We describe the variability of the East India Coastal Current (EICC) during 2010–2018 on the outer continental shelf using data from four ADCP (acoustic Doppler current profilers) moorings deployed off Gopalpur (\(\sim \)19.5\(^\circ \)N), Visakhapatnam (\(\sim \)18\(^\circ \)N), Kakinada (\(\sim \)16\(^\circ \)N), and Cuddalore (\(\sim \)12\(^\circ \)N) on the east coast of India. In general, the shelf EICC mirrors the slope EICC for the annual and semi-annual cycles, but the shelf-slope coherence is weaker and patchy for the 120-day and intraseasonal bands. The seasonal cycle, which consists of the annual, semi-annual, and 120-day bands, dominates the observed variability. The amplitude of the annual cycle varies over the time series. In the intra-annual band, variability tends to switch between the semi-annual and 120-day bands, but the former dominates throughout the time series off Cuddalore, the southernmost location. The EICC appears as a shallow current in all period bands, including the seasonal cycle, off Cuddalore, but even the intraseasonal EICC appears as a deep current at the other three locations. A wavelet analysis shows seasonal variation of the wavelet power in the intraseasonal band, suggesting that the amplitude of intraseasonal variability itself varies with season, but there is no clear seasonal pattern. As on the continental slope, the annual and semi-annual components are coherent along the coast, but alongshore coherence is weak at shorter time scales. Upward phase propagation is evident for the seasonal cycle at all locations, but downward phase propagation, seen on the slope off Cuddalore, is evident on the shelf as well. The 500-day low-pass filtered shelf EICC is not weak and the sub-annual variability is comparable to that on the slope. The long ADCP record allows us to confirm the dominance of seasonality in the EICC regime in a robust fashion; the data show that the EICC tends to flow in its canonical poleward (equatorward) direction during spring (winter). This dominance of seasonality enhances the predictability of the EICC.

我们使用来自Gopalpur（\（\ sim \） 19.5 \（^ \ circ）部署的四个ADCP（声学多普勒电流剖面仪）系泊设备的数据，描述了2010-2018年东印度洋陆架上东印度洋海流（EICC）的变化。\） N），维萨卡帕特南（\（\ sim \） 18 \（^ \ circ \） N），Kakinada（\（\ sim \） 16 \（^ \ circ \） N）和库达洛尔（\（\ sim \） 12 \（^ \ circ \）N）在印度东海岸。通常，架子EICC在年周期和半年周期中反映了EICC斜率，但是在120天和季节内波段中，架子与坡度的连贯性较弱且不连贯。由年度，半年和120天波段组成的季节周期主导着观察到的变化。年度周期的幅度随时间序列变化。在年内波段中，变异性倾向于在半年和120天波段之间切换，但前者在整个最南端的Cuddalore附近的时间序列中占主导地位。EICC在包括Cuddalore在内的所有周期带中都显示为浅流，但在其他三个位置，甚至季节内EICC都显示为深流。小波分析显示了季节内频带中小波功率的季节性变化，这表明季节内变异性的幅度本身随季节而变化，但是没有明确的季节性模式。与大陆坡一样，沿海岸的年和半年分量是连贯的，但是在较短的时间尺度上，沿岸的连贯性较弱。在所有位置的季节性周期中，向上相位的传播都是明显的，但是在库达洛尔斜面上看到的向下相位的传播在架子上也很明显。500天低通滤波后的架架EICC并不弱，并且亚年度变化与斜率相当。ADCP的长期记录使我们能够以强有力的方式确认EICC制度中季节性的主导地位。数据表明，在春季（冬季）期间，EICC倾向于沿其规范的极向（赤道）方向流动。季节性的这种优势增强了EICC的可预测性。