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Data obtained from over 250 CTD stations in December 2006 and April 2007 were used to analyze the temperature and salinity structure of the water masses of the South Yellow Sea in spring. Six basic water masses were identified: the Southwest Yellow Sea Coastal Water Mass (SWYSCWM), Southwest Yellow Sea Local Water Mass (SWYSLWM), Qingdao Cold Water Mass (QDCWM), Yellow Sea Warm Current Water Mass (YSWCWM), Inchon Cold Water Mass (ICWM), and Subei Coastal Water Mass (SBCWM). The mechanisms of formation of these water masses are very different. The SWYSCWM is affected by continental water, whereas the SWYSLWM and SBCWM are local water masses that are less affected by other waters. The QDCWM derives from cold northern water. The YSWCWM exists from winter to spring. Because of the limited data coverage, the mechanism of formation of the ICWM remains unclear.

Based on field hydrological, microstructural, and shipboard Acoustic Doppler Current Profiler data, we quantified the spatial and temporal variability of turbulent mixing in the near-field Changjiang (Yangtze) River plume. The surface dissipation rate (e) changed by three orders of magnitude from near-field (10−4 W/kg) to far-field (10−7 W/kg) plumes, indicating a decrease with distance from the river mouth. Below the river plume, e changed with depth to 10−8 W/kg, and increased to 10−6 W/kg at the layer where the Taiwan Warm Current (TWC) intruded. Thus, e in the near-field plume showed three layers: surface layer in the river plume, middle layer, and lower TWC layer. In the river plume, the strongest e and turbulent diffusivity (Kz) were greater than 10−4 W/kg and 10−2 m2/s, respectively, during strong ebb tides. A three-orders-of-magnitude change in e and Kz was observed in the tidal cycle. The depth of the halocline changed with tidal cycles, and stratification (N2) varied by one order of magnitude. Stratification in the TWC layer followed the distribution of the halocline, which is opposite to the dissipation structure. Tidal currents led to intrusion and turbulent mixing in the TWC layer. During ebb tides, e and Kz were as strong as those measured in the river plume, but did not last as long. The structure of the velocity shear was similar to the dissipation rate in both the river plume and TWC layer, whereas the velocity shear in the TWC layer did not match the stratification structure. In the high dissipation rate area, the gradient Richardson number was smaller than the critical value (Rig

Subtropical sea surface salinity (SSS) maximum is formed in the subtropical South Indian Ocean (SIO) by excessive evaporation over precipitation and serves as the primary salt source of the SIO. Space-borne SSS measurements by Aquarius satellite during September 2011–May 2015 detect three disconnected SSS maximum regions (>35.6) in the eastern (105°E–115°E, 38°S–28°S), central (60°E–100°E, 35°S–25°S), and western (25°E–10°E, 38°S–20°S) parts of the subtropical SIO, respectively. Such structure is however not seen in gridded Argo data. Analysis of Argo profile data confirms the existence of the eastern maximum patch and also reveals SSS overestimations of Aquarius near the western and eastern boundaries. Although subjected to large uncertainties, a mixed-layer budget analysis is employed to explain the seasonal cycle of SSS. The eastern and central regions reach the highest salinity in February–March and lowest salinity in August–September, which can be well explained by surface freshwater forcing (SFF) term. SFF is however not controlled by evaporation (E) or precipitation (P). Instead, the large seasonal undulations of mixed layer depth (MLD) is the key factor. The shallow (deep) MLD in austral summer (winter) amplifies (attenuates) the forcing effect of local positive E–P and causes SSS rising (decreasing). Ocean dynamics also play a role. Particularly, activity of mesoscale eddies is a critical factor regulating SSS variability in the eastern and western regions.

Both sporadic observations and modelling studies suggest that subthermocline eddies (SEs) exist east of the Philippines, where interhemispheric waters meet. However, effects of SEs on water mass mixing have never been observed. Here, using data from mooring and buoy deployed in the frontal region of the interhemispheric water masses, we show for the first time that the SEs act as an “underwater mixer” of intermediate waters from north and south Pacific oceans. The SEs have typical swirl speeds of 0.1~0.4 m s−1 between 200 and 800 m depth with a dominant period of ~90 days. Variation in intermediate water salinity also had a period of ~90 days, lagging eddy speed by ~8 days. Horizontal eddy diffusivity representative of eddy mixing rate was quantified using a mixing-length framework. Horizontal eddy diffusivity had both surface and subthermocline maxima. The vertically varying eddy diffusivity can be used to improve parameterization of eddy stirring in the tropical Pacific by coarse-resolution ocean climate models. The effect of the SEs on mixing of intermediate water masses seems not resolved by available eddy-resolving ocean models typically used for this region.

This paper discusses the long-term temperature variation of the Southern Yellow Sea Cold Water Mass (SYSCWM) and examines those factors that influence the SYSCWM, based on hydrographic datasets of the China National Standard Section and the Korea Oceanographic Data Center. Surface air temperature, meridional wind speed, and sea surface temperature data are used to describe the seasonal changes. Mean temperature of the two centers of the SYSCWM had different long-term trends. The temperature of the center in the west of the SYSCWM was rising whereas that of the center in the east was falling. Mean temperature of the western center was related to warm water intrusion of the Yellow Sea Warm Current, the winter meridional wind, and the winter air temperature. Summer process played a primary role in the cooling trend of temperature in the eastern center. A decreasing trend of salinity in the eastern half of the SYSCWM showed that warm water intrusion from the south might weaken, as could the SYSCWM circulation. Weakened circulation provided less horizontal heat input to the eastern half of the SYSCWM. Less lateral heat input may have led to the decreasing trend in temperature of the eastern center of the SYSCWM. Further, warmer sea surface temperatures and less heat input in the deep layers intensified the thermocline of the eastern SYSCWM. A stronger thermocline had less heat flux input from upper layers to this half of the SYSCWM. Stronger thermocline and weakened heat input can be seen as two main causes of the cooling temperature trend of the eastern center of the SYSCWM.

An extra-large subsurface anticyclonic eddy (SAE) with horizontal scale of 470 km was detected in the northwestern Pacific subtropical gyre by in situ measurements in October 2014. The SAE exhibited a lens-shaped vertical structure with shoaling of the seasonal thermocline and deepening of the main thermocline. Consequently, the water in the eddy core was colder above 200 m and warmer below 200 m than the surrounding waters with maximum temperature anomalies of -1.2°C and 3.5°C located at ~100 m and ~450 m depths, respectively. The central water mass of the SAE was characterized as low potential vorticity water, i.e., the north Pacific Subtropical Mode Water (STMW). Swirl velocity of the SAE was directly observed by ship-mounted ADCP (Acoustic Doppler Current Profilers). The maximum azimuthal velocity reached 0.35 ms-1 near a 110 km radius at ~ 200 m depth, which was comparable with the maximum velocity of the northward Kuroshio east of Taiwan at the same depth. Threedimensional structure and evolutionary process of the SAE were also presented using Argo float profile data as well as the satellite altimeter data. The results indicated that the SAE was generated in the region of the STMW in February, then propagated westward over 1500 km at a mean speed of ~0.06 ms-1 and finally disappeared east of Taiwan in December, transporting ~0.5 Sv (Sv=106 m3s-1) STMW.

Current measurements from three moored Acoustic Doppler Current Profilers (ADCPs) and hydrographic measurements from cruises in the Yellow and East China Seas were used to investigate the North Intrusion of the bottom Taiwan Warm Current Inshore Branch (NI-TWCIB) and its response to wind. The vertical structure of the mean current suggests that NI-TWCIB intrudes into the Jiangsu coasts from the bottom. The observed bottom residual currents run continuously northward at 32 ∘ N from June 12 to August 22, 2014. Synoptic-scale variations of the residual currents indicate that the bottom NI-TWCIB is highly influenced by synoptic process such as wind. Significant variations of the paths of NI-TWCIB are observed from salinity data. The intrusion paths are extracted using a horizontal salinity gradient method, and we characterize the paths by defining the eastern boundary, northern boundary and turning point. The monsoon over the Yellow and East China Seas plays an important role in the variations of the paths of the bottom NI-TWCIB. The pressure gradient set up through Ekman transport and surface transport by easterly and northerly winds promotes the offshore movement of the bottom NI-TWCIB, the northward intrusion, and the northward movement of the turning point. The westerly and southerly winds have opposite effects. We propose a regression method to estimate the intrusion path as a function of east–west winds and north–south winds. The regression results prove that the northern boundary of the bottom NI-TWCIB can arrive at approximately 32 ∘ N, which is consistent with ADCP measurements.

The pGenesil-1-Beclin1 eukaryotic expression vectors were constructed to establish an SH-SY5Y cell line stably expressing shRNA-Beclin1. The shRNA was connected to pGenesil-1 to construct the recombinant plasmid pGenesil-1-Beclin1, which was transformed into JM109 E. coli. Positive clones were identified by digestion with restriction endonuclease and DNA sequencing. SH-SY5Y cells were cultured by the conventional method. The pGenesil-1-Beclin1 and pGenesil-1 plasmids were transfected into SH-SY5Ycells, and the cells were screened by G418 until the stable G418-resistant monoclonal cells were acquired. Beclin1 mRNA and Beclin1 protein were detected by RT-PCR and Western blot analysis respectively. The results of restriction endonuclease analysis and DNA sequencing confirmed the correct construction of the eukaryotic expression vector pGenesil-1-Beclin1. Two SH-SY5Y transfected cell lines were successfully selected. Compared with the control group, RT-PCR and Western blot showed that the expression of Beclin1 mRNA and protein were down regulated 71.28% ± 1.45% (P0.05)and 75.50% ± 2.63% (P0.05), respectively. The results indicated that the eukaryotic expression vector pGenesil-1-Beclin1 was successfully constructed and the SH-SYSY cell lines with inhibited Beclin1 expression were established. It provides a useful cell model for studying the biological function of Beclin1.

This paper discusses the long-term variation in the salinity of the Southern Yellow Sea Cold Water Mass (SYSCWM) and examines factors influencing the SYSCWM based on hydrographic datasets of the China National Standard section and the Korea Oceanographic Data Center. The mean salinity at the center of the SYSCWM showed a decreasing long-term trend. In empirical orthogonal function (EOF) analysis, the second EOF mode showed a similar long-term trend. The mean salinity of the center of the SYSCWM was related to the intrusion of saline water from the Yellow Sea Warm Current (YSWC), the salinity of the source area of the YSWC, the evaporation minus precipitation (E–P) flux, and discharge from the Changjiang River. The decreasing salinity trend to the southwest of Cheju Island produced a freshening trend in the YSWC, resulting in a reduction in the salinity of the SYSCWM. The freshening trends of the water from the northwest Pacific and the South China Sea were seen as the reason for the decreasing salinity trend from the intrusion of water into the Yellow Sea (YS). The freshwater flux influenced the surface salinity and was brought to deep layers by strong mixing in winter. The mean E–P flux signal and Changjiang River discharge signal lagged the first principal component of the SYSCWM by approximately 5 months.