渤海夏季温盐年际变化时空模态与气候响应

Climate response and spatio-temporal model on the interannual temperature-salinity changes in summer of Bohai Sea

根据渤海夏季断面1978~2014年历年8月温度、盐度与气候要素、黄河年径流量等观测数据,采用旋转经验正交函数（REOF）、风驱海流模式诊断、最大熵谱分析和延迟相关分析等方法,研究了渤海夏季断面温度、盐度年际变化时空模态与气候响应.温度主要有4种时空模态,其中第一模态为准平衡态年际变化和10a尺度跃变,第二至四模态为显著线性降温趋势年际变化和10a尺度跃变.渤海夏季径向风应力强度是夏季温度年际变化的主要影响因素,夏季风应力强度逐年减弱使得夏季水温的季节增温减弱,并且抵消了夏季气温逐年升高对水温的增温影响,温度模态大部分分量出现显著线性降温趋势.夏季大尺度海洋温度、气温年际变化是夏季温度年际变化的次要影响因素.盐度主要有2种时空模态,其中第一模态是对辽河口入海径流量、夏季降水量和夏季风应力强度的响应;第二模态是对黄河口入海年径流量和夏季风应力强度的响应.黄河口、辽河口入海年径流量与夏季降水量是盐度年际变化的主要影响因素,夏季风应力强度是次要因素.盐度模态年际变化呈现准平衡态周期变化和10a尺度跃变.

Based on the temperature, salinity in August of a Bohai Sea section and annual runoff data of the Yellow River, meteorological data during 1978 to 2014, the climate response and spatio-temporal model on the interannual change of temperature and salinity in summer of the Bohai Sea section were studied with methods of Rotated Empiri- cal Orthogonal Function （REOF） , wind-driven current model diagnosis, maximum entropy spectrum and the delay correlation analysis and so on. The results show that the interannual change of temperature is divided into 4 spatio- temporal models. While the first model shows a quasi-equilibrium state interannual variety and decade scale jumps, the other 3 models show a remarkable linear declining annual variety and decade scale jumps. Summer meridial wind stress in Bohai Sea is the main factor which affects the interannual change of the summer temperature models. Owing to the yearly decrease of summer wind stress intensity, not only the process of seawater temperature incre- ment weakens in summer of Bohai Sea, but also the yearly increasing summer air temperature on the seawater tem- perature increment is neutralized. Therefore, most components of temperature models show a trend of remarkable declining. Large-scale interannual change of ocean temperature and air temperature in summer are secondary factorsthat affected the interannual change of the summer temperature models. The interannual change of salinity is divid- ed into 2 spatio-temporal models, While the first model was a response to annual runoff of the Liaohe River estuary, summer precipitation and summer wind stress intensity, the other one is a response to annual runoff of the Yellow River estuary and summer wind stress intensity. Annual runoff of the Yellow River estuary and Liaohe River estuary is the first factor that affected the interannual change of salinity models, and wind stress intensity in summer is the second. The interannual change of salinity models shows a periodic quasi-equilibrium state and decadal scale jumps.