Coastal wave measurements by exploitation of Jason-2 PISTACH in the vicinity of Visakhapatnam region on east coast of India
Autori: Acharyulu, P.S.N., Prasad, K.V.S.R, Vignudelli S., Rashmi, S., Venkata, R.
Rivista: Acta Scientific Microbiology
ISSN: 2581-3226
Abstract:
Satellite altimetry provides precise measurements of wind speed and significant wave height. They have been validated and widely used over open ocean, however, when they come closer to the coast, there is still a need to assess their accuracy and potential usage. This is especially true along Indian coasts, which experience quite opposite northeast and southwest monsoons and a calm period in between them. In this paper, Study on coastal wave heights using JASON-2 tracks in and around Visakhapatnam was carried out, on the east coast of India where the in situ measurements are available to us. Of the new additional three re-trackers available with the PISTACH coastal products, the results show that the RED3 re-tracker performs well with the coastal buoy. The coastal buoy as well as the altimeter capture all the oceanographic signals. The results from comparisons suggest that there is a significant improvement in the significant wave height (SWH) altimeter observations in terms of noise and accuracy after processing. In particular, it was observed that RED3 re-tracker shows better matching with the moderate wave height ranges and better results in proximity of the coast where as OCE3 re-tracker captures all the signals especially during severe weather conditions with less error and better results at intermediate and open waters. The wave height measurements obtained from Jason-2 PISTACH products in the coastal regions are substantially in good agreement with the coastal buoy measurement. There is a need to improve better detection of outliers, which were present even after processing. Also, there is a need to enhance or modify the collocation criteria for coastal regions otherwise the wave which was observed by the altimeter and the buoy will not be the same. These results shows that the Jason-2 PISTACH data able to extend the altimeter data up to ~10 km proximity to the coast and the potential use of RED3 re-tracker in the coastal zone and the use of both the re-trackers in understanding the wave climate in the coastal zone on the east coast of India especially where in-situ observations were scarce. This data will be useful to study the spatial variability and better understanding of coastal dynamics in these limited areas. The results were quite encouraging to use the altimetry data in the coastal regions on the east coast of India.
Keywords: Satellite Altimetry; Coastal Zone; Coastal Processes; Significant Wave Height; Seasons; Low Pressure Systems
