The project follows a preliminary experimental study on continuous monitoring and identification of the rip channels along the Visakhapatnam beaches.
| Photo Credit: File photo
Indian National Centre for Ocean Information Services (INCOIS) and Indian Space Research Organisation (ISRO) have embarked on a project to continuously monitor and issue operational forecast alerts of rip currents. They intend to do this through a coastal video surveillance system, which will also provide information on complex coastal and nearshore processes.
This follows a preliminary experimental study on continuous monitoring and identification of the rip channels along the Visakhapatnam beaches, especially the famous RK beach, known for the highest recorded number of drownings.
Rip currents are one of the most well-known coastal hazards on beaches around the world. While identification and continuous monitoring of these currents are essential for the safety of beachgoers, studies on the diversity of rip currents off the Indian coast have been minimal, though they have long been a subject of research worldwide.
Scientists at the INCOIS, located at Pragatinagar here and works under the Ministry of Earth Sciences (MoES), pointed out that not much attention was given to monitoring and safeguarding beachgoers from these furious currents. In this pioneering work, video imagery data was used by adopting and implementing an open-source Quantitative Coastal Imaging Toolbox (QCIT).
About 10 minutes of video data was collected from temporarily installed cameras for different months. Later, the the QCIT was used to pre-process the video data, camera calibration, domain definition followed by rectification products.
Rectification products contain single-image products and pixel instruments. Single-image products such as ‘Timex’ and bright and dark images are obtained by calculating the average, maximum and minimum intensity on the rectified frames, respectively, explained senior scientist T.M. Balakrishnan Nair.
The phenomenon of persistent gaps in wave-breaking events that appear as dark spots on bright background from ‘Timex’ images shows quasi-permanent rip channels. The locations of the rip channels extracted from the Timex images were accurately matched to the hotspot maps of the rip currents obtained from the high-resolution satellite images, drifter and die experiments at the study site.
“Once the video camera is permanently set up, further statistical analysis with continuous data availability is also possible. Further implementation of this study would be helpful in the continuous monitoring of coastal rip currents by considering parameters such as alongshore currents, shoreline mapping, wave run-up, up-to-date nearshore estimated bathymetry and implementation of numerical modelling of coastal processes for better inputs,” he said.
The research paper based on this study—Identifying rip channels along the RK beach in Visakhapatnam using video and satellite imagery analysis—had bagged the best category paper award for 2022 from the Journal of Indian Society of Remote Sensing.
