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Characterization of the East India Coastal Current using a Drifter, HF Radars and Altimetry during October -- November 2015
  • Paban Bhuyan,
  • Samiran Mandal,
  • Sourav Sil
Paban Bhuyan
Indian Institute of Technology Bhubaneswar

Corresponding Author:[email protected]

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Samiran Mandal
Indian Institute of Technology Bhubaneswar
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Sourav Sil
Indian Institute of Technology Bhubaneswar
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Abstract

This study presents the characterization of the equatorward propagating East India Coastal Current (EICC) using a drifter during October – November 2015 (source: NOAA) and the coastal High Frequency Radars (source: INCOIS and NIOT, India). The altimetry-derived sea surface height anomaly (SSHA, source: AVISO) and geostrophic currents indicate that the EICC is associated with three mesoscale cyclonic eddies along the western Bay of Bengal (BoB). The drifter follows the edges of these eddies (~0.12 m SSHA contour) on the inshore part of the EICC. The drifter currents are validated with the geostrophic currents (daily) as well as the HF Radar-derived surface currents (three hourly). The speed of the EICC is less (~ 0.6 m/s) on the north-western BoB, which increases to ~ 1.0 m/s in the western-central regions and further reaches to ~1.4 m/s at southern BoB. The comparison of drifter and daily geostrophic currents show higher correlation (~ 0.93) and lower errors (~0.16 m/s) when the drifter track is away from the coast, whereas, comparatively lower correlation (~ 0.41) and higher errors (~0.43 m/s) is observed when the track is near the coastline. This mismatch very near to the coasts is possibly due to the low quality of altimetry datasets. The drifter passes through the three HF Radar domains along the Indian coast of the BoB. The comparisons with HFRs indicate reasonable correlation (0.76, 0.71) and errors (0.19 m/s, 0.32 m/s) at the Odisha and Tamil Nadu coast.