Acharyulu PSN¹*, Vignudelli Stefano² and Prasad KVSR¹

¹Department of Meteorology and Oceanography, Andhra University, Visakhapatnam, Andhra Pradesh, India
²Consiglio Nazionale delle Ricerche, Istituto di Biofisica, Pisa, Italy

*Corresponding Author: Acharyulu PSN, Department of Meteorology and Oceanography, Andhra University, Visakhapatnam, Andhra Pradesh, India.

Received: May 27, 2021; Published: June 24, 2021

Abstract

Satellite altimetry provides an important measurement source for coastal studies. The main aim of this study was to make an effort to check the availability of valid altimeter data and to compare and validate altimeter data in the coastal region of India. The study shows that by adopting specific coastal processing, it is possible to retrieve valid altimeter measurements in the coastal regions. The combined use of improved coastal multi-altimeter data would allow us to efficiently observe the temporal and spatial scales of coastal dynamics [16]. Thus, in the present study, two different altimetry missions were considered. The coastal sea-level data was computed from two different altimeter missions the Jason-2 PISTACH coastal data and SARAL Altika data separately and for sea level validation only the RED3 re-tracker and for SARAL 40 Hz high-frequency data was analysed and validated with In-situ tide gauge and PSMSL data. The RED3 re-tracker from Jason-2 PISTACH coastal product with In-situ measurements show that the valid altimeter data can be retrieved around 10 km close to the coast also. Also, the 41 point filtered data was able to reduce the noise in the data set and be able to capture all the oceanographic signals in the raw RED3 re-tracker. The comparison of RED3 re-tracker and filtered data show good matching with the In-situ data. This data helps us to obtain valid altimetry measurements more close to the coast. Similarly, for the SARAL Altika, SSHA measurements show very promising results in the coastal regions of India. This SARAL also enables us to reach as close as 3 km close to the coast because it is the first of its kind to provide sea level measurements in the proximity of the coastal regions due to its narrow footprint size. The validation of altimeter data from multiple missions with tide gauge data shows encouraging results. Along-track comparison shows that valid altimeter measurements were available close to the coast. Improvement of both qualitative and quantitative measurements in the coastal zone was observed from the coastal altimetry.

Keywords: Satellite Altimetry; Coastal Zone; Coastal Processes; Sea Level; Seasons; Tide Gauge

References

1. LL Fu and A Cazenave. “Satellite altimetry and earth sciences: a handbook of techniques and applications 69”. Academic Press ( 2000).
2. A Pascual., et al. “Improved description of the ocean mesoscale variability by combining four satellite altimeters”. Geophysical Research Letters2 ( 2006).
3. L Roblou., et al. “X-track, a new processing tool for altimetry in coastal oceans”. 2007 IEEE International Geoscience and Remote Sensing Symposium ( 2007).
4. S Vignudelli., et al. “Improved satellite altimetry in coastal systems: Case study of the Corsica Channel ( Mediterranean Sea)”. Geophysical Research Letters7 ( 2005): 1-5.
5. H H Sepulveda., et al. “Assessment of SARAL/AltiKa Wave Height Measurements Relative to Buoy, Jason-2, and Cryosat-2 Data”. Marine Geodesy 1 ( 2015): 449-465.
6. M Passaro., et al. “Validation of significant wave height from improved satellite altimetry in the German bight”. IEEE Transactions on Geoscience and Remote Sensing 4 ( 2015): 2146-2156.
7. S Vignudelli., et al. Coastal altimetry (2011).
8. L a Ruiz Etcheverry., et al. “A comparison of the annual cycle of sea level in coastal areas from gridded satellite altimetry and tide gauges”. Continental Shelf Research 92 ( 2015): 87-97.
9. K S Madsen., et al. “Near-coastal satellite altimetry: Sea surface height variability in the North Sea-Baltic Sea area”. Geophysical Research Letters14 ( 2007): L14601.
10. C Desportes., et al. “On the wet tropospheric correction for altimetry in coastal regions”. IEEE Transactions on Geoscience and Remote Sensing7 ( 2007): 2139-2149.
11. S Vignudelli., et al. “Integrated use of altimeter and in situ data for understanding the water exchanges between the Tyrrhenian and Ligurian Seas”. Journal of Geophysical Research: OceansC8 ( 2000): 19649-19663.
12. D L Volkov., et al. “Improving the quality of satellite altimetry data over continental shelves”. Journal of Geophysical Research: OceansC6 ( 2007).
13. R Scharroo., et al. “Satellite altimetry and the intensification of Hurricane Katrina”. Eos, Transactions American Geophysical Union 40 ( 2005): 366.
14. X Deng and W E Featherstone. “A coastal retracking system for satellite radar altimeter waveforms: Application to ERS-2 around Australia”. Journal of Geophysical Research: OceansC6 ( 2006).
15. S Vignudelli., et al. “Reprocessing altimeter data records along European coasts: lessons learned from the ALTICORE project”. in Geoscience and Remote Sensing Symposium, 2008. IGARSS 2008. IEEE International 3 ( 2008): III--419.
16. J Bouffard., et al. “Exploiting the potential of an improved multimission altimetric data set over the coastal ocean”. Geophysical Research Letters 35 ( 2008).
17. P Cipollini., et al. “Developing radar altimetry in the oceanic coastal zone: the COASTALT project”. ( 2008): 17-18.
18. J Lambin., et al. “CNES initiative for altimeter processing in coastal zone: PISTACH, paper presented at the First Coastal Altimeter Workshop, Centre Natl”. D’Étud. Spat. Silver Spring, Md ( 2008): 5-7.
19. G Valladeau., et al. “Using SARAL/AltiKa to Improve Ka-band Altimeter Measurements for Coastal Zones, Hydrology and Ice: The PEACHI Prototype”. Marine Geodesy ( 2015).
20. P Cipollini., et al. “The role of altimetry in coastal observing systems”. Proceedings of Ocean 9 ( 2010): 181-191.
21. M N Tsimplis and P L Woodworth. “The global distribution of the seasonal sea level cycle calculated from coastal tide gauge data”. Journal of Geophysical Research: OceansC8 ( 1994): 16031-16039.
22. D T Pugh. “Tides, surges and mean sea-level: a handbook for engineers and scientists”. John Wiley, Chichester, UK ( 1987).
23. I Laiz., et al. “Seasonal sea level variations in the gulf of Cadiz continental shelf from in-situ measurements and satellite altimetry”. Continental Shelf Research 53 ( 2013): 77-88.
24. R G Bell and D G Goring. “Seasonal variability of sea level and sea-surface temperature on the north-east coast of New Zealand”. Estuarine, Coastal and Shelf Science 2 ( 1998): 307-318.
25. F Vivier., et al. “Contributions of wind forcing, waves, and surface heating to sea surface height observations in the Pacific Ocean”. Journal of Geophysical Research: OceansC9 ( 1999): 20767-20788.
26. J K Willis., et al. “Assessing the globally averaged sea level budget on seasonal to interannual timescales”. Journal of Geophysical Research: OceansC6 ( 2008).
27. D Shankar and S R Shetye. “Are interdecadal sea level changes along the Indian coast influenced by variability of monsoon rainfall?”. Journal of Geophysical Research: OceansC11 ( 1999): 26031-26042.
28. D Shankar. “Seasonal cycle of sea level and currents along the coast of India”. ( 2000).
29. D Stammer. “Global Characteristics of Ocean Variability Estimated from Regional TOPEX/POSEIDON Altimeter Measurements”. Journal of Physical Oceanography 8 ( 1997): 1743-1769.
30. V O Ivchenko., et al. “Comparing the steric height in the Northern Atlantic with satellite altimetry”. Ocean Science3 ( 2007): 441-457.
31. N H Hashimi., et al. “Holocene sea level fluctuations on western Indian continental margin: an update”. Geological Society of India ( 1995).
32. D Shankar and S R Shetye. “Why is mean sea level along the Indian coast higher in the Bay of Bengal than in the Arabian Sea?”. Geophysical Research Letters4 ( 2001): 563-565.
33. A S Unnikrishnan., et al. “Sea level changes along the Indian coast: Observations and projections”. Current Science ( 2006): 362-368.
34. A Lombard., et al. “Regional patterns of observed sea level change: insights from a 1/4 global ocean/sea-ice hindcast”. Ocean Dynamics3 ( 2009): 433-449.
35. S Levitus., et al. “World ocean heat content and thermosteric sea level change ( 0--2000 m), 1955--2010”. Geophysical Research Letters10 ( 2012).
36. A S Unnikrishnan and D Shankar. “Are sea-level-rise trends along the coasts of the north Indian Ocean consistent with global estimates?”. Global and Planetary Change 3 ( 2007): 301-307.
37. E Y Handoko., et al. “Assessment of Altimetric Range and Geophysical Corrections and Mean Sea Surface Models — Impacts on Sea Level Variability around the Indonesian Seas”. Remote Sensing102 ( 2017).
38. D Shankar. “Low-Frequency Variability of Sea Level Along the Coast of India”. Thesis 30 ( 1998): 1-10.
39. F Mercier., et al. “Coastal and Hydrology Altimetry product ( PISTACH) handbook”. Natl. d’{É}tudes Spat. ( CNES), Paris, Fr., ( 2010).
40. P Thibaut., et al. “Singular value decomposition applied on altimeter waveforms”. Ocean Surf. Topogr. Sci. Team Meet. ( OSTST), Seattle, USA, ( 2009).
41. S Labroue., et al. “Level 3 PISTACH Products for Coastal Studies”. in 5th coastal altimetry workshop ( 2011): 1-23.
42. R D Ray., et al. “Tide predictions in shelf and coastal waters: status and prospects”. in Coastal altimetry, Springer, ( 2011): 191-216.
43. F Lyard., et al. “Modelling the global ocean tides: modern insights from FES2004”. Ocean Dynamics5-6 ( 2006): 394-415.
44. J Goldhirsh and J R Rowland. “A tutorial assessment of atmospheric height uncertainties for high-precision satellite altimeter missions to monitor ocean currents”. IEEE Transactions on Geoscience and Remote Sensing.4 ( 1982): 418-434.
45. B Andersen and P Knudsen. “DNSC08 mean sea surface and mean dynamic topography models”. Journal of Geophysical Research: OceansC11 ( 2009).
46. F Hernandez and P Schaeffer. “The CLS01 Mean Sea Surface: A validation with the GSFC00 surface”. CLS Ramonv. St Agne, Fr., ( 2001).
47. M Passaro., et al. “ALES: A multi-mission adaptive subwaveform retracker for coastal and open ocean altimetry”. Remote Sensing of Environment 145 ( 2014): 173-189.
48. W Han and P J Webster. “Forcing mechanisms of sea level interannual variability in the Bay of Bengal”. Journal of Physical Oceanography 1 ( 2002): 216-239.
49. C Troupin., et al. “Illustration of the emerging capabilities of SARAL/AltiKa in the coastal zone using a multi-platform approach”. Advances in Space Research 1 ( 2015): 51-59.
50. E Y Handoko., et al. “Assessment of Altimetric Range and Geophysical Corrections and Mean Sea Surface Models — Impacts on Sea Level Variability around the Indonesian Seas”. Remote Sensing102 ( 2017).

Citation

Citation: Acharyulu PSN., et al. “Comparison and Validation of Coastal Sea Level Measurements in the Indian Ocean Regions Using Coastal Altimetry”. Acta Scientific Microbiology 4.7 (2021): 123-136.

Copyright

Copyright: © 2021 Acharyulu PSN., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.