西北太平洋温盐分布的时空尺度分析

Spatial-temporal scales of temperature and salinity variablity in the Northwest Pacific

为了更清晰地了解西北太平洋的温盐分布特征,基于全球实时海洋观测计划(Argo)浮标观测剖面,利用自相关函数方法,对西北太平洋海域(选取范围为120°E^160°W,10~40°N)温盐分布的时空尺度进行了分析,并通过高斯函数拟合得到了温盐的时空去相关尺度。研究表明,自相关函数随季节和深度发生变化,各层的自相关函数值随着空间增大而降低。表层,夏季温度的空间去相关尺度比冬季大,但时间去相关尺度小;次表层,夏季温度的自相关函数随空间增大迅速递减,空间去相关尺度比冬季小;深层,夏季和冬季的温度时空尺度相近。盐度的季节性变化较温度要小,但盐度的空间变化尺度比温度要大,而时间变化尺度则比温度小。2种要素的信噪比均大于2,可以用来指导精细化观测布网的采样间隔。

To investigate the physical characteristics of the water mass in part of the Northwest Pacific,the autocorrelation functions（ACF）of temperature and salinity in this region（120°E-160°W,10°N-40°N）were computed based on the array for real-time geostrophic oceanography（Argo）profiles.Then the temporal and spatial decorrelation scales were obtained by fitting the autocorrelation function into Gaussian function.The ACFs vary with the season and depth.The ACFs gradually decrease with the spatial lag increasing.On the surface,the spatial（temporal）decorrelation scale of temperature is longer（shorter）in the summer than that in the winter.At the subsurface,the ACFs in summer temperature decrease dramatically with the space increasing.However,the temporal decorrelation scale is shorter than that in winter.In the deep layers,the spatial（temporal）decorrelation scales of temperature are similar in summer and winter.The seasonal variability of salinity is weaker.The spatial（temporal）decorrelation scale of salinity is longer（shorter）than that of temperature.The signal-to-noise ratios are usually larger than 2.It proves that the decorrelation scales are useful for designing an optimal observational network.