This study describes biweekly (defined as periods between 10 and 15 days) ocean variability in relation to equatorial wave theory using a comprehensive set of moored ocean current velocities as well as satellite‐retrieved oceanic and atmospheric parameters in the Indian Ocean. Moored biweekly current velocities exhibit the meridional structure of mixed Rossby‐gravity waves: Symmetric for meridional velocity and antisymmetric for zonal velocity around the equator with a decay scale of 228–309 km. The biweekly meridional velocity along the equator has average zonal and vertical wavelengths of 3,430 ± 550 km and 0.76 ± 0.15 km, respectively, with phase propagating westward at speeds of 2.8–3.1 m s⁻¹ and upward at 54–56 m day⁻¹. Conversely, wave energy is inferred to propagate eastward and downward. The range of best fit constants (1.4–2.0 m s⁻¹) that result from the linear separation of horizontal and vertical wave structures suggests the second baroclinic wave mode is dominant over other low baroclinic modes in accounting for the velocity variability. The biweekly waves are forced by surface winds; satellite‐derived wind stress, sea level, and surface current anomalies, regressed against the first principal component of the biweekly moored velocities, illustrate the basin‐scale structure and temporal evolution of the waves.

中文翻译：

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赤道印度洋每两周混合一次罗斯比重力流

这项研究使用印度洋的系泊洋流速度以及卫星获取的海洋和大气参数的综合集合，描述了与赤道波理论有关的每两周一次（定义为10到15天之间的时间）海洋变化。双周系泊的当前速度表现出混​​合的Rossby重力波的子午线结构：子午线速度对称，而赤道附近速度速度反对称，衰减范围为228–309 km。沿赤道的双周子午速度分别具有3,430±550 km和0.76±0.15 km的平均纬向和垂直波长，相位以2.8–3.1 ms ^-1的速度向西传播，并以54–56 m day ^-1的速度向上传播。相反，推断波能向东和向下传播。由水平和垂直波结构的线性分离产生的最佳拟合常数范围（1.4–2.0 ms ^-1）表明，考虑到速度的变化性，第二斜压波模式比其他低斜压波模式占主导地位。每两周一次的波浪是由表面风强迫的。与两周一次的系泊速度的第一个主要分量相反的，卫星衍生的风应力，海平面和地表电流异常，说明了海浪的盆地尺度结构和时间演变。