Decoding the nesting fidelity of Olive ridley sea turtles along Odisha coast: A multi-dimensional approach Rabindra Kumar Sahoo, Subhajit Barik, C. Muthukumar, Meera Swain, Sanjukta Rani Padhi, Balaram Mahanty, Samiran Mandal, Mukunda Keshari Khadanga, Subhasis Pradhan, Pratap Kumar Mohanty, Uma Sankar Panda Ocean and Coastal Management, 2026 The Odisha coast is one of the world's largest mass nesting (arribada) sites for Olive ridley sea turtles ( Lepidochelys olivacea ), accommodating approximately 50% of the global population. Despite its extensive and ecologically diverse coastlines, Odisha remains the preferred nesting habitat, although its prime reason is poorly understood. This study focuses interdisciplinary approach that integrates environmental and anthropogenic factors to assess the fidelity of Olive ridley sea turtles to the Odisha coast. Socio-environmental data collected from various sources are assessed for fidelity and results indicate that conducive coastal water quality, stable/accreting shorelines, and predominance of coarse/medium sand play a significant role in facilitating mass nesting along the Odisha coast. Further, ocean waves characterized by low steepness, along with less coastal structures and anthropogenic activities, enhance nesting fidelity. The correlation analysis shows that the nesting population is positively correlated with higher genesis potential for tropical cyclone occurrence and negatively correlated with the percentage of beach littering. The cluster analysis reveals minimum coastal structure & erosion, low marine fishing harvest potential and litter activities associated with the maximum occurrence of tropical cyclone could be the plausible reason for mass nesting events. In addition, minimal anthropogenic disturbances, such as fishing activities and tourist flows in Odisha, contribute to minimal risks of bycatch and mortality of sea turtles. In contrast, other coastal states experiences increased habitat loss, pollution, and human interference, leading to a decline in nesting phenomena. The study suggests that Odisha's distinct blend of socio-environmental factors makes its beach vital for nesting habitat.
On Investigating the Dynamical Factors Modulating Surface Chlorophyll-a Variability along the South Java Coast Samiran Mandal, Raden Dwi Susanto, Balaji Ramakrishnan Remote Sensing, 2022 Twelve years of remotely sensed all-sat merged chlorophyll-a concentration unveils strong signatures of chlorophyll-a blooms along the south Java coast. An unprecedented three-times increase in chlorophyll-a concentration is significantly observed along the south Java coast during the southeast monsoon (June–October) than the northwest monsoon (December–April). The multiple regression analysis of dynamic factors evidently indicates that seasonal upwelling is predominantly controlled by the seasonally evolving coastal eddies associated with the seasonally reversing south Java coastal currents (SJCC) and Ekman mass transport (EMT), followed by the relative roles of sea surface temperature (SST) and wind stress curl. The eddy-induced upwelling and EMT-induced coastal upwelling lead to chlorophyll-a blooms during southeast monsoon, well-supported by the entrainment of cold and saline waters (thermocline doming) with low spiciness. On the other hand, the coastal eddies associated with SJCC and SST anomalies play a significant role in modulating the interannual surface chlorophyll-a variability in the domain. Intense chlorophyll-a blooms are observed during the positive IOD years, whereas the least chlorophyll-a concentration is observed during the negative IOD years. The unprecedentedly least chlorophyll-a concentrations during 2010 and 2016 are attributed to the intense and prolonged surface marine heatwaves.
Seasonal Circulation of Gulf of Khambhat, India using High Frequency Radars Sourav Sil, Shouvik Dey, Samiran Mandal Oceans Conference Record IEEE, 2022 The present work analyzed the high frequency radar-derived surface current data for seasonal variation of tidal and non-tidal currents in the Gulf of Khambhat, India during 2018. The analysis showed that the M2 tidal (time period 12.42 hours) current is the strongest tidal constituent of magnitude from 1.0 m/s to 1.5 m/s in different seasons. This M2 currents is more than three times higher than the K1 (time period 23.93 hours) tidal current, which varies from 0.2 to 0.5 m/s. The meridional component than the zonal majorly drives the total currents. The de-tided surface currents is much less than the tidal current. The percentages of the tidal current to the total current is around 80%. The inclination of the tidal ellipse varies between 60° – 70° in different seasons, indicate the direction of tidal flow. A convergence (divergence) of surface currents is noted during flood and ebb currents around 21 °N due to downslope on both the sides. In February 2018, a strong surface current with a magnitude of around 0.5 m/s was seen flowing from the Arabian sea to the Gulf on the western and southern Gulf. A flow with 0.1 to 0.3 m/s is noted on the eastern Gulf from the shallower bathymetry to deep regions near the Tapti River. A cyclonic circulation flow in noted in August. A time-series analysis of the daily currents showed that oscillations of 5-, 10-, 15- days exist in the current observation. This study also highlighted the need of subsurface ocean observation for studying the ocean dynamics in the Gulf.
Evolution of a Sub-Mesoscale Eddy Leeward of Andaman Islands from HF Radars Samiran Mandal, Avijit Gangopadhyay, Balaji Ramakrishnan, Sourav Sil IEEE Geoscience and Remote Sensing Letters, 2022 Remotely sensed high-resolution ocean surface currents from high-frequency radars (HFRs) on the western Andaman Sea (AnS) reveals signature of a sub-mesoscale coastal anticyclonic eddy leeward of Little Andaman (LA) Island during August 4–9, 2017. This “Lee eddy” had a mean radius of ~11 km, negative values of normalized vorticity, divergence, and Okubo–Weiss (OW) parameter, and smaller values of strain. A term-by-term vorticity budget analysis suggests that the vortex stretching term and wind stress curl dominate during the evolution and demise of the Lee eddy than does advection.
Impact of varying landfall time and cyclone intensity on storm surges in the Bay of Bengal using ADCIRC model V G Shashank, Samiran Mandal, Sourav Sil Journal of Earth System Science, 2021 This study focuses on the impact of varying landfall timing in a tidal cycle (i.e., the spring-neap phase) and varying wind speeds (i.e., cyclone intensities) on the surge tides for the tropical cyclone Fani in the Bay of Bengal using a hydrodynamic finite element-based 2D (ADvanced CIRCulation) ADCIRC model setup. For atmospheric forcing, the Cyclostrophic Symmetric Holland wind Model (H80) and Generalized Asymmetric Holland Model (GAHM) model are used to estimate the wind fields from the IMD best track data. Comparisons with in-situ winds from moored buoys within the proximity of cyclone track showed that H80 simulated winds underestimate the observed winds in terms of magnitude followed by a mismatch in the wind directions as well. In contrast, the GAHM simulated wind fields, which are statistically better in terms of both magnitude and direction are used for different wind experiments. To understand the impact of the varying landfall timing and varying wind speeds on storm surges, a series of sensitivity experiments have been performed during a tidal cycle with modulated high and low winds along the cyclone track. The experiments considering varying landfall timing during a tidal cycle indicate the strongest surge tides (1.99 m) during the spring high tide phase, whereas the lowest surge tide of 0.94 m is observed during spring low tide. However, the surge tide at the actual time of landfall is 1.20 m which is during the transition from low tide to high tide. On the other hand, the combined impact of wind speeds and varying landfall timing indicated the strongest surge tides of 2.25 m during high wind conditions associated with spring high tides. In contrast, the surge tides decrease significantly during low tide and low wind conditions. This study confirms the importance of both winds and landfall timing on the storm surges, which will be crucial to forecast the storm surges associated with the tropical cyclones.
Emerging Role of Marine Heatwaves in Tropical Cyclone Activity over the Arabian Sea K Javad, A Kumar, P Shah, RK Sahoo, S Mandal Estuarine, Coastal and Shelf Science, 109975 , 2026 2026
Decoding the nesting fidelity of Olive ridley sea turtles along Odisha coast: A multi-dimensional approach RK Sahoo, S Barik, C Muthukumar, M Swain, SR Padhi, B Mahanty, ... Ocean & Coastal Management 276, 108164 , 2026 2026
Estimating Mixed Layer Depth and Variability along the Western Andaman Sea: Insights from HF Radar Surface Currents A Kumar, S Mandal, BK Jena Ocean Dynamics 76 (4), 37 , 2026 2026
Multiscale sea level variability on the western Bay of Bengal: A study using tide gauge and satellite observations A Ray, S Sil, S Mandal Continental Shelf Research 284, 105361 , 2025 2025 Citations: 4
Geomorphological management strategies for cyclone-impacted sea turtle nesting habitat along the eastern seaboard of India RK Sahoo, S Barik, S Mandal, S Pradhan, T Palanisamy, US Panda, ... Environmental Science and Pollution Research 31 (57), 65698-65723 , 2024 2024 Citations: 1
Observed seasonality of M2 and M4 tidal currents in the Gulf of Khambhat using high-frequency radars S Mandal Ocean Dynamics 74 (3), 251-265 , 2024 2024 Citations: 2
Observed Tidal Currents in the Gulf of Khambhat, Northeastern Arabian Sea: An HF Radar Perspective S Mandal American Geophysical Union, Ocean Sciences Meeting, OP31E-08 , 2024 2024
Characterization of the East India Coastal Current using a Drifter, HF Radars and Altimetry during October--November 2015 P Bhuyan, S Mandal, S Sil Authorea Preprints , 2022 2022 Citations: 1
On investigating the dynamical factors modulating surface chlorophyll-a variability along the south Java coast S Mandal, RD Susanto, B Ramakrishnan Remote Sensing 14 (7), 1745 , 2022 2022 Citations: 44
Evolution of a sub-mesoscale eddy leeward of Andaman Islands from HF radars S Mandal, A Gangopadhyay, B Ramakrishnan, S Sil IEEE Geoscience and Remote Sensing Letters 19, 1-4 , 2022 2022 Citations: 4
Seasonal circulation of Gulf of Khambhat, India using high frequency radars S Sil, S Dey, S Mandal OCEANS 2022-Chennai, 1-5 , 2022 2022 Citations: 4
Impact of varying landfall time and cyclone intensity on storm surges in the Bay of Bengal using ADCIRC model VG Shashank, S Mandal, S Sil Journal of Earth System Science 130 (4), 194 , 2021 2021 Citations: 21
Evidence of a chlorophyll “tongue” in the Malacca Strait from satellite observations S Mandal, N Behera, A Gangopadhyay, RD Susanto, PC Pandey Journal of Marine Systems 223, 103610 , 2021 2021 Citations: 27
Hydrographic Processes in a Tropical Coastal Lagoon on Western Bay of Bengal RK Sahoo, S Sil, S Mandal, S Pradhan, SK Baliarsingh, R Samal 2021 Citations: 2
Surface and subsurface signatures of monsoon intraseasonal oscillations from moored buoys observation in the Bay of Bengal DP Bhuyan, S Mandal, A Ray, S Sil, R Venkatesan Dynamics of Atmospheres and Oceans 95, 101240 , 2021 2021 Citations: 7
Influence of coastal upwelling on the surface current in the Bay of Bengal using HF radar and satellite observations S Dey, S Sil, S Mandal EGU General Assembly Conference Abstracts, EGU21-15747 , 2021 2021
Multiscale Circulation Variability using High Frequency (HF) Radar Current Observations along the Indian Coast S Mandal Indian Institute of Technology Bhubaneswar , 2021 2021
Seasonal and Tidal Variability of Surface Currents in the Western Andaman Sea Using HF Radars and Buoy Observations During 2016-2017 S Mandal, S Sil, A Gangopadhyay, BK Jena, R Venkatesan, ... IEEE Transactions on Geoscience and Remote Sensing 59 (9), 7235-7244 , 2020 2020 Citations: 25
Sub-mesoscale circulation features along the Andhra Pradesh coast, Bay of Bengal: observations from HF radars S Mandal, S Pramanik, S Sil, KS Arunraj, BK Jena Journal of Coastal Research 89 (SI), 132-138 , 2020 2020 Citations: 10
Evolution of a Coastal Mesoscale Cyclonic Eddy along the Western Bay of Bengal using HF Radar Observations S Mandal, S Sil, A Gangopadhyay, BK Jena American Geophysical Union, Ocean Sciences Meeting, PL24C-2686 , 2020 2020
MOST CITED SCHOLAR PUBLICATIONS
Upper Ocean and Subsurface Variability in the Bay of Bengal During Cyclone ROANU: A Synergistic View Using In Situ and Satellite Observations S Mandal, S Sil, A Shee, R Venkatesan Pure and Applied Geophysics 175 (12), 4605–4624 , 2018 2018 Citations: 46
On investigating the dynamical factors modulating surface chlorophyll-a variability along the south Java coast S Mandal, RD Susanto, B Ramakrishnan Remote Sensing 14 (7), 1745 , 2022 2022 Citations: 44
Characteristics and evolution of a coastal mesoscale eddy in the Western Bay of Bengal monitored by high-frequency radars S Mandal, S Sil, S Pramanik, A KS, BK Jena Dynamics of Atmospheres and Oceans 88, 101107 , 2019 2019 Citations: 43
On extracting high-frequency tidal variability from HF radar data in the northwestern Bay of Bengal S Mandal, S Sil, A Gangopadhyay, T Murty, D Swain Journal of Operational Oceanography 11 (2), 65-81 , 2018 2018 Citations: 37
Role of interannual equatorial forcing on the subsurface temperature dipole in the Bay of Bengal during IOD and ENSO events S Pramanik, S Sil, S Mandal, D Dey, A Shee Ocean Dynamics, 1-19 , 2019 2019 Citations: 32
Comparative analysis of SCATSat-1 gridded winds with buoys, ASCAT, and ECMWF winds in the Bay of Bengal S Mandal, S Sil, A Shee, D Swain, PC Pandey IEEE Journal of Selected Topics in Applied Earth Observations and Remote … , 2018 2018 Citations: 30
Evidence of a chlorophyll “tongue” in the Malacca Strait from satellite observations S Mandal, N Behera, A Gangopadhyay, RD Susanto, PC Pandey Journal of Marine Systems 223, 103610 , 2021 2021 Citations: 27
On the nature of tidal asymmetry in the Gulf of Khambhat, Arabian Sea using HF radar surface currents S Mandal, S Sil, A Gangopadhyay, BK Jena, R Venkatesan Estuarine, Coastal and Shelf Science 232, 106481 , 2020 2020 Citations: 27
Seasonal and Tidal Variability of Surface Currents in the Western Andaman Sea Using HF Radars and Buoy Observations During 2016-2017 S Mandal, S Sil, A Gangopadhyay, BK Jena, R Venkatesan, ... IEEE Transactions on Geoscience and Remote Sensing 59 (9), 7235-7244 , 2020 2020 Citations: 25
Impact of varying landfall time and cyclone intensity on storm surges in the Bay of Bengal using ADCIRC model VG Shashank, S Mandal, S Sil Journal of Earth System Science 130 (4), 194 , 2021 2021 Citations: 21
Tide-current-eddy interaction: A seasonal study using high frequency radar observations along the western Bay of Bengal near 16° N S Mandal, S Sil, A Gangopadhyay Estuarine, Coastal and Shelf Science 232, 106523 , 2020 2020 Citations: 18
Sub-mesoscale circulation features along the Andhra Pradesh coast, Bay of Bengal: observations from HF radars S Mandal, S Pramanik, S Sil, KS Arunraj, BK Jena Journal of Coastal Research 89 (SI), 132-138 , 2020 2020 Citations: 10
Surface and subsurface signatures of monsoon intraseasonal oscillations from moored buoys observation in the Bay of Bengal DP Bhuyan, S Mandal, A Ray, S Sil, R Venkatesan Dynamics of Atmospheres and Oceans 95, 101240 , 2021 2021 Citations: 7
Time series analysis of observed maximum and minimum air temperature at four urban cities of India during 1951-2015 S Pramanik, S Sil, S Mandal Mausam 71 (1), 57-68 , 2020 2020 Citations: 7
Coastal Currents from HF Radars along Odisha Coast S Mandal, S Sil Ocean Digest : Quarterly Newsletter of the Ocean Society of India 4 (1), 1 - 12 , 2017 2017 Citations: 5
Multiscale sea level variability on the western Bay of Bengal: A study using tide gauge and satellite observations A Ray, S Sil, S Mandal Continental Shelf Research 284, 105361 , 2025 2025 Citations: 4
Evolution of a sub-mesoscale eddy leeward of Andaman Islands from HF radars S Mandal, A Gangopadhyay, B Ramakrishnan, S Sil IEEE Geoscience and Remote Sensing Letters 19, 1-4 , 2022 2022 Citations: 4
Seasonal circulation of Gulf of Khambhat, India using high frequency radars S Sil, S Dey, S Mandal OCEANS 2022-Chennai, 1-5 , 2022 2022 Citations: 4
Tidal circulation studies using regional model in the bay of Bengal S Pramanik, S Mandal, A Shee, S Halder, S Sil Proceedings of the Fourth International Conference in Ocean Engineering … , 2019 2019 Citations: 4
Statistical analysis of coastal currents from HF radar along the North-Western Bay of Bengal S Mandal, S Pramanik, S Halder, S Sil Proceedings of the Fourth International Conference in Ocean Engineering … , 2018 2018 Citations: 4
