vegetation in laboratory experiments, in particular in fluvial geomorphology. The results from these studies have provided useful insight into the role that vegetation plays in impacting and modifying geomorphic systems. However there has been little published on the seed preparation techniques and vegetation growing conditions required for use in these experiments. This commentary presents results from a series of experiments investigating these factors using Medicago sativa and Avena Sativa, with the aim of highlighting the optimal growing conditions found to provide a starting point for researchers interested in implementing these techniques. Copyright © 2014 John Wiley & Sons, Ltd.     

Magnetic resonance imaging of the Lake Agassiz–Lake Winnipeg transition

As part of the Geologic Survey of Canada (GSC) Lake Winnipeg Study, we have successfully imaged the Lake Agassiz to Lake Winnipeg transition in Section 4 of Core Namao 94-900-122a (i.e., from 313 cm to 465 cm), using a newly-developed magnetic resonance imaging (MRI) technique called SPRITE (Single-Point, Ramped Imaging with T₁ Enhancement). Whole core, gamma-ray attenuation measurements have been used to calculate the bulk porosity of the sediment at 1 cm intervals for comparison with the SPRITE images. Image contrast and image intensities observed in the SPRITE images of Section 4 are related to local porosity and magnetic susceptibility variations. In general, regions of the core with low signal intensity contain high porosity and low magnetic susceptibility. The best contrast between sediment layers is observed from regions of the core with high magnetic susceptibility. High signal intensity is observed from regions with low porosity and/or high magnetic susceptibility.