北阿拉伯海的光纤海洋观测网络:成功、挑战和机遇

2005年夏,一个先进的海洋观测网络——包括实时的光纤海洋观测系统和内部存储的自动化观测系统——被投放在了阿曼海和北阿拉伯海并运行至今.在2010年初,其中的自动化观测系统被升级到了新的深水光纤观测系统.这个海洋观测网络是在阿曼农业和渔业部的资助下,由美国的Lighthouse R&D公司设计、开发、安装和维护的.这2个观测系统作为一个整体已经连续工作了7年多的时间.所采集数据包括海流、温度、盐度、压力、溶解氧和浊度等.该海区是一个多水团的汇合区,波斯湾的高盐水和阿拉伯海的低盐水在这里汇合并蔓延南下到印度洋.对采集的数据研究表明,这一观测网络对研究该区域的物理和生物过程具有重要价值.在此,将系统介绍整个观测网络,并简要阐述已经完成和接近完成的4个研究主题:①对阿拉伯海有记载以来最强热带气旋“古怒”的海洋响应的研究；②阿曼海北部的季节性缺氧现象的季节及年际变化和成因分析；③深海声散射层的时空演变；④阿曼海和北阿拉伯海的高温高盐现象的成因.该观测网络采集的长期、连续的时间序列对这一地区的海洋动力研究、水文的季节性变化,以及气候的长期变化等研究都有很大帮助.此外,如果观测网络可以完成25年的设定观测目标,这将对验证和改进海洋环流模式和海气耦合模式具有重要意义.

A Cabled Oceanographic Monitoring Network in the Northern Arabian Sea: Success, Challenges and Opportunities

An ocean observatory-Consisting of a real time, cabled system in the Sea of Oman and an internally recording, autonomous mooring system upgraded in 2010 to a cabled system in the northern Arabian Sea-was installed in 2005. Lighthouse R & D Enterprises designed and installed and now operates and maintains the systems with permission from the Oman Ministry of Agriculture and Fisheries Wealth. The two systems have collected a continuous seven year time series record of current velocities, temperature, pressure, salinity, dissolved oxygen, and turbidity in a region where several water masses converge and subsequently spread southward to the Indian Ocean. The systems have provided new insights into physical and biological oceanographic processes of the northwestern Indian Ocean, which is strongly affected by monsoonal winds, along with lessons learned and best practices in the operation and application of ocean observatories to ocean science. In this presentation, we show four recent studies on the scientific highlights resulting from the data collected by the two systems with supporting data from other sources. The topics of those four studies include: ①The deep water oceanic responses excited by the passage of Cyclone Gonu, the largest ever recorded cyclone in the region; ② The seasonality associated with the upwelling of low oxygen water along the northern Oman coast and insights on the inter annual variability of this process; ③ The temporal and spatial evolution of an acoustic backscatter layer; ④ The pulse like salinity/temperature events in the northeastern Arabian Sea and Sea of Oman. The observatory provides a long term, time series data record useful for performing important scientific research related ot the general dynamical patterns of the region, quantifying seasonal variability of water column properties, and establishing a time series of sufficient duration to deduce the potential impacts of climate change. Furthermore, observations taken over the full, 25+ year lifetime of a typical cabled system will be extremely useful for evaluating numerical ocean circulation and coupled atmospheric oceanic models under various climate scenarios.