渤海夏季海水磷酸盐年际时空演变

Spatial-temporal changes of the annual phosphate in the Bohai Sea during summer

根据1978-2011年渤海断面历年8月海水表底层活性磷酸盐监测资料,采用REOF、最大熵谱和延迟相关分析等方法,分析渤海夏季表底层活性磷酸盐年际时空变化有3种模态:河口型、辽东湾型和开阔海型。其中河口型和开阔海型模态年际变化为显著周期和线性减小趋势。辽东湾型模态年际变化为显著周期的准平衡变化。磷酸盐3种时空模态之间存在延迟相关关系,夏季海流、水温、浮游植物生消以及磷酸盐再生、排放、海水-沉积物交换、磷酸盐沉积等过程年际变化与3种形态的磷酸盐年际变化位相延迟相关分布有关。渤海夏季断面海水磷酸盐浓度年际变化呈现波动形减小,2004年后,渤海中部磷酸盐浓度显著减小。

Based on the dataset of the phosphate in surface and bottom layers along the transfer in the Bohai Sea during August every year from 1978 to 2012,the spatial-temporal changes of the annual phosphate in surface and bottom layers in the Bohai Sea were studied with the analysis methods of Rotated Empirical Orthogonal Function （REOF）,maximum entropy spectrum and the delay correlation analysis.The results showed that the annual summer changes of phosphate in surface and bottom layers in the Bohai Sea were divided into three kinds of spatial-temporal models：estuary model,Liaodong bay model and open sea model,and that the annual changes of the estuary model and open sea model had notable cycle and linear trend decreasing,and that the annual change of the Liaodong bay model had the quasi-balance change with the notable cycle.The phosphate had the delay correlation among the three spatial-temporal models.Moreover,in summer,referring to the marine current,water temperature,the phytoplankton appearing and disappearing,and the phosphate regenerating,discharging and the seawater-sediment exchanging,and its sediment process and so on,the annual changes of these processes had the delay correlation distribution with the phosphate annual change phase on the three models.The annual changes of the phosphate along the transfer in the Bohai Sea during summer showed the wave-state decreasing.Especially,after 2004,the phosphate concentration in the middle of the Bohai Sea notably decreased.