A Strong Kuroshio Intrusion into the South China Sea and Its Accompanying Cold-Core Anticyclonic Eddy in Winter 2020–2021
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 quantitativel...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-07-01
|
| Series: | Remote Sensing |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2072-4292/13/14/2645 |
| _version_ | 1797526124954124288 |
|---|---|
| author | Zhenyu Sun Jianyu Hu Zhaozhang Chen Jia Zhu Longqi Yang Xirong Chen Xuewen Wu |
| author_facet | Zhenyu Sun Jianyu Hu Zhaozhang Chen Jia Zhu Longqi Yang Xirong Chen Xuewen Wu |
| author_sort | Zhenyu Sun |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-10T09:25:43Z |
| format | Article |
| id | doaj.art-767d8b305c1b4512915188f21657e54d |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T09:25:43Z |
| publishDate | 2021-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-767d8b305c1b4512915188f21657e54d2023-11-22T04:50:17ZengMDPI AGRemote Sensing2072-42922021-07-011314264510.3390/rs13142645A Strong Kuroshio Intrusion into the South China Sea and Its Accompanying Cold-Core Anticyclonic Eddy in Winter 2020–2021Zhenyu Sun0Jianyu Hu1Zhaozhang Chen2Jia Zhu3Longqi Yang4Xirong Chen5Xuewen Wu6State Key Laboratory of Marine and Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, ChinaState Key Laboratory of Marine and Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, ChinaState Key Laboratory of Marine and Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, ChinaState Key Laboratory of Marine and Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, ChinaState Key Laboratory of Marine and Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, ChinaState Key Laboratory of Marine and Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, ChinaState Key Laboratory of Marine and Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, ChinaMultiple 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.https://www.mdpi.com/2072-4292/13/14/2645Kuroshio intrusionKuroshio Current Loopcold-core anticyclonic eddy |
| spellingShingle | Zhenyu Sun Jianyu Hu Zhaozhang Chen Jia Zhu Longqi Yang Xirong Chen Xuewen Wu A Strong Kuroshio Intrusion into the South China Sea and Its Accompanying Cold-Core Anticyclonic Eddy in Winter 2020–2021 Remote Sensing Kuroshio intrusion Kuroshio Current Loop cold-core anticyclonic eddy |
| title | A Strong Kuroshio Intrusion into the South China Sea and Its Accompanying Cold-Core Anticyclonic Eddy in Winter 2020–2021 |
| title_full | A Strong Kuroshio Intrusion into the South China Sea and Its Accompanying Cold-Core Anticyclonic Eddy in Winter 2020–2021 |
| title_fullStr | A Strong Kuroshio Intrusion into the South China Sea and Its Accompanying Cold-Core Anticyclonic Eddy in Winter 2020–2021 |
| title_full_unstemmed | A Strong Kuroshio Intrusion into the South China Sea and Its Accompanying Cold-Core Anticyclonic Eddy in Winter 2020–2021 |
| title_short | A Strong Kuroshio Intrusion into the South China Sea and Its Accompanying Cold-Core Anticyclonic Eddy in Winter 2020–2021 |
| title_sort | strong kuroshio intrusion into the south china sea and its accompanying cold core anticyclonic eddy in winter 2020 2021 |
| topic | Kuroshio intrusion Kuroshio Current Loop cold-core anticyclonic eddy |
| url | https://www.mdpi.com/2072-4292/13/14/2645 |
| work_keys_str_mv | AT zhenyusun astrongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT jianyuhu astrongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT zhaozhangchen astrongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT jiazhu astrongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT longqiyang astrongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT xirongchen astrongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT xuewenwu astrongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT zhenyusun strongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT jianyuhu strongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT zhaozhangchen strongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT jiazhu strongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT longqiyang strongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT xirongchen strongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 AT xuewenwu strongkuroshiointrusionintothesouthchinaseaanditsaccompanyingcoldcoreanticycloniceddyinwinter20202021 |