We identify and analyze tropical instability waves (TIWs) in the equatorial Atlantic Ocean during 2010–2018 using satellite derived observations of sea surface salinity (SSS), sea surface temperature (SST), sea level anomaly, and Argo profiles. In particular, the weekly 50‐km resolution SSS time series from the climate change initiative project provides an unprecedented opportunity to observe the salinity structure at a scale closer to the SST scale. We examine the relative contributions of SSS and SST to the horizontal surface density gradient on seasonal and interannual time scales and how they contribute to the TIW properties and energetics. For the central Atlantic TIWs, the maximum of the SST contribution to the density anomaly lags the SSS one by approximately one month. Argo vertical profiles indicate that temperature and salinity both significantly contribute to TIW‐related density anomalies. In May–June, salinity contributes to 50% of the perturbation potential energy in the top 60 m, and between 30% and 45% from July to September. While variations in SST appear to be related to dynamic processes, the interannual variability of SSS is also influenced by precipitations. However, the two leading modes of variability in the region (Atlantic Meridional and Zonal modes) do not well explain at 1°N these interannual variations.

中文翻译：

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大西洋中的热带不稳定浪潮：调查2010年至2018年海表盐度和温度的相对作用

我们使用卫星衍生的海面盐度（SSS），海面温度（SST），海平面异常和Argo剖面的观测资料，确定并分析了2010-2018年赤道大西洋的热带不稳定波（TIW）。特别是，来自气候变化倡议项目的每周50公里分辨率的SSS时间序列提供了前所未有的机会来观察更接近SST尺度的盐度结构。我们研究了SSS和SST在季节和年际尺度上对水平面密度梯度的相对贡献，以及它们如何对TIW属性和能量学做出贡献。对于大西洋中部的TIW，SST对密度异常的最大贡献要比SSS滞后约一个月。Argo垂直剖面表明，温度和盐度均与TIW相关的密度异常有很大关系。在5月至6月，盐度占顶部60 m扰动势能的50％，而从7月至9月则占30％至45％。尽管SST的变化似乎与动态过程有关，但SSS的年际变化也受到降水的影响。但是，该区域的两种主要变率模式（大西洋子午线和分区模式）不能很好地解释在1°N时这些年际变化。SSS的年际变化也受降水影响。但是，该区域的两种主要变率模式（大西洋子午线和分区模式）不能很好地解释在1°N时这些年际变化。SSS的年际变化也受降水影响。但是，该区域的两种主要变率模式（大西洋子午线和分区模式）不能很好地解释在1°N时这些年际变化。