Feiyantan was the discharge area of Diaokou River distributary of the Yellow River during the period of 1964 to 1976. The coastal erosion feature and morphological evolution at the Feiyantan coast are studied in the l...Feiyantan was the discharge area of Diaokou River distributary of the Yellow River during the period of 1964 to 1976. The coastal erosion feature and morphological evolution at the Feiyantan coast are studied in the light of the topography and section depth, and the corresponding dynamics of wave and current. Results indicate that the protruding topography left after the Diaokou River distributary was abandoned is the main cause of strong coastal erosion. Further research suggests that waves start up the sediment and the tidal current transports it, and the waves and tidal current are combined to be the dominant dynamic mechanism of coastal erosion, in which the tidal residual current takes and transports the sediment outward, thus causing the sediment to wane in the coast.展开更多
Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring,thrives in summer, and fades in autumn as thermocline declines. TF intensity |ST| is defined to describe the distributio...Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring,thrives in summer, and fades in autumn as thermocline declines. TF intensity |ST| is defined to describe the distribution of TF. Based on the MASNUM wave-tide-circulation coupled model, temperature distribution in the Yellow Sea was simulated with and without tidal effects. Along 36°N, distribution of TF from the simulated results are compared with the observations, and a quantitative analysis is introduced to evaluate the tidal effects on the forming and maintaining processes of the TF. Tidal mixing and the circulation structure adapting to it are the main causes of the TF.展开更多
Based on the MASNUM wave-tide-circulation coupled numerical model, the temperature structure along 35°N in the Yellow Sea was simulated and compared with the observations. One of the notable features of the tempe...Based on the MASNUM wave-tide-circulation coupled numerical model, the temperature structure along 35°N in the Yellow Sea was simulated and compared with the observations. One of the notable features of the temperature structure along 35°N section is the double cold cores phenomena during spring and summer. The double cold cores refer to the two cold water centers located near 122°E and 125°E from the depth of 30m to bottom. The formation, maintenance and disappearance of the double cold cores are discussed. At least two reasons make the temperature in the center (near 123°E) of the section higher than that near the west and east shores in winter. One reason is that the water there is deeper than the west and east sides so its heat content is higher. The other is invasion of the warm water brought by the Yellow Sea Warm Current (YSWC) during winter.This temperature pattern of the lower layer (from 30m to bottom) is maintained through spring and summer when the upper layer (0 to 30m) is heated and strong thermocline is formed. Large zonal span of the 35°N section (about 600 km) makes the cold cores have more opportunity to survive. The double cold cores phenomena disappears in early autumn when the west cold core vanishes first with the dropping of the thermocline position.展开更多
Vertical wave-induced mixing parameter Bv expressed in wave number spectrum was estimated in the Yellow Sea. The spatial distributions of Bv averaged over upper 20 m in 4 seasons were analyzed. It is the strongest in ...Vertical wave-induced mixing parameter Bv expressed in wave number spectrum was estimated in the Yellow Sea. The spatial distributions of Bv averaged over upper 20 m in 4 seasons were analyzed. It is the strongest in winter because of winter monsoon, and the weakest in spring. Since in summer it plays an important role for circulation of upper layers, its vertical structure was also discussed. Two simulations with and without wave-induced mixing in this season were performed to evaluate its effect on temperature distribution. Numerical results indicate that wave-induced mixing could increase the mixed layer thickness greatly.展开更多
Based on the MASNUM wave-tide-circulation coupled numerical model, seasonal variability of thermocline in the Yellow Sea was simulated and compared with in-situ observations. Both simulated mixed layer depth (MLD) and...Based on the MASNUM wave-tide-circulation coupled numerical model, seasonal variability of thermocline in the Yellow Sea was simulated and compared with in-situ observations. Both simulated mixed layer depth (MLD) and thermocline intensity have similar spatial patterns to the observations. The simulated maximum MLD are 8 m and 22 m, while the corresponding observed values are 13 m and 27 m in July and October, respectively. The simulated thermocline intensity are 1.2℃/m and 0.5℃/m in July and October,respectively, which are 0.6℃/m less than those of the observations. It may be the main reason why the simulated thermocline is weaker than the observations that the model vertical resolution is less precise than that of the CTD data which is 1 m. Contours of both simulated and observed thermocline intensity present a circle in general. The wave-induced mixing plays a key role in the formation of the upper mixed layer in spring and summer. Tidal mixing enhances the thermocline intensity. Buoyancy-driven mixing destroys the thermocline in autumn and keeps the vertical temperature uniform in winter.展开更多
A harmonic method was used to analyze the tidal currents observed in summer at 11 stations made from 1996 to 2001 in the Bohai Sea, China. Data was compared among different instruments and intervals. Elliptic elements...A harmonic method was used to analyze the tidal currents observed in summer at 11 stations made from 1996 to 2001 in the Bohai Sea, China. Data was compared among different instruments and intervals. Elliptic elements were calculated based on harmonic constants, of which vertical distributions of the maximum speed and rotation direction were discussed for understanding the characteristics of diurnal and semi-diurnal tidal current components. The results indicate that the maximum speed of M2 tidal current component is much larger than that of K1; the rotation direction of M2 tidal current constituent is clockwise in the central part of the Bohai Sea and in the Laizhou Bay, but anticlockwise in the Liaodong Bay and Bohai Bay. For K1 tidal current constituent, it is clockwise in the central Bohai Sea but anti-clockwise in the Laizhou Bay and Liaodong Bay. The tidal currents in most stations in the Bohai Sea were regular semidiurnal except for those in the central Bohai Sea, being irregular semidiurnal.展开更多
文摘Feiyantan was the discharge area of Diaokou River distributary of the Yellow River during the period of 1964 to 1976. The coastal erosion feature and morphological evolution at the Feiyantan coast are studied in the light of the topography and section depth, and the corresponding dynamics of wave and current. Results indicate that the protruding topography left after the Diaokou River distributary was abandoned is the main cause of strong coastal erosion. Further research suggests that waves start up the sediment and the tidal current transports it, and the waves and tidal current are combined to be the dominant dynamic mechanism of coastal erosion, in which the tidal residual current takes and transports the sediment outward, thus causing the sediment to wane in the coast.
文摘Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring,thrives in summer, and fades in autumn as thermocline declines. TF intensity |ST| is defined to describe the distribution of TF. Based on the MASNUM wave-tide-circulation coupled model, temperature distribution in the Yellow Sea was simulated with and without tidal effects. Along 36°N, distribution of TF from the simulated results are compared with the observations, and a quantitative analysis is introduced to evaluate the tidal effects on the forming and maintaining processes of the TF. Tidal mixing and the circulation structure adapting to it are the main causes of the TF.
文摘Based on the MASNUM wave-tide-circulation coupled numerical model, the temperature structure along 35°N in the Yellow Sea was simulated and compared with the observations. One of the notable features of the temperature structure along 35°N section is the double cold cores phenomena during spring and summer. The double cold cores refer to the two cold water centers located near 122°E and 125°E from the depth of 30m to bottom. The formation, maintenance and disappearance of the double cold cores are discussed. At least two reasons make the temperature in the center (near 123°E) of the section higher than that near the west and east shores in winter. One reason is that the water there is deeper than the west and east sides so its heat content is higher. The other is invasion of the warm water brought by the Yellow Sea Warm Current (YSWC) during winter.This temperature pattern of the lower layer (from 30m to bottom) is maintained through spring and summer when the upper layer (0 to 30m) is heated and strong thermocline is formed. Large zonal span of the 35°N section (about 600 km) makes the cold cores have more opportunity to survive. The double cold cores phenomena disappears in early autumn when the west cold core vanishes first with the dropping of the thermocline position.
文摘Vertical wave-induced mixing parameter Bv expressed in wave number spectrum was estimated in the Yellow Sea. The spatial distributions of Bv averaged over upper 20 m in 4 seasons were analyzed. It is the strongest in winter because of winter monsoon, and the weakest in spring. Since in summer it plays an important role for circulation of upper layers, its vertical structure was also discussed. Two simulations with and without wave-induced mixing in this season were performed to evaluate its effect on temperature distribution. Numerical results indicate that wave-induced mixing could increase the mixed layer thickness greatly.
文摘Based on the MASNUM wave-tide-circulation coupled numerical model, seasonal variability of thermocline in the Yellow Sea was simulated and compared with in-situ observations. Both simulated mixed layer depth (MLD) and thermocline intensity have similar spatial patterns to the observations. The simulated maximum MLD are 8 m and 22 m, while the corresponding observed values are 13 m and 27 m in July and October, respectively. The simulated thermocline intensity are 1.2℃/m and 0.5℃/m in July and October,respectively, which are 0.6℃/m less than those of the observations. It may be the main reason why the simulated thermocline is weaker than the observations that the model vertical resolution is less precise than that of the CTD data which is 1 m. Contours of both simulated and observed thermocline intensity present a circle in general. The wave-induced mixing plays a key role in the formation of the upper mixed layer in spring and summer. Tidal mixing enhances the thermocline intensity. Buoyancy-driven mixing destroys the thermocline in autumn and keeps the vertical temperature uniform in winter.
基金the National Basic Research Program of China (973 Program) (No. 2005CB422308)and China International Science and Technology Cooperation Program (No.2006DFB21250)+2 种基金New Century Excellent Talents in University Program (No. NCET-04-0638)ST02 Section Environment Investigation and Research of the National Ocean Investigation Project 908 (No. 908-01-ST02)NNSF of China (No.40576005,40576008)
文摘A harmonic method was used to analyze the tidal currents observed in summer at 11 stations made from 1996 to 2001 in the Bohai Sea, China. Data was compared among different instruments and intervals. Elliptic elements were calculated based on harmonic constants, of which vertical distributions of the maximum speed and rotation direction were discussed for understanding the characteristics of diurnal and semi-diurnal tidal current components. The results indicate that the maximum speed of M2 tidal current component is much larger than that of K1; the rotation direction of M2 tidal current constituent is clockwise in the central part of the Bohai Sea and in the Laizhou Bay, but anticlockwise in the Liaodong Bay and Bohai Bay. For K1 tidal current constituent, it is clockwise in the central Bohai Sea but anti-clockwise in the Laizhou Bay and Liaodong Bay. The tidal currents in most stations in the Bohai Sea were regular semidiurnal except for those in the central Bohai Sea, being irregular semidiurnal.
