A note on the vertical scales of temperature and salinity and their signature in dynamic height in the western Pacific Ocean: Implications for data assimilation
A note on the vertical scales of temperature and salinity and their signature in dynamic height in the western Pacific Ocean: Implications for data assimilation
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DOI：
10.1029/1999jc900032
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发表时间：
1999-05
影响因子：
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通讯作者：
C. Maes
中科院分区：
文献类型：
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作者：
C. Maes
研究了西太平洋沿着165°E跨赤道剖面的温盐垂直结构与表层动力高度异常的同期特征之间的关系。这些数据来自于主要在1984-1992年期间作为TOGA计划的一部分进行的28次海洋学巡航中的电导率-温度深度模型。分析是基于经验正交函数，隔离的主要模式的变化，并提出了一些可能的物理解释。结果表明，前六个模式，解释约80%的方差，显示不同的垂直尺度和表现出连贯的和可观察的签名，在动态高度揭示复杂的模式在纬度和时间。此外，已经开发了一种方法来重建的温度和盐度剖面从他们的签名在地面动态高度异常使用占主导地位的EOF。该方法是新的意义上说，没有求助于T-S关系。重建后的垂直方向残差小于固有变率，且该方法能成功地再现ENSO时间尺度上的变率。动态高程异常的剩余误差小于1达因。在赤道带为2-4达因量级。在亚热带地区为厘米。结果表明，海平面观测可以转化为温度和盐度的异常在深度。海洋模式中的数据同化的影响进行了讨论。
The relationship between the vertical structures of ocean temperature and salinity and their concurrent signature in surface dynamic height anomalies are investigated along the 165°E transequatorial section in the western Pacific Ocean. The data are from conductivity-temperature depth casts made during 28 oceanographic cruises mainly conducted during the 1984–1992 time period as part of the TOGA program. The analysis is based on empirical orthogonal functions that isolate the primary modes of variability, and some possible physical interpretations are suggested. The results show that the first six modes, explaining roughly 80% of the variance, display distinct vertical scales and exhibit coherent and observable signatures in dynamic height which reveal complex patterns in latitude and time. In addition, a method has been developed to reconstruct the temperature and salinity profiles from their signature in the surface dynamic height anomaly using the dominant EOFs. The method is new in the sense that no recourse is made to T–S relations. Residual errors in the vertical after reconstruction are lower than the intrinsic variability, and the method can successfully reproduce the variability at ENSO timescales. The residual error in dynamic height anomalies is lower than 1 dyn. cm in the equatorial belt, and of the order of 2–4 dyn. cm in the subtropics. The results demonstrate that sea level observations may be translate into temperature and salinity anomalies at depth. The implications for data assimilation in ocean models are discussed.