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The relationship between significant wave height ( H 1 / 3 ) and period ( T 1 / 3 ) was obtained using wave data from the East and Yellow coasts of the Korean Peninsula to facilitate the calculations of the wave parameters. In addition, the JONSWAP spectral parameters were estimated and analyzed for all wave height ranges. The relational expression between the two wave variables ( H 1 / 3 ~ T 1 / 3 ) obtained from this study showed a significant difference from the previously proposed relational expressions, most of which tended to follow the lower limit of the data. Meanwhile, the suggested peak enhancement factor (PEF,   γ ) is 1–7; however, for this study, a peak control factor (PCF,   γ c ) with a range of 0–10 was introduced. As a result of the analysis, the PCF was determined to be 1.13–1.42, which is approximately 40% smaller than the previously proposed γ   =   3.3 . The probability density distribution of the appropriate PCF was then calculated, and the gamma and log-normal distributions for the East and Yellow coasts of the Korean Peninsula were found, respectively. This study covered waves of all range heights, and the analysis results can be used as important data to explain the characteristics of the sea area. [ABSTRACT FROM AUTHOR]

Primary support for ancient Martian oceans has relied on qualitative interpretations of hypothesized shorelines on relatively low‐resolution images and data. We present a toolkit for quantitatively identifying paleoshorelines using topographic, morphological, and spectroscopic evaluations. In particular, we apply the validated topographic expression analysis of Hare et al. (2001, https://doi.org/10.1029/2001JB000344) for the first time beyond Earth, focusing on a test case of putative shoreline features along the Arabia level in northeast Cydonia Mensae, as first described by Clifford and Parker (2001, https://doi.org/10.1006/icar.2001.6671). Our results show these curvilinear features are inconsistent with a wave‐generated shoreline interpretation. The topographic expression analysis identifies a few potential shoreline terraces along the historically proposed contacts, but these tilt in different directions, do not follow an equipotential surface (even accounting for regional tilting), and are not laterally continuous. Lineaments appear blocky in nature at small scales, and they bifurcate, truncate, and merge along track. These features are more consistent with material boundaries for lithological units exposed along a degraded crater wall. These results do not preclude the existence of an ancient hemispheric ocean, but the geophysical and high‐resolution topographic data at this site do not support such an interpretation. Plain Language Summary: There is an ongoing controversy about whether Mars had ancient oceans. Abundant evidence for past surface liquid water exists, but it is debated how much and for how long it persisted on Mars' surface. Features have previously been traced out in relatively low‐resolution images and interpreted as shorelines of episodic ancient oceans. However, new high‐resolution data allow for better and more complete analyses. Here we present methods to determine whether any proposed ancient shoreline feature meets the requirements to be classified as a shoreline using these improved data. Shorelines should form flat "step‐like" landforms at a near‐constant elevation, so one critical analysis looks at the shape and elevation of proposed features. We examine a site that has been promoted in the literature as an exemplar of ancient shorelines and find that this site lacks a diagnostic shoreline shape. Instead, features at this site are better explained as exposed and eroded rock layers that mimic shoreline shapes in low‐resolution images. Our findings do not mean that oceans never existed on Mars, only that this specific site does not support the ocean hypothesis. Application of our methods to similar sites could shed further light on the ocean hypothesis. Key Points: We apply a proposed paleoshoreline‐identification toolkit to newer high‐resolution data of an exemplar site for paleoshorelines on MarsAny wave‐generated paleoshorelines should exhibit expressions identifiable in the residual topography from an idealized slopeOur analysis of these curvilinear features does not support a paleoshoreline interpretation and is more consistent with eroded lithologies [ABSTRACT FROM AUTHOR]

Thirty two-year observations (1990–2022) of water level from a total of 14 high-quality acoustic tide stations around the coast of Australia deployed for the Australian Baseline Sea Level Monitoring Project were analyzed. The following three approaches were used: Fourier Transform (FT), Empirical Mode Decomposition (EMD), and Singular Spectrum Analysis (SSA). The water level anomaly was observed to have predominant annual variations with a period of about 12 months based on the Fourier transform. The intrinsic components of stations were extracted in the EMD analysis and the mean period of each of the components was calculated using the zero down crossing method. A regular association was observed between the order of modes and the mean period such that the periods increase by a factor of two on successive modes. The third method used for anomaly analysis was SSA. The number of the obtained components in this method was less than in the EMD. Moreover, the order observed for the components' period in the EMD was not seen in this method. Spectral analysis of Autocorrelation function (ACF) has demonstrated that peak frequencies are almost the same with anomaly spectra so the dominant modes in anomalies are also present in the ACF. • More than 30-year sea level data around the Australian coast have been analyzed. • Fourier Transform, Empirical Mode Decomposition, and Singular Spectrum Analysis have been used. • A predominant annual variation with a period of about 12 months was observed based on the Fourier transform. ACF analysis showed that: ✓ The periodic and regular signals have larger ACF with low rate decreasing amplitude. ✓ Irregular signal has a smaller ACF and its amplitude decreases more sever. ✓ In general, the more regular the time series, the more symmetrical its ACF. ✓ Spectral analysis of anomalies and ACF has demonstrated that peak frequencies are almost the same in both spectra. [ABSTRACT FROM AUTHOR]

Gonçalves, M.; Rusu, E., and Guedes Soares, C., 2015. Evaluation of two spectral wave models in coastal areas. The objective of the present work is to evaluate two wave models, SWAN and STWAVE, considering various coastal areas with different bathymetric features. Although both models are based on the spectrum concept and integrate the action balance equation over the computational domain using rectangular grids, there are also fundamental differences between them induced by the propagation schemes implemented and also by the different formulations considered for the basic source terms. The two models are evaluated in four coastal areas, three of them belonging to the Portuguese continental coastal environment and the other one located in the nearshore of Sardinia Island. The bathymetric characteristics of the computational domains considered are rather different. Two of them have smooth contours, another is characterized by very high bathymetric gradients, and finally the last one includes a harbor area. Comparisons of the models' predictions against measurements were carried out in both intermediate and very shallow water. Besides these, comparisons between the two models as regards the field distributions of the main wave parameters were also performed. The results of the work show that SWAN is a more complex model that can be better calibrated and adapted for a specific site, especially due to the multitude of options available. On the other hand, STWAVE is simpler, more robust, and quicker and can be used effectively in various coastal environments. [ABSTRACT FROM AUTHOR]

A conceptual model is proposed for the characteristic sub-ranges in the velocity and temperature spectra in the boundary layer of tropical cyclones (hurricanes or typhoons). The model is based on observations and computation of radial and vertical profiles of the mean flow and turbulence, and on the interpretation of eddy mechanisms determined by shear (namely roll and streak structures near the surface), convection, rotation, blocking and sheltering effects at the ground/sea surface and in internal shear layers. The significant sub-ranges, as the frequency increases, are associated with larger energy containing eddies, shear and blocking, inertial transfer between large and small scales, and intense small-scale eddies generated near the surface caused by waves, coastal roughness change, and the buoyancy force associated with the evaporation of spray droplets. These sub-ranges vary with the locations at which the spectra are measured, i.e. the level $$z$$ in relation to the height $$z_{max}$$ of the peak mean velocity and the depth $$h$$ of the boundary layer, and the radius $$r$$ in relation to the eyewall radius $$R_{ew}$$ and the outer-vortex radius $$R_{ov}$$ . For two tropical cyclones (Nuri and Hagupit), experimental data were analyzed. Spectra were measured where $$r$$ is near to $$R_{ew}$$ and $$R_{ov}$$ using four 1-h long datasets at coastal towers, at 10- and 60-m heights for tropical cyclone Nuri, and at 60-m height for tropical cyclone Hagupit at the south China coast. The field measurements of spectra within the boundary layer show significant sub-ranges of self-similar energy spectra (lying between the length scale 1,000 m and the smallest scales less than 40 m) that are consistent with the above conceptual model of the surface layer. However, with very high wind speeds near the eyewall, the energy of the independently generated intense surface eddy motions, associated with surface waves and water droplets in the airflow, greatly exceeds the energies of the small scales in the inertial sub-range of the boundary layer, over scales less than about 3-40 m depending on the height $$z$$ and the radius $$r$$ . This rise in the small-scale frequency weighted spectra ( $$nS_u (n)$$ , where $$n$$ is natural frequency, and $$S_u (n)$$ is the energy spectrum of the longitudinal wind component) is consistent with the hypothesis that these processes are only weakly correlated with the main boundary-layer turbulence. [ABSTRACT FROM AUTHOR]