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Evaluation of Water and Its Contaminants
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 5, 2017
William J. Rea, Kalpana D. Patel
In addition, natural oceanographic phenomena can cause deoxygenation of parts of the water column. For example, enclosed bodies of water, such as fjords or the Black Sea, have shallow sills at their entrances, causing water to be stagnant there for a long time. The eastern tropical Pacific Ocean and northern Indian Ocean have lowered oxygen concentrations which are thought to be in regions where there is minimal circulation to replace the oxygen that is consumed (e.g., Pickard and Emery 1982, p 47).124 These areas are also known as oxygen minimum zones (OMZ). In many cases, OMZs are permanent or semipermanent areas.
Assessment of the impact of spatial resolution on ROMS simulated upper-ocean biogeochemistry of the Arabian Sea from an operational perspective
Published in Journal of Operational Oceanography, 2019
Kunal Chakraborty, Nimit Kumar, M. S. Girishkumar, G. V. M. Gupta, Jayashree Ghosh, T. V. S. Udaya Bhaskar, V. P. Thangaprakash
The Arabian Sea has been characterised with one of the world ocean's most distinct and prominent oxygen minimum zone and its dynamics is closely linked to high upper column productivity and subsequent sinking flux (Sarma et al. 1998; Naqvi et al. 2000; Kumar, Madhupratap, et al. 2001, Devol et al. 2006). The mean vertical profiles of dissolved oxygen concentrations simulated by ROMS-1/12 show reasonable comparison with Argo observations (Figures 17, 21–23). However, the same is poorly captured by ROMS-1/4 as the presence of oxycline (characterised with <50 µM) is not captured in the upper 200 m although it is more clearly evident in the western Arabian Sea (Figure 23 – Argo float 2902120 and Figure 21 – Argo float 5903586). The ROMS-1/12 shows good skill to capture the low-oxygen water (<10 µM) below 150 m in the central and northeastern Arabian Sea as evident in the Argo floats, however, the ROMS-1/4 shows relatively poor skill (overestimate by 20–40 µM) to capture such low concentration of dissolved oxygen (Figure 22 – WMO number 2902092 and Figure 23 – WMO number 2902120). In the northern Arabian Sea, both the model simulation overestimate the dissolved oxygen concentration below 150 m, with respect to Argo, however, overestimation is relatively large in ROMS-1/4 (100 µM) than ROMS-1/12 ((10 µM) (Figure 21; WMO number 5903586). In the near surface layer both the model, simulations show slightly higher magnitude (5–10 µM) compared to Argo and it clearly evident in the mean vertical profile of dissolved oxygen (Figure 21–23).