Water Mass Analysis of the East China Sea and Interannual Variation of Kuroshio Subsurface Water Intrusion Through an Optimum Multiparameter Method

Zhou, Ping; Song, Xiuxian; Yuan, Yunbin; Cao, Xihua; Wang, Wentao; Chi, Lianbao; Yu, Zhiming

doi:10.1029/2018jc013882

Cited by 37 publications

(29 citation statements)

References 72 publications

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“…During an OMPA, the fraction of each water mass must be non-negative (Acharya and Panigrahi 2016). Though the extent that water mass properties are conservative across a transect varies (Zhou et al 2018a), classical OMPA has been used and described in a number of other oceanographic studies (Tomczak and Large 1989;Karstensen and Tomczak 1997;Poole and Tomczak 1999;Kim et al 2010;Zhang et al 2012;Acharya and Panigrahi 2016). Nevertheless, chemical parameters such as oxygen, phosphate, and nitrate are often only semi-conservative across large distances due to biological metabolisms.…”

Section: Ompa Theory and Applicationmentioning

confidence: 99%

“…1). While the appearance of iodide would be expected as an indicator for the absence of oxygen, lateral advection of iodide from reducing shelf sediments complicates this analysis (Moriyasu et al 2019;Cutter et al 2018;Zhou et al 2018a). The distribution of iodide within the oxygen deficient layer is depicted in Fig.…”

Section: Coupling Between the Nitrogen And Iodine Cycles In Low Oxygementioning

confidence: 99%

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The role of water masses in shaping the distribution of redox active compounds in the Eastern Tropical North Pacific oxygen deficient zone and influencing low oxygen concentrations in the eastern Pacific Ocean

Evans

Boles

Kwiecinski

et al. 2020

Limnology & Oceanography

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Oceanic oxygen deficient zones (ODZs) influence global biogeochemical cycles in a variety of ways, most notably by acting as a sink for fixed nitrogen (Codispoti et al. 2001). Optimum multiparameter analysis of data from two cruises in the Eastern Tropical North Pacific (ETNP) was implemented to develop a water mass analysis for the large ODZ in this region. This analysis reveals that the most pronounced oxygen deficient conditions are within the 13 C water (13CW) mass, which is distributed via subsurface mesoscale features such as eddies branching from the California Undercurrent. Nitrite accumulates within these eddies and slightly below the core of the 13CW. This water mass analysis also reveals that the 13CW and deeper Northern Equatorial Pacific Intermediate Water (NEPIW) act as the two Pacific Equatorial source waters to the California Current System. The Equatorial Subsurface Water and Subtropical Subsurface Water are synonymous with the 13CW and this study refers to this water mass as the 13CW based on its history. Since the 13CW has been found to dominate the most pronounced oxygen deficient conditions within the Eastern Tropical South Pacific ODZ and the Peru-Chile Undercurrent, the 13CW and the NEPIW define boundaries for oxygen minimum conditions across the entire eastern Pacific Ocean.

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Section: Ompa Theory and Applicationmentioning

confidence: 99%

Section: Coupling Between the Nitrogen And Iodine Cycles In Low Oxygementioning

confidence: 99%

The role of water masses in shaping the distribution of redox active compounds in the Eastern Tropical North Pacific oxygen deficient zone and influencing low oxygen concentrations in the eastern Pacific Ocean

Evans

Boles

Kwiecinski

et al. 2020

Limnology & Oceanography

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“…Vertical stratification varied considerably over time according to the movements of the Changjiang River plume and the strength of the Kuroshio subsurface water intrusion. The intrusion of the Kuroshio subsurface water introduces low‐temperature, high‐salinity water to the bottom of the East China Sea (Zhou et al, ). The water temperatures at the bottom of the Submarine Canyon and beyond were significantly lower than that of the Yangtze Bank (Figure S2 in the supporting information).…”

Section: Resultsmentioning

confidence: 99%

“…The strength of the Kuroshio subsurface water intrusion also contributes to the evolution of the stratification on which bottom hypoxia formation and sustainment depend. The Kuroshio is generally stronger in the summer (e.g., Yang et al, ); it provides a large amount of water mass to the East China Sea, which is far larger than the Changjiang River discharge (Zhou et al, ). The strength of the Kuroshio subsurface water intrusion determined its exchange with the ambient water over the shelf.…”

Section: Discussion: Factors Controlling the Establishment Of Summer mentioning

confidence: 99%

On Mechanisms Controlling the Seasonal Hypoxia Hot Spots off the Changjiang River Estuary

Zhang

Hetland

et al. 2019

JGR Oceans

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Large areas of seasonal hypoxia have been detected off the Changjiang River Estuary over the last decade. Although seasonal bottom hypoxia was transient due to complex dynamical processes, it occurred with high frequency in certain regions. Summer hypoxia hot spots off the estuary were first identified using a comprehensive, high-resolution ecosystem model and 17 years of observations collected from historical literature and research cruises. Comparisons between long-term observations, a 4-year averaged simulation, and a 1-year simulation implied that the geographical locations of summer hypoxia hot spots were generally consistent. This ecosystem model suggested that the Changjiang River plume predominantly spread either over the Yangtze Bank or the Submarine Canyon and the Mud Belt depending on the direction of the wind; the temperature, salinity, and residence time of bottom water mass off the estuary depended highly on the properties of the Kuroshio subsurface intrusion. The dual effects of stratification and prolonged bottom water residence time created favorable condition for hypoxia to develop. The analysis in this study identified wind and the Kuroshio subsurface intrusion as the factors that facilitated the migration of seasonal hypoxia and the establishment of summer hypoxia hot spots off the estuary. In spite of the persistent hypoxia hot spots, the timing of individual hypoxia can be variable because of distinct dynamical processes over a wide range of time scales. Tidal advection was quantified as a secondary factor that influences the spatial extent and migration of bottom hypoxia. Key Points:• Summer hypoxia hot spots off the estuary were identified based on both observed and modeled data • The geographical locations of summer hypoxia hot spots were persistent from year to year • Wind and Kuroshio subsurface intrusion were main factors facilitating the establishment of hot spots Supporting Information:• Supporting Information S1

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“…The scale of the typhoon-induced SST drop depends on the typhoon's characteristics, such as the intensity measured by the maximum surface wind speed, moving speed and size. Zhu and Zhang (2006) quantified the influence of SST variability on typhoon intensity using a numerical model. However, this is not the case for the coastal ocean at Longdong.…”

Section: Typhoon Intensitymentioning

confidence: 99%

Field investigations of coastal sea surface temperature drop after typhoon passages

Doong

Peng

Babanin

2019

Earth Syst. Sci. Data

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Abstract. Sea surface temperature (SST) variability affects marine ecosystems, fisheries, ocean primary productivity and human activities and is the primary influence on typhoon intensity. SST drops of a few degrees in the open ocean after typhoon passages have been widely documented; however, few studies have focused on coastal SST variability. The purpose of this study is to determine typhoon-induced SST drops in the near-coastal area (within 1 km of the coast) and understand the possible mechanism. The results of this study were based on extensive field data analysis. Significant SST drop phenomena were observed at the Longdong Buoy in northeastern Taiwan during 43 typhoons over the past 20 years (1998–2017). The mean SST drop (ΔSST) after a typhoon passage was 6.1 ∘C, and the maximum drop was 12.5 ∘C (Typhoon Fungwong in 2008). The magnitude of the SST drop was larger than most of the observations in the open ocean. The mean duration of the SST drop was 24 h, and on average, 26.1 h were required for the SST to recover to the original temperature. The coastal SST drops at Longdong were correlated with the moving tracks of typhoons. When a typhoon passes south of Longdong, the strong and persistent longshore winds induce coastal upwelling and pump cold water up to the surface, which is the dominant cause of the SST drops along the coast. In this study, it was determined that cold water mainly intruded from the Kuroshio subsurface into the Okinawa Trough, which is approximately 50 km from the observation site. The magnitude of coastal SST drops depends on the area of overlap between typhoons generating strong winds and the Kuroshio. The dataset used in this study can be accessed from https://doi.org/10.1594/PANGAEA.895002.

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Water Mass Analysis of the East China Sea and Interannual Variation of Kuroshio Subsurface Water Intrusion Through an Optimum Multiparameter Method

Cited by 37 publications

References 72 publications

The role of water masses in shaping the distribution of redox active compounds in the Eastern Tropical North Pacific oxygen deficient zone and influencing low oxygen concentrations in the eastern Pacific Ocean

The role of water masses in shaping the distribution of redox active compounds in the Eastern Tropical North Pacific oxygen deficient zone and influencing low oxygen concentrations in the eastern Pacific Ocean

On Mechanisms Controlling the Seasonal Hypoxia Hot Spots off the Changjiang River Estuary

Field investigations of coastal sea surface temperature drop after typhoon passages

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