IMPACT OF ENSO AND INDIAN OCEAN DIPOLE MODE (IODM) ON VARIABILITY OF THE OCEANOGRAPHIC PROCESSES IN THE EASTERN TROPICAL INDIAN OCEAN.

1999年，印度洋偶极模式(IODM)在印度洋被发现。这一现象与一次强烈的厄尔尼诺事件同时发生，并将印度洋赤道地区东半部转变为上升流状态，持续了几个月。这些发现使东热带印度洋地区成为气候重要的地区。该项目的目的是利用1997年9月至2003年12月的海面高度(SSH)、海面风、海面温度(SST)和浮游植物色素浓度(叶绿素a)等多传感器遥感时间序列数据，了解热带印度洋东部上升流现象的季节演变和年际变化。我们的研究重点是监测IODM和ENSO对该地区中尺度物理-生物海洋过程的影响。结果表明，热带印度洋东部海温变率最大，海温异常最大，w…最强1997-98年强厄尔尼诺和IODM事件同时发生时，IND较多。此外，在对东南季风的季节响应的大小和时间上，都与7年的月度叶绿素气候学有显著的偏离。在1997-98年厄尔尼诺和IODM的高峰期，异常的东风引起了强烈的上升流，并将温跃层抬高到远低于爪哇沿岸气候平均水平的深度，导致苏门答腊岛沿岸的叶绿素a浓度较高，随后高叶绿素a区向西北方向延伸。在1997年末、1998年初和1999年末连续出现的异常海况与早先报道的IODM的演变模式相一致。我们的结果突出了多传感器遥感数据在深入了解气候事件和生物海洋学过程之间的密切相互作用方面的作用，并有助于加深我们对该区域生物生产机制和远洋渔业的了解。较少

In 1999, Indian Ocean Dipole Mode (IODM) was discovered in the Indian Ocean. This phenomenon co-occurred with a strong El Nino event and transformed eastern half of the Indian Ocean equatorial region into an upwelling regime for several months. Such findings made the eastern tropical Indian Ocean region an area of major climatic importance. The purpose of this project is to understand the seasonal evolution and interannual variability of the upwelling phenomena in the eastern tropical Indian Ocean using multi-sensor remote sensing time series data i.e. sea-surface height (SSH), ocean surface winds, sea-surface temperature (SST) and phytoplankton pigment concentration (chlorophyll a) from September 1997 to December 2003. The focus of our research is to monitor impact of the IODM and ENSO on mesoscale physical-biological oceanographic processes in the region. Our results indicated that the eastern tropical Indian Ocean exhibits the largest SST variability, SSH anomaly and the strongest w … More inds during simultaneous occurrence of a strong El Nino and IODM events in 1997-98. Furthermore, there was a significant departure from the 7-year monthly chlorophyll climatology in both magnitude and timing of seasonal response to the SE monsoon. During the peak of the 1997-98 El Nino and IODM, anomalous easterly wind induced strong upwelling and lifted the thermocline to depths much shallower than the climatological mean along the coast of Java resulting higher chlorophyll a concentration and subsequently the high chlorophyll a area extended northwestward along the Sumatra coast. Sequential occurrence of anomalous ocean condition during late-1997, early-1998 and late-1999 was found to be consistent with the evolutionary pattern of the IODM reported earlier. Our results highlight usefulness of multi-sensor remote sensing data in providing significant insight into strong interplay between climatological events and biological oceanographic processes and contribute to furtherance of our understanding of biological production mechanism and pelagic fisheries in the region. Less