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The book describes an integrated theory that links estuary shape to tidal hydraulics, tidal mixing and salt intrusion.The shape of an alluvial estuary is characterised by exponentially varying width and the absence of bottom slope.

Tidal analysis was applied on 1 hour gravity data acquired by a subnet of 12 superconducting gravimeters situated in western and central parts of Europe. Tidal parameters for O and M were adjusted. Most of the gravity time series were provided by the Global geodynamics project. Filter effects of the decimation process were carefully studied and taken into account where necessary. The ocean loading effect included in observed tidal parameters was removed using 8 ocean models with different spatial resolutions. Two different comparisons of corrected tidal parameters were performed. As a result, the accuracy of ocean loading correction and global calibration error were evaluated. For O , amplitude factors are in good agreement with the hydrostatic/elastic model DDW/He while the non-hydrostatic/inelastic model DDW/NHi better describes the M amplitude factors. The analysis of residual vectors allowed assessing the efficiency of the used ocean loading models which is about 81% (O ) and 97% (M ).

Satellite altimetry observations have provided a significant contribution to the understanding of global sea surface processes, particularly allowing for advances in the accuracy of ocean tide estimations. Currently, almost three decades of satellite altimetry are available which can be used to improve the understanding of ocean tides by allowing for the estimation of an increased number of minor tidal constituents. As ocean tide models continue to improve, especially in the coastal region, these minor tides become increasingly important. Generally, admittance theory is used by most global ocean tide models to infer several minor tides from the major tides when creating the tidal correction for satellite altimetry. In this paper, regional studies are conducted to compare the use of admittance theory to direct estimations of minor tides from the EOT20 model to identify which minor tides should be directly estimated and which should be inferred. The results of these two approaches are compared to two global tide models (TiME and FES2014) and in situ tide gauge observations. The analysis showed that of the eight tidal constituents studied, half should be inferred (2N2, ϵ2, MSF and T2), while the remaining four tides (J1, L2, μ2 and ν2) should be directly estimated to optimise the ocean tidal correction. Furthermore, for certain minor tides, the other two tide models produced better results than the EOT model, suggesting that improvements can be made to the tidal correction made by EOT when incorporating tides from the two other tide models. Following on from this, a new approach of merging tidal constituents from different tide models to produce the ocean tidal correction for satellite altimetry that benefits from the strengths of the respective models is presented. This analysis showed that the tidal correction created based on the recommendations of the tide gauge analysis provided the highest reduction of sea-level variance. Additionally, the combination of the EOT20 model with the minor tides of the TiME and FES2014 model did not significantly increase the sea-level variance. As several additional minor tidal constituents are available from the TiME model, this opens the door for further investigations into including these minor tides and optimising the tidal correction for improved studies of the sea surface from satellite altimetry and in other applications, such as gravity field modelling.

This paper presents a study on depth modernization, paralleling height modernization for land elevations. Depth modernization integrates mean sea surface (MSS) models, ocean tide models, and precise ship positioning to achieve accurate seafloor depth measurements. Conventional methods rely on tidal corrections and chart datum from temporary tide gauges, which can be challenging in regions with complex tidal patterns and inconsistent chart datums. For depth modernization, we developed (1) a hybrid MSS model using satellite altimeter data, tide gauge records, and a regional geoid model, and (2) a hydrodynamic-driven ocean model with 26 tidal constituents to determine separations between the hybrid MSS and five tidal surfaces, resulting in five ellipsoid-based surfaces analogous to a geoid model for height modernization. Precise ship positioning is demonstrated using GNSS data collected by the Legend research ship in the Pacific Ocean east of Taiwan and the Canadian spatial reference system precise point positioning toolbox. We used measurements in the Taiwan Strait to show how modern depth is implemented. Comparisons of depths in four regions from the conventional and modern methods show small (a few cm) to moderate (a few dm) differences with some variability depending on the region and equipment. Discontinuities in depths from the conventional method are analyzed. Depth modernization has significantly benefited rapid and accurate bathymetric mapping for electronic navigation charts. Future work in MSS and ocean tide models and the availability of PPP tools for depth modernization are discussed. For mapping agencies worldwide, depth modernization should be prioritized alongside height modernization to ensure rapid and accurate depth data provision.

In the Province of San Juan, Argentina, high precision geodetic instruments are operated whose observations must be corrected to compensate for the effects of the Earth's tides. Currently, this can be done using the parameters predicted either by theoretical models or local parameters determined by in situ observations. This work reports the results of the analysis of San Juan's tide records acquired with a spring vertical gravimeter (Scintrex CG5). The success of the use of spring relative gravity data in tidal analysis depends on accurate calibration and the proper removal of the instrumental drift from the gravimeter. The instrumental drift of the different registry segments was modeled by polynomial functions. The amplitude calibration factor of the gravimeter was determined by simultaneous gravity measurements with an SG038 superconductor gravimeter, then analyzed in the time and frequency domains. The tidal parameters of the harmonics K1 and M2 derived from tidal analysis are consistent (better than ± 0.05%) with the theoretical parameters for different models of the Earth's interior. The difference between the tested ocean tide models is negligible.

Internal tides are ubiquitous in the ocean, and they play an important role in a range of ocean processes, for example, particle dispersal, acoustics, and vertical buoyancy flux. The wavelength of internal tides can be as much as 250 km in the open ocean, but as the generation of these tides depends on the angle between the depth-averaged current and the topography, there can be considerable local spatial variability. This range of scales makes it difficult to develop a comprehensive understanding of the processes involved from observations alone. Regional numerical modeling provides a way to study the generation and early propagation of internal tides at high resolution. Here, we review the role that regional internal tide models, primarily hydrostatic models, can play in increasing our understanding.

In this study, to meet the need for accurate tidal prediction, the accuracy of global ocean tide models was assessed in the South China Sea (0°–26°N, 99°–121°E). Seven tide models, namely, DTU10, EOT11a, FES2014, GOT4.8, HAMTIDE12, OSU12 and TPXO8, were considered. The accuracy of eight major tidal constituents (i.e., Q 1 , O 1 , P 1 , K 1 , N 2 , M 2 , S 2 and K 2 ) were assessed for the shallow water and coastal areas based on the tidal constants derived from multi-mission satellite altimetry (TOPEX and Jason series) and tide gauge observations. The root mean square values of each constituent between satellite-derived tidal constants and tide models were found in the range of 0.72–1.90 cm in the deep ocean (depth>200 m) and 1.18–5.63 cm in shallow water area (depth<200 m). Large inter-model discrepancies were noted in the Strait of Malacca and the Taiwan Strait, which could be attributable to the complicated hydrodynamic systems and the paucity of high-quality satellite altimetry data. In coastal regions, an accuracy performance was investigated using tidal results from 37 tide gauge stations. The root sum square values were in the range of 9.35–19.11 cm, with the FES2014 model exhibiting slightly superior performance.

This article deals with developing plurilingual digital content with future preschool teachers. We present the TiDE (Teaching in Digital Education) model which promotes the development of digital didactic materials and relevant digital competences through active, experience-based, and interdisciplinary learning. A qualitative study was conducted focused on the process of designing new digital didactic materials for raising plurilingual awareness, i.e. stop-motion videos for preschool children. The data were obtained by analysing 16 stop-motion videos and feedback from 60 Slovenian first-year students of preschool education at the University of Primorska. The results suggest that new digital technologies can be very effective in developing engaging, effective, and learner-centered resources that promote students' plurilingual awareness and an open attitude towards linguistic and cultural diversity. 

The north of Australia is known for its complex tidal system, where the highest astronomical tides (HATs) reach 12 m. This paper investigates the tidal behaviour in this region by developing spectral climatology for tide gauge and altimetry data. Power spectral density analysis is applied to detect the magnitude of ocean tides in 20 years of sea-level data from multimission satellite altimeters and tide gauges. The spectra of altimetry sea level anomaly (SLA) time series have their strongest peaks centred at approximately 2.11, 5.88, and 7.99 cycles per year (cpy), corresponding to the diurnal and semidiurnal tidal constituents K1, M2, and O1, respectively. Closer to the coastline, the spectra peak at high-frequency overtide and shallow-water constituents such as M4, MK4, and MK3. There have been many large, high-frequency spectral peaks near the coastline, indicating the difficulty of predicting tidal signals by coastal altimetry. Similar to altimetry observations, there are dominant semidiurnal and diurnal tidal peaks in tide gauge SLA time series accompanying a number of overtides. The semidiurnal and diurnal peaks are mostly higher on the northwest coast of Australia compared with the north and northeast coast. The results from both altimetry and tide gauges indicate that tidal range increases with increasing continental shelf.

Due to the coverage limitation of T/P-series altimeters, the lack of bathymetric data under large ice shelves, and the inaccurate definitions of coastlines and grounding lines, the accuracy of ocean tide models around Antarctica is poorer than those in deep oceans. Using tidal measurements from tide gauges, gravimetric data and GPS records, the accuracy of seven state-of-the-art global ocean tide models (DTU10, EOT11a, GOT4.8, FES2012, FES2014, HAMTIDE12, TPXO8) is assessed, as well as the most widely-used conventional model FES2004. Four regions (Antarctic Peninsula region, Amery ice shelf region, Filchner-Ronne ice shelf region and Ross ice shelf region) are separately reported. The standard deviations of eight main constituents between the selected models are large in polar regions, especially under the big ice shelves, suggesting that the uncertainty in these regions remain large. Comparisons with in situ tidal measurements show that the most accurate model is TPXO8, and all models show worst performance in Weddell sea and Filchner-Ronne ice shelf regions. The accuracy of tidal predictions around Antarctica is gradually improving.