Derivation of Sea Level Anomaly Based on the Best Range and Geophysical Corrections for Malaysian Seas using Radar Altimeter Database System (RADS)

Din, Ami Hassan Md; Ses, Sahrum; Omar, Kamaludin Mohd; Naeije, Marc; Yaakob, Omar; Pa’suya, Muhammad Faiz

doi:10.11113/jt.v71.3830

Cited by 9 publications

(6 citation statements)

References 14 publications

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“…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]. The multi-mission satellite altimetry data in this study are processed using the Radar Altimeter Database System (RADS).…”

Section: Altimetry Data Processingmentioning

confidence: 99%

“…The area for the crossover minimisation has been enlarged, extending outside the study area. The extension of the crossover area is to avoid inadequacy of crossover information to approximate the consistency (one cycle per orbital revolution) of orbit residual function fitting [12] [18]. Hence, the individual crossovers for the time frame are restricted to ±9 days to decrease the possibility of removing actual oceanic signals and sea level trends.…”

Section: Crossover Adjustmentmentioning

confidence: 99%

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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%

Section: Crossover Adjustmentmentioning

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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“…This includes rendering and removing invalid data as well as generating the corresponding refined geophysical corrections. Most of the range and geophysical corrections applied for this model are underpinned and guided by user manuals and progressive experiences from previous studies (Scharroo et al, 2013;Din et al, 2014;Yahaya et al, 2016;Hamid et al, 2018;Din et al, 2019;Zulkifle et al, 2019). Supplementary Table S1 differentiates a list of range and geophysical corrections implemented by Yahaya et al (2016), Zulkifle et al (2019), and UTM20 MSS.…”

Section: Data Sources and Pre-processingmentioning

confidence: 99%

Regional Mean Sea Surface and Mean Dynamic Topography Models Around Malaysian Seas Developed From 27 Years of Along-Track Multi-Mission Satellite Altimetry Data

et al. 2021

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Contemporary Universiti Teknologi Malaysia 2020 Mean Sea Surface (UTM20 MSS) and Mean Dynamic Topography (UTM20 MDT) models around Malaysian seas are introduced in this study. These regional models are computed via scrutinizing along-track sea surface height (SSH) points and specific interpolation methods. A 1.5-min resolution of UTM20 MSS is established by integrating 27 years of along-track multi-mission satellite altimetry covering 1993–2019 and considering the 19-year moving average technique. The Exact Repeat Mission (ERM) collinear analysis, reduction of sea level variability of geodetic mission (GM) data, crossover adjustment, and data gridding are presented as part of the MSS computation. The UTM20 MDT is derived using a pointwise approach from the differences between UTM20 MSS and the local gravimetric geoid. UTM20 MSS and MDT reliability are validated with the latest Technical University of Denmark (DTU) and Collecte Localisation Services (CLS) models along with coastal tide gauges. The findings presented that the UTM20, CLS15, and DTU18 MSS models exhibit good agreement. Besides, UTM20 MDT is also in good agreement with CLS18 and DTU15 MDT models with an accuracy of 5.1 and 5.5 cm, respectively. The results also indicate that UTM20 MDT statistically achieves better accuracy than global models compared to tide gauges. Meanwhile, the UTM20 MSS accuracy is within 7.5 cm. These outcomes prove that UTM20 MSS and MDT models yield significant improvement compared to the previous regional models developed by UTM, denoted as MSS1 and MSS2 in this study.

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“…The measurement of the sea surface height is the concept of satellite altimeter, which can be determined from the time back and forth of the microwave pulse emitted by the satellite altimeter to the sea surface, and the power of the microwave pulse radiation is acknowledged (Chelton et al, 2001;Din et al, 2014;Zulkifle et al, 2019;Hamden et al, 2021). The primary measurement taken by the satellite altimeter is the measurement range, satellite height above the sea surface height as well as the altitude of the satellite with relation to the ellipsoid (orbital height).…”

Section: < Accepted Manuscript >mentioning

confidence: 99%

“…The data extraction for SSH can be completed after the required correction has been made. Two corrections are found in the study, namely range and geophysical correction, to obtain the SSH (Din et al, 2014;Abazu et al, 2017). The range correction for obtaining the SSH was automatically applied in this system by using Equation 1.…”

Section: < Accepted Manuscript >mentioning

confidence: 99%

Estimating bathymetry from multi-mission satellite altimetry data using Gravity-Geologic Method over Malaysian Seas

Tugi¹,

Din²,

Yazid³

et al. 2021

Terr. Atmos. Ocean. Sci.

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The conventional bathymetry survey uses a single beam echo sounder (SBES) and multi-beam echo sounder (MBES). However, this technique is challenging to map large ocean areas due to complexity, cost, and time-consuming. This study aims to estimate the multi-mission satellite altimetry bathymetry across the Malaysian Seas. Six satellite altimeter missions with 11 years of data have been utilised to derive mean sea surface height (MSSH).The Gravity-Geologic Method, a conventional terrain inversion method based on gravity data, is employed in this study to estimate bathymetry using a density contrast of 1.67 g/cm 3 . The gravity-Geologic method utilises gravity effects to be converted into bathymetry by using an inversion process. The density contrast between the bedrock and the seawater influences the predicted bathymetry. Regional gravity was removed from the observed gravity in order to determine the short-wavelength gravity effects by using the control depths from the shipborne measurements. The findings were validated and compared with shipborne bathymetry data from the National Geophysical Data Centre (NGDC) and Global Bathymetry Models. The estimated bathymetry correlation analysis, R, showed the highest values recorded with 0.9942. These findings reveal that the estimated bathymetry using the Gravity-Geologic Method seems to improve the accuracy of the bathymetry by 69% when compared with the ETOPO1 global bathymetry model. Nonetheless, the estimated bathymetry records 38% improvement when compared to the DTU10 global bathymetry model. The final estimated bathymetry model in this study is known as the UTM18 Bathymetry Model.

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Derivation of Sea Level Anomaly Based on the Best Range and Geophysical Corrections for Malaysian Seas using Radar Altimeter Database System (RADS)

Cited by 9 publications

References 14 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

Regional Mean Sea Surface and Mean Dynamic Topography Models Around Malaysian Seas Developed From 27 Years of Along-Track Multi-Mission Satellite Altimetry Data

Estimating bathymetry from multi-mission satellite altimetry data using Gravity-Geologic Method over Malaysian Seas

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