A Reconstruction of Observed Profiles in the Sea East of Japan Using Vertical Coupled Temperature-Salinity EOF Modes
A Reconstruction of Observed Profiles in the Sea East of Japan Using Vertical Coupled Temperature-Salinity EOF Modes
复制标题
DOI：
10.1023/a:1025539104750
复制
发表时间：
2003-04
影响因子：
2.3
通讯作者：
Y. Fujii;M. Kamachi
中科院分区：
文献类型：
--
作者：
Y. Fujii;M. Kamachi
重要的是从易于观测的参数估计海洋内部难以观测的参数。因此，本研究演示了日本以东海域（30° <$40 °N，140° <$150 °E）观测温度和盐度剖面的重建。重建是通过估计次优状态从几个值的观测剖面和/或海面动态高度（SDH）计算的配置文件。估计使用的变分法与垂直耦合的温度-盐度的经验正交函数（ODF）模式。利用海温和海水盐度资料，可以有效地重建副热带地区的温盐廓线。例如，在亚热带地区，由SST和SDH分析的温度场精度可达1°C以内。然而，黑潮以北海域的盐度很难估计，因为其复杂的变化与温度的相关性低于亚热带地区。海水表层盐度可用于估计次表层结构。我们还表明，估计的可能性，提高考虑非线性方程计算SDH的温度和盐度分析值，以检查分析和观察之间的失配。还使用TOPEX/POSEIDON测高数据代替SDH进行了分析。
It is important to estimate hard-to-observe parameters in the ocean interior from easy-to-observe parameters. This study therefore demostrates a reconstruction of observed temperature and salinity profiles of the sea east of Japan (30°≈40°N, 140°≈150°E). The reconstruction was done by estimating suboptimal state from several values of the observed profiles and/or sea surface dynamic height (SDH) calculated from the profiles. The estimation used a variational method with vertical coupled temperature-salinity empirical orthogonal function (EOF) modes. Profiles of temperature and salinity in the subtropical region are effectively reconstructed fromin situtemperature profile data, or sea surface temperature (SST) and SDH. For example, the analyzed temperature field from SST and SDH has an accuracy to within 1°C in the subtropical region. Salinity in the sea north of Kuroshio, however, is difficult to estimate because of its complex variability which is less correlated with temperature than in the subtropical region. Sea surface salinity is useful to estimate the subsurface structure. We also show the possibility that the estimation is improved by considering nonlinearity in the equation calculating SDH from temperature and salinity analysis values in order to examine the misfit between analysis and observation. Analysis using TOPEX/POSEIDON altimetry data instead of SDH was also performed.