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This study presents 62 years of hindcast wave climate data for the south coast of Sweden from 1959–2021. The 100-km-long coast consists mainly of sandy beaches and eroding bluffs interrupted by headlands and harbours alongshore, making it sensitive to variations in incoming wave direction. A SWAN wave model of the Baltic Sea, extending from the North Sea to the Åland Sea, was calibrated and validated against wave observations from 16 locations distributed within the model domain. Wave data collected from open databases were complemented with new wave buoy observations from two nearshore locations within the study area at 14 and 15 m depth. The simulated significant wave height showed good agreement with the local observations, with an average R2 of 0.83. The multi-decadal hindcast data was used to analyse spatial and temporal wave climate variability. The results show that the directional distribution of incoming waves varies along the coast, with a gradually increasing wave energy exposure from the west towards the east. The wave climate is most energetic from October to March, with the highest wave heights in November, December, and January. In general, waves from westerly directions dominate the annual wave energy, but within the hindcast time series, a few years had larger wave energy from easterly directions. The interannual variability of total wave energy and wave direction is correlated to the North Atlantic Oscillation (NAO) index. In the offshore, the total annual wave energy had a statistically significant positive correlation with the NAO DJFM station-based index, with a Spearman rank correlation coefficient of 0.51. In the nearshore, the correlation was even stronger. Future studies should investigate the possibility of using the NAO index as a proxy for the wave energy direction and its effect on coastal evolution.

Combining hard and soft costal protection solutions can be an appropriate measure to enhance structure lifetime. This study aims to quantify the morphological evolution of the nourished stretch and adjacent coastlines. A small-scale beach nourishment has been performed in front of a rock revetment at site in Faxe Ladeplads in Zealand, Denmark. The overall objective is to learn more about the dynamics of small-scale nourishments in low energy environments. Monitoring techniques include repeated topographic (Trimble RTK-GPS, drone surveying) and bathymetric (single beam) measurements. To measure the hydrodynamic conditions two surface acceleration buoys deployed at -4 and -7 m water depth were used. Sediment volumes from nourishments of size 70,000 m3 and 20,000 m3 redistributed relatively quickly. The nourished material built up the cross-shore profile and a longshore bar in this area, and distributed sediments in the direction of the dominant littoral drift (SW). Results suggest that the morphological evolution of the nourishment is dependent on local hydrodynamic conditions and local geomorphology. These findings have implications for the main objectives of preventing wave overtopping onto an adjacent coastal road during extreme events and restoring a beach for recreation.

Highlights: • A first standardized and publicly available Holocene relative sea-level database for the Baltic Sea is presented. • The database holds 1099 revised data points with an estimation of vertical and chronological uncertainties. • Negative RSL tendencies prevail over the positive and complex tendencies in the Baltic Sea Basin. • Mid-Holocene RSL highstand occurred around 7.5–6.5 ka BP being consistent with the end of the final melting of the LIS. • The contribution of ice loading in the eastern Baltic Sea Basin is likely overestimated in the ICE-5G and ICE-6G_C models. Abstract: We present a compilation and analysis of 1099 Holocene relative shore-level (RSL) indicators located around the Baltic Sea including 867 relative sea-level data points and 232 data points from the Ancylus Lake and the following transitional phase. The spatial distribution covers the Baltic Sea and near-coastal areas fairly well, but some gaps remain mainly in Sweden. RSL data follow the standardized HOLSEA format and, thus, are ready for spatially comprehensive applications in, e.g., glacial isostatic adjustment (GIA) modelling. We apply a SQL database system to store the nationally provided data sets in their individual form and to map the different input into the HOLSEA format as the information content of the individual data sets from the Baltic Sea area differs. About 80% of the RSL data is related to the last marine stage in Baltic Sea history after 8.5 ka BP (thousand years before present). These samples are grouped according to their dominant RSL tendencies into three clusters: regions with negative, positive and complex (transitional) RSL tendencies. Overall, regions with isostatic uplift driven negative tendencies dominate and show regression in the Baltic Sea basin during the last marine stage. Shifts from positive to negative tendencies in RSL data from transitional regions show a mid-Holocene highstand around 7.5–6.5 ka BP which is consistent with the end of the final melting of the Laurentide Ice Sheet. Comparisons of RSL data with GIA predictions including global ICE-5G and ICE-6G_C ice histories show good fit with RSL data from the regions with negative tendencies, whereas in the transitional areas in the eastern Baltic, predictions for the mid-Holocene clearly overestimate the RSL and fail to recover the mid-Holocene RSL highstand derived from the proxy reconstructions. These results motivate improvements of ice-sheet and Earth-structure models and show the potential and benefits of the new compilation for future studies.

Arctic sea-ice loss is emblematic of an amplified Arctic water cycle and has critical feedback implications for global climate. Stable isotopes (δ18O, δ2H, d-excess) are valuable tracers for constraining water cycle and climate processes through space and time. Yet, the paucity of well-resolved Arctic isotope data preclude an empirically derived understanding of the hydrologic changes occurring today, in the deep (geologic) past, and in the future. To address this knowledge gap, the Pan-Arctic Precipitation Isotope Network (PAPIN) was established in 2018 to coordinate precipitation sampling at 19 stations across key tundra, subarctic, maritime, and continental climate zones. Here, we present a first assessment of rainfall samples collected in summer 2018 (n = 281) and combine new isotope and meteorological data with sea ice observations, reanalysis data, and model simulations. Data collectively establish a summer Arctic Meteoric Water Line where δ2H = 7.6⋅δ18O–1.8 (r2 = 0.96, p < 0.01). Mean amount-weighted δ18O, δ2H, and d-excess values were −12.3, −93.5, and 4.9‰, respectively, with the lowest summer mean δ18O value observed in northwest Greenland (−19.9‰) and the highest in Iceland (−7.3‰). Southern Alaska recorded the lowest mean d-excess (−8.2%) and northern Russia the highest (9.9‰). We identify a range of δ18O-temperature coefficients from 0.31‰/°C (Alaska) to 0.93‰/°C (Russia). The steepest regression slopes (>0.75‰/°C) were observed at continental sites, while statistically significant temperature relations were generally absent at coastal stations. Model outputs indicate that 68% of the summer precipitating air masses were transported into the Arctic from mid-latitudes and were characterized by relatively high δ18O values. Yet 32% of precipitation events, characterized by lower δ18O and high d-excess values, derived from northerly air masses transported from the Arctic Ocean and/or its marginal seas, highlighting key emergent oceanic moisture sources as sea ice cover declines. Resolving these processes across broader spatial-temporal scales is an ongoing research priority, and will be key to quantifying the past, present, and future feedbacks of an amplified Arctic water cycle on the global climate system. © Copyright © 2021 Mellat, Bailey, Mustonen, Marttila, Klein, Gribanov, Bret-Harte, Chupakov, Divine, Else, Filippov, Hyöky, Jones, Kirpotin, Kroon, Markussen, Nielsen, Olsen, Paavola, Pokrovsky, Prokushkin, Rasch, Raundrup, Suominen, Syvänperä, Vignisson, Zarov and Welker. We gratefully acknowledge all participating PAPIN stations. Tarja T?rm?nen and Aino Erkinaro assisted with sample analysis at the Stable Isotope Laboratory, University of Oulu. Shawn Marriott, Patrick Duke and Polar Knowledge Canada are acknowledged for their support with the Canadian High Arctic Research Station. Sergey Serikov and Aleksandr Sokolov assisted with Russian precipitation sampling. The NOAA Air Resources Laboratory (ARL) is gratefully acknowledged for provision of the HYSPLIT transport model used in this study. NCEP/NCAR data were obtained from the National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory?s (ESRL) Physical Sciences Laboratory database. Funding. The Pan-Arctic Precipitation Isotope Network (PAPIN) received funding from the European Union?s Horizon 2020 Project INTERACT, under Grant Agreement No.730938 (JW PI). An Academy of Finland Grant (316014-JW PI). Support was also provided by a University of the Arctic Research Chairship to JW that funded isotope analyses and provided postdoctoral support for HB and K-RM and postgraduate research support for MM. A Russian Science Foundation Grant (No. 18-11-00024) to KG funded isotope analyses. SK was thankful to Russian Science Foundation (No. 20-67-46018). Russian Foundation for Basic Research (BFBR) supported isotopic analyses conducted by AP (#18-05-60203-Arktika).

Detailed topographical data and high-resolution ground-penetrating radar (GPR) reflection data are presented from the present-day beach and across successive raised beach-ridges at Itilleq (Disko, West Greenland). In the western part of our study area, the present low-tide level is well-marked by an abrupt change in clast size, between the sandy foreshore and the upper shoreface, which is characterized by frequently occurring large clasts. The main part of both fine and large clasts appears to be locally derived. Seaward-dipping reflections form down-lap points, which are clearly identified in all beach-ridge GPR profiles. Most of them are located at the boundary between a unit with reflection characteristics representing palaeo foreshore deposits, and a deeper and more complex radar unit characterized by diffractions, which, however, is not penetrated to large depths by the GPR signals. Based on observations of the active shoreface regime, large clasts are interpreted to give rise to scattering observed near the top of the deeper radar unit. We regard the down-lap points located at this radar boundary as markers of palaeo low-tide level. In some places, scattering hyperbolas are more pronounced and frequent than in others, suggesting differences in the occurrence of large boulders.

Quantifying fluxes of water, sediment and dissolved compounds through Arctic rivers is important for linking the glacial, terrestrial and marine ecosystems and to quantify the impact of a warming climate. The quantification of fluxes is not trivial. This study uses a 8-years data set (2005–2012) of daily measurements from the high-Artic Zackenberg River in Northeast Greenland to estimate annual suspended sediment fluxes based on four commonly used methods: M1) is the discharge weighted mean and uses direct measurements, while M2-M4) are one uncorrected and two bias corrected rating curves extrapolating a continuous concentration trace from measured values. All methods are tested on complete and reduced datasets. The average annual runoff in the period 2005–2012 was 190 ± 25 mio · m3 y− 1. The different estimation methods gave a range of average annual suspended sediment fluxes between 43,000 ± 10,000 t y− 1 and 61,000 ± 16,000 t y− 1. Extreme events with high discharges had a mean duration of 1 day. The average suspended sediment flux during extreme events was 17,000 ± 5000 t y− 1, which constitutes a year-to-year variation of 20–37% of the total annual flux. The most accurate sampling strategy was bi-daily sampling together with a sampling frequency of 2 h during extreme events. The most consistent estimation method was an uncorrected rating curve of bi-daily measurements (M2), combined with a linear interpolation of extreme event fluxes. Sampling can be reduced to every fourth day, with both method-agreements and accuracies

A wide range of delta morphologies occurs along the fringes of the Young Sound in Northeast Greenland due to spatial heterogeneity of delta regimes. In general, the delta regime is related to catchment and basin characteristics (geology, topography, drainage pattern, sediment availability, and bathymetry), fluvial discharges and associated sediment load, and processes by waves and currents. Main factors steering the Arctic fluvial discharges into the Young Sound are the snow and ice melt and precipitation in the catchment, and extreme events like glacier lake outburst floods (GLOFs). Waves are subordinate and only rework fringes of the delta plain forming sandy bars if the exposure and fetch are optimal. Spatial gradients and variability in driving forces (snow and precipitation) and catchment characteristics (amount of glacier coverage, sediment characteristics) as well as the strong and local influence of GLOFs in a specific catchment impede a simple upscaling of sediment fluxes from individual catchments toward a total sediment flux into the Young Sound.

Overwash is an important process that controls short-term barrier dynamics, as well as long-term barrier migration, but this process is difficult to study in the field due to its rare occurrence and the challenging conditions under which it occurs. This paper uses data collected during the BARDEX II experiment in the Delta Flume, the Netherlands, where a proto-type barrier was subjected to a range of wave and water level conditions. The objectives of this research are to: (1) compare the morphologic response to overwash on a gravel barrier (BARDEX 2008 experiment) with that on a sandy barrier (BARDEX II); (2) understand the influence of wave period on overwash characteristics and sediment transport; and (3) improve current knowledge of overwash hydrodynamics. The comparative analysis shows that barrier overwash can be affected by negative feedback that stabilises the barrier through barrier crest accretion on gravel barriers, and by submerged bar development on sandy barriers. An increase in the wave period induced a reduction in overwash frequency over the crest, but no significant relation was found between wave peak period and overwash discharge. Nevertheless, overall water discharge during an overwash episode significantly correlates with overall overwash sediment transport rate. Overwash flow depths during the experiment were relatively shallow and velocities were similar compared to those measured during previous studies and reported in the literature. Despite the controlled laboratory conditions, collection of reliable and accurate measurements of overwash velocities remains challenging. (C) 2015 Elsevier B.V. All rights reserved. ANR-14-ASTR-0004-01

This chapter reviews recent trends and variability in river flows to the North Sea. The main contributors are the River Elbe and the River Rhine. In addition to these large rivers many smaller rivers also discharge into the North Sea. However, by far the biggest contributor is the Baltic Sea outflow. Observation records for the major rivers draining into the North Sea are relatively long, while records for the smaller rivers are typically much shorter. Variability in flow is dependent on variations in weather—mainly precipitation and temperature—from year to year, but also on a wide range of direct and indirect human interventions in the North Sea basin. Rivers draining into the North Sea show considerable interannual and decadal variability in annual discharge. In northern areas this is closely associated with variation in the North Atlantic Oscillation, particularly in winter. Discharge to the North Sea in winter appears to be increasing, but there is little evidence of a widespread trend in summer inflow. Higher winter temperatures appear to have led to higher winter flows, as winter precipitation increasingly falls as rain rather than snow. To date, no significant trends in response to climate change are apparent for most of the individual rivers discharging into the North Sea.

A multi-disciplinary study of settlement in north-east Greenland found that life in this High Arctic zone was actually favoured by the climate brought in by the Little Ice Age (fifteenth–nineteenth century). Extensive ice cover meant high mobility, and the rare polynyas — small patches of permanently open coastal water — provided destinations, like oases, where huge numbers of migrating marine mammals and birds congregated. One such place was Walrus Island on Sirius Water, a veritable processing plant for walrus, where every spring Thule people stocked up meat supplies that would get the rest of the region through the winter. It was a further drop in the temperature in the mid nineteenth century that led to the region being abandoned.

Statistical analysis of long-term morphological data on coastal sedimentary features provides important information on the processes governing these features and their evolution in space and time. In this paper, seasonal, yearly and decadal (i.e. long-term) behavior of coastal morphological features is derived from field data by using both simple and advanced statistical techniques. The sedimentary features which we are especially focusing on are a) nearshore bars, and b) large-scale shoreline undulations, for example, longshore sand waves and nesses. High-quality bathymetric field data of regularly sampled cross-shore profiles and shorelines were the basis of the available data sets at Noordwijk beach (The Netherlands), Duck, North Carolina (USA), Sylt (Germany), Lubiatowo (Poland) and Winterton (UK). Additional data sets from Argus video-images (see [Holman, R.A., Stanley, J., 2007. The history, capabilities and future of Argus. Coastal Engineering Special Issue of the CoastView project. doi: 10.1016/j.coastaleng.2007.01.003]) and aerial photographs were used to increase the temporal and spatial resolution of the data sets where possible. The statistical methods applied include some linear and non-linear techniques described by Larson et al. [Larson, M., Capobianco, M., Jansen, H., Rozyfiski, G., Southgate, H.N., Stive, M., Wijnberg, K.M., Hulscher, S., 2003. Analysis and modeling of field data on coastal morphological evolution over yearly and decadal time scales. Part 1: background and linear techniques. Journal of Coastal Research, 19-4, 760-775] and Southgate et al. [Southgate, H.N., Wijnberg, K.M., Larson, M., Capobianco, M., Jansen, H., 2003. Analysis of field data of coastal morphological evolution over yearly to decadal timescales. Part 2: non-linear techniques. Journal of Coastal Research, 19-4, 776-789]. The methods proved to be useful for extracting characteristics of the coastal sedimentary features concerning length scales (e.g., spacing and rhythmicity) and temporal scales (e.g., migration rates and evolutionary patterns). However, the success of the statistical analysis strongly depends on the total size of the data set characterized by the specific spatial coverage, spatial resolution, temporal resolution, and overall length in time. Recent data sets from remote sensing video systems like Argus often meet these requirements and are of major importance for the formulation of conceptual behavior models. (C) 2007 Elsevier B.V. All rights reserved. (Less)

This contribution outlines the philosophy and procedures adopted in a major European research project focused on the development of video systems in support of coastal zone management. The CoastView project has developed video-derived Coastal State Indicators (CSIs) that directly facilitate management decisions. Coastal State Indicators are defined here as, “A reduced set of issue-related parameters that can simply, adequately and quantitatively describe the dynamic-state and evolutionary trends of a coastal system”. The process of defining useful CSIs involves close interaction between coastal managers, scientists and policy makers. Even with frequent formal discussions and colloquia between these parties the process of defining useful indicators frequently fails. An approach [Van Koningsveld, M., 2003. Matching specialist knowledge with end-user needs. PhD Thesis, University of Twente, Enschede, The Netherlands, 173 p.] is described in this paper which guarantees the effectiveness of the resulting CSIs, and enhances the communication process between scientist and coastal managers. Some practical examples of the frame of reference are given by way of illustration and a detailed description is given of the procedure adopted within the CoastView project for defining and evaluating CSIs. The philosophies and methodologies used during the three year CoastView project have proved successful and provide a valuable template on which to base future research projects focussing on end-user oriented research.