A well‐defined Triple MOde of Salinity (TMOS) variability in the tropical Pacific thermocline layer (24–25.5 σ_θ isopycnal surfaces) is revealed from the Argo observations during 2004–2018. Thermocline salinity in the tropical northern and southwestern Pacific Ocean varies out of phase on interannual to near‐decadal time scales with that in the tropical southeastern Pacific Ocean. The TMOS is attributed to anomalous advection of mean salinity as well as advection of anomalous salinity by the mean oceanic current on isopycnal surfaces. While the TMOS pattern is quite different from the thermal patterns associated with the El Niño‐Southern Oscillation (ENSO) or the Pacific Decadal Oscillation (PDO), it is significantly associated with the ENSO and PDO indices with a time lag of 10 months. Isopycnal propagation of salinity anomalies and anomalous freshwater input in the outcropping region, also both associated with ENSO and PDO, are important in the formation of TMOS. The propagation speed of isopycnal salinity anomalies is close to documented phase speeds of baroclinic Rossby waves and velocities of zonal currents. The TMOS acts to shape the basin‐scale Pacific water masses and potentially plays an important role in climate.

中文翻译：

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观察到热带太平洋跃层盐度变化的三重模式

盐度的定义明确的三模式（TMOS）变异性在热带太平洋跃层层（24-25.5 σ _θ等渗面）从2004–2018年的Argo观测中揭示。热带北部和西南太平洋的温跃层盐度与热带东南太平洋的年际至近十年年代尺度不同。TMOS归因于平均盐度的平流以及同等表面上的平均洋流对流的异常盐度。尽管TMOS模式与厄尔尼诺-南方涛动（ENSO）或太平洋年代际涛动（PDO）的热力模式有很大不同，但它与ENSO和PDO指数显着相关，但有10个月的时滞。盐度异常的等渗传播和露头区域的淡水输入异常，也都与ENSO和PDO有关，在TMOS的形成中很重要。等渗盐度异常的传播速度接近斜压罗斯比波的相速度和纬向流速度。TMOS的作用是塑造流域规模的太平洋水团，并可能在气候中发挥重要作用。