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The track of Super Typhoon Muifa plotted on the map of the maximum cooling (unit: °C) during the passage of Typhoon Muifa. For the area south of 30°N, the super tropical cyclone cooling is defined as the difference between 1 August and 6 August. For the area north of 30°N, the super tropical cyclone cooling is defined as the difference between 5 August and 9 August. The numbers on the left side of the track represent the dates when the typhoon passed through the corresponding regions. The contours in the Yellow Sea indicate the outline of the multiyear‐averaged Yellow Sea Cold Water Mass as described in Figure 2. The black boxes represent the three sites used in the heat budget diagnosis and model experiments. The locations of the sites are (a) 121.5°E, 36°N, (b) 123°E, 36°N, and (c) 124°E, 36°N. STC = super tropical cyclone.
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A significant sea surface temperature (SST) drop was clearly identified to be confined exactly over the Yellow Sea Cold Water Mass (YSCWM) from satellite‐derived SSTs during Typhoon Muifa's passage over the Yellow Sea (YS) in early August 2011. With a simple one‐dimensional mixed‐layer model (Price‐Weller‐Pinkel [PWP]), the mixed‐layer heat budget...
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Investigating latent heat flux (LHF) variations in the western boundary current region is crucial for understanding air–sea interactions. In this study, we examine the LHF trend in the East China Sea Kuroshio Region (ECSKR) from 1959 to 2021 using atmospheric and oceanic reanalysis datasets and find that the LHF has a significant strengthening tren...
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... The YBS exhibits strong coastal stratification during the summer, with a substantial presence of cold bottom water masses known as yellow sea bottom cold water (YSBCW) beneath the seasonal thermocline in the YS throughout the year (Lee and Beardsley, 1999;Moon et al., 2009;Xia et al., 2006). A pronounced temperature gradient between the sea surface and YSBCW is conducive to significant SST cooling under TC wind forcing (Guan et al., 2021;Lee et al., 2016;Yang et al., 2019). When a TC passes through shallow marine areas, the strong wind stress from the TC can penetrate the seabed, resulting in rapid surface cooling and noticeable warming of the bottom layer (Glenn et al., 2016;Kim et al., 2017;Price, 2009;Yang et al., 2017). ...
... The dissipation of internal tidal energy in the SCS contributes to enhanced diapycnal mixing in the deep SCS (Tian et al., 2009), influencing the ocean's response to typhoons (Guan et al., 2014). Unlike in the deep ocean, the YBS exhibits a noticeable temperature gradient between the sea surface and YSBCW, which is conducive to significant SST cooling under TC wind forcing (Guan et al., 2021;Lee et al., 2016;Yang et al., 2019). Additionally, the SCS has both deeper water depths and deeper MLDs than the YBS (Wang and Xiu, 2022). ...
... Liu et al., 2022aX. Liu et al., , 2022bYang et al., 2019). Finally, int this study, we have introduced the continuous surface cooling during the autumn-winter season. ...
The Yellow Sea Cold Water Mass (YSCWM), a seasonal bottom‐layer water mass in the Yellow Sea (YS) most prominent in summer, has always been overlooked in previous studies investigating variations in the winter Sea Surface Temperature. Here, using observations and high‐resolution numerical modeling, we reveal for the first time the significant contribution of thermal stratification associated with the YSCWM to the sea surface cooling and the formation of the westward‐shifted Yellow Sea Warm Water Tongue (YSWT) in early winter. Heat budget analyses indicated that the impact of the YSCWM to surface cooling manifests in two aspects. First, the upward mixing of bottom cold water from the remnant YSCWM triggers cooling in the mixed layer. Second, the shallower local mixed layer above the YSCWM facilitates more pronounced cooling processes compared to the YSWT region under similar heat flux. The formation of the westward‐shifted YSWT is the result of intensified surface cooling in both the coastal shallow waters and the YSCWM region in the central YS. During the formation process of the YSWT, its main axis aligns with the western boundary of the YSCWM. As the YSCWM dissipates, the YSWT shows an eastward apparent displacement and eventually stabilizes near approximately 123°E. This study enriches our understanding of the transition from stratification to vertical homogeneity in the water temperature structure of the YS during early winter.
... In the spring, the solar radiation increases and rapidly warms the upper layer. Therefore, a strong seasonal thermocline forms quickly and reaches its peak in the summer at a depth of 10-20 m, which prevents vertical mixing (Yang et al. 2019). Therefore, oligotrophic surface water forms as a result of nutrient consumption in spring and reduced renewal of nutrient in the stratified water in summer. ...
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Functional traits determine the fitness of organisms and mirror their ecological functions. Although trait-based approaches provide ecological insights, it is underexploited for marine zooplankton, particularly with respect to seasonal variation. Here, based on four major functional traits, including body length, feeding type, trophic group, and reproduction mode, we quantified the seasonal variations of mesozooplankton functional groups in the South Yellow Sea (SYS) in the spring, summer, and autumn of 2018. Strong seasonal dynamics were identified for all traits but patterns varied among traits. Small zooplankton (47.7-88.6%), omnivores-herbivores (81.3-97.6%), and free spawners (54.8-92.5%) dominated in three seasons, while ambush feeders and current feeders dominated in spring (45.7%), and autumn (73.4%), respectively. Cluster analysis of the functional traits showed that the mesozooplankton in the SYS can be classified into eight functional groups. The biogeographic and seasonal variations of functional groups can be partially explained by environmental drivers. Group 1, represented by omnivores-herbivores, was the most dominant functional group, the abundance of which peaked in spring and was positively correlated with chlorophyll a concentration, indicating its close association with phytoplankton dynamics. The contribution of giant, active ambush carnivores, passive ambush carnivore jellyfish, current omnivores-detritivores, and parthenogenetic cladocerans increased with sea surface temperature. The proportion of giant, active ambush carnivores and active ambush omnivore-carnivore copepods decreased with salinity in autumn. This study presents a new perspective for understanding the dynamics of zooplankton and paves the way for further research on the functional diversity of zooplankton in the SYS.
Supplementary information:
The online version contains supplementary material available at 10.1007/s42995-022-00156-9.
... Previous studies have mainly focused on sea surface temperature (SST) responses in the central YS to typhoons moving northward/northeastward in the eastern YS (Kim et al., 2014;Lee et al., 2016;Yang, Li, Du, et al., 2019). The common results of these studies were that SST showed spatially coherent cooling and that the strongest cooling occurred just above the YSCWM due to strengthened vertical mixing. ...
... As shown in Figures 1b and 1c, the track of moving northward/northeastward in the eastern YS basically has the largest number of typhoons that passed over the YS during 1950-2020. For this kind of typhoon, SST responses have been well revealed, showing spatially coherent cooling with the strongest cooling appearing above the YSCWM (Yang, Li, Du, et al., 2019). However, temperature responses in the subsurface and bottom layers and the underlying dynamics are still rarely studied. ...
... For that purpose, Typhoon Bavi was chosen as a representative of typhoons that moved northward in the eastern YS (Figures 1b and 1c). Previous studies showed that typhoons moving northward induced stronger SST cooling than typhoons moving northeastward Yang, Li, Du, et al., 2019). This finding suggested that in the YS, the three-dimensional temperature responses induced by typhoons moving northward could be much more significant than those induced by typhoons moving northeastward. ...
Characterized by a sharp thermocline and large cold‐water mass below, the Yellow Sea (YS) in summer is a shelf sea that is one of the most vulnerable to typhoons in the world. With observations and high‐resolution numerical simulations, we investigated the three‐dimensional temperature changes and underlying dynamics during the passage of Typhoon Bavi in August 2020, which was representative of northward‐moving typhoons in the eastern YS. Bavi's cyclonic strong winds caused intense turbulent mixing and Ekman divergence. The intense vertical mixing generated spatially coherent temperature cooling in the surface layer and partly caused temperature warming in the subsurface layer on both sides of the typhoon track. The largest surface cooling and subsurface warming both occurred on the right side of the typhoon track. Wind‐induced Ekman divergence generated two overturning circulation systems zonally across the YS, consisting of upper layer shoreward currents, coastal downwelling, lower layer seaward currents and upwelling on the typhoon track. Downwelling and seaward currents caused temperature warming below the thermocline, especially in the bottom layer. Upwelling shoaled the thermocline, resulting in subsurface cooling on the typhoon track. Additionally, Ekman divergence produced sea surface height minima on the typhoon track, causing strong southward barotropic currents to the left, which subsequently drove strong temperature cooling above the southern bottom slope of the South YS and fast southward movement of the YS Cold Water Mass. Further numerical experiments indicated that the magnitudes of the above changes increased with increasing maximum wind speeds and/or decreasing moving speeds of typhoons.
... Research on the impact of typhoons on the distribution of water masses has predominantly been based on hydrographic parameters and satellite remote sensing (Doong et al. 2019;Yang et al. 2019). However, these methods present difficulties in quantitatively understanding the effects of typhoon events on water mass mixing and nutrient supplies. ...
... However, there was also lower temperature water from the bottom to the surface. Typhoons associated with strong winds usually cause strong vertical mixing in the water column, which can cause deeper water upwelling towards the surface (Doong et al. 2019;Yang et al. 2019). Vertical mixing can affect the water column and transport bottom water and material to the surface . ...
The issue of whether the increase in nutrients is supplied by increasing runoff or by enhancing upwelling in coastal marine ecosystems after a typhoon is considered controversial. This is because it is relatively difficult to quantify water mixing using traditional methods. Dual water isotopes in the northwestern South China Sea during Typhoon Wipha (July–August 2019) were investigated to address this issue. Weak mixing among different water masses was observed before the typhoon because of strong thermal stratification. After the typhoon, temperature and salinity dropped in the water column, particularly in the upper layer (<20 m), due to strengthened mixing. Mixing in the upper layer predominantly originated from coastal diluted water (36%) in the nearshore, whereas it changed to upwelling (51%) offshore. Upwelling was stronger on the right of the typhoon path (50%) than on the left (36%). Nutrients predominantly originated from the coastal diluted water input (50%) in the upper nearshore layer, while upwelling occurred (53%) offshore. The nutrient supply from upwelling on the right of the typhoon path (43%) was also more considerable than that on the left (25%). This study suggests that typhoon‐induced nutrient supply to the coastal upper water layers from the upwelling water (38%) was more substantial than that from the runoff input (30%), providing new insight into the biogeochemical and ecological responses of coastal marine systems to typhoons.
... shows the sea bottom water temperature in EXP1 in each month. The shapes of the modeled YSCWM (Figure 8h) and YSWC (Figure 8l) were also consistent with the historical observations reported byYang et al. (2019) andLü et al. (2013), respectively, suggesting that the model could capture the main hydrological phenomenon in the YS. Three types of typical bottom water temperature variations can be identified inFigure 8.The first type of typical sea bottom water temperature variation occurred along the coastal area. ...
... The star in (g) indicates station s-1. The star in (h) indicates station s-2, the black contour is the 10°C isotherm of the bottom water temperature derived from historical observations in summer(Yang et al., 2019), the black straight line indicates the position of the bottom water temperature front generated off the southern edge of the YSCWM, and the arrow indicates the movement direction of the front during the shrink of the YSCWM in autumn. The star in (k) indicates station s-3. ...
Previous in-situ observations have suggested that bottom water temperature variations in shelf seas can drive significant ocean bottom heat flux (BHF) by heat conduction. The BHF-driven bottom water temperature variations, however, have been overlooked in ocean general circulation models. In this study, we established a sea-sediment fully coupled model through incorporating the BHF. The coupled model included a sediment temperature module/model, and the BHF was calculated based on the sediment heat content variations. Meanwhile, we applied temporally varying BHF in the calculation of the bottom water temperature, which further determined the sediment temperature. The two-way coupled BHF process presents a more complete and physically reasonable heat budget in the ocean model and a synchronously varying sediment temperature profile. The coupled model was validated using a one-dimensional test case, and then it was applied in a domain covering the Bohai and Yellow Seas. The results suggest that when a strong thermocline exists, the BHF can change the bottom water temperature by more than 1°C because the effects of the BHF are limited to within a shallow bottom layer. However, when the water column is well mixed, the BHF changes the temperature of the entire water column, and the heat transported across the bottom boundary is ventilated to the atmosphere. Thus, the BHF has less effect on water temperature and may directly affect air-sea heat flux. The sea-sediment interactions dampen the amplitude of the bottom water temperature variations, which we propose calling the seabed d ampening ocean h eat content variation mechanism (SDH).
... Our regional model results suggest that climate warming may have long-term consequences to the coastal ecosystem. The Yellow Sea hosts biologically rich and productive fishing grounds in east China coastal waters, and the YSCWM is of central importance to local fishery (Li et al 2006, Fu et al 2016, Yang et al 2019. The increase of water temperature, the decrease of near-bottom oxygen concentration, and the disappearance of YSCWM may cause changes in fish distribution and migration pattern, and potentially lead to changes in fish species and shrink in fish stocks (Cheung et al 2016, Ho et al 2020. ...
The coastal region in east China experiences massive anthropogenic eutrophication, and the bottom water off the Changjiang River Estuary in the East China Sea faces the threat of severe seasonal hypoxia. We find that projected future climate changes will work in parallel with anthropogenic eutrophication to exacerbate current hypoxia and increase shelf vulnerability to bottom hypoxia. We use a coupled physical-biogeochemical regional model to investigate the differences of shelf hydrography and oxygen dynamics between present and future projected states. Model results indicate that the Yellow Sea Cold Water Mass which plays essential roles in nekton migration and shellfish farming practically disappears by the end of the 21st century, and shelf vertical stratification strengthens by an average of 12.7%. Hypoxia off the Changjiang River Estuary is exacerbated with increased (by one month) hypoxia duration, lower dissolved oxygen minima, and significant lateral (202%) and vertical (60%) expansions of hypoxic water. Reduced oxygen solubility, and accelerated oxygen consumption under increased primary production and rising water temperature contribute 42% and 58%, respectively, of bottom dissolved oxygen decrease in the East China Sea. Model results also show increased vertical diffusion of oxygen, despite vertical stratification strengthening, due to increased surface-bottom oxygen concentration gradient associated with increased oxygen release in surface water and exacerbated oxygen consumption in subsurface water.
... The Yellow Sea is a semi-enclosed marginal sea of the northwestern Pacific Ocean surrounded by the Korean Peninsula to the east and the Chinese mainland to the west and is recognized for its strong ocean-atmosphere interactions (Xie et al., 2002;Subrahamanyam et al., 2007Subrahamanyam et al., , 2009Kim et al., 2018;Sim et al., 2018;Yang et al., 2019). As a shallow basin with small bathymetric gradients, the Yellow Sea significantly contributes to the transfer of heat, moisture, and momentum owing to warm sea surface temperatures (Naimie et al., 2001;Chu et al., 2005;Ma et al., 2006;Belkin, 2009;Park et al., 2015), by controlling the oceanic conditions and modifying the properties of air masses passing over the ocean Heo et al., , 2012Kim et al., 2017;Yun et al., 2018;Pak et al., 2019). ...
The Yellow Sea is the most fog-prone region of the East Asian marginal seas. Since sea fog is caused due to complex interactions between atmospheric and oceanic environments, direct observations can help understand the physical processes involved in fogging over the oceans. Completed in 2014, the Socheongcho Ocean Research Station (S-ORS) plays a critical role in monitoring air-sea interactions over the Yellow Sea. This study aimed to evaluate the conditions favorable for fog generation and the physical processes underlying it using a suite of observations and turbulent heat flux data from S-ORS. First, we used the visibility data from S-ORS to quantify the frequency of sea fog over the Yellow Sea. From April to June 2016, sea-fog occurred 61 times, with a maximum duration of 135 h (approximately 5.6 days). Next, to understand the origin and characteristics of air mass associated with fog events, we classified the primary airflow paths in the region using a Hybrid Single-Particle Lagrangian Integrated Trajectory model. Among the four clusters identified from the cluster analysis, the third and fourth had distinct physical properties characteristic of cold and warm fog, respectively. The third cluster was characterized by relatively weak or negative heat advection and weak vertical mixing, while the fourth one featured strong positive heat transport and moisture convergence over the Yellow Sea. Finally, based on cluster analysis, we choose the representative cases related to these two clusters observed at S-ORS and compared the characteristics of turbulent air-sea fluxes associated with fog formations.
... nii.ac.jp/digital-typhoon/), implying that the entire YS was experiencing more typhoons under climate change (Kossin et al., 2014). Previous studies have demonstrated that typhoons exerted great influences on hydrodynamic processes in the YS (Fu et al., 2016;Yang et al., 2017Yang et al., , 2019bJi et al., 2019). In the central YS where the Yellow Sea Cold Water Mass (YSCWM; Fig. 1b) occupies nearly the entire bottom layer during summer, the most significant oceanic response to typhoons' passages was temperature cooling in the surface layer (Yang et al., 2019b;Guan et al., 2021). ...
... Previous studies have demonstrated that typhoons exerted great influences on hydrodynamic processes in the YS (Fu et al., 2016;Yang et al., 2017Yang et al., , 2019bJi et al., 2019). In the central YS where the Yellow Sea Cold Water Mass (YSCWM; Fig. 1b) occupies nearly the entire bottom layer during summer, the most significant oceanic response to typhoons' passages was temperature cooling in the surface layer (Yang et al., 2019b;Guan et al., 2021). Due to enhanced turbulent mixing and vertical entrainment of cold water from deep layers up to the surface mixed layer, the drastic surface layer temperature drop could be as large as 8-9 • C and mostly occurred ahead of the typhoon eye centers, different from the situation in the open ocean (Kim et al., 2014;Lee et al., 2016;Yang et al., 2019b). ...
... In the central YS where the Yellow Sea Cold Water Mass (YSCWM; Fig. 1b) occupies nearly the entire bottom layer during summer, the most significant oceanic response to typhoons' passages was temperature cooling in the surface layer (Yang et al., 2019b;Guan et al., 2021). Due to enhanced turbulent mixing and vertical entrainment of cold water from deep layers up to the surface mixed layer, the drastic surface layer temperature drop could be as large as 8-9 • C and mostly occurred ahead of the typhoon eye centers, different from the situation in the open ocean (Kim et al., 2014;Lee et al., 2016;Yang et al., 2019b). In coastal oceans of the YS, however, different oceanic responses were observed in sporadic regions. ...
During the passage of Typhoon Lekima over the stratified Yellow Sea (YS) in August 2019, dramatic bottom temperature cooling of 2–5 °C was observed in northern coastal oceans of the Shandong Peninsula. In the current study, satellite observations and high-resolution numerical simulations were combined to investigate three-dimensional temperature changes in the YS during Lekima's passage and the underlying dynamics. Results indicated that the YS showed spatially coherent surface cooling and subsurface warming, primarily due to enhanced vertical mixing. The strongest surface temperature cooling of 4–8 °C occurred just over the southern bottom slope in the North YS, for which tidal mixing and bottom slope were also important factors through maintaining strong thermal stratification and inducing locally enhanced upwelling. In contrast, bottom temperature changes were most significant in coastal oceans in the western YS, showing dramatic cooling in northern coastal oceans of the Shandong Peninsula but warming as high as 8 °C in southern coastal oceans of the Shandong and Liaodong Peninsulas. Surface winds drove northward/shoreward Ekman transports in the North/South YS. This resulted in surface water convergence and downwelling in southern coastal oceans of the Shandong and Liaodong Peninsulas but divergence and upwelling in northern coastal oceans of the Shandong Peninsula. Downwelling generated bottom warming through transporting downward surface warm water. In the bottom layer, southward pressure gradient force drove shoreward advection of cold water to induce temperature cooling in nearshore regions. The current study provides significantly more insights into oceanic responses to passages of typhoons in the YS, especially in coastal oceans, which are one of the most intensively maricultured areas in the world.
... This water mass persists throughout the entire summer, occupying almost 30% of the area of the Yellow Sea. Thus, it has been extensively investigated with respect to its formation, physical oceanographic features, and ecological role over the past few decades (Chen, 2009;Yang et al., 2019). However, limited data are available on the microbiological features of YSCWM, especially on the degradation potential for organic pollutants. ...
Cyclic alkanes (c-alkanes) are toxic compounds that are abundant in subsurface oil reservoirs and spilled condensate; hence, their environmental risk is significant. Although numerous studies have focused on the decomposition of other compound classes, e.g., acyclic alkanes and aromatic hydrocarbons, very little is known about the biodegradation of c-alkanes in the marine environment. Here, we enriched methylcyclohexane (MCH)-degrading bacteria derived from the cold bottom water (10–20°C) of China’s marginal seas in summer and characterized the changes to the bacterial community using high-throughput amplicon sequencing. MCH-consuming bacteria failed to grow from the warmer surface water (25–29°C) in the same geographic sites and seasons. Notably, MCH-consuming communities derived from the cold bottom water in the Yellow Sea exhibit distinct structures compared to the other treatments. Furthermore, almost all dominant species in this setting appear to be specifically adapted to deeper cold water as indicated by significantly negative correlations to temperature (P < 0.01). From these results, we proposed that the biodegradation of MCH is effectively limited to the colder waters (10–20°C) of China’s marginal seas, with uncultured psychrophiles acting as the key taxa for MCH decomposition. Overall, this study indicates key functions for uncultivated microbes in the marine environment.
