Optimised gravity anomaly fields from along-track multi-mission satellite altimeter over Malaysian seas

Yazid, Nornajihah Mohammad; Din, Ami Hassan Md; Omar, Abdullah Hisam; Abdullah, Norfadhilatuladha; Pa’suya, Muhammad Faiz; Hamden, Mohammad Hanif; Yahaya, Noor Anim Zanariah

doi:10.1007/s44195-022-00003-5

Cited by 5 publications

(2 citation statements)

References 33 publications

(26 reference statements)

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“…The data can be assessed through the Radar Altimeter Database System (RADS) server at Universiti Teknologi Malaysia (UTM), which provides the latest orbital information and geophysical corrections. Satellite altimetry data implemented in the computation have been preprocessed based on the optimal range and geophysical corrections for the Malaysian region [11]. Most of the ranges and geophysical corrections implemented in this study are based on user manuals and gradual experiences from prior studies [12][13][14][15].…”

Section: Altimetry Data Processingmentioning

confidence: 99%

The Verification of Sea Level Anomaly (SLA) Versus Tide Gauge for Geoid Modelling

Nornajihah Mohammad Yazid,

Ami Hassan Md Din,

Muhammad Faiz Pa’suya

et al. 2024

ARASET

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The increasing long-term sea level rise is of particular interest and needs a significant investment in coastal protection procedures. The coastal sea level has been verified with tide gauges and well maintained with reliable accuracy of data since a few centuries ago. Satellite altimeter has been used for sea level study and increasingly for operational purposes. However, the precision of altimetry data in coastal areas is frequently eliminated by the geographically correlated orbit errors, which induce a regional inhomogeneous mission bias. This study presents an effort to verify sea level anomaly based on altimetry data with tide gauge stations as an early procedure to provide a good sea level anomaly data for mean sea surface, gravity anomaly, and geoid determination over Malaysian seas. The altimetry data is validated by comparing the sea level anomaly with ground truth data (tidal data) near the coastal area. A total of nine selected areas were chosen to represent the ground truth data. The findings found that the altimetry data over the South China Sea (Pulau Tioman, Geting, Cendering, Bintulu, and Kota Kinabalu) provided a good pattern, high correlation, and a minimum root mean square error (RMSE) value after the verification with tidal sea level anomaly data. However, it clearly shows that Tawau station over the Celebes Sea provides a poor pattern, poor correlation, and a high RMSE value with tidal sea level anomaly data. In conclusion, further enhancements are expected from the refined processing and filtering of altimetry data for the sea level study in the coastal zone.

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Section: Altimetry Data Processingmentioning

confidence: 99%

The Verification of Sea Level Anomaly (SLA) Versus Tide Gauge for Geoid Modelling

Nornajihah Mohammad Yazid,

Ami Hassan Md Din,

Muhammad Faiz Pa’suya

et al. 2024

ARASET

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“…Geoid is an equipotential surface of the Earth's gravity information, which is directly correlated with the MSL and interpreted as a surface level perpendicular to gravity. In motionless ocean without long-term atmospheric or oceanographic effects, the sea surface usually coincides with the geoid (Mills and Dodd, 2014;Yazid, 2018). However, MSL determination can differ by up to 1 m from the geoid.…”

Section: Local Geoid Modelmentioning

confidence: 99%

Accuracy assessment of quasi-seamless hydrographic separation models in Malaysian waters

Hamden,

Din,

Alihan

et al. 2023

Front. Earth Sci.

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The hydrographic survey reduction using ellipsoid has been available since the advent of the global navigation satellite system (GNSS), with a potential to streamline operation and enhance bathymetric output. Spatially continuous separation surfaces connecting a chart datum (CD) to a geodetic ellipsoid is required for this technique. Universiti Teknologi Malaysia (UTM) has invented a new quasi-seamless separation model for Malaysian waters, known as the Malaysian Vertical Separation (MyVSEP) model, through semi-empirical models to capture the spatial variability of a tidal datum between coastal and offshore areas. A continuous vertical datum is established to develop MyVSEP models by combining the coastal and offshore datasets. The coastal datasets referred to the vertical reference point computed from coastal tide gauges, while the offshore datasets referred to the vertical reference surfaces derived from satellite altimetry. Mean sea level (MSL) or mean sea surface (MSS), mean dynamic topography (MDT), lowest astronomical tide (LAT), and highest astronomical tide (HAT) are the vertical datums involved in developing the continuous MyVSEP model. However, the integration of the vertical datum has only been conducted over the Peninsular Malaysia region. For Sabah and Sarawak, datum integration cannot be implemented due to the limitation of coastal datasets. The assessment of the integrated vertical datum with coastal tide gauges is discussed in this study. The finding shows that the root mean square error (RMSE) agreement between the integrated Universiti Teknologi Malaysia 2020 (iUTM20) model and coastal tide gauges yields below 2.0 cm. The iUTM20 lowest astronomical tide and highest astronomical tide models also show significant improvement compared to the altimetric-derived tidal models, which recorded the root mean square error agreement with coastal tide gauges of 1.8 cm and 2.0 cm, respectively. The development of a continuous vertical separation model for the Ellipsoidally Referenced Surveying technique indirectly optimizes marine geospatial information resources, especially for the National Hydrographic Centre in Malaysia.

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The optimization of marine geoid model from altimetry data using Least Squares Stokes modification approach with additive corrections across Malaysia

Mohammad Yazid,

Din,

Pa’suya

et al. 2023

International Journal of Remote Sensing

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Optimised gravity anomaly fields from along-track multi-mission satellite altimeter over Malaysian seas

Cited by 5 publications

References 33 publications

The Verification of Sea Level Anomaly (SLA) Versus Tide Gauge for Geoid Modelling

The Verification of Sea Level Anomaly (SLA) Versus Tide Gauge for Geoid Modelling

Accuracy assessment of quasi-seamless hydrographic separation models in Malaysian waters

The optimization of marine geoid model from altimetry data using Least Squares Stokes modification approach with additive corrections across Malaysia

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