Ekman dynamics variability along the southern coast of Java revealed by satellite data. Issue 21 (1st November 2020)

• Record Type: Journal Article
• Authors: Wirasatriya, Anindya; Setiawan, Joga Dharma; Sugianto, Denny Nugroho; Rosyadi, Insan Alfi; Haryadi, Haryadi; Winarso, Gathot; Setiawan, Riza Yuliratno; Susanto, R. Dwi
• Is Part Of: International journal of remote sensing. Volume 41:Issue 21(2020)
• Page Start: 8475
• Page End: 8496
• Publication Date: 2020-11-01
• Subjects: Remote sensing -- Periodicals; Télédétection -- Périodiques; 621.3678
• DOI: 10.1080/01431161.2020.1797215
• Languages: English
• ISSNs: 0143-1161

Abstract

ABSTRACT: It has been widely known that the coastal upwelling along the southern coast of Java is generated by southeasterly wind which induces offshore Ekman Mass Transport (EMT) during southeast monsoon. However, the variability of EMT has not been fully described in previous studies. The present study investigated the variability of Ekman dynamics which consist of EMT and Ekman Pumping Velocity (EPV) along the southern coast of Java, based on remotely sensed data. We demonstrated the incongruity between the distribution of southeasterly wind speed and sea surface temperature (SST) during southeast monsoon which is related to the distribution of Ekman dynamics. Offshore EMT at the western region of the southern coast of Java is stronger than offshore EMT at the eastern region. However, stronger offshore EMT at the western part is inhibited by downwelling EPV while weaker offshore EMT at the eastern part is accelerated by upwelling EPV. Consequently, SSTs at the eastern parts are lower than those at the western parts. Thus, the changes of offshore EMT intensity from eastern to western parts are balanced by their EPV distributions which explain the incongruity between the distribution of wind speed and SST during southeast monsoon. On an interannual timescale, the combination of La Niña and negative Indian Ocean Dipole (IOD) events tends to weaken offshore EMT and EPV which reduce the intensity of Chl- a bloom and SST cooling during southeast monsoon season. Furthermore, ENSO has a less significant impact on the Ekman dynamics variability than IOD.