2016 and 2017 were marked by strong El Niño and weak La Niña events, respectively, in the tropical East Pacific Ocean. The strong El Niño and weak La Niña events in the Pacific significantly impacted the sea surface temperature (SST) in the tropical Indian Ocean (TIO) and were followed by extreme negative and weak positive Indian Ocean Dipole (IOD) phases in 2016 and 2017, which triggered floods in the Indian subcontinent and drought conditions in East Africa. The IOD is an irregular and periodic oscillation in the Indian Ocean, which has attracted much attention in the last two decades due to its impact on the climate in surrounding landmasses. Much work has been done in the past to investigate global climate change and its impact on the evolution of IOD. The dynamic behind it, however, is still not well understood. The present study, using various satellite datasets, examined and analyzed the dynamics behind these events and their impacts on SST variability in the TIO. For this study, the monthly mean SST data was provided by NOAA Optimum Interpolation Sea Surface Temperature (OISST). SST anomalies were measured on the basis of 30-year mean daily climatology (1981–2010). It was determined that the eastern and western poles of the TIO play quite different roles during the sequence of negative and positive IOD phases. The analysis of air-sea interactions and the relationship between wind and SST suggested that SST is primarily controlled by wind force in the West pole. On the other hand, the high SST that occurred during the negative IOD phase induced local convection and westerly wind anomalies via the Bjerknes feedback mechanism. The strong convection, which was confined to the (warm) eastern equatorial Indian Ocean was accompanied by east–west SST anomalies that drove a series of downwelling Kelvin waves that deepened the thermocline in the east. Another notable feature of this study was its observation of weak upwelling along the Omani–Arabian coast, which warmed the SST by 1 °C in the summer of 2017 (as compared to 2016). This warming led to increased precipitation in the Bay of Bengal (BoB) region during the summer of 2017. The results of the present work will be important for the study of monsoons and may be useful in predicting both droughts and floods in landmasses in the vicinity of the Indian Ocean, especially in the Indian subcontinent and East African regions.

中文翻译：

---

2016年和2017年ENSO和IOD事件期间热带印度洋海表温度变化

2016年和2017年分别是热带东太平洋的强厄尔尼诺事件和弱拉尼娜事件。太平洋的强厄尔尼诺事件和弱拉尼娜事件严重影响了热带印度洋（TIO）的海表温度（SST），随后在2016年和2017年出现了极端负和弱正印度洋偶极子（IOD）阶段，引发了印度次大陆的洪水和东非的干旱情况。IOD是印度洋的一种不规则且周期性的振荡，由于它对周围陆地的气候影响，在过去的二十年中引起了人们的极大关注。过去，已经做了很多工作来调查全球气候变化及其对IOD演变的影响。然而，其背后的动力仍未得到很好的理解。目前的研究 使用各种卫星数据集，检查并分析了这些事件背后的动态及其对TIO中SST变异性的影响。对于这项研究，月平均SST数据由NOAA最佳插值海面温度（OISST）提供。SST异常是根据30年平均每日气候（1981-2010年）进行测量的。已确定，在IOD负相位和正相位阶段的顺序中，TIO的东西两极起着完全不同的作用。对海-气相互作用以及风与海温之间关系的分析表明，海温主要受西极的风力控制。另一方面，在负IOD阶段发生的高SST通过Bjerknes反馈机制引起局部对流和西风异常。强对流 它局限于（温暖的）东部赤道印度洋，同时伴有东西向海温异常，从而引发了一系列下沉的开尔文波，加深了东部的热跃层。该研究的另一个显着特征是观察到阿曼-阿拉伯海岸上空微弱的上升流，这在2017年夏季将SST升高了1°C（与2016年相比）。这种变暖导致2017年夏季孟加拉湾（BoB）地区的降水增加。本研究的结果对季风的研究非常重要，可能有助于预测附近陆地的干旱和洪水印度洋，特别是在印度次大陆和东非地区。