Seasonal cycle is the most significant signals of topography and circulation in the Bohai Sea (BS)and Yellow Sea (YS) forced by prevailing monsoon and is still poorly understood due to lack of data in their interiors....Seasonal cycle is the most significant signals of topography and circulation in the Bohai Sea (BS)and Yellow Sea (YS) forced by prevailing monsoon and is still poorly understood due to lack of data in their interiors. In the present study, seasonal cycles of topography in the BS and YS and its relationship with atmospheric forcing and oceanic adjustment were examined and discussed using TOPEX/Poseidon and ERS-1/2 Sea Level Anomalies (SLA) data. Analyses revealed complicated seasonal cycles of topography composed mainly of2 REOF modes, the winter-summer mode (WIM) and spring-autumn mode (SAM). The WIM with action center in the BS displayed peak and southward pressure gradient in July, and valley and northward pressure gradient in January, which is obviously the direct response to monsoon with about 1-month response time. The SAM with action center in the western south YS displayed peak and northward pressure gradient in October and valley and southward pressure gradient in April. After the mature period of monsoon, the action center in the BS became weakened while that in the western south YS became strengthened because of regional convergence or divergence induced by seasonal variations of the Taiwan Warm Current and Yellow Sea Coastal Current. The direct response of topography to monsoon resulted in the WIM, while oceanic adjustment of topography played an important role in the forming of the SAM.展开更多
It was found that the location and distributional pattern of certain sea bottom mud patches in the Yellow Sea and East China Sea are identical with the geographical location and flow pattern of the upwelling above. Fo...It was found that the location and distributional pattern of certain sea bottom mud patches in the Yellow Sea and East China Sea are identical with the geographical location and flow pattern of the upwelling above. Following a general description by Hu, (1984) of the role of upwelling in . sedimentation, this study presents a two - dimensional numerical model to further examine, the sedimentation dynamics in upwelling areas. The model shows that advection by ocean circulation, downward settling due to gravity and turbulent mixing are the main mechanisms controlling the "movement of suspended matters, and that the upwelling :on the shelf favors deposition near the bottom. It is concluded that on the shelf (1) wherever there is upwelling, mud sediment must exist; and . (2) the closer to the center of upwelling, the greater the concentration of suspended matters in the water, the greater the depositing rate near the bottom and the finer the sediment on the sea bed.展开更多
文摘Seasonal cycle is the most significant signals of topography and circulation in the Bohai Sea (BS)and Yellow Sea (YS) forced by prevailing monsoon and is still poorly understood due to lack of data in their interiors. In the present study, seasonal cycles of topography in the BS and YS and its relationship with atmospheric forcing and oceanic adjustment were examined and discussed using TOPEX/Poseidon and ERS-1/2 Sea Level Anomalies (SLA) data. Analyses revealed complicated seasonal cycles of topography composed mainly of2 REOF modes, the winter-summer mode (WIM) and spring-autumn mode (SAM). The WIM with action center in the BS displayed peak and southward pressure gradient in July, and valley and northward pressure gradient in January, which is obviously the direct response to monsoon with about 1-month response time. The SAM with action center in the western south YS displayed peak and northward pressure gradient in October and valley and southward pressure gradient in April. After the mature period of monsoon, the action center in the BS became weakened while that in the western south YS became strengthened because of regional convergence or divergence induced by seasonal variations of the Taiwan Warm Current and Yellow Sea Coastal Current. The direct response of topography to monsoon resulted in the WIM, while oceanic adjustment of topography played an important role in the forming of the SAM.
文摘It was found that the location and distributional pattern of certain sea bottom mud patches in the Yellow Sea and East China Sea are identical with the geographical location and flow pattern of the upwelling above. Following a general description by Hu, (1984) of the role of upwelling in . sedimentation, this study presents a two - dimensional numerical model to further examine, the sedimentation dynamics in upwelling areas. The model shows that advection by ocean circulation, downward settling due to gravity and turbulent mixing are the main mechanisms controlling the "movement of suspended matters, and that the upwelling :on the shelf favors deposition near the bottom. It is concluded that on the shelf (1) wherever there is upwelling, mud sediment must exist; and . (2) the closer to the center of upwelling, the greater the concentration of suspended matters in the water, the greater the depositing rate near the bottom and the finer the sediment on the sea bed.
