Xi Xi Lu

Xi Xi Lu
National University of Singapore | NUS · Department of Geography

Doctor of Philosophy

About

293
Publications
142,798
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
10,424
Citations
Introduction
I study fluvial sediment loads/fluxes/yield and riverine carbon cycles of large Asian rivers, e.g. Yellow River (Huanghe), Yangtze River (Changjiang), Pearl River (Zhujiang), Red River (Honghe), and Mekong River. Recent research focus includes sediment and carbon fluxes in the headwater regions of large Asian rivers.

Publications

Publications (293)
Article
Riverine islands are widespread fluvial landforms with exceptional economic and environmental values. However, anthropogenic pressures have further induced drastic changes worldwide in fluvial islands, which endanger fluvial organism habitation and enable potential ecological degradation. Here, the hydromorphodynamics on these prominent riverine la...
Article
Full-text available
Shallow eutrophic lake with submerged aquatic vegetation (SAV) has high primary productivity, but its diurnal variation of CO2 flux remains unclear. Moreover, algae bloom has become a serious environmental problem; however, its effects are still unclear. Thus, monthly measurement in Lake Ulansuhai, a shallow eutrophic lake in China, was conducted t...
Article
Full-text available
Traditionally, morphological channel change is monitored using field observations such as cross-section measurements or bathymetry surveys. However, in basins with poor field data, it is difficult to monitor historical changes of the river channel. Using only water level and discharge data from the Lower Mekong Basin (LMB), we plotted the stage cur...
Article
Full-text available
Monitoring and quantifying suspended sediment concentrations (SSC) in estuaries such as the Pearl River Estuary (PRE) provide crucial information for environmental processes, hydrological infrastructure, and navigation. Traditional SSC mapping based on in situ investigations lacks the spatial coverage necessitated by detailed analysis. In this stud...
Article
Full-text available
The utilization of regional climate methods (RCMs) to predict future climate is an important study under the changing environment. The primary objective of the paper is to correct the temperature and precipitation simulations for the period of 1980–2005 and 2026–2098 in the Wei River Basin (WRB), to evaluate the performance of RCMs for the period o...
Article
Shallow eutrophic lakes contribute disproportional to the emissions of CO2 and CH4 from inland waters. The processes that contribute to these fluxes, their environmental controls, and anthropogenic influences, however, are poorly constrained. Here, we studied the spatial variability and seasonal dynamics of CO2 and CH4 fluxes across the sediment-wa...
Article
Full-text available
Cascade damming can shape land surfaces; however, little is known about the specific impacts of dam construction on watershed land cover changes. Therefore, we developed a framework in which remote sensing, transition patterns, and landscape metrics were coupled to measure the impact of dam construction on watershed land cover changes and landscape...
Article
Full-text available
As an important soil and water conversation endeavor, the 'Grain for Green' project launched by the Chinese Central Government almost doubled the vegetation cover on the Loess Plateau between 1999 and 2013. The corresponding vegetation restoration considerably diminished slope erosion throughout the Loess Plateau, although erosion in gullies remain...
Article
Soil organic carbon (SOC) and soil inorganic carbon (SIC) are key components of the global wetland soil carbon pool, which plays a crucial role in carbon cycling. However, research on carbon storage in riparian wetland soils, especially in inland steppe river environments impacted by human activities, is relatively scarce. Thus, we evaluated the SO...
Article
Full-text available
Climate change will likely increase the total streamflow in most headwaters on the Tibetan Plateau in the next decades, yet the responses of runoff components to climate change and permafrost thaw remain largely uncertain. Here we investigate the changes in runoff components under a changing climate, based on a high‐resolution cryosphere‐hydrology...
Article
Global warming-induced melting and thawing of the cryosphere are severely altering the volume and timing of water supplied from High Mountain Asia, adversely affecting downstream food and energy systems that are relied on by billions of people. The construction of more reservoirs designed to regulate streamflow and produce hydropower is a critical...
Article
Full-text available
China has implemented the world's largest‐ever vegetation restoration program in marginal mountainous areas to sustain life on land. However, land competition between the demand for grain and the need for green has threatened sustainable vegetation restoration. Here, focusing on China's marginal mountainous areas with the highest density of slope c...
Article
Full-text available
Mangroves are typically found in tropical coastal areas, and these ecosystems face deterioration and loss due to threats from climate and human factors. In this study, sediment cores were collected from human-planted mangroves in sub-tropical Ximen Island, China, and were determined for sedimentary phosphorus (P) species. The objective was to inves...
Preprint
Full-text available
Glacial and proglacial erosion are important sediment sources in a river basin. The retreat of many glaciers on the Tibetan Plateau has important implications on the supply of fresh water and sediment dynamics for downstream river basins. Despite the importance of water and sediment dynamics at these catchments, existing quantification of suspended...
Article
The Mekong River in Asia is one of the world's longest rivers. Although it has some of the highest levels of biodiversity and productivity in Asia, the water quality in the basin has recently deteriorated as a consequence of land use changes, dam reservoir construction, population growth, and climate change. For the first time, this study estimates...
Article
Investigating the migration and transformation of carbonaceous and nitrogenous matter in the cryosphere areas is crucial for understanding global biogeochemical cycle and earth's climate system. However, water-soluble organic constituents and their transformation in multiple water bodies are barely investigated. Water-soluble organic carbon (WSOC)...
Article
A large amount of plastic waste has been released into the environment during the increase in global plastic production in the 21st century. Microplastics (0.1 µm to 5 mm in size) existing in hydro-systems, especially in aquatic sediments, can enter organisms and then human body through food chain. This paper provided the preliminary observation re...
Article
Full-text available
The Cambodian floodplains experience a yearly flood pulse that is essential to sustain fisheries and the agricultural calendar. Sixty years of data, from 1960–2019, are used to track the changes to the flood pulse there. We find that minimum water levels over 2010–2019 increased by up to 1.55 m at Kratie and maximum water levels decreased by up to...
Article
Full-text available
The response of suspended sediment load to climate change has important implications for downstream ecosystems and biogeochemical cycles. Glaciers, permafrost, vegetation and hydrological processes are rapidly changing in high-altitude regions. However, there is currently no consensus about how and to what extent these factors will affect interannu...
Article
The effect of reforestation on carbon sequestration has been extensively studied but there is less understanding of the changes that stand age and vegetation types have on changes in biomass carbon and soil organic carbon (SOC) after reforestation. In this study, 150 reforested plots were sampled across six provinces and one municipality in the Yan...
Article
Full-text available
Mangroves are highly productive blue carbon ecosystems that preserve high organic carbon concentrations in soils. In this study, particle size, bulk elemental composition and stable carbon isotope were determined for the sediment cores collected from the landward and seaward sides of two mangrove forests of different ages (M1, ca. 60; M2, ca. 4 yea...
Article
Full-text available
Strong anthropogenic activities and climate change have caused distinct hydrology and sediment dynamics in river systems worldwide. Yet, the integrated picture of sediment discharge changes and quantitative attribution of these changes from a basin-wide perspective were limitedly understood. In this study, we quantified the variations of sediment d...
Article
Full-text available
Muddied waters The climate of High Mountain Asia is becoming warmer and wetter. Li et al . present data showing that rivers originating in this region have experienced large increases in runoff and sediment fluxes over the past six decades, most dramatically since the mid-1990s. The authors project that sediment flux from those rivers could more th...
Article
Full-text available
Study Region Panxi mining area (15061 km², located in Sichuan, China). Study Focus This study aims to delineate groundwater potential zones in mining areas using a new method based on the cusp catastrophe model (CCM) and principal component analysis (PCA). First, 13 indicators were selected from natural and anthropogenic dimensions, and a comprehe...
Article
Full-text available
Accelerated glacier-snow-permafrost erosion due to global warming amplifies the sediment availability in cold environments and affects the time-varying suspended sediment concentration (SSC) and discharge (Q) relationship. Here, the Sediment-Availability-Transport (SAT) model is proposed to simulate dynamic SSC-Q relationships by integrating the se...
Article
Full-text available
Gradual riparian wetland drying is increasingly sensitive to global warming and contributes to climate change. Riparian wetlands play a significant role in regulating carbon and nitrogen cycles. In this study, we analyzed the emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from riparian wetlands in the Xilin River basin to...
Article
Suspended particulates and sediments are the main substances of lake organic pollutants and organic carbon, and their stable isotope research is of great significance for effectively identifying lake eutrophication. We select Lake Wuliangsuhai as our research site to measure and analyze the index, such as δ13C, C/N, total organic carbon (TOC, POC)...
Article
Understanding extreme temperature variations is important for countries to manage risks associated with climate change. Yet, the characteristics of temperature extremes and possible climate change impacts have not been adequately investigated in Singapore. In this study, we attempted to do so by defining 14 extreme temperature indices (ETIs) for th...
Preprint
Full-text available
The Cambodian floodplains experience a yearly floodpulse that is essential to sustain fisheries and the agricultural calendar. Sixty years of data from 1960–2019 are used to track the changes to the floodpulse there. We find that minimum water levels in 2010–2019 have increased by up to 1.55 m at Kratie and maximum water levels have decreased by up...
Article
Full-text available
Terrestrial vegetation growth activity plays pivotal roles on regional development, which has attracted wide attention especially in water resources shortage areas. The paper investigated the spatiotemporal change characteristics of vegetation growth activity using satellite-based Vegetation Health Indices (VHIs) including smoothed Normalized Diffe...
Article
Full-text available
While 1992 marked the first major dam – Manwan – on the main stem of the Mekong River, the post-2010 era has seen the construction and operationalisation of mega dams such as Xiaowan (started operations in 2010) and Nuozhadu (started operations in 2014) that were much larger than any dams built before. The scale of these projects implies that their...
Article
Full-text available
Research on the ionic chemistry of rivers and weathering types provides the basis for elucidating the dynamics of river chemistry and exploring carbon cycling in river systems. There is a lack of water chemistry study in the river systems in the Tibet Plateau, especially in the streams/rivers flowing from and through glaciers and permafrost. Sample...
Article
Eutrophic lakes, especially shallow eutrophic lakes, disproportionately contribute to greenhouse gas (GHG) emissions. To investigate the effects of eutrophication on GHG dynamics, we conducted field measurements every three months from January 2019 to October 2019 in Lake Ulansuhai, a shallow eutrophic lake (mean depth of 0.7 m) located in a semi-a...
Article
Full-text available
Despite growing research on greenhouse gas (GHG) emissions from inland waters, few systematic efforts have been made to assess the regional-scale GHG emissions from Asian rivers under increasing anthropogenic stress. We examined factors controlling longitudinal and seasonal variations in the partial pressure of CO2 (pCO2), and CH4 and N2O concentra...
Article
Full-text available
Human-induced land use change and climate change are two interacting factors that affect vegetation productivity. In the Yangtze River Basin (YRB), reforestation projects have been implemented in the last few decades while urbanization is rapid because of the Yangtze River economic belt. However, few studies have explored the roles of human activit...
Preprint
Full-text available
While 1992 marked the first major dam – Manwan – on the main stem of the Mekong River, the post-2010 era has seen the construction and operationalisation of mega dams such as Xiaowan (started operations in 2010) and Nuozhadu (started operations in 2014) that were much larger than any dams built before. The scale of these projects implies that their...
Article
Full-text available
Greenhouse gas (GHG) emissions from rivers and lakes have been shown to significantly contribute to global carbon and nitrogen cycling. In spatiotemporal-variable and human-impacted rivers in the grassland region, simultaneous carbon dioxide, methane and nitrous oxide emissions and their relationships under the different land use types are poorly d...
Article
Full-text available
Approximately 40% of the Tibetan Plateau (TP) is underlain by continuous permafrost, yet its impact on fluvial water and sediment dynamics remains poorly investigated. Here we show that water and sediment dynamics in the permafrost-dominated Tuotuohe basin on the TP are driven by air temperature and permafrost thaw, based on 33-year daily in-situ o...
Article
Accurate water depth data are essential to ensure navigational safety of ships operating in regions with coral islands and reefs; however, it is often difficult or impossible to conduct in situ bathymetric surveys in such areas. In this study, a Long-Short Term Memory (LSTM) neural network in deep learning was introduced for multispectral remote se...
Article
Groundwater discharge to river networks makes up a major source of riverine CO2 emission, available evidence however comes mainly from headwater streams which are directly connected to terrestrial ecosystems and spatially limited in terms of system size. Here relying on coupled water and CO2 mass balances, we quantified the groundwater-mediated CO2...
Article
This review provides focused insights into the contamination status, sources, and ecological risks associated with multiple classes of antibiotics in surface water from the East and Southeast Asia based on publications over the period 2007 to 2020. Antibiotics are ubiquitous in surface water of these countries with concentrations ranging from <1 ng...
Article
Full-text available
AimsAny grouping of tree species concerned with SOC sequestration should include trees that are as homogeneous as possible in their carbon sequestration. We propose a classification of tree species into deciduous broadleaf, evergreen broadleaf, deciduous conifer and evergreen conifer and assess the validity of such classification.Methods We conduct...
Article
Key message Different tree species have dissimilar capacities to sequester soil organic carbon (SOC). Deciduous broadleaved trees show the most stable increase in SOC stock after afforestation than other tree species, while sempervirent conifer trees show the lowest rate of SOC stock change. Sempervirent broadleaved trees show the greatest increase...
Article
Full-text available
As an important source of non‐rainfall input of land–surface liquid water, dew has considerable ecological and hydrological significance in desert ecosystems. Dew moisture regime is commonly used for characterizing available dew. It discloses not only the contributions of dew to plants, small animals, and biological crusts but also the mechanism by...
Article
Full-text available
Extreme precipitation indices (EPIs) were defined to quantify the precipitation extremes in Singapore, a typical tropical country situated near the equator. The paper investigated the spatial and temporal variability of precipitation extremes based on seventeen EPIs using non‐parametric Mann‐Kendall test and Sen’s slope, and further explored the li...
Preprint
Full-text available
Riparian wetlands play a significant role in regulating carbon and nitrogen cycles. Gradual riparian wetland drying is increasingly sensitive to global warming and contributes to climate change. In this study, we analyzed the emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from riparian wetlands in the Xilin River Basin to...
Article
Full-text available
The long-term effects of increased temperatures on sediment fluxes in cold regions remain poorly investigated. Here, we examined the multidecadal changes in runoff and sediment fluxes in the Tuotuohe River, a headwater river of the Yangtze River on the Tibetan Plateau (TP). The sediment fluxes and runoff increased at rates of 0.03 ± 0.01 Mt/yr (5.9...
Article
Full-text available
One of the most frequent natural perils affecting the world today is flooding, and over the years, flooding has caused a large loss of life and damage to property. Remote sensing technology and satellite imagery derived data are useful in mapping the inundated area, which is useful for flood risk management. In the current paper, commonly used sate...
Conference Paper
Forest has great value both in storing carbon and timber production. Afforestation has been widely undertaken across countries to achieve their goals in poverty alleviation and environment protection, specifically in mitigating the atmosphere carbon concentration. This study determines the optimal rotations of different forest types in China's affo...
Article
Full-text available
Soil erosion modulates the atmospheric CO2 level by affecting the redistribution of young biospheric organic carbon (OCbio) and ancient petrogenic organic carbon (OCpetro) in different order streams. However, the fate of soil organic carbon (SOC) in low‐order stream systems is still uncertain due to the complex influences of terrain, land uses, and...