Cabled ocean observatories in Sea of Oman and Arabian Sea

Abstract

An ocean observatory—consisting of a real‐time, cabled array in the Sea of Oman and an internally recording, autonomous mooring array recently upgraded to a cabled array in the northern Arabian Sea—celebrated more than 2500 days of continuous operation in July 2012. The observatory, which measures a range of properties, such as water current velocities, temperature, salinity, pressure, dissolved oxygen, and turbidity, is part of the Lighthouse Ocean Research Initiative (LORI) project [du Vall et al., 2011], which was designed as a pilot project and installed in 2005 in the region off Abu Bakara (Figures 1a and 1b). The initial goal of the project was to prove that an in situ, cabled ocean observatory can return high‐quality scientific data on a real‐time basis over longer time periods than conventional moored systems. That same year, an autonomous array was deployed off Ras al Hadd and on Murray Ridge in the Arabian Sea (Figure 1a).

Monsoon-driven seasonal hypoxia along the northern coast of Oman

“…Deployed in summer 2005 in the Sea of Oman off the northern coast of Abu Bakara, Sultanate of Oman between the 65-and 1050m isobaths (Figure 1A), the Lighthouse Ocean Research Initiative (LORI) system, designed and operated by Lighthouse R&D Enterprises, Inc (DiMarco et al, 2012;Ingle et al, 2012;Wang et al, 2013b), provided real-time measurements of currents, temperature, salinity, pressure, dissolved oxygen, and turbidity. The LORI system was the first cabled seabed observatory in the study region.…”

“…In Oman, the project was coordinated alongside the Ministry of Agriculture and Fisheries Wealth through the Marine Science and Fisheries Centre. Planned to be a sustained observing system, it was designed to provide real-time monitoring of water-column properties to allow shareholders and users to make informed decisions, as well as to study a range of oceanic phenomena, including potential impacts of climate change, characterization of the general dynamical patterns of the region, and quantification of seasonal variability of water-column properties (DiMarco et al, 2012;Wang et al, 2012;Wang et al, 2013a;Wang et al, 2014). One key objective was to support the Omani Ministry in its efforts to develop and manage the Sultanate's important fisheries resources within the country's EEZ (exclusive economic zone).…”

“…In this manuscript, we will first report observations of seasonally recurrent hypoxic/anoxic conditions found in the Sea of Oman over the region of the northern continental shelf and slope of Oman using five continuous years of hourly current velocity and dissolved oxygen measurements from a cabled observing system (DiMarco et al, 2012;Ingle et al, 2012). We then examine the causes of the seasonal hypoxia in relation to monsoonal driven seasonal upwelling/downwelling and the seasonal extension of the OMZ into the coastal regions.…”