01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-04-0368 |
| Title of Abstract | Analysis of Seasonal and Interannual Variability of Surface Currents in the Northern Indian Ocean Using in-situ and Satellite products. |
| Authors | V. S. K. Rajan*, Sreelakshmi S, S. Prasanakumar, K. Jossia Joseph, Martin V Mathew, M Kalyani, Arul M. Muthiah |
| Organisation | National Institute of Ocean Technology |
| Address | kammattiparambil (H), Kumbalam Ernakulam, Kerala, India Pincode: 682506 E-mail: vaishnavsharun@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | Understanding ocean currents in the Indian Ocean is vital for forecasting, assessing climate varia-bility, and modelling regional circulation. Circulation in this basin is strongly influenced by mon-soonal winds, which drive seasonal reversals of surface currents. In this study, we integrate in situ Acoustic Doppler Current Profiler (ADCP) measurements from a moored buoy deployed in the southern Arabian Sea for the period 2012 to 2020. The in-situ measurements are also utilized for validating satellite-derived currents from OSCAR, and numerical outputs from the GLORYS12V1 reanalysis model, and to assess seasonal and interannual variability of surface currents. Seasonal summaries from GLORYS show circulation patterns across the basin in summer, winter, spring, and fall, providing context for point-based observations. To reduce spikes in variability, 30-day moving averages of current speeds from buoy measurements, OSCAR, and GLORYS were analysed for 2012⿿2020. The ADCP recorded stronger magnitudes and fluctuations, while OSCAR and GLORYS often underestimated speeds, especially during the northeast (winter) monsoon. De-spite these differences, all three datasets captured the seasonal cycle and directional reversals with minor phase offsets. To address directional variability, in-situ current speeds from 2019 were analysed with vectors superimposed on the time series to show the evolution of current direction and magnitude. De-composing ADCP currents into zonal (u) and meridional (v) components improved dataset agree-ment, with OSCAR and GLORYS aligning more closely with ADCP than in speed-only compari-sons. Significant deviations are being analysed to determine the influence of various meteorologi-cal conditions and upper ocean dynamics. These findings highlight the critical role of long-term in situ ADCP observations in validating sat-ellite and reanalysis data in the Indian Ocean. Such integrated approaches are crucial for maintain-ing ocean observing systems, improving seasonal forecasting, and understanding regional climate variability amidst changing conditions |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Indian Ocean, ADCP, OSCAR, GLORYS, monsoon currents, surface circulation, validation |
| For Awards | yes |
| Date Of Birth | 03-04-2000 |
| ECSN Registration Number | IIOE2-ECSN-0186 |