Physical processes leading to the development of an anomalously large Cochlodinium polykrikoides bloom in the East sea/Japan sea

Kim, Dae-Won; Jo, Young‐Heon; Choi, Jong-Kuk; Choi, Jiwon; Bi, Hongsheng

doi:10.1016/j.hal.2016.03.019

Cited by 17 publications

(11 citation statements)

References 42 publications

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“…[] relied on several days ship time to map the eddy flow field in this region. An improved understanding of the currents to the east of the Korean peninsula is essential for monitoring the transport of harmful algae [ Kim et al ., ], so all techniques that give high‐resolution quantitative information on the flow field will assist in the prediction of such blooms.…”

Section: Potential Oceanographic Applicationsmentioning

confidence: 99%

Estimation of ocean surface currents from maximum cross correlation applied to GOCI geostationary satellite remote sensing data over the Tsushima (Korea) Straits

et al. 2016

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Attempts to automatically estimate surface current velocities from satellite‐derived thermal or visible imagery face the limitations of data occlusion due to cloud cover, the complex evolution of features and the degradation of their surface signature. The Geostationary Ocean Color Imager (GOCI) provides a chance to reappraise such techniques due to its multiyear record of hourly high‐resolution visible spectrum data. Here we present the results of applying a Maximum Cross Correlation (MCC) technique to GOCI data. Using a combination of simulated and real data we derive suitable processing parameters and examine the robustness of different satellite products, those being water‐leaving radiance and chlorophyll concentration. These estimates of surface currents are evaluated using High Frequency (HF) radar systems located in the Tsushima (Korea) Strait. We show the performance of the MCC approach varies depending on the amount of missing data and the presence of strong optical contrasts. Using simulated data it was found that patchy cloud cover occupying 25% of the image pair reduces the number of vectors by 20% compared to using perfect images. Root mean square errors between the MCC and HF radar velocities are of the order of 20 cm s−1. Performance varies depending on the wavelength of the data with the blue‐green products out‐performing the red and near infra‐red products. Application of MCC to GOCI chlorophyll data results in similar performance to radiances in the blue‐green bands. The technique has been demonstrated using specific examples of an eddy feature and tidal induced features in the region.

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Section: Potential Oceanographic Applicationsmentioning

confidence: 99%

Estimation of ocean surface currents from maximum cross correlation applied to GOCI geostationary satellite remote sensing data over the Tsushima (Korea) Straits

et al. 2016

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“…This seawater with high nutrient and chlorophyll levels is transported north of Ulleungdo by the EKWC. Due to these characteristics, the East/Japan Sea is considered an important biogeochemical research region (Joo et al, 2014;Kim et al, 2016;Shin et al, 2017). Thus, we selected a point in the East/Japan Sea (130.0˚E, 38.0˚N) where the EKWC and NKCC meet (Fig.…”

Section: Resultsmentioning

confidence: 99%

A single-column ocean-biogeochemistry model (GOTM-TOPAZ) version 1.0

Jung¹,

Moon²,

Wie³

et al. 2018

Preprint

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Abstract. Recently, Earth System Models (ESMs) have begun to consider the marine ecosystem to reduce errors in climate simulations. However, many models are unable to fully represent the ocean biology-induced climate feedback, which is due in part to a significant amount of bias in the simulated biogeochemical properties. We developed the Generic Ocean Turbulence Model–Tracers of Phytoplankton with Allometric Zooplankton (GOTM-TOPAZ) model, a single-column ocean-biogeochemistry model, which can be used to improve the ocean-biogeochemical processes of ESMs. This model was developed by combining GOTM, a single-column model (SCM) that can simulate the ocean's physical environment, and TOPAZ, a biogeochemical module. Here, the original form of TOPAZ was modified and modularized to allow easy coupling with other ocean physical models. For interactions between the ocean physics and biogeochemical processes, the model was designed to allow the ocean temperature to change due to absorption of visible light by phytoplankton chlorophyll. We also added a module to reproduce upwelling and the air-sea gas transfer process for O2 and CO2, which are of particular importance for marine ecosystems. To evaluate the simulation performance of GOTM-TOPAZ, simulated variables (e.g., chlorophyll, oxygen, nitrogen, phosphorus, silicon) were compared against observations. Our newly developed GOTM-TOPAZ model was able to capture the observed the temporal variations of upper-ocean chlorophyll reasonably well. Moreover, the simulated levels of dissolved oxygen, nitrogen, phosphorus, and silicon were consistent with the observations, which confirmed that GOTM-TOPAZ is reliable enough to be used in studies on climate systems. In particular, the TOPAZ module developed in this study may be used to couple complex biogeochemical processes with various ocean global circulation models and contribute to improved understanding of the feedback between climate and ocean-biogeochemical processes.

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“…NKCC flows along the east coast from the northwest of the East Sea to the south, whereas EKWC flows along the east coast of the Korean Peninsula from the southwest of the East Sea to the north. Phytoplankton have no swimming ability and mainly remain in the sea surface layer, and so their horizontal distribution can be determined from the sea surface currents (Kim et al, ; Onitsuka et al, ). Consequently, we considered that the phytoplankton affected by coastal upwelling was likely advected to the sampling sites by the sea surface current.…”

Section: Methodsmentioning

confidence: 99%

Variability of Phytoplankton Size Structure in Response to Changes in Coastal Upwelling Intensity in the Southwestern East Sea

et al. 2017

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The aim of this study was to examine the size structure of phytoplankton under varying coastal upwelling intensities and to determine the resulting primary productivity in the southwestern East Sea. Samples of phytoplankton assemblages were collected on five occasions from the Hupo Bank, off the east coast of Korea, during 2012–2013. Because two major surface currents have a large effect on water mass transport in this region, we first performed a Backward Particle Tracking Experiment (BPTE) to determine the coastal sea from which the collected samples originated according to advection time of BPTE particles, following which we used upwelling age (UA) to determine the intensity of coastal upwelling in the region of origin for each sample. Only samples that were affected by coastal upwelling in the region of origin were included in subsequent analyses. We found that as UA increased, there was a decreasing trend in the concentration of picophytoplankton, and increasing trends in the concentration of nanophytoplankton and microphytoplankton. We also examined the relationship between the size structure of phytoplankton and primary productivity in the Ulleung Basin (UB), which has experienced significant variation over the past decade. We found that primary productivity in UB was closely related to the strength of the southerly wind, which is the most important mechanism for coastal upwelling in the southwestern East Sea. Thus, the size structure of phytoplankton is determined by the intensity of coastal upwelling, which is regulated by the southerly wind, and makes an important contribution to primary productivity.

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Physical processes leading to the development of an anomalously large Cochlodinium polykrikoides bloom in the East sea/Japan sea

Cited by 17 publications

References 42 publications

Estimation of ocean surface currents from maximum cross correlation applied to GOCI geostationary satellite remote sensing data over the Tsushima (Korea) Straits

Estimation of ocean surface currents from maximum cross correlation applied to GOCI geostationary satellite remote sensing data over the Tsushima (Korea) Straits

A single-column ocean-biogeochemistry model (GOTM-TOPAZ) version 1.0

Variability of Phytoplankton Size Structure in Response to Changes in Coastal Upwelling Intensity in the Southwestern East Sea

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