FIG Peer Review Journal


Validation of SARAL/AltiKA Retracked Sea Levels with Tide Gauge over the Marginal Seas in Southeast Asia (9228)

Noor Nabilah Abdullah, Nurul Hazrina Idris, Nurul Hawani Idris (Malaysia), Angela M Maharaj (Australia) and Ami Hassan Md Din (Malaysia)
Dr Nurul Hazrina Idris
Faculty of Geoinformation and Real Estate
Universiti Teknologi Malaysia
Faculty of Geoinformation and Real Estate
Universiti Teknologi Malaysia
Johor Bahru
Corresponding author Dr Nurul Hazrina Idris (email: nurulhazrina[at], tel.: 60182118283)

[ abstract ] [ paper ] [ handouts ]

Published on the web n/a
Received 2018-07-14 / Accepted n/a
This paper is one of selection of papers published for the FIG Congress 2018 in Istanbul, Turkey and has undergone the FIG Peer Review Process.

FIG Congress 2018
ISBN n/a ISSN 2308-3441
URL n/a


Currently, demand for accurate coastal altimetry data, particularly for the sea level has increased since human activities have become increasingly concentrated along coastal areas. Several initiatives were conducted by major Space Agencies (e.g. European Space Agencies (ESA), French Centre d’Etude Spatial (CNES), and Indian Space Research Organisation (ISRO)) and researchers to improve altimeter product over coastal regions. This includes the improvement in the altimetry range measurement (that is related to sea level) via waveform retracking and the ocean geophysical corrections. The exploration of coastal altimetry continues with the launch of SARAL/AltiKa mission, which carries a new Ka-band altimeter technology and a dual-frequency radiometer operating at 24 GHz and 37 GHz. This study validates the retracked sea level anomaly (SLA) from SARAL/AltiKa satellite passes over the Marginal Seas of Southeast Asia. The retracked data from MLE-4, Ice-1 and Ice-2 retracking algorithms in the AVISO-Sensor Geographical Data Record (SGDR) are examined. In general, the results show that Ice-1 and Ice-2 retrackers have excellent data coverage (>72%) for distance that is <10 km to the coastline. Beyond 10 km, all retrackers shows excellent data coverage with >83% data availability. In terms of accuracy, for distances <5 km, validation near Ko Taphao Noi and Geting shows that the Ice-1 retracker has better performance with a correlation >0.66 and RMS error <34 cm. Near Lubang, the Ice-2 retracker outperforms the other two retrackers with a correlation of 0.72 and RMS error of 15 cm. Near Bintulu, the MLE-4 retracker shows better performance with a correlation of 0.53 and RMS error of 8 cm. Within the 5-10 km band, the Ice-2 retracker has excellent performance near Vung Tau, Geting and Bintulu with a correlation >0.75 and RMS error <34 cm, meanwhile Ice-1 has a better performance near Lubang and Ko Taphao Noi with a correlation of >0.67 and RMS error <14 cm.
Keywords: Remote sensing; SARAL/AltiKa; Coastal Sea Level; Validation; Retracking; Tide Gauge; Southeast Asia