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Luhar, Rakesh Kumar
- Design And Development of a Low-Cost GNSS Drifter for Rip Currents
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Authors
Affiliations
1 Earth, Ocean, Atmosphere, Planetary Sciences and Applications Area, Ahmedabad 380 015, IN
2 Mechanical Engineering Systems Area, Space Applications Centre (ISRO), Ahmedabad 380 015,, IN
1 Earth, Ocean, Atmosphere, Planetary Sciences and Applications Area, Ahmedabad 380 015, IN
2 Mechanical Engineering Systems Area, Space Applications Centre (ISRO), Ahmedabad 380 015,, IN
Source
Current Science, Vol 118, No 2 (2020), Pagination: 273-279Abstract
Lagrangian drifters are analogues of particles that are relevant to flow-field characterization and therefore they represent realistic surface currents compared to Eulerian techniques. The use of global navigation satellite system (GNSS) in such drifters with Differential Global Positioning System mode at high frequency (5–10 Hz) sampling and post-processing kinematic results in position estimates with centimeter-level accuracy. In the complex nearshore zone, deploying expensive instruments is a risk due to greater chances of loss. To avoid this, two drifters have been designed and developed using a low-cost Emlid Reach® GNSS receivers, antennae and ‘off-the-shelf’ PVC components to measure the surface currents. The dimensions of the drifters were optimally chosen to minimize the wind and wave impacts and to increase the subsurface current drag. An analysis of relative position and velocity errors from stationary observations indicates that the drifter can resolve motion accurately with minimal errors of ±1 cm and ±2 cm/s respectively. These drifters were used to measure surf zone currents at the RK Beach, Visakhapatnam during May 2018 and to successfully identify dangerous rip current zones. This study presents the design, development aspects, error analysis and testing of GNSS drifters. Although these drifters are primarily developed to measure the rip current velocities and trajectories in the nearshore zone, they can also be operated in any marine environment like rivers, lakes, estuaries, etc. without change in the design. An extensive study using a fleet of such drifters is required to understand the complex physical processes in the marine environment.Keywords
Drifter, Error Estimation, Rip Currents, Relative Position and Velocity.Full Text
References
- Poje, A. C. et al., Submesoscale dispersion in the vicinity of the Deepwater Horizon spill. Proc. Natl. Acad. Sci. USA, 2014, 111, 12693–12698.
- Stocker, R. and Imberger, J., Horizontal transport and dispersion in the surface layer of a medium-sized lake. Limnol. Oceanogr., 2003, 48, 971–982.
- Schroeder, K. et al., Targeted Lagrangian sampling of submesoscale dispersion at a coastal frontal zone. Geophys. Res. Lett., 2012, 39.
- MacMahan, J., Brown, J. and Thornton, E., Low-cost handheld global positioning system for measuring surf-zone currents. J. Coast. Res., 2009, 744–754.
- Schmidt, W. E., Woodward, B. T., Millikan, K. S., Guza, R. T., Raubenheimer, B. and Elgar, S., A GPS-tracked surf zone drifter. J. Atmos. Ocean. Techolnol., 2003, 20, 1069–1075.
- Spydell, M., Feddersen, F., Guza, R. T. and Schmidt, W. E., Observing surf-zone dispersion with drifters. J. Phys. Oceanogr., 2007, 37, 2920–2939.
- Boehm, A. B. et al., Decadal and shorter period variability of surf zone water quality at Huntington Beach, California. Environ. Sci. Technol., 2002, 36, 3885–3892.
- Nasello, C. and Armenio, V., A new small drifter for shallow water basins: application to the study of surface currents in the Muggia Bay (Italy). J. Sensors, 2016; http://dx.doi.org/10.1155/2016/65896362016.
- Earle, M. D., Riverine drifter. Technical Report, Planning Systems Inc Slidell LA, 2007.
- Suara, K., Wang, C., Feng, Y., Brown, R. J., Chanson, H. and Borgas, M., High-resolution GNSS-tracked drifter for tudying surface dispersion in shallow water. J. Atmos. Ocean. Technol., 2015, 32, 579–590.
- Murray, S. P., Trajectories and speeds of wind-driven currents wear the coast. J. Phys. Oceanogr., 1975, 5, 347–360.
- Johnson, D., Stocker, R., Head, R., Imberger, J. and Pattiaratchi, C., A compact, low-cost GPS drifter for use in the oceanic nearshore zone, lakes, and estuaries. J. Atmos. Oceanogr. Technol., 2003, 20, 1880–1884.
- Johnson, D. and Pattiaratchi, C., Transient rip currents and nearshore circulation on a swell-dominated beach. J. Geophys. Res.: Oceans, 2004, 109.
- Arun Kumar, S. V. V. and Prasad, K. V. S. R., Rip current-related fatalities in India: a new predictive risk scale for forecasting rip currents. Nat. Hazards, 2014, 70, 313–335.