We deployed two ADCP mooring systems west of the Luzon Strait in August 2008,and measured the upper ocean currents at high frequency.Two typhoons passed over the moorings during approximately one-month observation per...We deployed two ADCP mooring systems west of the Luzon Strait in August 2008,and measured the upper ocean currents at high frequency.Two typhoons passed over the moorings during approximately one-month observation period.Using ADCP observations,satellite wind and heat flux measurements,and high-resolution model assimilation products,we studied the response of the upper ocean to typhoons.The first typhoon,Nuri,passed over one of the moorings,resulting in strong Ekman divergence and significant surface cooling.The cooling of surface water lagged the typhoon wind forcing about one day and lasted about five days.The second typhoon,Sinlaku,moved northward east of the Luzon Strait,and did not directly impact currents near the observation regions.Sinlaku increased anomalous surface water transport exchange across the Luzon Strait,which modulated the surface layer current of the Kuroshio.展开更多
The Yellow Sea Warm Current (YSWC) is one of the principal currents in the Yellow Sea in winter. Former examinations on current activity in the Yellow Sea have not observed a stable YSWC because of the positioning of ...The Yellow Sea Warm Current (YSWC) is one of the principal currents in the Yellow Sea in winter. Former examinations on current activity in the Yellow Sea have not observed a stable YSWC because of the positioning of current meters. To further understand the YSWC, a research cruise in the southern Yellow Sea was carried out in the winter of 2006/2007. Five moorings with bottom-mounted acoustic Doppler current profilers (ADCP) were deployed on the western side of the central trough of the Yellow Sea. The existence and distributional features of the YSWC were studied by analyzing three ADCP moorings in the path of the YSWC in conjunction with conductivity-temperature-depth (CTD) data over the observed area in the southern Yellow Sea. The results show the following. (1) The upper layer of the YSWC is strongly influenced by winter cold surge; its direction and speed often vary along a south-north axis when strong cold surges arrive from the north. (2) The YSWC near the bottom layer is a stable northwest flowing current with a speed of 4 to 10 cm/s. By combining the analyses of the CTD data, we speculate that the core of the YSWC may lie near the bottom. (3) On a monthly average timescale, the YSWC is stably oriented with northward flow from the sea surface to the sea floor.展开更多
The effects of typhoon intrusion on the Guangdong coastal upwelling system were investigated on the basis of in situ CTD （conductivity-temperature-depth） cruise observations and especially upward-looking ADCP （Acou...The effects of typhoon intrusion on the Guangdong coastal upwelling system were investigated on the basis of in situ CTD （conductivity-temperature-depth） cruise observations and especially upward-looking ADCP （Acoustic Doppler Current Profilers） measurements obtained from a comprehensive survey of the Guangdong coastal region carded out by the Chinese Off- shore Investigation and Assessment Project in the summer of 2006. It was found that northeastward geostrophic advection driven by the summer monsoon has a significant near-seabed onshore component adjacent to Shantou, which in conjunction with upper-level offshore Ekman flow, constitutes the canonical Guangdong coastal upwelling system. Further analyses suggested that the Guangdong coastal upwelling system is sensitive to subtle changes in the typhoon intensity and migration pathway. On one hand, as a typhoon approaches from north of the upwelling system （e.g. Typhoon 0604 （Bilis） and Typhoon 0605 （Kaemi）） in the early phase of inmasion, the enhanced southwesterly leads to exceptional enhancement of the onshore flow; i.e., enhanced upwelling. Afterward, irrespective of the forced ocean responses resulting from the stronger local winds （Typhoon 0604） or the moderate typhoon-induced inertial oscillations （Typhoon 0605）, the situation is not conducive to sustaining a stable, persistent upwelling system. On the other hand, when there is typhoon intrusion south of the upwelling system （e.g. Typhoon 0606 （Prapiroon））, the favorable southwesterly tends to be substituted by an anomalous northeasterly, which destroys the traditional coastal upwelling pattern. However, the canonical upwelling system tends to recover within 1-2 days of the typhoon passing.展开更多
基金Supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (Nos.KZCX1-YW-12-01KZCX2-YW-BR-04)+1 种基金the National Natural Science Foundation of China (Nos.40876007,40806006)the National High Technology Research and Development Program of China (863 Program) (No.2008AA09A402)
文摘We deployed two ADCP mooring systems west of the Luzon Strait in August 2008,and measured the upper ocean currents at high frequency.Two typhoons passed over the moorings during approximately one-month observation period.Using ADCP observations,satellite wind and heat flux measurements,and high-resolution model assimilation products,we studied the response of the upper ocean to typhoons.The first typhoon,Nuri,passed over one of the moorings,resulting in strong Ekman divergence and significant surface cooling.The cooling of surface water lagged the typhoon wind forcing about one day and lasted about five days.The second typhoon,Sinlaku,moved northward east of the Luzon Strait,and did not directly impact currents near the observation regions.Sinlaku increased anomalous surface water transport exchange across the Luzon Strait,which modulated the surface layer current of the Kuroshio.
基金Supported by Chinese National Special Project (Nos. 908-01-I-ST03 and 908-01-BC12)National Key Basic Research Program of China (No. G2005CB422302)+1 种基金National Natural Science Foundation of China (No.40776019)Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-YW-BR-15)
文摘The Yellow Sea Warm Current (YSWC) is one of the principal currents in the Yellow Sea in winter. Former examinations on current activity in the Yellow Sea have not observed a stable YSWC because of the positioning of current meters. To further understand the YSWC, a research cruise in the southern Yellow Sea was carried out in the winter of 2006/2007. Five moorings with bottom-mounted acoustic Doppler current profilers (ADCP) were deployed on the western side of the central trough of the Yellow Sea. The existence and distributional features of the YSWC were studied by analyzing three ADCP moorings in the path of the YSWC in conjunction with conductivity-temperature-depth (CTD) data over the observed area in the southern Yellow Sea. The results show the following. (1) The upper layer of the YSWC is strongly influenced by winter cold surge; its direction and speed often vary along a south-north axis when strong cold surges arrive from the north. (2) The YSWC near the bottom layer is a stable northwest flowing current with a speed of 4 to 10 cm/s. By combining the analyses of the CTD data, we speculate that the core of the YSWC may lie near the bottom. (3) On a monthly average timescale, the YSWC is stably oriented with northward flow from the sea surface to the sea floor.
基金supported by the Chinese Offshore Physical Oceanography and Marine Meteorology Investigation and Assessment Project (Grant No.908-ZC-I-01)the Chinese Main Estuarine Dynamic Sedimentary Processand Its Impacts on Coastal Economic Development (Grant No.908-02-01-04)+2 种基金the Chinese Main Estuarine and the Adjacent Sea Environmental Quality Evaluation (Grant No. 908-02-02-02)the National Natural Science Foundation of China (Grant Nos. 40806013 and 41176031)the China Ocean University Physical Oceanography Key Laboratory Open Fund (Grant No. 200904)
文摘The effects of typhoon intrusion on the Guangdong coastal upwelling system were investigated on the basis of in situ CTD （conductivity-temperature-depth） cruise observations and especially upward-looking ADCP （Acoustic Doppler Current Profilers） measurements obtained from a comprehensive survey of the Guangdong coastal region carded out by the Chinese Off- shore Investigation and Assessment Project in the summer of 2006. It was found that northeastward geostrophic advection driven by the summer monsoon has a significant near-seabed onshore component adjacent to Shantou, which in conjunction with upper-level offshore Ekman flow, constitutes the canonical Guangdong coastal upwelling system. Further analyses suggested that the Guangdong coastal upwelling system is sensitive to subtle changes in the typhoon intensity and migration pathway. On one hand, as a typhoon approaches from north of the upwelling system （e.g. Typhoon 0604 （Bilis） and Typhoon 0605 （Kaemi）） in the early phase of inmasion, the enhanced southwesterly leads to exceptional enhancement of the onshore flow; i.e., enhanced upwelling. Afterward, irrespective of the forced ocean responses resulting from the stronger local winds （Typhoon 0604） or the moderate typhoon-induced inertial oscillations （Typhoon 0605）, the situation is not conducive to sustaining a stable, persistent upwelling system. On the other hand, when there is typhoon intrusion south of the upwelling system （e.g. Typhoon 0606 （Prapiroon））, the favorable southwesterly tends to be substituted by an anomalous northeasterly, which destroys the traditional coastal upwelling pattern. However, the canonical upwelling system tends to recover within 1-2 days of the typhoon passing.
