Coastal currents from Jason-2 and SARAL/AltiKa in the Indian region

ABSTRACT

In this study, data from space-based altimeters (Jason-2 and Satellite for ARgos and AltiKa [SARAL/AltiKa]) have been used to compute alongshore geostrophic currents in the coastal regions of the Indian mainland. These derived currents are compared with high-frequency (HF) radar observations. Beyond 30–40 km away from the coastline, altimeter-derived currents match fairly well with the HF radar data. Root mean square error (RMSE) of Jason-2-derived currents ranges between 0.3 and 0.6 m s⁻¹ while the same in the case of SARAL/AltiKa lies between 0.3 and 0.7 m s⁻¹. Satellite-derived across-track geostrophic current components (alongshore current) were also used to study the spatiotemporal variations of the east India coastal current (EICC). The coastal trapping of the EICC, its annual and intra-seasonal peaks are clearly observed in the power spectrum of time-series of Jason-2 and SARAL/AltiKa derived currents.

Acknowledgements

Authors sincerely thank the Director, Space Applications Centre (SAC), the Group Director AOSG, SAC for their encouragement and support. HF radar data were thankfully obtained from the ESSO-Indian National Centre for Ocean Information Services (INCOIS). The preview of this dataset is available at http://www.incois.gov.in/portal/datainfo/hfradar.jsp. This study has been conducted using altimetry dataset downloaded from E.U. Copernicus Marine Environment Monitoring Service (CMEMS; http://marine.copernicus.eu). The authors also like to acknowledge the two anonymous reviewers whose constructive comments have improved the quality of our manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.