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While the variations of tidal range are large and fairly well known across Australia (less than 1 m near Perth but more than 14 m in King Sound), the properties of the tidal currents are not. We describe a new regional model of Australian tides and assess it against a validation dataset comprising tidal height and velocity constituents at 615 tide gauge sites and 95 current meter sites. The model is a barotropic implementation of COMPAS, an unstructured-grid primitive-equation model that is forced at the open boundaries by TPXO9v1. The mean absolute error (MAE) of the modelled M2 height amplitude is 8.8 cm, or 12 % of the 73 cm mean observed amplitude. The MAE of phase (10∘), however, is significant, so the M2 mean magnitude of vector error (MMVE, 18.2 cm) is significantly greater. The root sum square over the eight major constituents is 26 % of the observed amplitude. We conclude that while the model has skill at height in all regions, there is definitely room for improvement (especially at some specific locations). For the M2 major axis velocity amplitude, the MAE across the 95 current meter sites, where the observed amplitude ranges from 0.1 to 156 cm s−1, is 6.9 cm s−1, or 22 % of the 31.7 cm s−1 observed mean. This nationwide average result is encouraging, but it conceals a very large regional variation. Relative errors of the tidal current amplitudes on the narrow shelves of New South Wales (NSW) and Western Australia exceed 100 %, but tidal currents are weak and negligible there compared to non-tidal currents, so the tidal errors are of little practical significance. Looking nationwide, we show that the model has predictive value for much of the 79 % of Australia's shelf seas where tides are a major component of the total velocity variability. In descending order this includes the Bass Strait, the Kimberley to Arnhem Land, and southern Great Barrier Reef regions. There is limited observational evidence to confirm that the model is also valuable for currents in other regions across northern Australia. We plan to commence publishing “unofficial” tidal current predictions for chosen regions in the near future based on both our COMPAS model and the validation dataset we have assembled.

At the northeastern Black Sea research site, observations from 2010–2020 allowed us to study the dynamics and evolution of the vertical distribution of mesozooplankton in oxygen-deficient conditions via analysis of sound-scattering layers associated with dominant zooplankton aggregations. The data were obtained with profiler mooring and zooplankton net sampling. The profiler was equipped with an acoustic Doppler current meter, a conductivity–temperature–depth probe, and fast sensors for the concentration of dissolved oxygen [O2]. The acoustic instrument conducted ultrasound (2 MHz) backscatter measurements at three angles while being carried by the profiler through the oxic zone. For the lower part of the oxycline and the hypoxic zone, the normalized data of three acoustic beams (directional acoustic backscatter ratios, R) indicated sound-scattering mesozooplankton aggregations, which were defined by zooplankton taxonomic and quantitative characteristics based on stratified net sampling at the mooring site. The time series of ∼ 14 000 R profiles as a function of [O2] at depths where [O2] < 200 µm were analyzed to determine month-to-month variations of the sound-scattering layers. From spring to early autumn, there were two sound-scattering maxima corresponding to (1) daytime aggregations, mainly formed by diel-vertical-migrating copepods Calanus euxinus and Pseudocalanus elongatus and chaetognaths Parasagitta setosa, usually at [O2] = 15–100 µm, and (2) a persistent monospecific layer of the diapausing fifth copepodite stages of C. euxinus in the suboxic zone at 3 µm < [O2] < 10 µm. From late autumn to early winter, no persistent deep sound-scattering layer was observed. At the end of winter, the acoustic backscatter was basically uniform in the lower part of the oxycline and the hypoxic zone. The assessment of the seasonal variability of the sound-scattering mesozooplankton layers is important for understanding biogeochemical processes in oxygen-deficient waters.

A current meter has been designed, intended for surveillance of low-power battery driven devices with a large dynamic range in their current consumption. Among such devices may, for example, be nodes in a wireless sensor network (WSN). The large dynamic range originates in the nodes’ states from an active mode for data collection and communication to a sleep mode for preserving very limited energy and prolonging the lifetime of the device. The active mode draws current up to hundreds of milliamperes whilst the sleep mode’s current may be as low as 22 nA. This makes the dynamic range larger than 6 orders of magnitude. To perform measurements that prevail over noise sources and resolution of involved components, an increase in the SNR must be made. If the current is measured with a shunt resistor, this may be done by varying its resistance as required. The resistance should be as high as possible to maximize the SNR, but low enough such that the burden voltage of the current meter is kept within tolerances of the device. A literature study was done, and with the gained knowledge a circuit was designed and simulated in LTSpice. Then a printed circuit board (PCB) of the circuit was designed and implemented using Altium Designer (an ECAD program), manufactured and hand-soldered. The final PCB was tested but shown to have some design flaws that deteriorated the performance, for example too frequent switching of the current range.

A Ground Penetrating Radar for bathymetry and water current velocity was used to estimate the discharge value of Lesser Zab River at Klesa station with coordinates (35º 53’ 08.21′′ N, 44º 35′ 35.90′′ E). Two traverses were taken across the river which represented two sites in the Klesa area which were (A-B) traverse with the coordinates (N 3970652 and E 491898), and (C-D) traverse with the coordinates (N 3972195 and E 487681). Measuring water flow rate by velocity area method was done by Mid-section method, to confirm the validity of the data; two sections were conducted for each of the two traverses to deduce two radargrams along the profiles (A-B) and (D-C). The radargrams drew by using sophisticated software and were very helpful in detecting the river floor topography and depth variation along both profiles, the distance between the two sites was 5 km. The results indicate that the maximum width of the river at stations is 36.5m and the maximum water depth of Lesser Zab River is 4.75m, maximum velocity is 1.88 m/s. The water flow rate deviates from 136.737m3/s to 147.23m3/s. The average discharge for Lesser Zab river = 141.983 m3/s. This discharge is under normal average because the data was taken in November 2019. Because of the mild weather and the lack of electricity consumption, so using these results in water resource management and planning for satisfying domestic consumption, irrigation, industrial consumption, …etc. in the Klesa area, will be economically beneficial for the water management policy of the country Validerad;2022;Nivå 1;2022-03-01 (sofila)

Earthquake-induced submarine slope destabilization is known to cause debris flows and turbidity currents, but the hydrodynamic processes associated with these events remain poorly understood. Records are scarce and this notably limits our ability to interpret marine paleoseismological sedimentary records. An instrumented frame comprising a pressure recorder and a Doppler recording current meter deployed at the seafloor in the Sea of Marmara Central Basin recorded consequences of a MW = 5.8 earthquake occurring Sept 26, 2019 and of a Mw = 4.7 foreshock two days before. The smaller event caused sediment resuspension but no strong current. The larger event triggered a complex response involving a mud flow and turbidity currents with variable velocities and orientations, which may result from multiple slope failures. A long delay of 10 hours is observed between the earthquake and the passing of the strongest turbidity current. The distance travelled by the sediment particles during the event is estimated to several kilometres, which could account for a local deposit on a sediment fan at the outlet of a canyon, but not for the covering of the whole basin floor. We show that after a moderate earthquake, delayed turbidity current initiation may occur, possibly by ignition of a cloud of resuspended sediment. Some caution is thus required when tying seismoturbidites with earthquakes of historical importance. However, the horizontal extent of the deposits should remain indicative of the size of the earthquake.

International audience; We report current meter measurements obtained by four moorings deployed across the Malvinas Current (MC) at 44.7ºS during 18 months between December 2015-June 2017. Previous measurements of the MC strength have been reported only close to the Brazil-Malvinas Confluence, hindering the interpretation of the flow variability. The record-length time averaged velocities and variance ellipses indicate a strong northward along-isobath flow with an equivalent-barotropic structure. The meridional velocities at the western and eastern moorings are not correlated and show large amplitude oscillations which are coherent with the passage of mesoscale features over the moorings. Satellite altimetry data, that are highly correlated with 20-day low-pass filtered in situ velocities (r~0.80), show that the MC variability is affected by the propagation of sea level anomalies (SLA) along the Patagonian slope with phase speeds that range between 0.21 ± 0.04 m s-1 and 0.14 ± 0.01 m s-1. SLAs propagate northward along the slope following contours of constant potential vorticity and its phase speeds decrease towards the east across the slope. SLAs that mostly affect the western mooring originate in the northern flank of the North Scotia Ridge while SLAs that mostly affect the eastern mooring originate along the Malvinas Escarpment, along the northern edge of the Malvinas Plateau. We suggest that the interaction between eddies and the complex bathymetry at those locations generate instabilities that enhance the generation of mesoscale structures that propagate in the flow direction along the western boundary of the Argentine Basin affecting the variability of the MC velocities.

Piñeiro, S., González-Pola, C., Fernández-Díaz, J. M., Naveira-Garabato, A. C., Sánchez-Leal, R., Puig, P., et al. (2021). Persistent, depth-intensified mixing during the Western Mediterranean Transition's initial stages. Journal of Geophysical Research: Oceans, 126, e2020JC016535. https://doi.org/10.1029/2020JC016535. © 2020. American Geophysical Union. All Rights Reserved., © 2020. American Geophysical Union. All Rights Reserved. Major deep-convection activity in the northwestern Mediterranean during winter 2005 triggered the formation of a complex anomalous deep-water structure that substantially modified the properties of the Western Mediterranean deep layers. Since then, evolution of this thermohaline structure, the so-called Western Mediterranean Transition (WMT), has been traced through a regularly sampled hydrographic deep station located on the outer continental slope of Minorca Island. A rapid erosion of the WMT's near-bottom thermohaline signal was observed during 2005–2007. The plausible interpretation of this as local bottom-intensified mixing motivates this study. Here, the evolution of the WMT structure through 2005–2007 is reproduced by means of a one-dimensional diffusion model including double-diffusive mixing that allows vertical variation of the background mixing coefficient and includes a source term to represent the lateral advection of deep-water injections from the convection area. Using an optimization algorithm, a best guess for the depth-dependent background mixing coefficient is obtained for the study period. WMT evolution during its initial stages is satisfactorily reproduced using this simple conceptual model, indicating that strong depth-intensified mixing (K ∞ (z) ≈ 22 × 10−4 m2 s−1; z ⪆ 1,400 dbar) is a valid explanation for the observations. Extensive hydrographic and current observations gathered over the continental slope of Minorca during winter 2018, the first deep-convective winter intensively sampled in the region, provide evidence of topographically localized enhanced mixing concurrent with newly formed dense waters flowing along-slope toward the Algerian sub-basin. This transport-related boundary mixing mechanism is suggested to be a plausible source of the water-mass transformations observed during the initial stages of the WMT off Minorca., CTM2014-54374-R. BES-2015-074316., Estudio de la anomalía termohalina en las aguas profundas del Mediterráneo Occidental y su relación con las oscilaciones climáticas, ATHAPOC, SI

A field study was carried out to collect fish from the lake and streams/rivers around the peatland from December 2020 to February 2021. Fishing gears such as gillnet, snakehead pole and line, lift net, trap net ("sawaran", "julu"), and fish pot ("tokong", "pangilar", "bubu" or "lukah" and "tempirai") were operated. Sampling sites, water velocities, and water depth were measured using GPS Garmin 60 CSX, current meter hydrologic velocity meter, and fishfinder Portable, respectively. Generally, water velocities of streams measured were much more rapid than the lakes ranging between 0.33 m/s (at water depth: 4.20 m) and 0,69 m/s (at water depth: 6.80 m); and "not detected" (at water depth: 2.40 m) and 0.34 m/s (at water depth: 1.20 m) respectively. Of 7,377 fish samples, there were 50 species discovered belonging to 19 families. Cyprinidae was the most populated in individuals and species as well (1,022 Ind.; 21 taxa). It was followed by Bagridae (63 Ind.; five taxa), Channidae (53 Ind.; three taxa), Clariidae (10 Ind.; three taxa), Siluridae (403 Ind.; three taxa), while other families had just one taxon. Diversity was observed higher in streams (35 species) than lakes (30 species). Local fishers are still performing unselective fishing for feeding fish cage culture.

In order to study the detection performance of compact surface wave radar on ocean surface current in the west of Guangdong Province, firstly, the bistatic radar is set up to collect ocean echo data on the west coast of Guangdong Province. Then, by using the Multiple Signal Classification (MUSIC) algorithm, the comparative analysis results of ocean surface current information and the actual measurement results of DVS Current Meter are obtained. The root mean square error of flow velocity less than 10cm/s and the root mean square error of flow direction less than 25 degrees were obtained. It shows that compact surface wave radar can achieve good results and has good detection capability in the west of Guangdong, china.

Ocean current refers to the relatively stable flow of the surface water of the ocean in a certain direction, and is the main regulator of the thermal environment on the surface of the earth. At present, the ocean current velocity detection at sea is basically a field measurement by a staff member in a boat, and the adjustment of the detector position during the measurement process is very inconvenient. This paper designs a new submarine current velocity measuring device that includes the measuring ship, cable, fixed anchor and ocean current velocity detector. The cable on the reel is retracted through the cable retracting room, and the end of the cable is fixedly provided with a fixed anchor. The fixed anchor is fixedly provided with a plurality of ocean current flow rate detectors, which have a built-in control chip, a wireless communication module, and Pressure Sensor. The ocean current detector adopts the acoustic time difference current meter, which runs stably and is the most widely used current meter at present. This device can flexibly adjust the depth of the detector according to actual needs, so as to measure the flow velocity of different depths.

Headland rips, sometimes referred to as boundary rips, are rip currents flowing against natural or artificial obstructions extending seaward from the beach, such as headland or groynes. They can be driven either by the deflection of the longshore current against the obstacle or by alongshore variation in breaking wave height due to wave shadowing in the lee of the obstacle. The driving mechanism therefore essentially depends on the angle of wave incidence with respect to the natural or artificial obstruction. We analyze 42 days of velocity profile measurements against a natural headland at the high-energy meso-macrotidal beach of Anglet, southwest France. Measurements were collected in 6.5&ndash, 10.5-m depth as tide elevation varied, during the autumn&ndash, winter period with offshore significant wave height and period ranging 0.9&ndash, 6 m and 8&ndash, 16 s, respectively, and the angle of wave incidence ranging from &minus, 20 ∘ to 20 ∘ . Here we analyze deflection rip configurations, corresponding to approximately 24 days of measurements, for which the current meter was alternatively located in the rip neck, rip head or away from the rip as wave and tide conditions changed. Deflection rips were associated with large offshore-directed velocities (up to 0.6 m/s depth-averaged velocities) and tide modulation for low- to moderate-energy waves. The vertical profile of deflection rips was found to vary from depth-uniform in the rip neck to strongly depth-varying further offshore in the rip head with maximum velocities near the surface. Very low frequency motions of the rip were dramatic, ranging 10&ndash, 60 min with a dominant peak period of approximately 40 min, i.e., with longer periods than commonly reported. The strong offshore-directed velocities measured well beyond the surf zone edge provide new insight into deflection rips as a dominant mechanism for water and sediment exchanges between embayed (or structurally-controlled) beaches and the inner-shelf and/or the adjacent embayments.

In this study, the power generated by a thin-film photovoltaic panel was measured under real atmospheric conditions in Mersin between October and March. The experimental setup involves a stand with adjustable inclination around a single axis, current meter and voltage meter, pyrometer, and two computers on a mobile rack. The power generated was determined as a function of solar irradiance using the data recorded with three minutes intervals in each measured day, during the six months period. The average generated power, irradiance, and efficiency were calculated for each measured month using the data collected. The generated power and efficiency values are found to be different from that of the values provided in photovoltaic panel manufacturer specifications.

We investigated ship navigation records known as Automatic Identification System (AIS) data near the source region of the 2011 Tohoku, Japan, tsunami. The AIS data of 16 ships in the offshore navigation could be compiled by about 40 min after the tsunami generation. Most of the AIS data showed notable deviation of the ship heading from the course over ground during the tsunami passage. There was good agreement in terms of amplitude/phase between the ship velocity and the simulated tsunami velocity in the direction normal to the ship heading. An equation of motion due to wave drag and inertia forces was examined for an offshore movable floating body. We explain that the ship movement in the direction normal to the heading immediately responds to the tsunami current, and relative velocity between the ship and the tsunami current asymptotically become zero. This indicates the movement velocity of navigating ships in the direction normal to the heading derived from AIS data will work as an offshore tsunami current meter. We examined the AIS data during the 2011 Tohoku tsunami and showed these data could be useful for tsunami source estimation and forecast. The AIS data in the current framework will possibly be a crowd-sourced tool for monitoring offshore tsunami current and tsunami forecast.

The lower reach of the Rupnarayan River has been deteriorated and incapacitated due to continuous sedimentation (26.57 million m3 shoaling in last 25 years). Attempts have been made to explain the causes and mechanisms of sedimentation in connection to the seasonal fluctuation of shear stress. River depth and water velocity was measured by echo-sounder and current meter respectively. Textural analysis of grains was done by sieving technique. Available and critical shear stress (N/m2) have been calculated following Du Boys (1879), Shield (1936) and Van Ledden (2003) formula. The lack of available energy to transport a particular grain size during low tide (in dry season) is the main reason behind the rapid sedimentation in this area. Most of the places (>75%) having negative deviation of shear stress (available shear stress lesser than critical shear stress), during low tide are characterized by deposition of sediments. The presence of mud (silt and clay) above the critical limit (15%) in some of the sediment samples generates the cohesive property, restricts sediments entrainment and invites sedimentation.

A hydraulic model was implemented for interpreting the real-scale hydraulic tests conducted in a vegetated drainage channel, colonized by dormant Phragmites australis (Cav.) Trin. ex Steud. (common reed), located in the San Rossore-Migliarino-Massaciuccoli Regional Park (Tuscany, Italy). The hydraulic tests encompassed six flow rates and three vegetation scenarios: (a) natural scenario, with common reed fully covering the drainage channel; (b) side vegetation scenario, achieved by removing the in-stream reed just in the central portion of the channel, with two lateral buffers of undisturbed vegetation and (c) unvegetated scenario, corresponding to the complete removal of the riparian reed plants. The outputs of the simulation were compared with the experimental flow average velocities and vegetative Manning’s roughness coefficient, obtained from measured punctual flow velocities by means of an acoustic Doppler velocimeter (ADV) and a propeller-type current meter, respectively located at the upstream and downstream cross sections of the experimental stretch of the drainage channel. The results of this study are discussed for assessing the impact of the vegetation management scenarios on both hydraulic conveyance and riparian habitat functionality of the examined vegetated drainage channel.

Surface gravity waves retrieved by a network of HF (High Frequency) radars and measured in situ by an ADCP (Acoustic Doppler Current Profiler) current meter connected to an elastic beacon were used to carry out a multiple-year characterization of the wave field of the Gulf of Naples (south-eastern Tyrrhenian Sea, western Mediterranean). The aim of the work was to create a climatology of the study area and to demonstrate the potential of an integrated platform for coastal studies. The patterns recorded by the different instruments were in agreement with the wave climatology of the southern Tyrrhenian Sea as well as with previous scores for the same area. The results presented in this work also highlight seasonal and interannual consistency in the wave patterns for each site. In a wider context, this study demonstrates the potential of HF radars as long-term monitoring tools of the wave field in coastal basins, and supports the development of integrated observatories to address large-scale scientific challenges such as coastal ocean dynamics and the impact of global change on the local dynamics.

The coastal currents and forcing agents that conduct them are still little-known in the internal continental shelf of Santa Catarina. Therefore, this work aimed to analyze the data of currents measured off the Island of Santa Catarina in order to better comprehend its patterns and forcing agents. The three measuring stations were installed in shallow water near the Arvoredo Biological Marine Reserve (ST01), Jurerê Beach (ST02) and Ingleses Beach (ST03). Data were collected by a current meter from January 22, 2014 to December 17, 2014. In the consisted data set, it was performed a basic statistical analysis, spectral decomposition and harmonic analysis in the tide components. All the stations presented a resulting southward flow, especially the station next to Arvoredo Marine Biological Reserve (ST01). The meteorological forcing has a strong contribution to the magnitude and direction of component v (alongshore). While the tidal component has greater importance in the cross-shore flow (component u). The wind showed a strong correlation with currents and the local level, indicating to be the main forcing agent of the flow in the subtidal frequency. RESUMO As correntes costeiras e as forçantes que as regem ainda são pouco conhecidas na plataforma continental interna de Santa Catarina. Por isso, este trabalha teve como objetivo analisar os dados de correntes medidos ao largo da Ilha de Santa Catarina a fim de compreender melhor os seus padrões e forçamentos. As três estações de medição foram instaladas em águas rasas próximas à Reserva Marinha Biológica do Arvoredo (ST01), Praia de Jurerê (ST02) e Praia dos Ingleses (ST03). Os dados foram coletados por um medidor de correntes no período compreendido entre 22/01/2014 à 17/12/2014. No conjunto de dados consistido foi realizada uma análise estatística básica, decomposição espectral e análise harmônica nas componentes de maré. Todas as estações apresentaram um escoamento resultante para sul, especialmente a estação próxima a Reserva Biológica Marinha o Arvoredo (ST01). A forçante meteorológica possui forte contribuição na magnitude e direção da componente v (ao longo da costa). Enquanto a componente mareal tem maior importância no fluxo através da costa (componente u). O vento apresentou uma forte correlação com as correntes e o nível local, indicando ser a forçante principal do escoamento na frequência submareal.

Observations from five different systems provide a robust picture of the structure and variability of the Antilles Current, an important contributor to the oceanic flux budget, at 26.5°N during 2005–2015. The analysis includes three direct measurement technologies (current meters, shipboard acoustic Doppler current profilers, and lowered acoustic Doppler current profilers) and two geostrophy‐based measurement technologies (conductivity‐temperature‐depth profilers and pressure‐equipped inverted echo sounders). The direct systems are shown to produce weaker, and less variable, Antilles Current transport estimates than the geostrophy‐based systems. The record‐length‐mean geostrophic estimate for the Antilles Current is 4.7 Sverdrups (Sv; 1 Sv = 106 m3/s), and the daily temporal standard deviation is 7.5 Sv. The variations of the Antilles Current transport exceed those of the entire basin‐wide meridional overturning circulation, illustrating the impact of this unusual current. Seasonal variability shows a maximum northward transport in August–September; however, the seasonal component of the variability is weak, and aliasing of higher frequencies is still a problem even with 10.5 years of data. The dominant time scales of variability in the spectra are at 70 and 180 days, and there is indication of westward propagation of Rossby Wave‐like features into the region at a speed of 9 cm/s. There is no significant correlation between the Antilles Current transport variations and those of the Florida Current at 27°N, in phase or at lags/leads of up to 5 years, likely reflecting the varying coastal wave/wall jet time scales for information to pass from the basin interior through the Bahamas Islands.

Intraseasonal oscillation of deep currents in the Kuroshio Extension region is examined using observations from a collection of current meter moorings. The moored observations reveal variability with characteristic time scales of 23–38 days for velocity time series and of 38–99 days for temperature time series. The time series of normalized temperature (NT) in the deep ocean change correspondingly with sea level anomaly (SLA). The maximum correlation coefficient between NT in the deep ocean and SLA is also up to 0.7. Positive correlation is observed between deep currents and surface geostrophic current. Furthermore, the influence of mesoscale eddies on deep currents is examined by analyzing the data collected when cyclonic and anticyclonic eddies crossed the current meter mooring. Whether anticyclonic or cyclonic eddy intensified the deep currents from 2000 m to 4000 m in the same direction and increased the amplitude. These results provide observational evidence of intraseasonal oscillation in the deep ocean and the effect of mesoscale eddies on deep currents in the Kuroshio Extension region.

Direction-finding SeaSonde (4.463 MHz; 5.2625 MHz) and phased-array WEllen RAdar WERA (9.33 MHz; 13.5 MHz) High-frequency radar (HFR) systems are routinely operated in Australia for scientific research, operational modeling, coastal monitoring, fisheries, and other applications. Coverage of WERA and SeaSonde HFRs in Western Australia overlap. Comparisons with subsurface currents show that both HFR types agree well with current meter records. Correlation (R), root-mean-squares differences (RMSDs), and mean bias (bias) for hourly-averaged radial currents range between R = (−0.03, 0.78), RMSD = (9.2, 30.3) cm/s, and bias = (−5.2, 5.2) cm/s for WERAs; and R = (0.1, 0.76), RMSD = (17.4, 33.6) cm/s, bias = (0.03, 0.36) cm/s for SeaSonde HFRs. Pointing errors (θ) are in the range θ = (1°, 21°) for SeaSonde HFRs, and θ = (3°, 8°) for WERA HFRs. For WERA HFR current components, comparison metrics are RU = (−0.12, 0.86), RMSDU = (12.3, 15.7) cm/s, biasU = (−5.1, −0.5) cm/s; and, RV = (0.61, 0.86), RMSDV = (15.4, 21.1) cm/s, and biasV = (−0.5, 9.6) cm/s for the zonal (u) and the meridional (v) components. Magnitude and phase angle for the vector correlation are ρ = (0.58, 0.86), φ = (−10°, 28°). Good match was found in a direct comparison of SeaSonde and WERA HFR currents in their overlap (ρ = (0.19, 0.59), φ = (−4°, +54°)). Comparison metrics at the mooring slightly decrease when SeaSonde HFR radials are combined with WERA HFR: scalar (vector) correlations for RU, V, (ρ) are in the range RU = (−0.20, 0.83), RV = (0.39, 0.79), ρ = (0.47, 0.72). When directly compared over the same grid, however, vectors from WERA HFR radials and vectors from merged SeaSonde⁻WERA show RU (RV) exceeding 0.9 (0.7) within the HFR grid. Despite the intrinsic differences between the two types of radars used here, findings show that different HFR genres can be successfully merged, thus increasing current mapping capability of the existing HFR networks, and minimising operational downtime, however at a likely cost of slightly decreased data quality.

Field experiments investigating biodiversity and ecosystem functioning require the observation of abiotic parameters, especially when carried out in the intertidal zone. An experiment for biodiversity–ecosystem functioning was set up in the intertidal zone of the back-barrier salt marsh of Spiekeroog Island in the German Bight. Here, we report the accompanying instrumentation, maintenance, data acquisition, data handling and data quality control as well as monitoring results observed over a continuous period from September 2014 to April 2017. Time series of abiotic conditions were measured at several sites in the vicinity of newly built experimental salt-marsh islands on the tidal flat. Meteorological measurements were conducted from a weather station (WS, https://doi.org/10.1594/PANGAEA.870988), oceanographic conditions were sampled through a bottom-mounted recording current meter (RCM, https://doi.org/10.1594/PANGAEA.877265) and a bottom-mounted tide and wave recorder (TWR, https://doi.org/10.1594/PANGAEA.877258). Tide data are essential in calculating flooding duration and flooding frequency with respect to different salt-marsh elevation zones. Data loggers (DL) for measuring the water level (DL-W, https://doi.org/10.1594/PANGAEA.877267), temperature (DL-T, https://doi.org/10.1594/PANGAEA.877257), light intensity (DL-L, https://doi.org/10.1594/PANGAEA.877256) and conductivity (DL-C, https://doi.org/10.1594/PANGAEA.877266) were deployed at different elevational zones on the experimental islands and the investigated salt-marsh plots. A data availability of 80 % for 17 out of 23 sensors was achieved. Results showed the influence of seasonal and tidal dynamics on the experimental islands. Nearby salt-marsh plots exhibited some differences, e.g., in temperature dynamics. Thus, a consistent, multi-parameter, long-term dataset is available as a basis for further biodiversity and ecosystem functioning studies.

Empirically quantifying tidally-influenced river discharge is typically laborious, expensive, and subject to more uncertainty than estimation of upstream river discharge. The tidal stage-discharge relationship is not monotonic nor necessarily single-valued, so conventional stage-based river rating curves fail in the tidal zone. Herein, we propose an expanded rating curve method incorporating stage-rate-of-change to estimate river discharge under tidal influences across progressive, mixed, and standing waves. This simple and inexpensive method requires (1) stage from a pressure transducer, (2) flow direction from a tilt current meter, and (3) a series of ADP surveys at different flow rates for model calibration. The method was validated using excerpts from 12 tidal USGS gauging stations during baseflow conditions. USGS gauging stations model discharge using a different more complex and expensive method. Comparison of new and previous models resulted in good R2 correlations (min 0.62, mean 0.87 with S.D. 0.10, max 0.97). The method for modeling tidally-influenced discharge during baseflow conditions was applied de novo to eight intertidal stations in the Mission and Aransas Rivers, Texas, USA. In these same rivers, the model was further expanded to identify and estimate tidally-influenced stormflow discharges. The Mission and Aransas examples illustrated the potential scientific and management utility of the applied tidal rating curve method for isolating transient tidal influences and quantifying baseflow and storm discharges to sensitive coastal waters.