Jin Sha

In the context of the global transition from fossil fuels to renewable energy, offshore wind power has emerged as a critical resource and gained increasing attention, requiring accurate assessments of coastal wind energy potential. This study presents an integrated suitability evaluation framework for offshore wind energy around Hainan Island, utilizing multi-satellite remote-sensing observations. A fused wind product was generated by applying the optimal interpolation (OI) algorithm to scatterometer data and was subsequently used to construct a wind farm suitability index (WFSI). The results classify the coastal waters of Hainan Island into three suitability tiers, with the most favorable zones located along the west coast and near the Qiongzhou Strait, collocating with 62.5% of documented wind farm projects. Further analysis on a decadal-long comparative experiment reveals a clear linkage between local wind energy potential and the El Niño-Southern Oscillation (ENSO) cycle that causes wind resources and high-suitability areas to contract during El Niño and expand during La Niña. These findings provide a refined natural source baseline for Hainan Island, clarify regional responses to climate variability, and offer a transferable remote-sensing framework for coastal wind energy assessments in similar maritime regions.

This volume presents recent advances in our understanding of Mesozoic palaeontology, sedimentology and geochemistry of the Junggar Basin, China. This basin is of particular interest because it provides rare insights into life on the continents from a region that was at high latitudes during the Triassic and Jurassic.

The generation of shoreward nonlinear internal waves (NLIWs) on the continental shelf south of the Hainan Island (SHI) is investigated based on spaceborne synthetic aperture radar (SAR) observations and numerical simulations. Two types of shoreward NLIWs are identified from SAR images according to their distinct geographic distribution. One type of NLIWs, named Type‐N NLIWs, is distributed in the northern part of SHI, and the other one is named Type‐S NLIWs, distributed in the southern part of SHI. The SAR‐observed wave occurrence frequency during the spring and neap tides, combined with the calculated body force, suggests that the Type‐N NLIWs originate from the Xisha Islands, whereas the Type‐S NLIWs originate from both the Xisha Islands and the continental shelf break, and the shelf break has a larger contribution. The synergistic analyses of the internal tidal raypath, gamma parameter and earliest SAR‐observed NLIWs suggest that the Type‐N NLIWs are caused by the impingement of the diurnal internal tidal beams emanating from the Xisha Islands on the near‐surface pycnocline close to the continental shelf. Based on the realistic shelf‐slope topography and tidal forcing, the two‐dimensional numerical simulations using the MITgcm suggest that the Type‐S NLIWs result from the nonlinear disintegration of a mode‐1 diurnal internal tide, which develops from a depression formed at the continental shelf break. Furthermore, numerical experiments show that the background current can greatly affect the nonlinear evolution of the internal waves generated at the shelf break.

The generation of shoreward nonlinear internal waves (NLIWs) on the continental shelf south of the Hainan Island (SHI) is investigated based on spaceborne synthetic aperture radar (SAR) observations and numerical simulations. Two types of shoreward NLIWs are identified from SAR images according to their distinct geographic distribution. One type of NLIWs, named Type-N NLIWs, is distributed on the northern SHI, and the other one is named Type-S NLIWs, distributed on the southern SHI. The SAR-observed wave occurrence frequency during the spring and neap tides, combined with the calculated body force, suggests that the Type-N NLIWs originate from the Xisha Islands, whereas the Type-S NLIWs originate from both the Xisha Islands and the continental shelf break, and the shelf break has a larger contribution. The synergistic analyses of the internal tidal ray path, gamma parameter and earliest SAR-observed NLIWs reveal that the Type-N NLIWs are excited by the impingement of the diurnal internal tidal beams emanating from the Xisha Islands on the near-surface pycnocline close to the continental shelf. Based on the realistic shelf-slope topography and tidal forcing, the two-dimensional numerical simulations using the MITgcm suggest that the Type-S NLIWs result from the nonlinear disintegration of a mode-1 diurnal internal tide which develops from a lee wave formed at the continental shelf break. Furthermore, the sensitive numerical experiments show that the background current can greatly affect the nonlinear evolution of the internal waves generated at the shelf break.

Seawater temperature and salinity are the two key parameters related to the regional sea level variability. In this study, the spatial-temporal variabilities of the thermal and halo steric height over the South China Sea (SCS) are investigated using multi-senor satellite remote sensing products, in-situ measurements and reanalysis. The sea surface temperature and salinity products are used to reconstruct the upper layer sea level components, and the relative contribution of these two components are quantified. It is revealed that the thermal and halo components vary in an out-of-phase pattern, and dominant different regions within SCS. Variabilities of the sea level components on different timescale are further analyzed, and the linkage with large scale processes, such as the indo-pacific warm pool, will be presented.

The wind wake on the lee side of Hainan Island in the winter covers the southwest entrance of Beibu Gulf (or Gulf of Tonkin) and is essential to regional ocean dynamics. Using multiple satellite observations including advanced synthetic aperture radar (ASAR), we revisited the wake process during the winter of 2011. Asymmetric oceanic thermal responses were found with a warm band expanding northwestwardly while a cold tongue formed to the southeast. Combining satellite observations, model simulations, and reanalysis data, heat advection terms (ADV) are reconstructed and compared to air-sea heat flux terms. The observed thermal evolution process across the wake footprint is closely related to the balanced spatial variability from the Ekman ADV, the barotropic geostrophic ADV, and the latent heat flux (LHF), which are all on the order of 10⁻⁵ K·m·s⁻¹. Specifically, the Ekman ADV tends to heat the northwestern side of the wake and cool the southeastern side, while the geostrophic ADV compensates with the Ekman ADV across the wake footprint. This study reveals detailed oceanic responses associated with the wind wake and clarifies the contribution of ADV to the asymmetric spatial thermal variabilities. The identified role of heat advection on a sub-seasonal timescale may further benefit the understanding of regional oceanic dynamics.

The refraction and reconnection of internal solitary waves (ISWs) around the Dongsha Atoll (DSA) in the northern South China Sea (SCS) are investigated based on spaceborne synthetic aperture radar (SAR) observations and numerical simulations. In general, a long ISW front propagating from the deep basin of the northern SCS splits into northern and southern branches when it passes the DSA. In this study, the statistics of Envisat Advanced SAR (ASAR) images show that the northern and southern wave branches can reconnect behind the DSA, but the reconnection location varies. A previously developed nonlinear refraction model is set up to simulate the refraction and reconnection of the ISWs behind the DSA, and the model is used to evaluate the effects of ocean stratification, background currents, and incoming ISW characteristics at the DSA on the variation in reconnection locations. The results of the first realistic simulation agree with consecutive TerraSAR‐X (TSX) images captured within 12 h of each other. Further sensitivity simulations show that ocean stratification, background currents, and initial wave amplitudes all affect the phase speeds of wave branches and therefore shift their reconnection locations while shapes and locations of incoming wave branches upstream of the DSA profoundly influence the subsequent propagation paths. This study clarifies the variation in reconnection locations of ISWs downstream of the DSA and reveals the important mechanisms governing the reconnection process, which can improve our understanding of the propagation of ISWs near the DSA.

The upper ocean horizontal heat advection over the middle and outer shelf of the Middle Atlantic Bight (MAB) is investigated using satellite and in situ observations. In the upper mixed layer, the heat advection is mostly positive indicating that it decreases the shelf heat content by bringing cold water from upstream. The domain‐averaged heat advection driven by the barotropic geostrophic current is one‐order larger relative to the density‐driven geostrophic shear and the wind‐driven current. The barotropic geostrophic advection components in the alongshore and offshore direction are of the same order. To investigate the temporal properties of the heat advection, the temperature and currents are decomposed into different time scales using Fast Multidimensional Ensemble Empirical Decomposition (FMEEMD). The cross‐spectral interactions within the advection are quantitatively evaluated with major components identified. Due to the cross‐spectral interaction, energy within the heat advection is found to be redistributed through different time scales, with at least 46.5% variation retained within the original band for the barotropic geostrophic advection. Our results help to better understand the temporal variability of the heat advection, provide a baseline of the nonlinear energy transfer framework within different time scales in the heat advection, and imply the possibility of interplays between short and long‐term oceanic phenomena.