scholarly journals A Strong Kuroshio Intrusion into the South China Sea and Its Accompanying Cold-Core Anticyclonic Eddy in Winter 2020–2021

2021 ◽  
Vol 13 (14) ◽  
pp. 2645
Author(s):  
Zhenyu Sun ◽  
Jianyu Hu ◽  
Zhaozhang Chen ◽  
Jia Zhu ◽  
Longqi Yang ◽  
...  
Keyword(s):  
Kuroshio Current ◽  
Anticyclonic Eddy ◽  
Ekman Transport ◽  
Maximum Diameter ◽  
Current Loop ◽  
Coastal Current ◽  
Kuroshio Intrusion ◽  
Wind Stress Curl ◽  
The Kuroshio ◽  
Cold Core

Multiple remote sensing datasets, combined with in-situ drifter observations, were used to analyze the Kuroshio intrusion through the Luzon Strait (LS). The results showed that a strong Kuroshio Current Loop (KCL) and accompanying anticyclonic eddy (ACE) existed in winter 2020–2021. As quantitatively demonstrated by the Double Index (DI), the Kuroshio Warm Eddy Index (KWI) had low values during a long sustained period compared to those in all other years in the available historical records. Remarkable kinematic properties (i.e., amplitude, diameter, propagated distance, lifespan and propagating speed) of the accompanying ACE were extracted by automatic eddy detection algorithms, showing that the ACE had a maximum diameter of 381 km and a peak amplitude of 50 cm, which significantly exceeded the previous statistics in winter. The orographic negative wind stress curl southwest of Taiwan Island and the westward Ekman transport through the LS during the winter half year of 2020–2021 both had large values beyond their historical maxima. Hence wind forcing is regarded as the primary forcing mechanism during this event. Alternating cyclonic eddies (CEs) and ACEs approaching on the east of the LS were identified, indicating that the interaction between the Kuroshio and the impinging CEs at proper locations made extra contributions to enhancing the KCL. The accompanying ACE had a distinctive feature of a cold-core structure at the surface layer, so as to be categorized as a cold core ACE (CC-ACE), and the temperature difference between the cold core and outer warm ring was maintained for three months. The generation and long duration of the CC-ACE may be due to the sustaining entrainment supported by the warm water from Kuroshio intrusion and the Northwest Luzon Coastal Current (NWLCC) successively.

scholarly journals Impacts of the Kuroshio Intrusion through the Luzon Strait on the Local Precipitation Anomaly

2021 ◽  
Vol 13 (6) ◽  
pp. 1113
Author(s):  
Wen-Pin Fang ◽  
Ding-Rong Wu ◽  
Zhe-Wen Zheng ◽  
Ganesh Gopalakrishnan ◽  
Chung-Ru Ho ◽  
...  
Keyword(s):  
Kuroshio Current ◽  
Precipitation Anomaly ◽  
Luzon Strait ◽  
Sea Surface ◽  
Research Quality ◽  
Northwestern Pacific ◽  
Kuroshio Intrusion ◽  
Vertical Advection ◽  
Budget Analysis ◽  
The Kuroshio

The Kuroshio Current has its origin in the northwestern Pacific, flowing northward to the east of Taiwan and the northern part of Luzon Island. As the Kuroshio Current flows northward, it quasi-periodically intrudes (hereafter referred to as Kuroshio intrusion (KI)) into the northern South China Sea (SCS) basin through the Luzon Strait. Despite the complex generation mechanisms of KI, the purpose of this study is to improve our understanding of the effects of KI through the Luzon Strait on the regional atmospheric and weather variations. Long-term multiple satellite observations, including absolute dynamic topography, absolute geostrophic currents, sea surface winds by ASCAT, multi-scale ultra-high resolution sea surface temperature (MURSST) level-four analysis, and research-quality three-hourly TRMM multi-satellite precipitation analysis (TMPA), was used to systematically examine the aforementioned scientific problem. Analysis indicates that the KI is interlinked with the consequential anomalous precipitation off southwestern Taiwan. This anomalous precipitation would lead to ~560 million tons of freshwater influx during each KI event. Subsequently, independent moisture budget analysis suggests that moisture, mainly from vertical advection, is the possible source of the precipitation anomaly. Additionally, a bulk formula analysis was applied to understand how KI can trigger the precipitation anomaly through vertical advection of moisture without causing an evident change in the low-level flows. These new research findings might reconcile the divisiveness on why winds are not showing a synchronous response during the KI and consequential anomalous precipitation events.

scholarly journals Biogeographic Role of the Kuroshio Current Intrusion in the Microzooplankton Community in the Boundary Zone of the Northern South China Sea

2021 ◽  
Vol 9 (5) ◽  
pp. 1104
Author(s):  
Ping Sun ◽  
Silu Zhang ◽  
Ying Wang ◽  
Bangqin Huang
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Kuroshio Current ◽  
Equation Modeling ◽  
Rrna Gene ◽  
Kuroshio Intrusion ◽  
China Sea ◽  
Ciliate Community ◽  
The Kuroshio

Kuroshio Current intrusion (KCI) has significant impacts on the oceanographic conditions and ecological processes of the Pacific-Asian marginal seas. Little is known to which extent and how, specifically, the microzooplankton community can be influenced through the intrusion. Here, we focused on ciliates that often dominated the microzooplankton community and investigated their communities using high-throughput sequencing of 18S rRNA gene transcripts in the northern South China Sea (NSCS), where the Kuroshio Current (KC) intrudes frequently. We first applied an isopycnal mixing model to assess the fractional contribution of the KC to the NSCS. The ciliate community presented a provincial distribution pattern corresponding to more and less Kuroshio-influenced stations. Structural equation modeling revealed a significant impact of the KCI on the community, while environmental variables had a marginal impact. KCI-sensitive OTUs were taxonomically diverse but mainly belonged to classes Spirotrichea and Phyllopharyngea, suggesting the existence of core ciliates responding to the KCI. KCI-sensitive OTUs were grouped into two network modules that showed contrasting abundance behavior with the KC fraction gradient, reflecting differential niches (i.e., winner and loser) in the ciliate community during the Kuroshio intrusion scenarios. Our study showed that the Kuroshio intrusion, rather than environmental control, was particularly detrimental to the oligotrophic microzooplankton community.

scholarly journals The Kuroshio Onshore Intrusion along the Shelf Break of the East China Sea: The Origin of the Tsushima Warm Current

2006 ◽  
Vol 36 (12) ◽  
pp. 2205-2231 ◽  
Author(s):  
Xinyu Guo ◽  
Yasumasa Miyazawa ◽  
Toshio Yamagata
Keyword(s):  
Taiwan Strait ◽  
Density Field ◽  
Shelf Break ◽  
Ekman Transport ◽  
Kuroshio Intrusion ◽  
The East China Sea ◽  
Kuroshio Water ◽  
Warm Current ◽  
The Taiwan Strait ◽  
The Kuroshio

Abstract A 1/18° nested ocean model is used to determine locations, volume transports, and temporal variations of Kuroshio onshore fluxes across the shelf break of the East China Sea (ECS). The Kuroshio onshore flux shows strong seasonality: maximum (∼3 Sv; 1 Sv ≡ 106 m3 s−1) in autumn and minimum (<0.5 Sv) in summer. Another short-term (∼17 days) variation due to Kuroshio meanders introduces large fluctuations in the onshore fluxes but its seasonal average almost vanishes. The Kuroshio onshore fluxes have two major sources, Kuroshio intrusion northeast of Taiwan and Kuroshio separation southwest of Kyushu; the former provides larger onshore flux than the latter. Therefore, in addition to the waters from the Taiwan Strait and the Kuroshio separation region southwest of Kyushu, the water due to the Kuroshio intrusion northeast of Taiwan is also a major source of the Tsushima Warm Current. A vorticity equation is used to separate the contribution of surface Ekman transport to the Kuroshio onshore fluxes in the ECS from that relating to density fields. For the total Kuroshio onshore flux across the entire shelf break, its seasonal variation is primarily controlled by the Ekman transport while the change in density field is secondary. For the Kuroshio onshore flux at a fixed location along the shelf break, its seasonal variation is primarily related to the change in density field and the Ekman transport is secondary. Furthermore, the role of the Taiwan Strait water and the Kuroshio water across the shelf break on material transport in the ECS is examined with passive tracer experiments. In summer, about half of the tracer in the Tsushima Strait originates in the Taiwan Strait, while the other half comes from the Kuroshio. From summer to winter, the ratio changes dramatically; the contribution from the Taiwan Strait decreases to 20% and that from the Kuroshio increases up to 80%. The tracer originating in the Kuroshio water dominates the bottom layer of the continental shelf in the ECS throughout the year.

scholarly journals Zooplankton Fluctuations in the Surface Waters of the Estuary of a Large Subtropical Urban River

2021 ◽  
Vol 9 ◽  
Author(s):  
Pei-Wen Lee ◽  
Shih-Hui Hsiao ◽  
Chi Chou ◽  
Li-Chun Tseng ◽  
Jiang-Shiou Hwang
Keyword(s):  
Catchment Area ◽  
Seasonal Succession ◽  
Kuroshio Current ◽  
Coastal Current ◽  
Similar Data ◽  
Physico Chemical ◽  
Variable Chemical ◽  
Parvocalanus Crassirostris ◽  
First Time ◽  
The Kuroshio

The Danshuei River has a third largest catchment area and third longest in Taiwan. It flows through the capital, Taipei, and more than six million people live within its catchment area. Its estuary is characterized by a highly variable chemical and physical environment that is affected by the interaction of inland freshwater runoff with wastewater, and toward the coast is also influenced by the China Coastal Current and the Kuroshio Current. By collecting zooplankton bimonthly in 2014 from the surface layer (0–2 m depth) at five sites in the estuary, we were able to demonstrate that the composition of the zooplankton, and particularly its copepod fraction, varied significantly among sampling stations and months, thereby revealing seasonal succession. Fourteen higher taxa or other categories of zooplankter were identified, with the following being most common taxa: Decapoda, Copepoda (including Calanoida, Cyclopoida, and Harpacticoida), and “other larvae.” The Copepoda comprised 44 taxa (including eight only identified to genus) belonging to 3 orders, 17 families, and 29 genera, the five most abundant of which were Bestiolina n. sp. (undescribed), Corycaeus spp., Parvocalanus crassirostris, Acartia sp., and Paracalanus parvus. The highest and lowest copepod abundances were recorded in July (2557.88 inds. m–3) and January (1.3 inds. m–3), respectively. Observed changes in abundance of many kinds of copepod appeared to be significantly related to changes in physico-chemical parameters (e.g., salinity, temperature, pH, and dissolved oxygen concentration). Cluster analysis confirmed the existence of distinct copepod communities, each characterized by a preference for a different set of environmental conditions. Our comprehensive literature review of the copepod biodiversity of Taiwan’s major rivers for comparison with similar data compiled for other estuaries in the world, the first time such a review has been compiled, shows that 32 copepod taxa have been recorded from the brackish and freshwater parts of the Danshuei River. They represent 58.2% of the total number of brackish- and freshwater copepod species in Taiwan, and five of them have so far only been recorded in the Danshuei River: the calanoids Acartiella sinensis and Pseudodiaptomus forbesi, the cyclopoids Oithona fragilis and Oithona simplex, and the harpacticoid Tachidius (Tachidius) discipes.

Seasonal Variation of the Surface Kuroshio Intrusion into the South China Sea Evidenced by Satellite Geostrophic Streamlines

2021 ◽  
Author(s):  
Yisen Zhong ◽  
Meng Zhou ◽  
Joanna J. Waniek ◽  
Lei Zhou ◽  
Zhaoru Zhang
Keyword(s):  
Lateral Wall ◽  
Reanalysis Data ◽  
Frictional Stress ◽  
Kuroshio Intrusion ◽  
Wind Stress Curl ◽  
Positive Vorticity ◽  
Seasonal Characteristics ◽  
Axis Position ◽  
The Kuroshio

AbstractThe long-term satellite altimeter and reanalysis data show that large seasonal variations are associated with geostrophic Kuroshio intrusion, but not with the current intensity, width and axis position east of Philippine. To address this issue, we examine the seasonal variability of surface intrusion patterns by a new streamline-based method. The along-streamline analysis reveals that the seasonality of geostrophic intrusion is only attributed to the cyclonic shear part of the flow, while the anticyclonic shear part always leaps across the Luzon Strait. A possible physical mechanism is proposed to accommodate these seasonal characteristics based on globally the vorticity (torque work) balance between the basin-wide negative wind stress curl and the positive vorticity fluxes induced by the lateral wall, as well as locally loss of balance between the torques of frictional stresses and normal stresses owing to the boundary gap. Through modifying the nearshore sea surface level, the northeasterly/southeasterly monsoon increases/decreases the positive vorticity fluxes in response to global vorticity balance, and simultaneously amplifies/alleviates the local imbalance by enhancing/reducing the positive frictional stress torque within the cyclonic shear layer. Therefore, in winter when the positive torque is large enough, the Kuroshio splits and the intrusion occurs, while in summer the stress torque is so weak that the entire current keeps flowing north.

Chemical speciation of iron in the euphotic zone along the Kuroshio Current

2021 ◽  
Vol 233 ◽  
pp. 103966
Author(s):  
Mitsuhide Sato ◽  
Jun Nishioka ◽  
Kazuyuki Maki ◽  
Shigenobu Takeda
Keyword(s):  
Chemical Speciation ◽  
Euphotic Zone ◽  
Kuroshio Current ◽  
The Kuroshio

Growth pattern of the siliceous skeletons of living Spumellaria (Radiolaria) from the Kuroshio Current, offshore southwestern Shikoku Island, Japan

2021 ◽  
pp. 100504
Author(s):  
Rie S. Hori ◽  
Takenobu Shinki ◽  
Akihiro Iwakiri ◽  
Atsushi Matsuoka ◽  
Noritoshi Suzuki ◽  
...  
Keyword(s):  
Growth Pattern ◽  
Kuroshio Current ◽  
The Kuroshio

scholarly journals Review of the Japanese records of an endangered grouper, Epinephelus tukula, with comments on its population status (Teleostei, Serranidae)

ZooKeys ◽  
2018 ◽  
Vol 772 ◽  
pp. 153-163 ◽  
Author(s):  
Atsunobu Murase ◽  
Ryohei Miki ◽  
Masaaki Wada ◽  
Masahide Itou ◽  
Hiroyuki Motomura ◽  
...  
Keyword(s):  
Distribution Pattern ◽  
Continuous Distribution ◽  
Kuroshio Current ◽  
Red List ◽  
The Internet ◽  
Ryukyu Islands ◽  
Population Status ◽  
Warm Current ◽  
Japanese Waters ◽  
The Kuroshio

The Potato Grouper, Epinephelustukula, is relatively rare worldwide. Records from the northernmost part of its range (Japan) have been few, resulting in a “Critically Endangered” listing on the Red List for Japan. The Japanese records were revised by examining literature, new specimens, photographs, and the internet, and a continuous distribution pattern from the tropical Ryukyu Islands (including adult individuals) to temperate regions affected by the Kuroshio Current were delineated; this suggests the species inhabits tropical Japan and can spread to temperate regions via the warm current. The species possibly reproduces in Japanese waters but further reproductive ecology research is required.

Sign in / Sign up

Export Citation Format

Share Document