渤海冬季温盐年际变化时空模态与气候响应

Climate response and spatial-temporal model on the inter-annual change of temperature-salinity in the Bohai Sea during winter

根据渤海断面1978-2012历年2月表、底层海水温度、盐度和气候要素观测资料,采用旋转经验正交函数(REOF)、最大熵谱分析和延迟相关分析等方法,研究了渤海冬季表底层温度、盐度年际变化时空模态与气候响应。渤海冬季表底层温度年际变化分为三种时空模态:开阔海型、黄河口型和辽河口型,其中只有开阔海型模态是对冬季气温变暖的响应,时间分量有显著线性升高趋势和跃变升高。黄河口型模态是对冬季西北季风强度逐渐减弱的响应,时间分量有显著线性降低趋势。辽河口型模态是对局地海冰年际变化的响应,时间分量准平衡变化。渤海冬季表底层盐度年际变化分为二种时空模态:辽东湾型和黄河口型,其中黄河口型模态与黄河口年径流量滞后5年显著负线性相关,该模态时间分量有显著线性升高趋势和跃变;辽东湾型模态与黄河年径流量滞后7年显著负线性相关;滞后2年显著非线性相关,该模态时间分量年际变化为准平衡形态。黄河口年径流量是影响渤海冬季盐度年际变化的主要因素。

By use of the dataset of the temperature and salinity at the surface and bottom layers, and the climate data,along the transfer in the Bohai Sea in February every year from 1978 to 2012, the climate response and spatial-temporal model on the inter-annual change of temperature-salinity at the surface and bottom layers in the Bohai Sea during winter 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 inter-annual changes of temperature at the surface and bottom layers in the Bohai Sea during winter were divided into three kinds of spatial-temporal models open sea model, Yellow River estuary model and Liaohe River estuary model, and only open sea model of them was the response to the status that air temperature in winter was becoming warm, and its temporal component variable had a linear rise trend and jump; Yellow River estuary model was the response to the fact that the intensity of the north-west monsoon in winter was gradually decreasing, and its temporal component variable had a declining trend; Liaohe River estuary model was the response to the inter-annual change of the local sea ice, and its temporal component variable had a quasi-balance change. The inter-annual winter change of salinity at the surface and bottom layers in the Bohai Sea was divided into two kinds of spatial-temporal models Yellow River estuary model and Liaohe river estuary model. The Yellow River estuary model had notably minus linear correlation with the inter-annual runoff in the Yellow River estuary lagging behind 5 years, and its temporal component variable had a remarkably linear rise trend and jump; the Liaohe River estuary model had notably minus linear correlation with the inter-annual runoff in the Yellow River estuary lagging behind 7 years and had notably non-linear one lagging behind 2 years, and the inter-annual variable of its temporal component variable showed a quasi-balance mode. Thus, the inter-annual runoff into the sea in the Yellow River was the main factor to affect the inter-annual winter change of temperature-salinity in the Bohai Sea.