Complementary Use of Glider Data, Altimetry, and Model for Exploring Mesoscale Eddies in the Tropical Pacific Solomon Sea

Gourdeau, Lionel; Verron, Jacques; Chaigneau, Alexis; Cravatte, Sophie; Kessler, William S.

doi:10.1002/2017jc013116

Cited by 10 publications

(8 citation statements)

References 37 publications

(74 reference statements)

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“…Their typical signature on temperature, salinity, and velocities are weak (±0.6°C, ±0.1, and 10 cm s −1 , respectively); they do not appear to be able to trap and transport waters, but AE seem to contribute to the mixing of these upper waters, in and below the mixed layer. This is consistent with the recent investigations of eddy properties inside the nearby Solomon Sea (Gourdeau et al, ). It is also consistent with previous conclusions, highlighting that at these latitudes, equatorward of 20°, most of the propagating energy is in the form of linear Rossby waves, not of nonlinear eddies.…”

Section: Discussionsupporting

confidence: 94%

Observed Characteristics and Vertical Structure of Mesoscale Eddies in the Southwest Tropical Pacific

et al. 2018

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In the Southwest Pacific Ocean, waters transit from the subtropical gyre before being redistributed equatorward and poleward. While the mean pathways are known, the contribution to the mixing and transport of the water from mesoscale eddies has not been comprehensively investigated. In this research, satellite altimetry data, combined with an eddy detection and tracking algorithm is used to investigate the distribution and surface characteristics of mesoscale eddies in this region of complex bathymetry (10°S–30°S, 140°E–190°E). Detected eddies are then colocalized with in situ data from Argo floats to determine their vertical structure and the effect of eddies on the water masses. The numerous islands affect the eddy behavior as most eddies are formed in the lee of islands, propagate westward and decay when encountering shallow bathymetry. Eddies are sparse and short‐lived in the tropical area north of Fiji, impacting only the top 200 meters of water. They do not appear to be able to trap and transport waters in this region. In the Coral Sea, a region of lateral shear between currents transporting waters of different origins, eddies are more numerous and energetic. They affect the water properties down to at least 500 m depth, and anticyclonic eddies trap water to ∼200 m, contributing to the upper thermocline waters mixing and transport. South of New Caledonia, mesoscale eddies are ubiquitous, with typical lifetimes longer than 5 months. They affect the temperature, salinity, and velocities down to ∼1,000 m depth, and weakly contribute to the mixing of lower thermocline waters.

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Section: Discussionsupporting

confidence: 94%

Observed Characteristics and Vertical Structure of Mesoscale Eddies in the Southwest Tropical Pacific

et al. 2018

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“…Potential temperature versus salinity relationships from the 2012 to 2017 mooring deployments at the Misima (western side) and Gizo (eastern side) sites shows a lower salinity range in the water column at Gizo relative to that at Misima (Figure ), similar to the salinity profiles measured by gliders (Gourdeau et al, ). The signature of the South Pacific Tropical Water (SPTW), identified by a salinity maximum at σ θ = 24.5, is apparent at both locations.…”

Section: Mean and Variability Of The Ngcc And Ngcusupporting

confidence: 88%

“…Our observations show the abundance of the extreme transport events during the 2015/2016 El Niño (the end of 2014 to August 2015; Figure a) suggesting that the events are not related to the presence of mesoscale eddies. Also, the extreme transport events are often associated with sudden changes in both the surface and thermocline layers (Figure b), while the eddies are thought to intensify roughly over the upper 150 m (Gourdeau et al, ; Hristova et al, ).…”

Section: Mean and Variability Of The Ngcc And Ngcumentioning

confidence: 99%

Mooring and Seafloor Pressure End Point Measurements at the Southern Entrance of the Solomon Sea: Subseasonal to Interannual Flow Variability

et al. 2019

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Variability of the flow across the Solomon Sea's southern entrance was examined using end point subsurface moorings and seafloor pressure sensors, reconstructed velocity profiles based on satellite‐derived surface velocity and bottom pressure‐derived subsurface velocity, and 1993–2017 proxy volume transport based on satellite altimetry. The reconstructed velocity correctly represents the fluctuating surface flow and subsurface core providing a high‐frequency continuous observing system for this sea. The mean equatorward volume transport over 0‐ to 500‐m depth layer is 15.2 Sv (1 Sv ≡ 106 m3/s) during July 2012 to May 2017. The measurements resolve the full spectrum of the volume transport including energetic subseasonal variability that fluctuates by as much as 25 Sv over one week. At low‐frequency timescales, the study finds that linear Rossby waves forced by Ekman pumping in the interior of the Pacific influence not only seasonal fluctuations as found by previous studies but also interannual variability. As found previously, the El Niño–Southern Oscillation highly influences interannual volume transport. During the 2015/2016 El Niño, observations show the seasonal cycle to be suppressed from the second half of 2014, prior to the mature phase of the El Niño, to September 2016 along with an increase in across‐transect transport. At subseasonal timescales, local Ekman pumping and remote wind stress curl are responsible for a third of the subseasonal variance. The study highlights the importance of high‐frequency observations at the southern entrance of the Solomon Sea and the ability of a linear Rossby model to represent the low‐frequency variability of the transport.

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“…Other dynamical features, such as mesoscale eddies, may have a stronger influence on transport variability across Solomon Strait East, potentially responsible for the enhanced variance observed at intraseasonal time scales. Both observations (Gourdeau et al., ; Melet et al, ) and simulations (Djath et al., ; Hristova et al., ; Srinivasan et al., ) indicate that mesoscale and submesoscale eddies are enhanced at Solomon Strait and are a likely source of intraseasonal transport variability.…”

Section: Discussionmentioning

confidence: 98%

Moored Observations of Transport in the Solomon Sea

et al. 2019

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The Solomon Sea is a marginal sea in the western Pacific warm pool that contains the South Pacific low latitude western boundary currents. These low latitude western boundary currents chiefly exit the Solomon Sea through three channels (Vitiaz Strait, St. George's Channel, and Solomon Strait) and serve as the primary source water for the Equatorial Undercurrent. Simulations have shown that transport partitioning between the straits determines the water mass structure of the Equatorial Undercurrent, but the relative contributions of transport through each strait have not been observed before. As part of the Southwest Pacific Ocean Circulation and Climate Experiment, an array of moorings was deployed simultaneously in the three outflow channels of the Solomon Sea from July 2012 until March 2014 to resolve transport and water properties in each strait. Above deep isopycnals (σ0 ≤ 27.5), Vitiaz and Solomon Straits account for 54.2% and 36.2% of the mean transport, respectively, with the remaining 9.6% exiting through St. George's Channel. The strongest subinertial transport variability is observed in Solomon Strait and dominates total Solomon Sea transport variability, and a significant fraction of this variability is at intraseasonal time scales. Finally, a previously unobserved deep current at 1,500‐m depth is found to enter the Solomon Sea through Solomon Strait, with a deployment‐mean transport of 4.6 Sv (Sv ≡106 m3/s).

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Complementary Use of Glider Data, Altimetry, and Model for Exploring Mesoscale Eddies in the Tropical Pacific Solomon Sea

Cited by 10 publications

References 37 publications

Observed Characteristics and Vertical Structure of Mesoscale Eddies in the Southwest Tropical Pacific

Observed Characteristics and Vertical Structure of Mesoscale Eddies in the Southwest Tropical Pacific

Mooring and Seafloor Pressure End Point Measurements at the Southern Entrance of the Solomon Sea: Subseasonal to Interannual Flow Variability

Moored Observations of Transport in the Solomon Sea

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