Cross-calibrating ALES Envisat and CryoSat-2 Delay-Doppler: A coastal altimetry study in the Indonesian Seas

Passaro, M; Dinardo, S; Quartly, GD; Snaith, H; Benveniste, J; Cipollini, P; Lucas, B. 2016 Cross-calibrating ALES Envisat and CryoSat-2 Delay-Doppler: A coastal altimetry study in the Indonesian Seas. Advances in Space Research, 58. 289-303. 10.1016/j.asr.2016.04.011

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Abstract/Summary

A regional cross-calibration between the first Delay Doppler altimetry dataset from Cryosat-2 and a retracked Envisat dataset is here presented, in order to test the benefits of the Delay-Doppler processing and to expand the Envisat time series in the coastal ocean. The Indonesian Seas are chosen for the calibration, since the availability of altimetry data in this region is particularly beneficial due to the lack of in-situ measurements and its importance for global ocean circulation. The Envisat data in the region are retracked with the Adaptive Leading Edge Subwaveform (ALES) Retracker, which has been previously validated and applied successfully to coastal sea level research. The study demonstrates that CryoSat-2 is able to decrease the 1-Hz noise of sea level estimations by 0.3 cm within 50 km of the coast, when compared to the ALES-reprocessed Envisat dataset. It also shows that Envisat can be confidently used for detailed oceanographic research after the orbit change of October 2010. Cross-calibration at the crossover points indicates that in the region of study a sea state bias correction equal to 5% of the significant wave height is an acceptable approximation for Delay-Doppler altimetry. The analysis of the joint sea level time series reveals the geographic extent of the semiannual signal caused by Kelvin waves during the monsoon transitions, the larger amplitudes of the annual signal due to the Java Coastal Current and the impact of the strong La Nina event of 2010 on rising sea level trends.

Item Type: Publication - Article
Additional Keywords: Coastal Altimetry; ALES; SAR altimetry; Indonesia; sea state bias
Subjects: Earth Observation - Remote Sensing
Oceanography
Divisions: Plymouth Marine Laboratory > Science Areas > Sea from Space
Depositing User: Graham Quartly
Date made live: 20 Jun 2016 10:47
Last Modified: 06 Jun 2017 16:16
URI: http://plymsea.ac.uk/id/eprint/7103

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