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Staff Highlights: Prof. Joseph AWANGE

Consistently ranked among the world's top 2% most-cited scientists since 2020 (Stanford), Joseph AWANGE is a Professor of Environmental Geoinformatics at The Hong Kong Polytechnic University's Land Surveying and Geoinformatics (LSGI) Department, having previously worked at Curtin University, Australia for over 18 years.   Prof. AWANGE began his academic journey with BSc and MSc degrees in Surveying from the University of Nairobi, Kenya. His exceptional promise was recognized through a DAAD merit scholarship, enabling him to earn a second MSc and a PhD in Geodesy at Stuttgart University, Germany, under the supervision of the late, world-renowned geodesist Prof. Erik W. Grafarend. His postdoctoral training was completed at Kyoto University (Japan) under the prestigious Japanese Society for the Promotion of Science (JSPS) Fellowship.   His distinguished research career has been honoured with several international awards, including multiple Alexander von Humboldt Fellowships, a 2015 JSPS Fellowship, and recognition from the Brazil Frontier of Science. Beyond his research, Prof. AWANGE holds a Postgraduate Diploma in Environmental Impact Assessment from Murdoch University, Australia. He actively contributes to the global scientific community as the Acquisition Manager for Earth Sciences, Geography, and Environment at Springer Nature, and as an Associate Editor for the top-ranked journal Remote Sensing of Environment and Science of Remote Sensing. His scholarly output includes more than 26 books and over 260 high-impact journal articles, and he has cultivated the next generation of scientists by mentoring more than 50 BSc (Honours), MSc, PhD, and postdoctoral researchers globally.   We are at a pivotal moment. By employing cutting-edge Artificial Intelligence (AI), we can now unravel complex environmental challenges that were previously unachievable, fully unlocking the potential of Earth Observation (EO) data for environmental monitoring and applications, i.e., Environmental Geoinformatics. Prof. Joseph AWANGE who joined the LSGI in November 2024 leads the Environmental Geoinformatics team whose goal is to integrate geospatial science, environmental science, and informatics to tackle our planet's most pressing issues. Their core focus is on leveraging AI as a powerful engine to manipulate massive EO datasets, providing critical insights into: ➡️ Climate change, extremes, and variability ➡️ The impacts of climate change on our environment ➡️ Hydroclimate dynamics   Specifically, the team emphasizes the importance of geospatial data and AI in providing spatially explicit, synoptic, time-series data for various earth system processes. The teams' interest is to bring the three multidiscipline (Geoinformatics, Climate, and AI) together, i.e., utilise AI as a powerful computing engine to manipulate EO data to assess, evaluate and understand the impacts of climate extremes, climate variability and climate change on the environment. This is the future of environmental science: where Geoinformatics, Climate Science, and AI/ML converge to create actionable, data-driven solutions. Professor AWANGE's teaching transforms geospatial science education through his acclaimed textbooks. He bridges theory and practice for both surveyors and engineers, fostering a deep, shared understanding. His project-based approach and clear computational focus equip students with the practical skills and collaborative mindset essential for modern professional success.   A Glimpse at Their Impact: ✔️ Bridging Continents and Disciplines in Hydroclimate Science: For almost two decades, Prof. Joseph AWANGE has been at the forefront of hydroclimate research, applying geospatial expertise to water-related challenges across Australia, Africa, Asia, and South America. This global perspective culminates in his authoritative work on one of the world's great lakes. His upcoming 2026 book, "Lake Victoria from Space and AI Perspective," is more than a publication—it's a comprehensive decision-support tool. By harnessing the power of Artificial Intelligence and five decades of satellite data, Prof. AWANGE provides unprecedented insights into the Lake Victoria Basin. His research demystifies complex phenomena, from the floating islands that threaten hydropower to the dramatic swings in water levels that impact millions. This work is celebrated for its cross-disciplinary value. As Professor C.K. Shum notes, it articulates climatic impacts and their socio-economic consequences, making it vital reading for scientists, policymakers, and engineers committed to building resilient futures (e.g., Awange 2026; https://link.springer.com/book/9783031847356).   ✔️ Pioneering Climate Science: Filling Africa's Critical Data Gap: Accurate climate modeling for Africa has long been hampered by a critical lack of upper-atmosphere data. Traditional radiosonde measurements are sparse, leaving the continent's tropopause—a key climate boundary—poorly understood and leading to significant gaps in global climate models. Led by Professor AWANGE, a groundbreaking project has successfully harnessed two decades (2001-2020) of GPS Radio Occultation (GNSS-RO) satellite data to fill this void (e.g., Ding et al., 2022). Our research confirms that GNSS-RO provides highly accurate temperature profiles, outperforming leading reanalysis models which exhibit a consistent warm bias. This breakthrough establishes GNSS-RO as a reliable tool for infilling missing data, finally enabling a detailed study of Africa's upper atmosphere. This new data revealed the profound influence of global and regional climate drivers on the African tropopause. The study identified teleconnections from major phenomena like El Niño (ENSO) and the Quasi-Biennial Oscillation (QBO), as well as complex interactions between coupled drivers such as ENSO and the Indian Ocean Dipole. Regional features like the African Easterly Jet were also shown to have a direct local impact. By bridging this major data gap, our work opens the door to precise quantification of climate trends and a deeper understanding of the atmospheric processes affecting Africa, marking a vital step towards more resilient environmental planning.   ✔️ Unlocking Water Solutions for Food Security in the Greater Horn of Africa: In the Greater Horn of Africa (GHA), perennial food insecurity and climate extremes create unbearable conditions for over 310 million people. While often attributed to drought, the crisis is far more complex, rooted in a web of environmental, political, and socio-economic challenges. Professor AWANGE’s groundbreaking new book provides the first comprehensive analysis of this crisis through the lens of hydroclimate science. Leveraging state-of-the-art data from NASA's GRACE and GRACE-FO satellites, alongside hydrological models and centennial rainfall records, his work delivers an unprecedented view of the region’s water resources. He presents a powerful paradox: the GHA is home to immense freshwater reserves, including Lake Victoria and the Ethiopian Highlands, yet its potential remains locked. Professor AWANGE’s research identifies the critical barriers, from obsolete Nile treaties and poor governance to the devastating "triple threats" of locusts, climate change, and COVID-19. More than just diagnosing the problem, his work charts a path forward. By quantifying the actual availability of surface and groundwater, this book provides the essential scientific foundation needed to break the cycle of crisis. It empowers policymakers and stakeholders to unlock the region’s agricultural potential through sustainable irrigation and resilient pastoralism, offering a vital step from coping with drought to achieving lasting food security (e.g., Awange 2022; https://link.springer.com/book/10.1007/978-3-030-91002-0).   ✔️ Bridging the Digital and Physical Worlds: From AI Algorithms to a Thirsty Planet: Professor Joseph AWANGE stands at a unique intersection, wielding the abstract power of mathematics to solve the tangible problems of our changing planet. With a career spanning the globe, he has dedicated himself to understanding Earth's hydroclimate systems—from the vast basin of Lake Victoria to water resources on four continents. But observing complex environmental systems is not enough. Prof. AWANGE also pioneers the sophisticated computational tools needed to decipher them. In the realm of Mathematical Geoscience, his work includes the co-authored second edition of Hybrid Imaging and Visualization (Awange et al., 2025; https://link.springer.com/book/9783031728167), a collaboration with colleagues from Hungary; the late Professor Béla Paláncz and Professor Lajos Völgyesi. This text is a seminal resource where he introduces next-generation AI tools such as the Black Hole optimization algorithm and neural networks for time series analysis. These are not just theoretical exercises; they are the very engines that power the AI-driven insights in his applied hydroclimate research. This synergy defines his work: using machine learning to classify a drought's fingerprint, optimizing models to predict lake level rise, and providing policymakers with the clear, data-driven intelligence needed for action. He is not only mapping the world's water but also inventing the compass to navigate its future.   ✔️ Bridging Disciplines: A Foundational Resource for Surveyors and Engineers: In the interconnected fields of engineering and surveying, a shared understanding of precise measurement and robust computation is paramount. Professor AWANGE’s comprehensive textbooks, Engineering Surveying (Walker and Awange 2018, 2020; https://link.springer.com/book/10.1007/978-3-319-53129-8) and Surveying Computations (Walker and Awange 2026; https://link.springer.com/book/10.1007/978-3-030-45803-4), are masterfully designed to bridge the traditional gap between these disciplines. They provide an indispensable foundation for aspiring surveyors while giving engineers the deep-seated competency needed for effective collaboration and project oversight. These works stand out for their systematic, project-based pedagogy, refined through years of academic experience. They guide readers from fundamental principles—coordinate systems, traversing, and earthwork—to advanced computational techniques like least squares adjustment and complex alignment design. With hundreds of diagrams, worked examples, and practical exercises, the material emphasizes clarity and real-world application. For the surveyor, the books offer a rigorous computational foundation and a clear exposition of the methods behind their craft. For the engineer, they demystify surveying processes, fostering an appreciation for data quality and the critical decisions surveyors make. Together, these volumes create a common language, ensuring that both professionals are equipped to tackle the intricate challenges of modern construction, mining, and environmental monitoring with shared precision and understanding.   More details can be found in his personal website (https://www.josephawange.org/index.html) as well as LSGI website: https://www.polyu.edu.hk/lsgi/people/academic-staff/prof-joseph-awange/   [1] Awange JL (2026). Lake Victoria from Space and AI Perspective. Second Edition. Springer Nature Switzerland AG. [2] Ding, T., Awange, J. L., Scherllin-Pirscher, B., Kuhn, M., Khandu, K., Anyah, R., et al. (2022). GNSS radio occultation infilling of the African radiosonde data gaps reveals drivers of tropopause climate variability. Journal of Geophysical Research: Atmospheres, 127, e2022JD036648, doi: 10.1029/2022JD036648. [3] Awange JL (2022). Food Insecurity & Hydroclimate in Greater Horn of Africa. Potential for Agriculture Amidst Extremes. Springer Nature Switzerland AG. ISBN 978-3-030-91001-3, doi: 10.1007/978-3-030-91002-0 [4] Awange JL, Palancz B and Völgyesi L (2025) Hybrid Imaging and Visualization. Employing Machine Learning with Mathematica - Python. Second Edition. Springer Nature International, Berlin. ISBN 978-3-031-72816-7 [5] Walker J, Awange JL, (2026) Surveying Computations. A Necessity for Surveyors and Engineers. Springer International Publishing AG. ISBN 978-3-031-94382-9 [6] Walker J, Awange JL, (2020) Surveying for Civil and Mining Engineers. Acquire the skills in weeks. Springer International Publishing AG. ISBN 978-3-030-45802-7, doi: 10.1007/978-3-030-45803-4. [7] Walker J, Awange JL, (2018) Surveying for Civil and Mining Engineers. Theory, Workshops and Practicals. Springer International Publishing AG. ISBN 978-3-319-53128-1, doi: 10.1007/978-3-319-53129-8.

8 Oct, 2025

Research

Prof Wallace LAI WaiLok

LSGI Researchers Develop Advanced Technologies for Underground Utilities Inspection

Ir Prof. Wallace Wai Lok LAI, Associate Head (Teaching) and Professor at the Department of Land Surveying and Geo-informatics (LSGI), and his research team have leveraged advanced underground exploration technologies to develop underground utilities inspection systems that support early detection of urban infrastructure anomalies, including voids and pipe leakages, for enhanced urban management.   Press Release: English - https://polyu.me/46xOdS4 Chinese - https://polyu.me/4nvg77q Online Coverage: Mirage - https://polyu.me/42mKkgq Ta Kung Pao - https://polyu.me/488TXmD Wen Wei Po - https://polyu.me/3VIW896 Bastille Post - https://polyu.me/4o0IOsB HK01 - https://polyu.me/4pPsNYc

3 Oct, 2025

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PolyU Info Day 2025

Attracting over 43,000 visitors, PolyU Info Day on 27th October 2025 held at the campus was a major success. The Department of Land Surveying & Geo-Informatics (LSGI) showcased its cutting-edge programmes and facilities to future students. The event's success was fueled by the enthusiastic participation of LSGI academic staff, supporting staff, student ambassadors, and alumni. Throughout the event, the visitors engaged in a variety of activities, including programme consultations, BSc admission talks, alumni sharing, and guided lab tours. A special highlight went to the guided tour to HiVE led by Ir Prof. Wallace LAI, Associate Head and Professor, who shared his insights related to Hong Kong’s WWII history. Participants also engaged with an immersive art-tech exhibition showcased in a 4D CAVE. During the two BSc admission talks, Ir Prof. Wallace LAI and Dr. Sissi CHEN, Deputy Programme Leader and Lecturer, offered the comprehensive insights of the curriculum and the opportunities available within the LSGI programmes. Meanwhile, two LSGI alumni, Mr. Alan NG, Land Surveyor at the Lands Department, and Ms. Pinky LEE, Executive Director of Signature Consulting and Engineering Ltd shared their professional experiences on the career opportunities in both the public sector and private sector. Their experiences provided the visitors with a real-world perspective, helping them envision the diverse paths available in the field of land surveying and geo-informatics.

27 Sep, 2025

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LSGI Scholar Received 'STEM Outstanding PhD Thesis Award' on Soil Drought and Climate Change

We are pleased to announce that Dr. Yamin QING, a PhD student in LSGI, has been awarded the 'PolyU PhD Thesis Award - STEM Outstanding Award'. Under the supervision of Prof. Shuo WANG, Dr. QING completed her thesis “Advancing the Understanding of Soil Drought Dynamics and Mechanisms in a Warming Climate”. Dr. QING's research addresses a critical challenge of the climate change. The sudden and severe droughts would endanger food security, water resources, and livelihoods. These rapidly evolving droughts could develop within days, leaving farmers, communities, and governments little time to respond. She developed a new and reliable method to identify such events, enabling earlier warnings that can help safeguard crops, secure water supplies, and reduce wildfire risks. Dr. QING reveals that droughts are intensifying more quickly than previously understood, even in regions once considered as water-secure. The study highlights a critical and dangerous situation: sudden soil drying often precedes dangerous heat waves or leads to extreme floods when rains return. By understanding soil drought dynamics and its critical role in multi-hazard climate extremes, her research provides knowledge that helps societies better prepare, protect vulnerable communities, and build sustainable resilience. Congratulations Dr. QING!

26 Sep, 2025

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PolyU Partners with Lands Department to Advance Geospatial Innovation and Smart City Development

The Hong Kong Polytechnic University (PolyU) and the Lands Department of the HKSAR Government signed a Memorandum of Understanding (MoU) on 12 September 2025. The partnership aims to drive smart city development and digital transformation in Hong Kong.    The MoU was signed at PolyU by Prof WANG Zuankai, Associate Vice President (Research and Innovation), and Mr CHANG Kwok-fai, Deputy Director (Survey and Mapping) of the Lands Department, in the presence of representatives from both organisations. Lands Department representatives: Mr CHANG Kwok-fai, Deputy Director (Survey and Mapping) Mr CHU Siu-ki, Assistant Director (Survey and Mapping) Mr. AU Chi-ho, Tommy, Chief Land Surveyor (Development) Mr. CHOI Wai-man, Raymond, Chief Land Surveyor (Land Information Centre) Mr. YEUNG Cheuk-man, Danny, Chief Land Surveyor (Technical)  Mr. CHAN Ka-lok, Alvin, Senior Land Surveyor (Technical Information) The PolyU representatives: Prof. WANG Zuankai, Associate Vice President (Research and Innovation) of PolyU Prof. CHEN Qingyan, Director of the PolyU Academy for Interdisciplinary Research (PAIR) Prof. CHEN Wu, Head of LSGI Prof. DING Xiaoli, Director of the PolyU Research Institute for Land and Space (RILS) Prof. John SHI Wenzhong, Director of the PolyU Otto Poon Charitable Foundation Smart Cities Research Institute (SCRI) Prof. WENG Qihao, Director of Research Centre for Artificial Intelligence in Geomatics (RCAIG)   Welcoming the partnership, Prof Wang said: ‘From urban planning and environmental monitoring to disaster response and resource management, spatial data and artificial intelligence are transforming the way we understand and interact with our environment. By bringing together the Survey and Mapping Office’s authoritative expertise with PolyU’s academic excellence and innovative drive, this MoU will strengthen Hong Kong’s position as a global smart city leader and create a legacy of innovation and prosperity for our community.’ Mr Chang remarked: ‘This partnership combines PolyU’s research excellence with the Lands Department’s practical experience, marking a significant step towards modernising Hong Kong’s geospatial technologies. We will promote innovative solutions that enhance land administration efficiency and support the city’s smart development.’   Prof. CHEN Wu, Head and Chair Professor of LSGI, emphasized the significance of the partnership, “SMO possesses valuable datasets, regulatory frameworks and practical insights into urban challenges, while PolyU contributes cutting-edge research, technical expertise, and innovative solutions. By working together, we can bridge the gap between theory and practice, ensuring that scientific advancements are effectively translated into real-world applications. Ultimately, this collaboration will accelerate the creation of a smarter, more sustainable Hong Kong by leveraging the strengths of both sectors to address complex urban issues and improve the quality of life for citizens.”   Under the MoU, four PolyU units — LSGI, RILS, SCRI and RCAIG — will collaborate with the Survey and Mapping Office (SMO) on research, education and knowledge exchange in land surveying, geographic information systems, remote sensing, smart city applications, AI and location-based technologies. The parties plan to establish a joint research centre. PolyU will contribute personnel and technical resources, while SMO will provide professional and industry insights. The collaboration will also explore training for industry practitioners and relevant government staff on the latest surveying and geospatial technologies.   This MoU underscores PolyU’s commitment to impactful research and further strengthens Hong Kong’s leadership in geomatics and smart city development.

12 Sep, 2025

News

Prof Wallace LAI WaiLok 2

LSGI Scholar Highlights Preserving Hong Kong's WWII Heritage in Nanfang Daily

Professor Lai Wai-lok, Associate Head (Teaching) of the Department of Land Surveying and Geo-Informatics (LSGI) was recently interviewed by Nanfang Daily to share his project, "Unfolding Hong Kong's Lost World War II Heritage". A key focus of the project is creating immersive experiences for the public. Using advanced technologies like global navigation satellite systems and ground-based laser scanning, the team has developed 3D models that transport viewers back in time to these historical sites. “When you walk into this immersive image, it’s like being on a battlefield and experiencing history firsthand,” Lai explained. He believes that when young people see these historical sites in a tangible way, it will spark their curiosity and encourage them to ask questions about the past. “This is a good start,” he remarked, emphasizing the collective responsibility to keep history from being forgotten. Professor Lai concluded the interview by stressing the urgency of documenting these relics before they disappear entirely. “We are not doing science for science, but for inheritance,” he stated, reaffirming the project's commitment to preserving Hong Kong’s rich historical legacy. Click here for more details of the interview.

11 Sep, 2025

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LSGI Student won ESRI Young Scholars Award 2025

Congratulations to the PolyU LSGI student - Mr. TONG Lai Yiu Jimmy has won the Esri Young Scholars Award 2025 (Individual Application). The Eris Young Scholars Award 2025 is a competition aimed at recognising exemplary work in geospatial sciences and the creative use of applications for a smarter Hong Kong.  The awarded project titled “Assessing Rooftop Solar Energy Potentials in Hong Kong” aims to enhance rooftop solar energy assessment in Hong Kong by developing a GIS-based framework and algorithms to improve the accuracy of estimation models. It investigates the spatial-temporal patterns of solar energy potential across different districts and land-use categories, as well as the influence of cloud cover on solar radiation received by rooftops. Additionally, the research explores the relationship between rooftop solar energy potential and urban building morphology, including factors such as building density, height, and roof area. It also evaluates the benefits of rooftop solar energy in terms of energy savings, carbon reduction, and economic value. The findings indicate that over 90% of rooftop solar projects yield profitable returns, with more than 60% achieving an economic payback period of six years. This research provides valuable insights for promoting green building and sustainable development in Hong Kong. Congratulations on this remarkable achievement, contributing to a sustainable future through innovative research! For more information about the project, please visit Assessing Rooftop Solar Energy Potentials in Hong Kong.

10 Sep, 2025

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PolyU co-organised the 3rd International Deep Space Exploration Conference (Tiandu Forum)

From 4 to 5 September 2025, the 3rd International Deep Space Exploration Conference (Tiandu Forum) was successfully held in Hefei, Anhui Province. Attracting over 400 participants from various regions to discuss frontier topics in deep space exploration, advanced technology, and scientific research. Prof. WU Bo, Associate Head of the Department of Land Surveying and Geo-Informatics (LSGI) and Research Centre for Deep Space Explorations of PolyU, served as a conference co-organizer, underscoring the University's leading position in space research. He hosted an academic and scientific session that stimulated fruitful discussions and knowledge sharing among experts in the field. A notable highlight was the official induction of PolyU into the International Deep Space Exploration Association (IDSEA). Professor Wu accepted the membership certificate on behalf of the University, marking a significant milestone in strengthening PolyU's international footprint in space research. Looking forward, PolyU will participate in the 76th International Astronautical Congress in Sydney, Australia, hosting a booth to showcase its latest space research and innovations. On 30 September, PolyU will also organise the ‘PolyU Space Connect’ event in Sydney, bringing together global space experts and innovators to exchange ideas and explore collaborations. Registration is now open to interested partners.  

5 Sep, 2025

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PolyU LSGI STEAM Talks for Secondary Schools Students 2026

The Department of Land Surveying and Geo-Informatics (LSGI) is organizing a STEAM Talk Series with the aim of introducing daily life applications and potential developments in Geo-Informatics. The series will cover a wide range of topics, including Land Surveying, Remote Sensing, Global Positioning System (GPS), Global Navigation Satellite System (GNSS), Geographic Information Science (GIS), and Underground Utilities Imaging and Diagnosis. We are delighted to invite all secondary schools to participate in our STEAM Talk Series in 2026. STEAM Talk Series Topics: Smart City and 3D Mapping in HK (智慧城巿及三維地圖的應用) Global Navigation Satellite System (GNSS) and Smart City Applications (全球導航衛星系統與智慧城市應用) Unfolding HK Lost WWII and Cultural Heritage with Geo-spatial Science (尋找隱世二戰及文化遺跡:地理空間科學篇) Problem Solving by Digital Maps and Geographic Information System (GIS) (以數字地圖和地理訊息系統解難) Seeing and Unseen Underground Utilities in 3D (三維地下管線測量) Observing and Measuring the Earth from Space (從太空觀測地球) IoT and Remote Sensing for Tree Monitoring (如何利用IoT及遙感技術監測城市樹木) Date:   From October 2025 to July 2026 (exact date to be suggested by school) Target audience:   S.1 – S.6 Students (both Art and Science students are welcome) Medium:   Cantonese or English Venue:   Secondary School or PolyU (a lab tour to be arranged at PolyU) Speaker:   Academic Staff from the Department of LSGI Please click here to know more the description for the STEAM talk topics. Interested parties please fill in the online application form to indicate your preference of talk. For any questions, please feel free to contact Ms. April SO at 2766 4350 or april.so@polyu.edu.hk. Please find more about LSGI at our Facebook, Instagram or Youtube channel.  LSGI Undergraduate Programme in 2026/27 BSc (Hons) Scheme in Spatial Data Science and Smart Cities (JS3130)

3 Sep, 2025

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PolyU researchers use novel satellite laser ranging technique to reveal accelerated global average sea-level rise with 90 mm surge over past 30 years

The rise in global mean sea level (GMSL) is a critical indicator of climate change. The Hong Kong Polytechnic University (PolyU) researchers have utilized advanced space geodetic technologies to deliver the first precise 30-year (1993-2022) record of global ocean mass change (also known as barystatic sea level), revealing its dominant role in driving GMSL rise. Their research further indicates that GMSL has been increasing at an average rate of approximately 3.3 mm per year with a notable acceleration observed, highlighting the growing severity of climate change. The research findings have been published in the Proceedings of the National Academy of Sciences. GMSL is primarily driven by two factors: the thermal expansion of seawater — as the oceans absorb around 90% of the excess heat in the Earth’s climate system — and the increase in global ocean mass, which is mainly caused by the influx of freshwater from melting land ice. Therefore, long-term monitoring of global ocean mass change is essential for understanding present-day GMSL rise. A research team led by Prof. Jianli CHEN, Chair Professor of Space Geodesy and Earth Sciences of the PolyU Department of Land Surveying and Geo-Informatics (LSGI) and a core member of the PolyU Research Institute for Land and Space, together with Dr. Yufeng NIE, Research Assistant Professor of LSGI and the lead and corresponding author of the research, has, for the first time, provided direct observations of global ocean mass estimates between 1993 and 2022 by utilizing time-variable gravity field data derived from satellite laser ranging (SLR). In the past, scientists have relied on long-term observations from satellite altimetry to project sea-level rise. Barystatic sea level records based on satellite gravimetry only became available with the launch of the Gravity Recovery and Climate Experiment in 2002. SLR is a traditional space geodetic technique used to accurately measure the distance between satellites and ground stations via laser ranging. However, fundamental constraints of SLR, such as the limited number of satellites and ground stations, the high altitude of the satellites (which means SLR-derived gravitational changes capture only the longest wavelengths) and the low-degree gravitational measurements, have restricted its direct application in estimating ocean mass change. To effectively utilize SLR-derived gravitational fields for accurate estimates of ocean mass change, the research team implemented an innovative forward modelling technique that tackles spatial resolution limitations by incorporating detailed geographic information of ocean-land boundaries. This approach enables long-term monitoring of global ocean mass changes. The research revealed that an increased rate of GMSL resulted in a global average sea-level rise of approximately 90 mm between 1993 and 2022, with about 60% of this rise attributable to ocean mass increase. Since around 2005,  the rise in GMSL has been primarily driven by the rapid increase in global ocean mass. This overall increase is largely driven by the accelerated melting of land ice, particularly in Greenland. Throughout the entire study period, land ice melt from polar ice sheets and mountain glaciers accounted for over 80% of the total increase in global ocean mass. Prof. Jianli CHEN said, “In recent decades, climate warming has led to accelerated land ice loss, which has played an increasingly dominant role in driving global sea-level rise. Our research enables the direct quantification of global ocean mass increase and provides a comprehensive assessment of its long-term impact on sea-level budget. This offers crucial data for validating coupled climate models used to project future sea-level rise scenarios.” Dr. Yufeng NIE said, “The research showed that the ocean mass changes derived from SLR analysis align well with the total sea level changes observed by satellite altimeters, after accounting for the effect of ocean thermal expansion. This demonstrates that the traditional SLR technique can now serve as a novel and powerful tool for long-term climate change studies.” Online coverage: Medium - https://polyu.me/4272D8X Guangzhou Daily - https://polyu.me/4p2SZ16 Nanfang Daily - https://polyu.me/4p5N3V2 Science Daily - https://polyu.me/4kTZzFC Mirage - https://polyu.me/4cIzNlt            

2 Sep, 2025

Research

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