渤海夏季三维温度场的数值模拟

Numerical Simulation to 3-D Structure of Water Temperature of Bohai Sea in Summer

基于近岸海洋模式FVCOM(Finite Volume Coastal Ocean Model),利用NCEP-CFSR(Climate Forecast System Reanalysis)的海表温度、太阳短波辐射通量、动量通量等数据作为强迫,考虑潮流混合和风应力作用,在季节尺度上研究了渤海夏季温度场的三维结构。模拟结果准确刻画了夏季渤海中部浅滩暖水及其南北两侧洼地冷水构成的"非对称双中心底层冷水"结构。研究发现,北侧洼地底层水的海温比南侧洼地底层水的海温低2℃,该低温中心位于渤中浅滩至洼地的斜坡上,冷中心有爬坡现象;在15m层和底层,渤中浅滩北侧存在2个低温中心,并和周围的冷水构成西南-东北向的椭圆状冷水带,流场结构中存在着与冷水带形状相似的逆时针流环和流涡,表明地形和岸线是冷水带形成的主要原因。

Based on the Finite Volume Coastal Ocean Model （FVCOM） with the effects of tides and wind, this study successfully simulated the 3D structure of summer temperature of the Bohai Sea, by using the high spatial and temporal resolution data from NCEP-CFSR dataset. The structure of ＂asymmetric du-al-core bottom cold water＂, which is constituted by the cold water in the depressions located in the north and south of the central shallow ridge, is successfully reproduced. The temperature in the north depres-sion is 2℃lower than that in the south depression, and the north low-temperature center is located in the slope between the central ridge and the depression. Specially, in the contour maps of the temperature field of the 15 m layer and bottom layer, the study found two low temperature centers, which formed with the surrounding cold water an oval-shaped cold water belt（distributed in southwest-northeast direction）, exist near the north depression. This phenomenon has been verified by the investigation data of the Bohai Sea hydrographical survey in summer 2006, which, however, have not been mentioned in precious studies. The current structures in this place suggest that the oval-shaped counterclockwise flow ring and vortex, partially induced by the terrain and coastline, should play an important role in the formation and mainte- nance of the low-temperature center.