Energy Transfer in the Western Tropical Pacific

Abstract

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Bi‐Directional Energy Cascades in the Pacific Ocean From Equator to Subarctic Gyre

“…That the separation scale L S in both the NEC and equatorial bands of the western tropical Pacific is on the order of 200 ∼ 300 km, is consistent with the high‐resolution regional model study by Zedler et al. (2019). In terms of the dissipation rate in the forward cascade range, the NEC band has an inferred $$\varepsilon =$$ 0.3 × 10 −8 m 2 /s 3 rate similar to the equatorial band.…”

“…Notice that because the flow field in this band is so depleted of the balanced eddy variability, 𝐴𝐴 𝐴𝐴3𝐿𝐿(𝑟𝑟) remains negative until reaches 300 km (Figure 3h). That the separation scale L S in both the NEC and equatorial bands of the western tropical Pacific is on the order of 200 ∼ 300 km, is consistent with the high-resolution regional model study by Zedler et al (2019). In terms of the dissipation rate in the forward cascade range, the NEC band has an inferred 𝐴𝐴 𝐴𝐴= 0.3 × 10 −8 m 2 /s 3 rate similar to the equatorial band.…”

Nonlinear Short-Term Upper Ocean Circulation Variability in the Tropical Western Pacific

“…The first objective is to provide large-scale upper ocean circulation variability context for intensive nearfield observations conducted around Palau during 2016-2017 as part of the Office of Naval Research (ONR) Departmental Research Initiative (DRI) project Flow Encountering Abrupt Topography (FLEAT). Regarding this objective, our study complements the articles of Schönau et al (2019), Andres et al (2019), and Zedler et al (2019) in this issue. The second objective of this study is to quantify the relative importance of basin-scale wind-forced variability in circulation versus that induced by nonlinear dynamical processes that originate from the interaction between the wind-forced baroclinic Rossby waves and the background NECC in the tropical western Pacific Ocean.…”

Stirring and Mixing in the Wake of Angaur and Peleliu Islands, Palau

“…Palau is well suited for studies of such processes because its islands and submarine ridges are situated between the westward North Equatorial Current (NEC) and the eastward North Equatorial Countercurrent (NECC; Figure 1a). In Palau, wake eddies from 1 to 100 km scales and lee waves at 1‐km scales have been observed and modeled at the north and south points along with some estimates of their dissipation and drag on the total flow, which is often a combination of tidal, inertial, and lower‐frequency flows (Andres et al., 2020; Gopalakrishnan & Cornuelle, 2019; Johnston, MacKinnon, et al., 2019; MacKinnon et al., 2019; Merrifield et al., 2019; Rudnick et al., 2019; Siegelman et al., 2019; Simmons et al., 2019; St. Laurent et al., 2019; Voet et al., 2020; Wijesekera et al., 2020; Zedler et al., 2019; Zeiden et al., 2019, 2021).…”

“…For large Rossby numbers ( Ro = U / fL , where the Coriolis frequency is f ), both meso‐ and submesoscale anticyclonic eddies become unstable and produce vorticity streaks at the south point during westward flow, while at the north point a street of distinct cyclonic eddies extends at least 100 km downstream (Dong et al., 2007; Johnston, MacKinnon, et al., 2019; MacKinnon et al., 2019; Simmons et al., 2019; White & Helfrich, 2013). The models of Palau with <1 km resolution and the lowest k h display submesoscale wakes, while coarser resolution models with larger k h resolve the mesoscale wake with scales typical of the topographic extent (1–100 km; Gopalakrishnan & Cornuelle, 2019; Johnston, MacKinnon, et al., 2019; Johnston, Schönau, et al., 2019; Simmons et al., 2019; Zedler et al., 2019).…”