Ami Hassan Md Din

• Senior Lecturer at University of Technology Malaysia

Sea surface salinity (SSS) is a crucial but often overlooked oceanic parameter that significantly influences the environment, mainly marine ecosys-tems. It plays a vital role in shaping the water cycle, predicting the global water balance, and enhancing our comprehension of ocean currents. Generally, Sea Surface Salinity (SSS) measurements obtained...

Global Geopotential Model (GGM) is a mathematical representation of the Earth’s gravity field and geoid, which is developed to provide accurate information about the variations in the Earth’s gravitational potential across the entire globe. Recently numerous organizations and research centres have developed multi GGMs derived from several types of...

The open-source Global Digital Elevation Model (GDEM) such as the Shuttle Radar Topography Mission (SRTM), Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Advanced Land Observing Satellite World-3D (ALOSW3D), and TerraSAR-X Digital Elevation Measurement (TanDEM-X) are among the commonly used GDEM for environmental modelling...

Geodetic methods are used to track the amount of vertical land displacement resulting from the extraction of surplus water from beneath. Excessive use of groundwater without recharge causes sediment deposition. It will bring a lower water level. When water has been pumped through the aquifer, the pore pressure can be reduced in the aquifer and will...

The exploration of tidal variability holds fundamental significance in various practical applications such as safety navigation, port operations, coastal management, environmental planning, and scientific studies. Prior to the implementation of satellite altimeters, tide gauges functioned as the primary data sources for tidal measurements. However,...

Integration of land and marine vertical datums is an important aspect of geospatial reference systems. Therefore, this study has been conducted to identify an optimum approach to integrate the marine and land vertical datums. Two hybrid geoid models have been developed and fitted to the the land levelling datum at benchmark and to the tide gauge-be...

The external gravitational field of the Earth is mathematically represented using spherical harmonic (SH) coefficients in the global geopotential model. Hence, the appropriate global geopotential model for a region needs to determine a reference surface that refers to geoid heights specific for coastal erosion, flood and many more. The aim of this...

Conventionally, information from the tide gauge stations was used to establish the localized tidal datum. However, limitations in coverage, due to the sparse station distribution along the coast, have caused insufficient tidal datum information in some areas. Therefore, this study aims to develop the Peninsular Malaysia Quasi-Continuous Tidal Datum...

Space geodetic and optical imaging techniques are employed to assess the coastal vulnerability index (CVI) in order to adapt to the contemporary approach to coastal classification. Satellite altimeter, Satellite Pour l'Observation de la Terre (SPOT) and integrated multi-satellite retrievals for GPM (IMERG) were among the satellite data used. The va...

Space technology advancements have enabled the acquisition of marine data that support the research on wave energy as an alternative to reduce fossil fuel dependency and mitigate climate change. Malaysia's ocean renewable energy potential lacks attention from local authorities due to insufficient in-situ data, posing challenges in investigating oce...

Tides are dynamic in nature and are generally difficult to predict accurately. When combined with meteorological effects and natural disasters, tidal analysis, and prediction require extensive research with the appropriate methods and software to predict the tides accurately. Some of the commonly used software in Malaysia are GeoTide and TOTIS base...

Geoid represents Earth’s surface, ocean, and gravitational field, which influence the elevations, shape, and mass distribution of the geopotential surface, a hypothetical surface that is perpendicular to the direction of gravity at every point. This geopotential surface serves as a reference for measuring elevations and is used as a fundamental ref...

Coastline extraction plays important functions in coastal resource management, natural resource preservation, and sustainable coastal development. Long-term records of Landsat data series are available for free downloading, being highly potential for coastline extraction. Furthermore, remote sensing imagery systems along with the application of dig...

The Southeast Asian (SEA) region represents a complex coastal geographical location. Most countries in SEA are encircled by the ocean, with lowlands coastal areas. The advantages of long-term satellite altimetry and tide gauge measurements have enabled climate-related research, particularly sea level rise, to be examined extensively in spatial and...

Groundwater demand is increasing due to global population growth, climate change and rapid urbanization, however, poor planning and over-exploitation are leading to rapid depletion of groundwater, which in turn causes adverse impacts such as land subsidence, soil salinization and water quality deterioration. Groundwater storage (GWS) monitoring is...

Since the first launch of the altimeter mission in 1978, it has been significant for ocean studies in many fields. Today, satellite altimeters enable users to use their products for resource assessment. The inadequacy of in-situ data in the coastal and offshore Malaysian Sea has deprived the tidal range resource assessment. The depletion of natural...

During the last decades, freely available GDEMs, such as ASTER, SRTM, and AW3D30, have been widely used in many applications such as for environmental, spatial analysis, research in geomorphology, hydrology, etc. However, these available GDEMs suffer from various limitations. In order to enhance the quality and accuracy of GDEMs, several GDEMs have...

This systematic review article focuses on the geospatial issues of radicalism and extremism. The scholar has intensified the application of geospatial in radicalism and extremism study to understand better the causes, patterns, and trends of the radicalism and extremism incidents. The advanced geospatial approach provides more spatio-temporal infor...

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 Tek...

The delimitation of maritime boundaries plays a significant role in preserving the country’s sovereignty and jurisdiction. The maritime baseline was established based on the combination of maritime basepoints, which represents the Lowest Astronomical Tide (LAT) along the coast. However, the current approach still relies on the limited and sparsely...

In December 2021, the worst flood outbreak in Malaysia occurred in Selangor and Pahang States. Focused on the Klang district, the rainfall amount during the flooding month, which happened in December, has been analyzed. This study aims to examine the rainfall data in this area during the occurrence of the flood. Hourly rainfall data were obtained f...

Virtual Reference Station (VRS), Master-Auxiliary Corrections (MAX), Individualised Master-Auxiliary Corrections (IMAX), Nearest Base, and Network D-GNSS are among the Network Real-Time Kinematic (NRTK) techniques supported by the Malaysia Real-Time Kinematic GNSS Network (MyRTKnet) in providing network-based solutions to users. However, different...

Modern, very precise gravity models are now being created in the discipline of geodesy, using purely satellite techniques. Thanks to the GOCE and GRACE missions, high quality global gravitational models have been computed and made available to users. The models allow for the derivation of gravity field functionals when coupled with reference equipo...

The jackfruit (Artocarpus heterophyllus) is one of six high-value non-seasonal tropical fruits identified as a target for export fruit products in the Malaysia National Key Economic Area (NKEA) report. It is challenging to sustain the jackfruit crop’s productivity and achieve the targets for the growth of premium fruits because of the emergence of...

Erosion and accretion assessment on mangrove-populated riverbanks is complicated as it requires a technique that can reduce the uncertainty of tree and water boundaries through the vegetation line as a geo-indicator. Hence, this study utilised mangrove vegetation line shift detection using a Geographic Information System (GIS) and remote sensing te...

Numerous measurements can be made to extract the forest structure. Forest structure is one of the main aspects of forest management. The precise estimation of forest structure is vital for some forestry applications. Thus, this study presents a novel non-destructive approach for the measurement of forest structure using laser scanning technologies...

Absolute sea-level rise has become an important topic globally due to climate change. In addition, relative sea-level rise due to the vertical land motion in coastal areas can have a big societal impact. Vertical land motion (VLM) in Southeast Asia includes a tectonically induced component: uplift and subsidence in plate boundary zones where both P...

Coastal inundation is one of the most visible consequences of rising sea levels, affecting socioeconomics and human activities. Coastal inundation is the flooding of normally dry land. This is related to the long-term effects of rising sea levels and the short-term effects, such as floods and storm surges. This study aims to establish a coastal inu...

Water stored beneath the Earth’s surface, known as groundwater is a major water supply for living things. The increase in human population leading to high urban development and industrial needs in Malaysia has made the use of groundwater more critical. The current issue faced by Malaysia is the limitation of freshwater source from dam resulting in...

In the diverse domains of earth observation, elevation data are essential for a wide range of applications with various technical requirements and use cases. The Advanced Spaceborne Thermal Emission and Reflection Radiometer-Global Digital Elevation Model (ASTER GDEM), Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010), Shuttle Radar T...

Tidal data has been used to determine long-term water level alterations. Tides are high-powered and notoriously hard to ascertain. Tidal analysis and prediction need substantial study with the requisite approaches, techniques, and tools in conjunction with weather parameters and natural calamities. TOtal TIde Solution (TOTIS) software, which is roo...

Coastal Inundation is the amount of water levels that reach above normal level due to flooding in coastal areas. This natural phenomenon is due to the rising of local sea level. This study aims to develop a coastal inundation simulation along the coastline of Terengganu. To ensure the success of this study, the rate and magnitude of sea level rise...

Tidal correction is vital in shipborne bathymetric survey. This research uses two different tide gauge stations as tidal corrections to reduce the sounding depth. The tide corrections used are from the tidal observation at the survey site and the nearest tide gauge established by the Department of Survey and Mapping Malaysia (DSMM). The issue that...

Sea level is the height of the ocean surface in relation to a benchmark or vertical control point. The rising of sea level has become a crucial topic, which frequently discussed among professionals, government, non-government, and researchers upon their devastating impacts on daily human life and human survival. Nevertheless, there is a great deal...

This study investigates hydrocarbon pollution in the Ahoada community of the Niger Delta region of Nigeria. The study uses a geographic information system (GIS) for mapping oil spill hotspots in the region. The resistivity method was used to delineate the extent of hydrocarbon pollution to a depth of 19.7 m in the Ahoada area of the region. Three c...

This study sought to assess the influence of causal factors related to anthropogenic activities on landslide occurrence in Bukit Antarabangsa, a township northeast of Kuala Lumpur in Ampang Jaya Municipal Council. Anthropogenic factors were chosen based on the township's rapid growth, numerous landslide records and intensity of hillside development...

The Peninsular Malaysia Geodetic Vertical Datum 2000 (PMGVD2000) inherited several deficiencies due to offsets between local datums used, levelling error propagations, land subsidence, sea level rise, and sea level slopes along the southern half of the Malacca Strait on the west coast and the South China Sea in the east coast of the Peninsular rela...

Marine gravity anomalies are crucial parameters and elements for determining coastal and ocean geoid, tectonics and crustal structures, as well as offshore studies. This study aims to derive and develop a marine gravity anomaly model over Malaysian seas from multi-mission altimetry data. Universiti Teknologi Malaysia 2020 Mean Sea Surface Model is...

We describe the development of a hybrid geoid model for Peninsular Malaysia, based on two approaches. The first approach is utilising an ordinary method fitting the gravimetric geoid to the geometric undulation derived from GNSS-levelling data; the second approach directly fits the gravimetric geoid to the reference mean sea level derived from the...

Developing a gravimetric geoid model requires gravity data covering the whole surface of the earth. In practice, terrestrial data within a spherical cap is used, causing a truncation error, which may be minimised if the terrestrial data is combined with a Global Geopotential Model (GGM). The choice of a GGM that fits the observed terrestrial data b...

The effect of the atmospheric error in the spaceborne synthetic aperture radar (SAR) signal is more prominent in Malaysia due to its hot and wet conditions. Because the atmospheric error is believed to happen constantly in space and randomly in time, low-pass filtering in space and high-pass filtering in time is employed to measure it. However, wit...

The evaluation towards global geopotential models represents a significant part in modelling the localised Marine Geoid. The marine geoid provides the vertical reference information in Marine Spatial Data Infrastructures (MSDI) development response to United Nations Sustainable Development Goals 14 for the sustainable development in marine environm...

Geodetic observations in any country or region require a precise local geoid model. Hence, this study has improved the geoid modelling using simulated terrestrial gravity data. However, the sparse and limited number of terrestrial gravity data is the primary reason for the inability to develop an accurate gravimetric geoid model in Iraq, including...

As the need for elevation data grows, it is more vital than ever for users to match the data degree of dependability, precision, and spatial resolution to their specific uses to produce a useful and cost-effective product. This article will describe several sources of elevation data, ranging from space-based to aerial-based techniques, and classify...

Sea level rise has currently become a major issue for climate change. It has globally drawn attention because as time passes, global sea levels will continue to rise at an accelerating rate in the 21st century. It will cause a serious impact on environmental problems such as coastal inundation, salt intrusion, coastal erosion, and other phenomena....

To develop a gravimetric geoid, a Global Geopotential Model (GGM) is required to minimise the truncation error arising from using the Stokes integral with a limited number of gravity data points. The choice of a best-fitting GGM determines the accuracy of a gravimetric geoid solution. Selecting a suitable GGM is a rigorous process, requiring both i...

Shuttle Radar Topography Mission (SRTM), Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER ), Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010), Advanced Land Observing Satellite World-3D (ALOSW3D), and TerraSAR-X Digital Elevation Measurement (TanDEM-X) are open-source Digital Elevation Model (DEM) datasets for en...

With massive geospatial coverage and adequate time series of sea surface height, spatio-temporal multi-mission satellite altimetry tidal modelling emerges as a profound potential solution for increasing accuracy and minimising variation across multiple offshore applications. Therefore, this article attempts to review the current implementation of s...

Assessing large scale topography and surface elevation changes usually requires temporal remote sensing and aerial photogrammetrically-based data. Usually, very high resolution (VHR) elevation data, for instance, digital surface models (DSM) from light detection and ranging (LiDAR) and unmanned aerial vehicles (UAV), are used to visualise the chang...

Land subsidence are deposition processes that lead to the earth's surface sinking slowly or suddenly as a result of movement of underground structures. It occurs when the amount of underground water has been pumped out from the certain types of sedimentary rock such as fine grains. Over-exploitation of subsurface water causes compression between cl...

This study investigates hydrocarbon pollution in Ahoada community of the Niger Delta region of Nigeria. The study uses geographic information system (GIS) for mapping oil spill hotspots in the region. Resistivity method was used for delineating the extent of hydrocarbon pollution to a depth of 19.7m at Ahoada area of the region. Three categories of...

Technology advancement has urged the development of Interferometric Synthetic Aperture Radar (InSAR) to be upgraded and transformed. The main contribution of the InSAR technique is that the surface deformation changes measurements can achieve up to millimetre level precision. Environmental problems such as landslides, volcanoes, earthquakes, excess...

Estimating surface elevation changes in mangrove forests requires a technique to filterthe mangrove canopy and quantify the changes underneath. Hence, this study estimates surfaceelevation changes underneath the mangrove canopy through vegetation filtering and Difference ofDEM (DoD) techniques using two epochs of unmanned aerial vehicle (UAV) data...

Upwelling is a vital ocean behaviour, especially for the Fisheries Industry, where upwelling will help to detect fish ground at a particular ocean area. However, the study of upwelling is minimal and not well understood due to some reasons and constraints, such as limited observation. Upwelling lacks a comprehensive in-situ observation system where...

Global sea level is expected to rise consistently in the future, causing severe damage to the coastal areas and threatening nearby populations. Malaysian coast has numerous low-lying areas, which are at risk of inundation resulting from the increment of sea level, particularly in Kelantan coast. In this study, the potential vulnerability impact of...

The description of the earth’s gravity field is usually expressed in terms of spherical harmonic coefficients, derived from global geopotential models. These coefficients may be used to evaluate such quantities as geoid undulations, gravity anomalies, gravity disturbances, deflection of the vertical, etc. To accomplish this, a global reference norm...

A detailed understanding of wind characteristics is very important for offshore wind energy development. A 26 years of wind speed data (1993-2018) were retrieved using Radar Altimeter Database System (RADS) to assess the potentiality of offshore wind energy in Terengganu waters. Seasonal assessment and wind energy density derivation was carried out...

The Geocentric Datum of Malaysia (GDM200) is realised with respect to International Terrestrial Reference Frame (ITRF) 2000 at epoch 2nd January 2000. In comparison with the 2000 frame, ITRF2014 has significant improvement in terms of its definition and realisation. Moreover, several great earthquakes that struck the Indonesian region for the past...

Height or depth on the surface of the Earth is the crucial element in the three-dimensional coordinate system. Commonly, the height or depth value will denote a particular reference surface known as a vertical datum. Conventionally, the vertical datum is divided into two major categories which are Geoid/ Mean Sea Level and Lowest Astronomical Tide....

Gravity data and computing gravity anomalies are regarded as vital for both geophysics and physical geodesy fields. The mountainous areas of Iraq are characterized by the lack of regional gravity data because gravity surveys are rarely performed in the past four decades due to the Iraq-Iran war and the internal unstable political situation of this...

Satellite altimetry technology has been widely used in exploring Earth’s Ocean activities. Achieving a remarkable accuracy in measuring sea level for ocean tide analysis has led the local researchers to investigate more details on tidal behaviour in the regional area. This study is an attempt to assess the reliability of derived tidal constituents...

Estimating surface elevation changes at bare earth riverbank is challenging because of the non-visibility effect of this phenomenon, especially for short observation periods. Hence, the spatio-temporal detection at a short-term period determines the geomorphological changes by comparing the same area at different observation epochs. This study atte...

Virtual Reference Station (VRS), Master-Auxiliary Corrections (MAX) and Individualised Master-Auxiliary Corrections (IMAX) are among the Network Real-Time Kinematic (NRTK) techniques supported by Malaysia Real-Time Kinematic GNSS Network (MyRTKnet) in rendering network-based solution to users. However, different network corrections have different l...

Sustaining coastal ecosystems from the impact of rising sea levels is vital since they offer environmental services that are considered critical for humans’ well-being. The Coastal Vulnerability Index (CVI) is favoured in coastal hazard studies, as it provides a predictive approach to coastal changes through its simple numerical basis in classifyin...

We compute a new gravimetric geoid model for Peninsular Malaysia (PMGG2020) based on the Royal Institute of Technology (KTH) method. The PMGG2020 was computed from 8474 terrestrial gravity points, satellite altimetry-derived gravity anomaly (DTU17), 24,855 airborne gravity data, and the TanDEM-X Digital Elevation Model. All the gravity datasets wer...

The essential parameter in computing three-dimensional coordinate system is the height or depth of the Earth’s surface. It represents a particular reference surface that recognised as a vertical datum. The vertical datum is alienated into two foremost categories recognised as Mean Sea Level and Lowest Astronomical Tide. Different modifications appr...

Tidal datums are important for calculating spatial coordinates especially the elevation relative to mean sea level and also crucial for defining the state sovereignty boundaries over maritime areas. Normally, sea level was measured by tide gauges along the coastal for tidal datums computation. However, knowledge of tides is still restricted in coas...

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 mis...

This special issue (SI) includes papers related to some recent efforts on geoid modeling in the Asia-Pacific region. In total, twelve papers were submitted to this SI, covering geoid models in Australia, mainland China, India, Indonesia, South Korea, Malaysia, Nepal, the Philippines, Taiwan, and Thailand. The methods for geoid modeling are rather d...

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 estab...

Assessing large scale topography and surface elevation changes usually require temporal remote sensing and aerial photogrammetrically-based data. Usually, very high resolution (VHR) elevation data, for instance, digital surface model (DSM) from light detection and ranging (LiDAR) and unmanned aerial vehicle (UAV) are used to visualise the changes o...

Malaysia is situated at Sunda plate that experience highly dynamic of earth’s crust with frequent earthquake and volcano activities. The effect of plate motion causing the static-based geodetic reference frame in Malaysia is no longer relevant to support the centimeter level of Global Positioning System (GPS) application. Therefore, an updated Sund...

Fluid extraction or injection from reservoirs, which corresponds to subsidence or uplift, can cause offshore platform surface deformation. Extremely large deformation of offshore platforms often lead to production losses, threat to the structure integrity and loss of life. Therefore, preventing severe deformation incidents is important by monitorin...

Deriving a riverbank line at a tidal river is complicated, since dynamic factors such as tide and slope topography influence its location. Hence, this study utilises the Unmanned Aerial Vehicle (UAV), geodetic, and tidal data to identify the exact riverbank line based on Mean Sea Level (MSL) value from UAV products. We carried out two epochs of UAV...