arXiv subjects

P. N. Vinayachandran

Publications and source records attributed to P. N. Vinayachandran.

5 recordsLinked to original sources

arXiv2025

A Scalable System for Visual Analysis of Ocean Data

Oceanographers rely on visual analysis to interpret model simulations, identify events and phenomena, and track dynamic ocean processes. The ever increasing resolution and complexity of ocean data due to its dynamic nature and multivariate relationships demands a scalable and adaptable visualization tool for interactive exploration. We introduce pyParaOcean, a scalable and interactive visualization system designed specifically for ocean data analysis. pyParaOcean offers specialized modules for common oceanographic analysis tasks, including eddy identification and salinity movement tracking. These modules seamlessly integrate with ParaView as filters, ensuring a user-friendly and easy-to-use system while leveraging the parallelization capabilities of ParaView and a plethora of inbuilt general-purpose visualization functionalities. The creation of an auxiliary dataset stored as a Cinema database helps address I/O and network bandwidth bottlenecks while supporting the generation of quick overview visualizations. We present a case study on the Bay of Bengal (BoB) to demonstrate the utility of the system and scaling studies to evaluate the efficiency of the system.

cs.GR↗

arXiv2024

Arabian Sea high salinity core supplies oxygen to Bay of Bengal oxygen minimum zone

The oxygen minimum zone (OMZ) in the Bay of Bengal (BoB) is unique owing to its curious capability to maintain steady dissolved oxygen (DO) levels. In this study, we identify a process by which the oxygen levels in BoB are sustained above the tipping point, using DO and microstructure profiles in the southern BoB and Argo profiles over the entire basin. High salinity core (HSC) rich in DO is advected by the Summer Monsoon Current (SMC) into BoB. Vertical mixing driven by turbulent and salt-fingering processes recharge DO concentration in thermocline above OMZ. HSC identified in the Argo data, also rich in oxygen, can be traced up to 19$^\circ$ N, confirming that HSC is a source of DO and potentially prevents OMZ from moving to the denitrification regime. In changing climate conditions, this might be the only significant oxygen source for the BoB OMZ in the future.

physics.ao-ph↗

arXiv2023

pyParaOcean: A System for Visual Analysis of Ocean Data

Visual analysis is well adopted within the field of oceanography for the analysis of model simulations, detection of different phenomena and events, and tracking of dynamic processes. With increasing data sizes and the availability of multivariate dynamic data, there is a growing need for scalable and extensible tools for visualization and interactive exploration. We describe pyParaOcean, a visualization system that supports several tasks routinely used in the visual analysis of ocean data. The system is available as a plugin to Paraview and is hence able to leverage its distributed computing capabilities and its rich set of generic analysis and visualization functionalities. pyParaOcean provides modules to support different visual analysis tasks specific to ocean data, such as eddy identification and salinity movement tracking. These modules are available as Paraview filters and this seamless integration results in a system that is easy to install and use. A case study on the Bay of Bengal illustrates the utility of the system for the study of ocean phenomena and processes.

cs.GR↗

arXiv2023

Response of Indian East coast upwelling to river runoff in an OGCM

Along the east coast of India (ECI), local winds are oriented alongshore during the summer monsoon, favouring coastal upwelling. The East India Coastal Current (EICC) during this period converges at 17$^{\circ}$N with northward flow from the south and southward flow from the north. A high-resolution Ocean general circulation model (OGCM) which includes runoff from major rivers (RIVER) simulates the upwelling along the east coast of India during the summer monsoon reasonably well. The model simulation shows that the upwelling increases towards south, where salinity influence is lesser compared to the northern parts. The presence of rivers suppresses upwelling, the depth of the source of subsurface water becomes shallow from 100 to 60 m, and reduces the SST cooling by 0.5$^{\circ}$C owing to the increase in stratification of the water column.

physics.ao-ph↗

arXiv2017

Dynamics of Summer Monsoon Currents around Sri Lanka

$ $From June--September, the summer monsoon current (SMC) flows eastward south of Sri Lanka and bends northeastward to form a swift jet that enters the Bay of Bengal (BoB). As such, it is a crucial part of the water exchange between the Arabian Sea (AS) and BoB. The processes that determine the evolution, intensification and meandering of the SMC are only partly understood. They involve both local and remote forcing by the wind, as well as interactions with westward-propagating Rossby waves and eddies. In this study, we investigate these processes using an Indian-Ocean general circulation model (MOM4p1) that is capable of simulating the SMC realistcally. Because eddies and meanders are smoothed out in the climatology, our analyses focus on a single year of 2009, a period when a strong anticyclonic bend in the SMC was observed. An eddy-kinetic-energy budget analysis shows the region to be a zone of significant eddy activity, where both barotropic and baroclinic instabilities are active. Based on the analysis, we classify the evolution of SMC into stages of onset, intensification, anticyclonic bend, anticyclonic vortex formation, meandering and termination. In addition, analysis of eddy-potential-vorticity flux and eddy-enstrophy decay reveal when, where, and how the eddies tend to drive the mean flow. Rossby waves and westward-propagating eddies arriving from the east energize the SMC in June and accelerate the mean flow through an up-gradient eddy-potential-vorticity flux. At the same time, local winds also strengthen the flow, by increasing its mean, near-surface, kinetic energy and raising isopycnals, the latter building up available potential energy (APE). The baroclinic instability that takes place in late--July and early--August releases APE, thereby generating the SMC meanders.

physics.ao-ph↗