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SUSTech's Yan Zheng speaks at University of Birmingham’s 2021 Li Siguang Distinguished Lecture
Li Siguang (October 26, 1889-April 29, 1971) was one of the most distinguished geologists in China. He is well known for his work in the theory of plate dynamics and understanding how continents and oceans move around the planet. He was also a pioneer in predicting earthquakes and discovered much of China’s oil and gas reserves.He studied abroad at the University of Birmingham (UoB) in 1913 and received a master’s degree in 1919. In memory of his work, the China Institute at UoB established the Li Siguang Distinguished Lecture.On October 28, Chair Professor Yan Zheng from the Southern University of Science and Technology (SUSTech) was invited to deliver the Institute’s annual Li Siguang Distinguished Lecture for 2021 and discuss in-depth groundwater sustainability and its role in adapting to climate change.Groundwater is invisible, so it is easily forgotten. Although scientists have become alarmed by overexploitation and pollution of this precious resource, the public, in general, is not aware that groundwater is key to society’s water supply and food security. Furthermore, groundwater supports adaptation and builds resilience to climate change.The lecture, entitled “Enhancing Groundwater Sustainability for Climate Resilience,” described the role of the MAR technology system in the integrated management of surface water and groundwater resources with resilience to climate change.After the lecture, a panel discussion was held involving Professor Zheng and chaired by Iseult Lynch, Professor of Environmental Nanosciences at UoB. Other guests to the panel included Stefan Krause, Professor of Ecohydrology and Biogeochemistry at UoB; Dr. Shirley Ye, Lecturer in Asian History at UoB; and Dr. Mike Jones of Water Resources Modelling Lead at Thames Water.Professor Jon Frampton, Director of UoB’s China Institute, said, “On the eve of world leaders gathering at COP26 in Glasgow to discuss the environmental challenges facing our planet, we’re looking forward to hearing Professor Zheng’s exploration of the important role that groundwater can play in securing precious water supplies.” Introduction of Professor Yan ZhengProfessor Yan Zheng is a global expert in the geochemistry of hydrosphere studies and has published extensively on drinking water safety, environmental health, and sustainable development. Professor Zheng is from the School of Environmental Science and Engineering (ESE) at SUSTech. She was elected as a Fellow of the Geological Society of America in 2010 and a Fellow of the American Geophysical Union (AGU) in 2021.To watch the lecture in full, please follow the link below: https://www.youtube.com/watch?v=cKE3DUMGKFg
First-ever satellite mapping of lake ice over Northern Temperate Zone (NTZ) unveiled
Widespread reductions in lake ice have been detected worldwide, yet spatially detailed characterization of global lake ice is currently unavailable.Using more than half a million Landsat satellite images obtained over the past thirty-five years, a group of researchers from SUSTech provided the first long-term wall-to-wall mapping of lake ice cover over the entire Northern Temperate Zone (NTZ). The mapping comprised of more than 33,000 lakes, representing 48% of the global lake area in total.Dr. Lian Feng’s Group from the School of Environmental Science and Engineering (ESE) at SUSTech conducted this research. They tracked spatially detailed changes in lake ice across the entire NTZ and examined how ice change patterns have differed geographically and temporally in response to climate change. In doing so, they achieved new developments in ice cover changes in over 33,000 lakes across the NTZ.Their research paper, entitled “High-Resolution Mapping of Ice Cover Changes in Over 33,000 Lakes Across the North Temperate Zone,” was published in Geophysical Research Letters, a high-impact journal documenting major advances in geoscience.Nearly half of the world’s lakes periodically freeze. The phenology of lake ice influences not only physical conditions (such as heat storage, temperature, mixing) but also provides important opportunities for transportation, recreation, and fishing. Recently, widespread reductions in lake ice have been detected due to recent climate warming, and this problem will become more severe in the future due to ongoing warming trends and escalating climate extremes. However, few field records are available, and the thermodynamics of lakes are difficult to characterize separately due to lake-specific features. Therefore, a spatially detailed quantification of the changes in lake ice at the global scale is extremely needed.This study provides the first long-term wall-to-wall mapping of lake ice cover over the entire Northern Hemisphere temperate zone using 0.55 million Landsat images from 1985 to 2020 (Figure 1). The study also finds a remarkable reduction in median ice cover occurrence from 61% to 43%. Extensive lake ice retreats are located in central and southern Europe, the northern US, and central and southeastern Asia (Figure 2).Figure 1. Cross-period differences for ICOFigure 2. Coefficient of variation (CV) of ICO between the 4-time periodsThere is a strong logistic regression relationship between surface temperature and ICO (Figure 3). The air temperature of lakes in Europe fluctuated around 0°C and had small interquartile ranges, satisfactorily explaining why lakes in Europe show more significant variations in ice cover than those in Asia and North America.In addition, logistic regression curves of lakes in the Tibet Plateau (Region 1) and the Yangtze River (Region 2) are different from others. It may be caused by the exceptional lake conditions and human activities. For example, the depth of lakes in the Tibet Plateau can exceed 100m. Most of the lakes in the Yangtze River are shallow, exhibit great interannual changes in water depth, and have suffered from extensive human activities in recent decades.Figure 3. Scatter plot between ICO and the corresponding mean surface temperatureXinchi Wang, a master’s student in Dr. Lian Feng’s group at SUSTech, is the first author of this research paper. Dr. Feng is the corresponding author of this paper.This study was supported by the National Natural Science Foundation of China (NSFC), the Strategic Priority Research Program of the Chinese Academy of Sciences, and the Shenzhen Science and Technology Innovation Committee.Paper link: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL095614 
Recent advances in hydrology and environmental science
Recently, Dr. Haiyun Shi’s group from the School of Environmental Science and Engineering at the Southern University of Science and Technology (SUSTech) has achieved a series of research progress in the field of hydrology and environmental science. Five research papers have been published in the top journals, such as Water Resources Research, Journal of Geophysical Research: Atmospheres, and Environmental Research Letters.The first paper, entitled “Characteristics of propagation from meteorological drought to hydrological drought in the Pearl River Basin,” was published in the Journal of Geophysical Research: Atmospheres. In this study, the Pearl River Basin (PRB) was classified into five sub-regions with similar dry and wet characteristics. The hydrological drought was more serious than meteorological drought in the PRB, and the drought propagation times (DPTs) were 2-6 months (Figure 1). It also noted that large-scale climate patterns (ENSO and PDO) are important factors that affect the DPT from meteorological to hydrological drought in the PRB.Figure 1. Spatial distributions of (a) the MPCC and (b) the DPT from meteorological drought to hydrological drought in the PRB.The second paper, entitled “Investigating the propagation from meteorological to hydrological drought by introducing the nonlinear dependence with directed information transfer index,” was published in Water Resources Research. In this study, a directed information transfer index (DITI) was introduced in a drought propagation study to build a new drought response time (DRT) evaluation system for the first time (Figure 2). Additionally, trigger thresholds from meteorological to hydrological drought were determined by a drought propagation model. It also illustrated that sub-regions with smaller meteorological drought trigger thresholds had longer durations of hydrological drought events.Figure 2. Spatial distributions of (a) the DRT-differences between mutual information (MI) and DITI; (b) the values of different months between the DRT-linear and DRT-nonlinear in each grid.The third paper, entitled “Impacts of dams and reservoirs on local climate change: a global perspective,” was published in Environmental Research Letters. This study explored the impacts of reservoir characteristic factors (RCFs) on local climate change near the reservoir by examining the correlations between the RCFs (e.g., water surface (AREA), storage capacity (CAP), and average depth (DEP)) and meteorological variables (e.g., evaporation (E), precipitation (P), surface temperature (ST), and temperature 2 m above the surface (T2M)) all over the world (Figure 3).The researchers found that the correlations of the RCFs with evaporation are opposite to those with precipitation. It also observed that dams and reservoirs could have completely opposite (weakening or enhancing) effects on different meteorological variables. Additionally, the RCFs outperformed the geographical factors in terms of the impact on precipitation, whereas the variation of evaporation is more sensitive to geographical factors.Figure 3. Correlations between the RCFs and meteorological variables in the center-grid of a reservoir.The fourth paper, entitled “Impacts of regional characteristics on improving the accuracy of groundwater level prediction using machine learning: The case of central eastern continental United States,” was published in the Journal of Hydrology: Regional Studies. This study built a gated recurrent unit (GRU) neural network model for groundwater level simulation (Figure 4). It showed that the input features for the GRU model were effectively determined by the principal component analysis method and summarized the attributes suitable for machine learning simulation. It also exhibited that groundwater autocorrelation had a negative effect on machine learning simulation.Figure 4. (a) Model workflow; (b) structure of Recurrent Neural Network; (c) structure of Long Short-Term Memory; and (d) structure of Gate Recurrent Unit.The fifth paper, entitled “Evolution characteristics of potential evapotranspiration over the Three-River Headwaters Region,” was published in Hydrological Sciences Journal. This study investigated the evolution characteristics of potential evapotranspiration (PET) over the Three-River Headwaters Region (TRHR) based on observations at fourteen stations during 1960-2014.The research team analyzed the spatial-temporal changes at annual and seasonal scales (Figure 5) and built machine learning models to predict the monthly PET. The outcomes can help to understand better the future hydrometeorological conditions in the TRHR, which would be valuable for better protection of the ecological environment in this region.Figure 5. Spatial distributions of the mean annual PET and the seasonal PET over the TRHR from 1960 to 2014.Dr. Haiyun Shi is the corresponding author of all five papers. The first authors of these papers are all members of Dr. Shi’s group, including Ph.D. candidates Zhaoqiang Zhou and Hejiang Cai, master’s graduate Zhipeng Jiang, and research assistant Yiyang Zhao.These studies were supported by the National Natural Science Foundation of China (NSFC), Basic and Applied Basic Research Foundation of Guangdong Province, Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, and State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control.Related papers (In order of appearance above):Journal of Geophysical Research: Atmospheres:https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JD033959Water Resources Research:https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021WR030028Environmental Research Letters:https://iopscience.iop.org/article/10.1088/1748-9326/ac263cJournal of Hydrology: Regional Studies:https://www.sciencedirect.com/science/article/pii/S2214581821001592Hydrological Sciences Journal:https://www.tandfonline.com/doi/full/10.1080/02626667.2021.1957105
SUSTech’s Junguo LIU awarded as the Paul A. Witherspoon Lecturer
The American Geophysical Union (AGU) recently announced its list of AGU awards/honors for renowned experts in various fields in 2021. Seventy-eight scientists from all over the world received accolades, including thirty awards for named lectureships to recognize distinguished scientists with proven leadership in their fields of science.Junguo LIU, Chair Professor of the School of Environmental Sciences and Engineering at the Southern University of Science and Technology (SUSTech) and member of the European Academy of Sciences, received the Paul A. Witherspoon Lecture in the Hydrology Section. He is the first Asian scholar to receive the award since its formation.Junguo LIU is a recipient of the Outstanding Young Scientist from the National Science Foundation of China and has long been engaged in scientific research and teaching water resources and ecological restoration. He proposed the three-dimensional water shortage theory and the ecological restoration theory in protecting and utilizing water resources. His innovative research work has had an important impact in the field of water resources at home and abroad.He is the first hydrologist and Chinese scientist to receive the Outstanding Young Scientist Award by the European Geosciences Union (EGU) and the first Chinese scientist to receive the Technology Communication Award from the Society for Ecological Restoration (SER). In 2020, he received the World Academy of Science (TWAS) Award and the Science and Technology Award by the Chinese Soil and Water Conservation Society (CSWCS).Established in 1919 with more than 62,000 members from 137 countries, AGU is the world’s largest society in Earth Sciences. AGU’s activities are focused on the organization and dissemination of scientific information in the interdisciplinary and international fields within the Earth and space sciences.The Paul A. Witherspoon Lecture is presented annually. It recognizes significant and innovative contributions by mid-career scientists to the hydrologic sciences through research aimed at socially important problems and through mentoring of young scientists.Related link: https://eos.org/agu-news/2021-agu-section-awardees-and-named-lecturers
SUSTech scholars win Young Scientist Award from Chinese Society for Environmental Sciences
The Chinese Society for Environmental Sciences (CSES) recently announced its list of candidates for the 4th CSES Young Scientist Award. Assistant Professor Jun-Jian WANG from the School of Environmental Science and Engineering (ESE) at the Southern University of Science and Technology (SUSTech) won the Young Scientist Gold Award, and Associate Professor Hong CHEN won the Young Scientist Excellence Award.Dr. Jun-Jian WANG joined SUSTech in 2017. He is dedicated to developing and applying cutting-edge and molecular-level analyses of natural organic matter and pollutants to study the critical impacts of global change and anthropogenic disturbance on the plant-soil-water system and environmental quality. He received more than 10 research grants, including National Science Fund for Excellent Young Scholars of China and Natural Science Fund for Distinguished Young Scholars of Guangdong Province. He has published more than 60 papers in top-tier journals, including Nature Communications, New Phytologist, Environmental Science & Technology, and Water Research. He is serving as an associate editor of the Journal of Environmental Quality and on the editorial boards of the Frontier in Soil Science, Chinese Chemical Letters, and Journal of Agricultural Resources and Environment. He has also served as an international reviewer for National Science Foundation (US) and France National Research Agency (ANR) proposals.Dr. Hong CHEN joined SUSTech in 2018. He is mainly engaged in research on resource recycling and utilization chemistry. He has published more than 100 papers in renowned journals such as Nature Materials, Science Advances, PNAS, and Nature Communications, with a total number of more than 4,620 citations. Earlier this year, he also won the Gold Award from the Guangdong Society of Environmental Sciences (GDSES). The Young Scientist Award of CSES was first established in 2018 to reward outstanding young scientists under 40 years of age engaged in environmental science and technology research. The accolade is awarded yearly, with thirty recipients being honored with the prize. 
SUSTech's Yan ZHENG selected as Fellow of American Geophysical Union
On September 28, 2021, the American Geophysical Union (AGU) announced the 2021 Class of Fellows.Amongst them included Chair Professor Yan ZHENG of the School of Environmental Science and Engineering (ESE) at the Southern University of Science and Technology (SUSTech).She became the 22nd scientist from China (including Hong Kong, Macao, and Taiwan) to receive this honor. Worldwide, 59 scientists in the field of Earth and space sciences will become AGU fellows in 2021.Yan ZHENG joined ESE at SUSTech in 2016. She received her Ph.D. degree from the Department of Earth and Environmental Sciences at Columbia University in 1999 and was elected as a Fellow of the Geological Society of America in 2010.AGU was founded in 1919, with more than 130,000 members worldwide in Earth and space sciences. The AGU Fellow is one of the highest honors in the international Earth and space sciences research community. It recognizes individuals who have made outstanding contributions through scientific research, education, science communication, and outreach.
SUSTech researchers publish study on typhoon redistributed microplastics in coastal areas and uniformed plastisphere community
The increasing microplastic pollution, together with the plastisphere-associated ecological threats in coastal areas, have aroused global concern. Tropical cyclones have increased in both frequency and intensity under global warming, causing an intense impact on the microplastics distribution and the structure of coastal ecosystems. However, until most currently, the extent to which typhoon impacts the microplastics and plastisphere community remains poorly known.Recently, researchers from the Southern University of Science and Technology (SUSTech) published a paper on the subject. Their study, entitled “Typhoon-induced turbulence redistributed microplastics in coastal areas and reformed plastisphere community,” was published in the journal Water Research.The emergence of plastic has provided huge social benefits but also brought serious environmental problems. Due to the long half-life and the hydrophobic surface of plastics, it is generally believed that microplastics can be served as vehicles to promote microbial colonization and biofilm formation, the so-called “plastisphere”, and eventually become a pelagic habitat for microorganisms. At the same time, microplastics provide more ways for the long-distance transmission of potentially pathogenic microorganisms, posting ecological impacts on the original ecosystem.Extreme storm events, such as tropical cyclones (i.e., tropical storms and typhoons), can significantly affect coastal ecosystems. However, limited studies have been conducted to investigate the effect of typhoons on microplastic abundance, composition, and distribution to date. Given the growing ecological concerns aroused by increasingly frequent and severe tropical cyclones, such effort is of no doubt inadequate to clarify the impacts of typhoons on the coastal microplastic distribution.Furthermore, even though plastisphere has been recognized to modify the environmental fate of microplastic particles, no study has demonstrated the influence of typhoons on plastisphere to date. Therefore, more research is urgently needed to better understand how typhoons impact the microplastic distribution in the environment and ultimately impact ecosystem function by regulating plastisphere composition.Figure 1. Mean (±SD) abundance of microplastics in surface water (a) and sediments (b) collected in Shenzhen coastal areas before and after a typhoon (B: before the typhoon; A: after the typhoon). The bar plot at the upright corner shows differences in microplastic abundance before and after typhoon (paired-sample t-test). Correlation analysis of microplastic abundance in surface water (c) and sediment (d) before and after the typhoon.Figure 2. The microplastic characteristics before and after the typhoon (B: before the typhoon; A: after the typhoon). (a) Distribution of size, color, and shape of microplastics in surface water and sediment. (b) PCoA biplot shows the differences in microplastic characteristics before and after the typhoon for water and sediment samples.The study found a significant typhoon-induced increase in microplastic abundance in surface water, whereas an opposite trend was observed in sediment. Despite the evident transportation of microplastics from sediment to surface water by agitation, a possible microplastics influx was introduced by typhoons, as evidenced by the prominent attribution of unknown force in source tracking analysis.Additionally, typhoons have adeptly uniformed the plastisphere community in the sediment along the 190km coastal line overnight. A significant increase of nitrogen fixer, Bradyrhizobiaceae, was observed ubiquitously after a typhoon, which might alter the nitrogen cycling and increase the eutrophic condition of the coastal ecological system. Together, this study expanded the knowledge about the impact of a typhoon-induced influx of microplastics on coastal biogeochemical cycling.Figure 3. Bacterial community diversity of plastisphere and their shaping factors (B: before the typhoon; A: after the typhoon). (a) Bacterial community composition of plastisphere displayed at the phylum level. (b) Alpha diversity profiles of plastisphere community. Shannon and Pielou’s Evenness indices comprehensively denote the richness and homogeneity of the bacterial community. (c) Principal coordinate analysis of the plastisphere communities. (d) Bray–Curtis db-RDA plots displaying the relationships between plastisphere communities and microplastic characteristics.Figure 4. Spearman correlation between the relative abundance of each OTU and microplastic characteristics. OTU_1 was the most abundant taxon and affiliated with Bradyrhizobiaceae. The bar plot shows differences in the relative abundance of OTU_1 between before and after the typhoon.Liming Chen, a postdoctoral fellow, and Jiangpeng Li, a Ph.D. student, are the co-first authors of this paper. Associate Professor Yuanyuan Tang and Assistant Professor Yu Xia from the School of Environmental Science and Engineering at SUSTech are the co-corresponding authors.The study was supported by the National Natural Science Foundation of China (NSFC), Natural Science Foundation of Guangdong Province, State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, and the Center for Computational Science and Engineering at SUSTech.Paper link:https://doi.org/10.1016/j.watres.2021.117580Additional contact information:Associate Professor Yuanyuan Tang: tangyy@sustech.edu.cnAssistant Professor Yu Xia: xiay@sustech.edu.cn
SUSTech's Junguo Liu co-authors paper on food waste and its environmental impact
Recently, Chair Professor Junguo Liu from the School of Environmental Science and Engineering at the Southern University of Science and Technology (SUSTech) co-authored a paper in Nature Food, an online journal publishing top-tier food-related research in the natural, applied, and social sciences. The paper was entitled “China's food loss and waste embodies increasing environmental impacts.”In recent years, food loss and waste have become a global problem, which has attracted widespread attention from academia, government, and the public. Food loss and waste are closely related to food security, food safety, nutrition and health, resources, environment, economy, and society. They are considered to be major environmental issues for the sustainable development of the global food system. However, monitoring and benchmarking food loss and waste reduction is often constrained by the lack of reliable and consistent data, especially for emerging economies. This research is based on the large-scale field investigations conducted by the Ministry of Agriculture and Rural Affairs and the Chinese Academy of Sciences (CAS) from 2013 to 2018 on food losses in the supply chain, food waste in households, and catering industries. It quantifies the food loss and waste of major agrifood products along the entire farm-to-fork chain in China.Figure 1. Food flow and waste in China’s supply chain from the farm to the tableThe result shows that 27% of food annually produced for human consumption in the country (349 ± 4 Mt) is lost or wasted. 45% of this is associated with postharvest handling and storage and 17% with consumption activities. The paper also shows that the land, water, carbon, nitrogen, and phosphorus footprints associated with total food loss and waste are similar to those of a medium-sized country, such as the United Kingdoms, in the case of carbon footprint.Figure 2. Land footprint, water footprint, carbon footprint, nitrogen footprint, and phosphorus footprint of food waste in ChinaThese results highlight that food loss and waste in China have a greater impact on resources and the environment. Reducing food waste at the consumption stage has a significant effect on reducing various environmental footprints.This paper is the work of a collaborative effort between researchers from the Chinese Academy of Sciences (CAS), the University of Southern Denmark, Ministry of Agriculture (MOA) of the People’s Republic of China, Wuhan University, the University of Pennsylvania, and SUSTech.It is worth mentioning that Junguo Liu was one of the earliest scholars in China who paid attention to food waste and its environmental impact. In 2013, as the first corresponding author, he published an article entitled “Food Loss and Waste in China and their Implication for Water and Land” in Environmental Science and Technology (ES&T). The results showed that food waste and food loss have a huge environmental impact on water and land resources. The food waste rate in China is 19% (+5%), which is far lower than the waste rate in the United States and European countries. The study found that the food waste rate in Chinese canteens and households is only 5-7%, but the food waste rate in restaurants is as high as 19%. This shows that Chinese food culture and habits play an important role in influencing the rate of food waste.Paper links:https://www.nature.com/articles/s43016-021-00317-6https://pubs.acs.org/doi/10.1021/es401426b 
Southeast Asia's forest clearance is climbing to higher elevations at an accelerating rate, resulting in unprecedented forest carbon stock loss
Recently, a joint research team led by the Southern University of Science and Technology (SUSTech) shows that forest clearance in Southeast Asia is accelerating during the 21st century, with clearance frontier climbing to higher elevations and steeper slopes with high forest carbon stocks. Forest losses have resulted in a tremendous biomass carbon loss (424 Tg C yr−1), potentially nudging Southeast Asian forests to be a net carbon source in the global carbon budget.Most tropical deforestation is believed to occur in lowlands where forests are easy to access and deforested lands are feasible to plantations. However, recent studies have reported new croplands and plantations converted from mountain forests in Southeast Asia, generating a deeply divided debate on forest dynamics in the region. The study, entitled “Upward expansion and acceleration of forest clearance in the mountains of Southeast Asia,” was published on June 28 in Nature Sustainability. It uncovered forest loss dynamics and associated topographical patterns using multiple high-resolution satellite products of forest change and topography.The authors found that forest clearance in the mountains of Southeast Asia has accelerated during the 21st century, accounting for a third of total forest loss in the region. New plantations primarily drove deforestation at high elevations. Zhenzhong Zeng, who led the research and works as an associate professor at SUSTech, visually interpreted high-resolution satellite imagery in Southeast Asia three years previously. He found substantial mountain forests converted to croplands, although mechanical and intensive plantations in the mountains are not technically possible and economically feasible.“I was shocked by the tremendous deforestation in the mountains and think we should contribute to the sustainable development of forests. My Ph.D. student, Yu Feng, and I worked with Zhenzhong to figure out how Southeast Asia’s forests change. We combined multiple satellite data to quantify forest dynamics and associated topography, and surprisingly found accelerating mountain forest loss in the region,” said Professor Chunmiao Zheng of SUSTech.Figure 1. Example of massive forests that have been lost for cultivations in the mountains of Southeast AsiaThe researchers discovered that the frontier of forest clearance climbed to higher elevations and steeper slopes where forests have high carbon stocks. This means that forest loss shifted to regions with high carbon stocks, resulting in more forest carbon loss than expected. Combining forest loss data with a forest biomass carbon map, they discovered that carbon loss resulting from forest clearance was mainly in the lowlands in the 2000s, e.g., Indonesia. In the 2010s, however, lowland forest carbon loss decreased while mountain forest carbon loss in regions like Myanmar and Laos increased significantly. As mountain forests hold more biomass carbon than lowland forests, accelerating mountain forest clearance exacerbated carbon stock loss in the region.“I have spent three years doing a deforestation project in Nan Province, sponsored by the Kasikornbank and Princeton University, and took many pictures of mountain deforestation there as shown above. I’m glad to see the situation is becoming much better in Nan Province according to our new findings. Unfortunately, the situation of mountain deforestation is becoming worse in many other mountain regions of Southeast Asia,” said Professor Zeng.“Forest loss in the lowlands of Southeast Asia has rightly received a lot of attention, but that has shifted focus from an emerging pattern of extensive loss in the mountains that is increasing rapidly and threatens many species found nowhere else,” said Paul Elsen, Climate Adaptation Scientist for the Wildlife Conservation Society (WCS) and one of the co-authors of the study.Although multiple lines of evidence reveal that tropical forests likely act as a neutral contributor to the global carbon cycle, the accelerating clearance of mountain forests with high carbon density portends forest carbon loss in the near future. Consequently, this could potentially nudge Southeast Asia’s forests to be a net carbon source in the global carbon budget. Most deforested lands in the mountains have been turned into croplands, which may further intensify climate warming in the region through biochemical and biophysical feedbacks. The study provides important implications for regional land-use management and climate change adaption and mitigation.Figure 2. Corn and dasheen fields converted from forests in Southeast AsiaIn addition to Associate Professor Zhenzhong Zeng, Yu Feng, Professor Chunmiao Zheng, and Dr. Paul Elsen are also co-authors of this study. Other researchers included Yang Liu, Xinyue He, and Xin Jiang of SUSTech, Professor Alan D. Ziegler of MaeJo University (MJU), and Professors Dominick V. Spracklen and Joseph Holden, both of the University of Leeds.This project was supported in part by the National Natural Science Foundation of China (NSFC) and the start-up fund provided by SUSTech.Paper link: https://www.nature.com/articles/s41893-021-00738-y
SUSTech Xingxing Kuang's team publishes findings on relative air permeability for multiphase flow in porous media
Recently, Associate Professor Xingxing Kuang's group from the School of Environmental Science and Engineering at the Southern University of Science and Technology (SUSTech) published a research article, entitled “Effects of water retention curves and permeability equations on the prediction of relative air permeability” in Geophysical Research Letters, a top journal in Geoscience category. Through model derivation and measured data validation, this research revealed the predominant role of the permeability equation in determining the relative air permeability in disturbed soils.Relative air permeability, a key parameter in multiphase flow numerical simulators like TOUGH2 and STOMP, is indispensable when investigating several geophysical issues such as soil aeration and evapotranspiration, the simulation of reservoir CO2 injection, and the study of hydraulic fracturing fluid migration in the subsurface. Currently, a lot of effort has been dedicated to studying the relative water permeability, whereas research upon relative air permeability is comparatively less. In addition, measured data on relative air permeability that is used for model validation is not plentiful in literature.Combining two traditional and two fractal water retention curves, respectively, with six permeability equations, they obtained twelve statistical and twelve fractal relative air permeability models (six statistical and nine fractal models were derived for the first time). These models were subsequently tested with thirty-one experimental datasets of disturbed soils to examine their predictive ability for relative air permeability. Results showed that compared to the selection of traditional or fractal water retention curves, the choice of permeability equations is more critical for the appropriate prediction of relative air permeability, indicating the dominant role of the pore tortuosity-connectivity in determining air permeability in disturbed soils. This research sheds light on the appropriate selection of relative air permeability, which will be used in the multiphase flow numerical simulators for the accurate modeling of airflow in porous/fractured media.Figure 1. Comparison of measured data for Poudre river sand with predicted results. (a) BCB, VGB, ASVB, and LB models and (b) BCMB, VGMB, ASVMB, and LMB models.Figure 2. Comparison of measured data for Columbia sandy loam with predicted results. (a) BCM, VGM, ASVM, and LM models and (b) BCMM, VGMM, ASVMM, and LMM models.Figure 3. Scatter charts of measured versus predicted relative air permeability values by (a) VGM, (b) VGMM, (c) LM, and (d) LMM models.Associate Professor Xingxing Kuang at SUSTech is the corresponding author for this paper. Westlake University’s research scientist Zhenlei Yang and Chair Professor Ling Li are the first and co-author, respectively. Assistant Professor Xin Tong at Inner Mongolia Agricultural University (IMAU) and Regent Professor Binayak P. Mohanty at Texas A&M University also participated in this study. This work was funded by the National Natural Science Foundation of China (NSFC).Paper link: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL092459
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