Derek W.T. Jackson

Ulster University · School of Environmental Sciences

Wind on Mars is a significant agent of contemporary surface change, yet the absence of in situ meteorological data hampers the understanding of surface–atmospheric interactions. Airflow models at length scales relevant to landform size now enable examination of conditions that might activate even small-scale bedforms (ripples) under certain contemp...

The Little Ice Age is the most noted climatological event in recent history with dramatic consequences for a large part of the western European coastal landscape. A major morphological feature associated with this event is the presence of large-scale transgressive dune fields that actively advanced inland, encroaching, in some cases, human settleme...

In the context of global climate change and sea-level rise, coastal dunes are often important elements in the coastal response to storm wave and storm surge impacts on coastal lowlands. Vegetation cover, in turn, has profound impacts on coastal dune morphology and storm-buffering function; it binds existing sediment, promotes fresh sediment accumul...

Sandy beaches represent some of the most dynamic environments on Earth and examining their morphodynamic behaviour over different temporal and spatial scales is challenging, relying on multidisciplinary approaches and techniques. Sandy Beach Morphodynamics brings together the latest research on beach systems and their morphodynamics and the ways in...

Classification of beach morphodynamic state relies on accurate representation of breaking wave conditions, Hb (plus grain size and spring tidal range). Measured breaking wave data, however, are absent from all but a handful of sites worldwide. Here, we apply process-based wave modelling for propagating offshore waves to the breaking zone using high...

Anegada, the easternmost island of the Virgin Islands group (Caribbean Sea), is a low Pleistocene carbonate platform surrounded by Horseshoe Reef, the world's third-largest fringing reef. The western part of the island consists of an extensive beachridge plain (>40 ridges). The sandy carbonate shoreline exists in three morphodynamic domains that ex...

Almar and colleagues (2023) are correct in stating that, “understanding and predicting shoreline evolution is of great importance for coastal management.” Amongst the different timescales of shoreline change, the interannual and decadal timescales are of particular interest to coastal scientists as they reflect the integrated system response to the...

Shoreline evolution over the last two centuries was analysed for Dundrum Bay, Co. Down, Northern Ireland using historical and recent shoreline datasets from 1833 to 2020. The area of interest comprises two sandy beaches and vegetated coastal dune fields, Newcastle-Murlough and Ballykinler, separated by an inlet channel which connects the inner with...

Although morphologically persistent in the long term, Multiple Intertidal Bar Systems (MITBs) display short-term, especially seasonal, morphodynamic behaviour. Analysis of high-density, monthly DGPS surveys conducted at Murlough and Ballykinler beaches, inter- and supratidal sediment volumes and hydrodynamic forcing (wave conditions and water level...

Shorefaces are transitional zones between the shelf and surfzone/beach systems. They are subdivided into ‘upper’ and ‘lower’ shoreface sectors, which display particular morphodynamic behaviour. The upper shoreface is morphologically active over short (annual) time scales, while the lower shoreface changes over much longer time scales (decadal and b...

The processes that initiate and sustain sediment transport which contribute to the modification of aeolian deposits in Mars' low-density atmosphere are still not fully understood despite recent atmospheric modelling. However, detailed microscale wind flow modelling, using Computational Fluid Dynamics at a resolution of <2 m, provides insights into...

Determining the size and shape of coarse sediment is of paramount importance to many applications (e.g. sediment transport, flow resistance in numerical hydraulic models, estimation of current velocity and direction, habitat classification). One of the current challenges is that to reach statistical significance, one needs to collect large amounts...

Multiple intertidal bar (MITB) beach systems comprise a succession of subdued, shore-parallel sandbars, developed under low energy conditions in meso- to macrotidal settings. Their relatively stable morphologies over long timescales are commonly attributed to a dynamic equilibrium, driven primarily by seasonal morphodynamics. The seasonal behaviour...

Significance Statement Climate change has many negative impacts on coastal areas with sea level rise and more frequent and intense storms leading to higher rates of coastal flooding and erosion. Natural coastal features such as beaches and sand dune systems can boost resilience to climate change and provide an effective buffer against negative impa...

Coastal dunes are sensitive to both anthropic and natural processes of erosion. In this study, we analyse the geomorphic changes in 15 dune-fringed coastlines of Asturias (NW Spain) for the period 1992 to 2014 to determine specific drivers of erosion. Coastline migration patterns were obtained using geospatial analysis of vertical aerial images and...

Output from planetary atmospheric models is crucial for a diverse range of NASA-supported activities: from assessing risks for spacecraft and human exploration, to studying the geology of ancient Mars or magnetospheres of giant planets, to engaging the public. It is right for NASA to fund work that includes the development and use of planetary atmo...

The morphodynamic approach to the study of beaches had its origins at the Coastal Studies Institute at Louisiana State University in the late 1960s and formed the basis of the Australian approach beginning in the mid-1970s where it was formalized by Wright and Thom (1977). Unlike the previous fragmented approach to beach studies, the morphodynamic...

Recent advances in structure-from-motion (SfM) techniques have proliferated the use of unmanned aerial vehicles (UAVs) in the monitoring of coastal landform changes, particularly when applied in the reconstruction of 3D surface models from historical aerial photographs. Here, we explore a number of depth map filtering and point cloud cleaning metho...

Meso-scale airflow conditions can be observed at spatial scales of 2 – 2,000 km and temporal scales of days to months. In complex aeolian environments, where topographic steering alters regional airflow patterns, larger scale phenomena can modify micro-scale dune dynamics. Whole-island topographic steering has been observed around Gran Canaria, a h...

Modern coastal dune management is viewed largely through the prism of dune ecology. Achieving maximum biodiversity and preserving priority species are the primary objectives and management is based on interventions (grazing, mowing, burning, reseeding, and artificial destabilisation) to achieve that purpose. Under non-managed conditions, dune veget...

Ridge and runnel features were originally described by King and Williams (1949) from observations at Blackpool beach (U.K.) and laboratory experiments. They were characterised as intertidal, shore-parallel sandbars (ridges), commonly 2 to 6 bars in total, and disconnected from each other by troughs (runnels). The nomenclature ‘ridge and runnel’ was...

At seasonal to century timescales (mesoscale), the shoreface is a critical zone seaward of the surf zone and/or beachface, in which waves interact with the mobile seafloor to cause morphological change. This has important (and often unacknowledged) implications for adjacent shoreline form and behaviour both now and in the near-future. The shoreface...

Airflow dynamics across dune surfaces are the primary agent of sediment transport and resulting dune migration movements. Using 3D computational fluid dynamic modelling, this study examined the behaviour of near surface airflow travelling over transverse (reversing) dunes on a beach system. Wind direction was modelled in two opposing directions (bo...

Regular, long-term coastal monitoring of sandy beaches using cross-shore profiling provides important insights into longer term morphodynamic behaviour which cannot be achieved from infrequent, event-led measurements. The need for rapid survey excursions to capture contemporary morphological impacts from storms and dynamic bedforms moving across in...

To understand physical form and process in coastal environments requires acknowledgement that both are interlinked and are part of a temporally and spatially variable system. ‘Morphodynamic’ was the catch-all phrase to describe this approach which evolved from early pioneers in the 1970s in the United States and Australia. Since then it has become...

Beaches that are geologically controlled by rock and coral formations are the rule, not the exception. This paper reviews current understanding of geologically controlled beaches, bringing together a range of terminologies (including embayed beaches, shore platform beaches, relict beaches, and perched beaches among others) and processes, with the a...

In northern Europe, beach erosion, coastal flooding and associated damages to engineering structures are linked to mid-latitude storms that form through cyclogenesis and post-tropical cyclones, when a tropical cyclone moves north from its tropical origin. The present work analyses the hydrodynamic forcing and morphological changes observed at three...

The shoreline evolution and the occurrence of storm events are analysed for the last two centuries in Dundrum Bay, Co. Down in the SE coast of Northern Ireland (U.K.) as part of the INTERREG MarPAMM project. The study site is a macrotidal beach (5.5 m max spring tidal range) predominantly sandy and characterised by multiple intertidal bars ('ridge...

DGPS surveys were undertaken on two beaches of Dundrum Bay (east coast of Northern Ireland, Co.Down, U.K.) and analysed to investigate the short-term morphodynamics of a multiple intertidal bar ('ridge and runnel') system, as part of the INTERREG MarPAMM project. Ballykinler (east) and Murlough beach (west) are medium to coarse sand environments su...

Wind flows on Mars are the dominant contemporary force driving sediment transport and associated morphological change on the planet's dune fields. To fully understand the atmospheric-surface interactions occurring on the dunes, investigations need to be conducted at appropriate length scales (at or below that of any landform features being examined...

Coastal monitoring of sandy beach areas requires data gathering at regular time scales to capture daily to weekly geomorphological changes that are modified through tidal and wave action. Regular GPS profiling surveys carried out at medium (weekly) to long-term (month/annual) frequency can lead to misinterpretation of beach changes as they are not...

It has been asserted by Vousdoukas et al., that climate change, in particular global sea-level rise (SLR), poses a threat to the existence of sandy beaches. The authors used global data bases of sandy beaches, bathymetry, wave conditions and SLR to drive a simple model based on the ‘Bruun Rule’ to quantitatively evaluate shoreline retreat. To this...

Conventional aeolian sand transport models relate mass transport rate to wind speed or shear velocity, usually expressed and empirically tested on a 1‐second time‐scale. Projections of total sand delivery over long time‐scales based on these models are highly sensitive to any small bias arising from statistical fitting on empirical data. We analyse...

Understanding coastal morphodynamics involves investigating a system of processes and landforms operating over variable spatial and temporal scales in a environment, where the hydrosphere, lithosphere and atmosphere meet to form one of Earth's most complex systems. Understanding its short-(event) to long-term (evolution) dynamics requires a multidi...

Parabolic dunes are ‘U’ or ‘V’-shaped aeolian landforms that form on pre-existing sand deposits. Their morphology consists of an upwind deflation basin, bordered by often vegetated trailing arms and a downwind depositional lobe. The orientation of parabolic dunes is commonly attributed to the prevailing or resultant wind direction. Consequently, th...

Coastal systems are the result of a natural equilibrium between hydrodynamic, atmospheric, and terrestrial parameters and sediment dynamics. In the Anthropocene, this equilibrium in many coastal regions can be altered by human activities. These activities may globally magnify the effects of extreme meteorological events and sea level rise and direc...

Most assessments of coastal vulnerability are undertaken from the perspective of the risk posed to humans, their property and activities. This anthropocentric view is based on widespread public perception (a) that coastal change is primarily a hazard to property and infrastructure and (b) that sea defences (whether soft or hard) are required to mit...

Infrequent but high energy storm events can radically modify coastlines, at times displacing significant sediment volumes and changing shoreline configuration. More frequent and stronger Atlantic storms over the last 40 years have heightened the potential risk to coastal environments, population and infrastructure. Understanding local environmental...

The interplay of eustatic and isostatic factors causes complex relative sea‐level (RSL) histories, particularly in paraglacial settings. In this context the past record of RSL is important in understanding ice‐sheet history, earth rheology and resulting glacio‐isostatic adjustment. Field data to develop sea‐level reconstructions are often limited t...

Beaches of tropical island coasts exhibit high levels of diversity in composition and form in comparison with their continental counterparts. To investigate the nature and origin of this diversity, individual beach morphology and sedimentology was investigated in the British Virgin Islands (BVI), a Caribbean archipelago of > 60 high volcanic and lo...

The complex morphodynamic interactions between nearshore, shoreface and dune systems are usually simplified by studying these zones and their associated processes in isolation. However, the established relationships between each of them suggests that an integrated approach is required to examine the genesis, evolution and adaptation of the entire m...

The barrier islands that fringe the western shore of the Outer Hebrides are globally unusual in that they are developed on a planated bedrock (strandflat) surface. They also contain the most extensive area of machair (a distinctive vegetated sandy plain) in the British Isles. This paper presents the first investigation of the internal structure and...

Understanding dynamic earth surface processes requires various spatial and temporal information to help produce patterns of landform change. Recent developments in sensor technology such as Structure from Motion (SfM), camera-mounted airborne Unmanned Aerial Vehicles (UAVs) and Terrestrial Laser Scanning (TLS) have provided a means of acquiring hig...

Parabolic dunes are widespread aeolian landforms found in a variety of environments. Despite modeling advances and good understanding of how they evolve, there is limited empirical data on their dynamics at short time scales of hours and on how these dynamics relate to their medium-term evolution. This study presents the most comprehensive data set...

Dune length scale airflow modelling provides new insights on aeolian bedform response and complex near surface 3D wind patterns not previously resolved by mesoscale models. At a 1-m surface resolution, Curiosity wind data is used to investigate the aeolian environment of the Namib dune on Mars, providing improved seasonal constraints on grainfall,...

The storm sequence of the 2013/14 winter left many beaches along the Atlantic coast of Europe in their most eroded state for decades. Understanding how beaches recover from such extreme events is essential for coastal managers, especially in light of potential regional increases in storminess due to climate change. Here we analyze a unique dataset...

This study achieves the highest resolution of airflow modelling thus far in the study of martian aeolian dynamics by employing a High Resolution Imaging Science Experiment (HiRISE) Digital Terrain Model (DTM) of the Namib dune in Gale Crater at a 1-meter resolution. At this resolution, sub-dune scale bedforms, not previously resolved by mesoscale m...

Aeolian sand transport is crucial for post-storm recovery of beach and dune systems, protodune formation and early stage embryonic dune forms that may go on to accumulate into foredune ridges. The sand transport process is driven by the momentum transfer from the local boundary layer to the surface. An important component of this process are the tu...

Parabolic dunes are U or V shaped aeolian landforms that form on pre-existing sand deposits. Their morphology consists of an upwind deflation basin, bordered by often-vegetated trailing arms and a downwind depositional lobe. The orientation of parabolic dunes commonly aligns and is attributed to prevailing or the resultant wind direction. As a resu...

Models relating wind forcing to resulting sand transport flux have been at the core of the discipline from its conception and remain an important central focus. The desired capability to accurately predict the amounts of sand that are moved in response to any given wind regime is one of the key practical applications of our scientific efforts. A pl...

Coastal blowouts are acknowledged as highly effective transport pathways on dune-fringed coasts. Their morphological form is indicative of aeolian transport and the propensity of their topography to modify airflow sufficiently to support transport has been extensively researched [1, 2]. As the evolution of sandy coastlines is governed by sediment e...

In 2015, an active dune field on Mars was visited up close by the Curiosity rover in Gale Crater providing the first high resolution ground images of fine scale windblown features not previously resolved from orbital-based imagery. For the first time, these images allow for direct comparison with terrestrial aeolian dynamics and provide critical gr...

Coral reefs help reduce incoming wave energy by up to 90% and decrease wave related hazards for coastal communities. Acting as a submarine breakwater, the sudden change from oceanic depths to shallow reef bathymetry reduces wave heights and modifies their frequency. Coastal communities benefitting from coral reef protections are now at risk with in...

Low frequency, high magnitude storm events can dramatically alter coastlines, helping to relocate large volumes of sediments and changing the configuration of landforms. Increases in the number of intense cyclones occurring in the Northern Hemisphere since the 1970s is evident with more northward tracking patterns developing. This brings added pote...

Grain flows are an integral part of sand dune migration; they are a direct response to the local wind regime and reflect complex interactions between localized over-steepening of a dune slipface and complex turbulent airflow on the lee slope. Grain flows are primarily responsible for delivering sediment to the base of a dune, thus driving slipface...

Geomorphometry is a cross-cutting discipline that has interwoven itself into multiple research themes due to its ability to encompass topographic quantification on many fronts. Its operational focus is largely defined as the extraction of land-surface parameters and earth surface characterisation. In particular, the coastal sciences have been enric...

Coastal dunes are natural buffers against the threat of climate change-induced sea level rise. Their evolution is largely controlled by sediment exchanges between the geomorphic sub-units of the nearshore, beach, foredune and dune field. Coastlines characterised by multiple blowouts at the beach-dune interface may be more susceptible to coastline r...

In December 2015, the Curiosity rover relayed images of the Namib dune slipface in Gale Crater and presented a unique opportunity for direct comparison to terrestrial aeolian dynamics. These images delivered critical ground truth data of martian aeolian dynamics improving morphometric studies of slipface grainflow activity and aeolian modelling. Th...

Long-term monitoring of beach dynamics is an important element in risk prevention and management of both natural and human resources at the coast. The predicted intensification in storminess (frequency, duration and magnitude), partly associated with climate change, represents a pressing concern for coastal communities globally and has undoubtedly...

Large-scale atmospheric turbulence can have a large impact on the regional wind regime effecting dune environments. Depending on the incident angle of mesoscale airflow, local topographic steering can also alter wind conditions and subsequent aeolian dynamics. This research analyses the influence of large-scale airflow perturbations occurring at th...

Large-scale blowouts are fundamental features of many coastal dune fields in temperate areas around the world. These distinctive erosional (mostly unvegetated) landform features are often characterised by a significant depression area and a connected depositional lobe at their downwind edges. These areas also provide important transport corridors t...