An Eddy-Resolving Hindcast Simulation of the Quasiglobal Ocean from 1950 to 2003 on the Earth Simulator

Sasaki, Hideharu; Nonaka, Masami; Masumoto, Yukio; Sasai, Yoshikazu; Uehara, Hiroki; Sakuma, Hirofumi

doi:10.1007/978-0-387-49791-4_10

Cited by 247 publications

(230 citation statements)

References 43 publications

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“…4 We use the (time-dependent) horizontal velocity vector fields taken from the Ocean General Circulation Model for the Earth Simulator (OFES model). OFES is a global highresolution ocean-only model 14,15 configured on a 1/10 horizontal resolution grid with 54 vertical levels and forced with observed winds from the NCEP/NCAR reanalysis, with velocity data available at three-day temporal resolution. Figure 1 shows the mean speed of the surface flow (in red) and the mean direction of the surface flow (arrows).…”

Section: Data Description Definitions and Methodsmentioning

confidence: 99%

How well-connected is the surface of the global ocean?

Froyland

Stuart

Sebille

2014

Chaos: An Interdisciplinary Journal of Nonlinear Science

117

153

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The Ekman dynamics of the ocean surface circulation is known to contain attracting regions such as the great oceanic gyres and the associated garbage patches. Less well-known are the extents of the basins of attractions of these regions and how strongly attracting they are. Understanding the shape and extent of the basins of attraction sheds light on the question of the strength of connectivity of different regions of the ocean, which helps in understanding the flow of buoyant material like plastic litter. Using short flow time trajectory data from a global ocean model, we create a Markov chain model of the surface ocean dynamics. The surface ocean is not a conservative dynamical system as water in the ocean follows three-dimensional pathways, with upwelling and downwelling in certain regions. Using our Markov chain model, we easily compute net surface upwelling and downwelling, and verify that it matches observed patterns of upwelling and downwelling in the real ocean. We analyze the Markov chain to determine multiple attracting regions. Finally, using an eigenvector approach, we (i) identify the five major ocean garbage patches, (ii) partition the ocean into basins of attraction for each of the garbage patches, and (iii) partition the ocean into regions that demonstrate transient dynamics modulo the attracting garbage patches. V C 2014 AIP Publishing LLC.[http://dx.doi.org/10.1063/1.4892530]Ocean dynamics operate and affect climate on timescales of months to millenia. In this paper, we investigate phenomena on the ocean's surface that manifest over very long time periods: we look for regions in which water, biomass, and pollutants become trapped "forever" (which we refer to as attracting regions), or for long periods of time before eventually exiting (which we refer to as almostinvariant regions). While attracting regions may be quite small in size or irregular in shape, they can nonetheless exert great influence on the global ocean surface dynamics if their basins of attraction are large.

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Section: Data Description Definitions and Methodsmentioning

confidence: 99%

How well-connected is the surface of the global ocean?

Froyland

Stuart

Sebille

2014

Chaos: An Interdisciplinary Journal of Nonlinear Science

117

153

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“…For the averaging shown in Figures 2 and 3, we used data from a Sasaki et al [2008]. We used the results of 3 day snapshots over the period of 2011-2012 for this paper.…”

Section: Data Sourcementioning

confidence: 99%

Ocean variability east of Mindanao: Mooring observations at 7°N, revisited

2015

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Two subsurface moorings were deployed east of Mindanao Island, the Philippines, at 7°01′N, 126°55′E and 7°01′N, 127°46′E, at the location of the inshore and offshore cores of the Mindanao Undercurrent (MUC) suggested by past studies, from September 2011 to October 2012 and March 2013. A steady northward undercurrent, the MUC, was not confirmed by these observations, not only at the location of its inshore core but also of the offshore core. The observed mean flow at the mooring sites seems to be part of an anticyclonic eddy rather than the MUC. A particle‐tracking experiment using a high‐resolution general circulation model output showed that the northward mean flow, called the MUC by past studies, was too weak to advect water to the north. The Mindanao Current during 2011–2012 was weaker than during 1999–2002 because the sea surface height in the Philippine Sea during 2011–2012 was lower than that during 1999–2002. Intraseasonal variability with periods of 50–100 days was observed at the mooring sites, comparable to the previous observations during 1999–2002. Westward signal propagations were observed with periods and speeds of 50 days and 0.20 m s−1 at 300 m depth and of 60–72 days and 0.11–0.14 m s−1 at 960 m depth.

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“…The length of simulation was 20 yr, during which the model reached quasi-steady state. Along the southern and eastern open boundaries, climatological momentum and thermal fluxes from the Ocean General Circulation Model For the Earth Simulator (Sasaki et al, 2008) were implemented through the open boundary conditions of Gan and Allen (2005). The model was validated with observed sea surface temperature, dynamic height derived from Archiving, Validation, and Interpretation of Satellite Oceanographic data and other climatological mean conditions (Gan et al, 2013a).…”

Section: Model Descriptionmentioning

confidence: 99%

Inter-shelf nutrient transport from the East China Sea as a major nutrient source supporting winter primary production on the northeast South China Sea shelf

et al. 2013

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Abstract. The East China Sea (ECS) and the South China Sea (SCS) are two major marginal seas of the North Pacific with distinct seasonal variations of primary productivity. Based upon field observations covering both the ECS and the northern SCS (NSCS) during December 2008-January 2009, we examined southward long-range transport of nutrients from the ECS to the northeastern SCS (NESCS) carried by the China Coastal Current (CCC) driven by the prevailing northeast monsoon in wintertime. These escaped nutrients from the ECS shelf, where primary production (PP) was limited in winter, might however refuel the PP on the NESCS shelf at lower latitude, where the water temperature remained favorable, but river-sourced nutrients were limited. By combining the field observation of nitrate+nitrite (NO 3 +NO 2 , DIN) with our best estimate of volume transport of the CCC, we derived a first-order estimate for DIN flux of 1430 ± 1024 mol s −1 . Under the assumption that DIN was the limiting nutrient, such southward DIN transport would have stimulated 8.84 ± 6.33 × 10 11 gC of new production (NP), accounting for 33-74 % of the NP or 14-22 % of PP in winter on the NESCS shelf shallower than 100 m.

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An Eddy-Resolving Hindcast Simulation of the Quasiglobal Ocean from 1950 to 2003 on the Earth Simulator

Cited by 247 publications

References 43 publications

How well-connected is the surface of the global ocean?

How well-connected is the surface of the global ocean?

Ocean variability east of Mindanao: Mooring observations at 7°N, revisited

Inter-shelf nutrient transport from the East China Sea as a major nutrient source supporting winter primary production on the northeast South China Sea shelf

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