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spatiotemporal variability in Extreme Temperature Events in an Arid-Semiarid Region of China and Their Teleconnections with Large-Scale Atmospheric Circulation

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Journal of Earth Science 2023年第4期34卷 1201-1217页

作者： Lin Zhang Yanfeng Liu Menggui Jin Xing Liang State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430078China School of Environmental Studies China University of GeosciencesWuhan 430078China

With a warming climate,temperature extremes have been a main global issue in recent decades due to their potential influence on the sustainable development of human life and natural ecosystems.In this study,12 indicators of extreme temperature events are used to evaluate the spatiotemporal distribution,periodic structure and teleconnections with large-scale atmospheric circulation in Xinjiang,Northwest China by combining wavelet coherence(WTC) analysis based on continuous wavelet transform(CWT) analysis with the sequential Mann-Kendall test.We find that over the past six decades,the climate in Xinjiang has become warmer and has suffered from increases in the frequency of warm extremes and decreases in the frequency of cold extremes.Warm extremes have mainly occurred in the southern Tianshan Mountains surrounding the Tarim Basin and western part of the Taklamakan Desert,and cold extremes have primarily occurred in the southwestern Altai Mountains and northern foot of the Tianshan Mountains.Extreme temperature events,including warm extremes,cold extremes,and other temperature indices,have significant interannual variability,with the main oscillation periods at smaller(2–4-year band),intermediate(4–7-year band),and greater time scales in recent decades.Furthermore,cold-extreme indices,including frost days,cool days,and cool nights all show a clear changepoint during 1990–1997 at the 95% confidence level,and both ice days and cold spell duration indicator have a potential changepoint during 1981–1986.However,the changing points for warmextreme indices are detected during 1992–1998.The temperature variables are significantly correlated with the EI Ni?o-Southern Oscillation(ENSO) and Arctic Oscillation(AO),but less well correlated with the Pacific Decadal Oscillation(PDO).The phase difference in the WTC spectra is not uniform between temperature extremes and climatic oscillations.Our findings will have important implications for local governments in taking effective measures to mitigate the potential effects of regiona

关键词： extreme temperature events spatiotemporal variability large-scale atmospheric circu-lation inland arid-semiarid region wavelet analysis climate change.

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Quantifying spatiotemporal variability in occupant exposure to an indoor airborne contaminant with an uncertain source location

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Building Simulation 2023年第6期16卷 889-913页

作者： John E.Castellini Jr Cary A.Faulkner Wangda Zuo Michael D.Sohn Department of Mechanical Engineering University of Colorado BoulderUCB 427BoulderCO80309USA Department Architectural Engineering The Pennsylvania State UniversityUniversity ParkPA16802USA National Renewable Energy National Laboratory GoldenCO80401USA Energy Analysis and Environmental Impacts Division Lawrence Berkeley National Laboratory1 Cyclotron RoadBerkeleyCA94720USA

Well-mixed zone models are often employed to compute indoor air quality and occupant exposures.While effective,a potential downside to assuming instantaneous,perfect mixing is underpredicting exposures to high intermittent concentrations within a room.When such cases are of concern,more spatially resolved models,like computational-fluid dynamics methods,are used for some or all of the zones.But,these models have higher computational costs and require more input information.A preferred compromise would be to continue with a multi-zone modeling approach for all rooms,but with a better assessment of the spatial variability within a room.To do so,we present a quantitative method for estimating a room’s spatiotemporal variability,based on influential room parameters.Our proposed method disaggregates variability into the variability in a room’s average concentration,and the spatial variability within the room relative to that average.This enables a detailed assessment of how variability in particular room parameters impacts the uncertain occupant exposures.To demonstrate the utility of this method,we simulate contaminant dispersion for a variety of possible source locations.We compute breathing-zone exposure during the releasing(source is active)and decaying(source is removed)periods.Using CFD methods,we found after a 30 minutes release the average standard deviation in the spatial distribution of exposure was approximately 28%of the source average exposure,whereas variability in the different average exposures was lower,only 10%of the total average.We also find that although uncertainty in the source location leads to variability in the average magnitude of transient exposure,it does not have a particularly large influence on the spatial distribution during the decaying period,or on the average contaminant removal rate.By systematically characterizing a room’s average concentration,its variability,and the spatial variability within the room important insights can be gained as to how much uncertainty is introduced into

关键词： uncertainty variability airborne contaminant spatiotemporal variability well-mixed heterogeneity

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Elevation,bedrock exposure,land use,interbedded limestone and clastic rock,and vegetation coverage dominate the spatiotemporal variability of soil erosion in karst basin

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Journal of Mountain Science 2023年第9期20卷 2519-2535页

作者： CHEN Mei GAO Jia-yong CHEN Hong-lian JING Jun LI Rui School of Karst Science Guizhou Normal UniversityGuiyang 550001China State Engineering Technology Institute for Karst Desertification Control Guiyang 550001China

Soil erosion is a prominent environmental problem in karst regions.Exploring the spatiotemporal variability of soil erosion and the factors that influence soil erosion is of great significance for regional soil erosion prevention and control.However,the mechanisms influencing the characteristic features of the karst basins,such as bedrock exposure and lithology,still need to be further explored.This study used GIS technology,the Revised Universal Soil Loss Equation model,Getis–Ord Gi*,and partial least squares regression(PLSR)to identify the dominant factors influencing soil erosion and the spatiotemporal variability of soil erosion in 31 sub-basins of the Dabang River Basin(DRB),a typical karst area of Southwest China,from 2010 to 2020.The results indicated that soil erosion in the DRB from 2010 to 2020 was generally decreasing,the mean soil erosion in the DRB in 2010,2015 and 2020 was 18.46,16.51 and 15.29 t ha^(-1)a^(-1),respectively.During the study period,the area of slight erosion increased by 26.39%(706.54 km^(2)),while severe erosion enlarged by 26.36 km^(2).Spatially,the DRB was primarily affected by medium and slight soil erosion.The hot spot areas of soil erosion(key control areas)were mainly concentrated in the central and southern parts of the basin,decreasing each year,and the area of soil erosion hot pots has decreased from 43.22%to 20.60%.PLSR decoupling results show that elevation,bedrock exposure,land use type,interbedded limestone and clastic rock,and vegetation coverage were identified as the key variables affecting soil erosion,explaining 52.8%of soil erosion variability,with a high value of the Variable Importance on Projection(VIP)more than 1.These results can be used as a reference for comprehensive control of soil erosion and water loss in the basin.

关键词： Soil erosion Karst basin RUSLE model spatiotemporal variability PLSR

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Implementing hardware primitives based on memristive spatiotemporal variability into cryptography applications

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Chip 2023年第1期2卷 33-44页

作者： Bo Liu Yudi Zhao YinFeng Chang Han Hsiang Tai Hanyuan Liang Tsung-Cheng Chen Shiwei Feng Tuo-Hung Hou Chao-Sung Lai Faculty of Information Technology College of MicroelectronicsBeijing Univer-sity of TechnologyBeijing 100124BeijingChina School of Information and Communication Engineering Beijing Information Science&Technology Univer-sityBeijing 100101BeijingChina Artificial Intelligence and Green Technol-ogy Research Center Chang Gung UniversityGuishan Dist.Taoyuan 33302TaiwanChina Department of Electronic Engineering Chang Gung UniversityGuishan Dist.Taoyuan 33302TaiwanChina School of Electrical Engineer-ing and Computer Science The Pennsylvania State UniversityUniversity ParkPA 16802USA Institute of Electronics National Yang Ming Chiao Tung UniversityHsinchu 300TaiwanChina Department of Nephrology Chang Gung Memorial HospitalGuishan Dist.Linkou 33305TaiwanChina Department of Materials Engineering Ming Chi University of TechnologyTaishan Dist.New Taipei City 24301TaiwanChina

Implementing hardware primitives into cryptosystem has become a new trend in electronic community.Memristor,with intrinsic stochastic characteristics including the switching voltages,times and energies,as well as the fluctuations of the resistance state over time,could be a naturally good entropy source for cryptographic key generation.In this study,based on kinetic Monte Carlo Simula-tion,multiple Artificial Intelligence techniques,as well as kernel density map and time constant analysis,memristive spatiotemporal variability within graphene based conductive bridging RAM(CBRAM)have been synergistically analyzed to verify the inher-ent randomness of the memristive stochasticity.Moreover,the ran-dom number based on hardware primitives passed the Hamming Distance calculation with high randomness and uniqueness,and has been integrated into a Rivest-Shamir-Adleman(RSA)cryptosystem.The security of the holistic cryptosystem relies both the modular arithmetic algorithm and the intrinsic randomness of the hardware primitive(to be more reliable,the random num-ber could be as large as possible,better larger than 2048 bits as NIST suggested).The spatiotemporal-variability-based random number is highly random,physically unpredictable and machinelearningattack resilient,improving the robustness of the entire cryptosystem.

关键词： spatiotemporal variability Graphene based memristor RTN True random number generator Rivest-Shamir-Adleman cryptosystem

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Effects of land use change on the spatiotemporal variability of soil organic carbon in an urban-rural ecotone of Beijing,China

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Journal of Integrative Agriculture 2016年第4期15卷 918-928页

作者： YE Hui-chun HUANG Yuan-fang CHEN Peng-fei HUANG Wen-jiang ZHANG Shi-wen HUANGShan-yu HOU Sen Key Laboratory of Digital Earth Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijing 100094P.R.China Hainan Key Laboratory of Earth Observation Sanya 572029P.R.China College of Resources and Environment China Agricultural UniversityBeijing 100193P.R.China State Key Laboratory of Resources and Environment Information System Institute of Geographic Science and Natural Resources ResearchChinese Academy of SciencesBeijing 100101P.R.China College of Earth and Environment Anhui University of Science and TechnologyHuainan 232001P.R.China Institute of Geography University of CologneKoln 50923Germany

Understanding the effects of land use changes on the spatiotemporal variation of soil organic carbon （SOC） can provide guidance for low carbon and sustainable agriculture. In this paper, based on the large-scale datasets of soil surveys in 1982 and 2009 for Pinggu District -- an urban-rural ecotone of Beijing, China, the effects of land use and land use changes on both temporal variation and spatial variation of SOC were analyzed. Results showed that from 1982 to 2009 in Pinggu District, the following land use change mainly occurred： Grain cropland converted to orchard or vegetable land, and grassland converted to forestland. The SOC content decreased in region where the land use type changed to grain cropland （e.g., vegetable land to grain cropland decreased by 0.7 g kg-1; orchard to grain cropland decreased by 0.2 g kg-l）. In contrast, the SOC content increased in region where the land use type changed to either orchard （excluding forestland） or forestland （e.g., grain cropland to orchard and forestland increased by 2.7 and 2.4 g kg-1, respectively; grassland to orchard and forestland increased by 4.8 and 4.9 g kg-1, respectively）. The organic carbon accumulation capacity per unit mass of the soil increased in the following order： grain cropland soil〈vegetable land/grassland soil〈orchard soil〈forestland soil. Therefore, to both secure supply of agricultural products and develop low carbon agriculture in a modern city, orchard has proven to be a good choice for land using.

关键词： land use change soil organic carbon spatiotemporal variability urban-rural ecotone

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Surface Water Processes in Coping with Anthropogenic Impact in a Coastal Eastern Mediterranean Region

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Open Journal of Modern Hydrology 2024年第2期14卷 69-86页

作者： Nour Abboud Zeinab Matar Elias Maatouk Véronique Kazpard Research and Analysis Platform for Environmental Sciences (PRASE) Doctoral School of Sciences and Technology (EDST) Lebanese University Hadat Lebanon Laboratory of Georessources Geosciences and Environment (L2GE) Faculty of Sciences Lebanese University Fanar Lebanon Department of Earth and Life Sciences Faculty of Sciences Lebanese University Hadat Lebanon

Rivers are progressively being exposed to increased anthropogenic pollution stresses that are undermining their designated uses and affecting sensitive coastal areas. In this study, three adjacent eastern Mediterranean coastal rivers, Ibrahim, Kaleb and Beirut, were evaluated. Water quality samples were collected in dry and wet seasons from different sampling sites along the river from the source to the outlet which represent a gradient of increased urbanization. The spatiotemporal variability of the physio-chemical properties, heavy metals (Zn, Pb, Cu, Cr, and Cd) and organic matter (DOC) were statistically analyzed to better understand the contribution of point and nonpoint pollution sources. The three rivers (Beirut, Kaleb and Ibrahim) show a similar behavior in calcium and carbonate alkalinity due to the carbonate mineral weathering effect, so they are of calcium bicarbonate type due to their calcareous geological nature. The speciation of anions was affected by temporal variation. Moreover, it is obvious that the Beirut River has a different behavioral characteristic where the water is a sulfate type water with a preferable metal-OM complexation mainly with lead, zinc and copper, whereas Kaleb and Ibrahim are considered to be of a nitrate phosphate type with a preferable metal inorganic complexation, especially copper, that has a consistent behavior in both types of waters. This difference is attributed to the urbanization effect highly impacting the Beirut River.

关键词： Anions/Cations Metals DOC Complexation Coastal Rivers spatiotemporal variability

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Study on the spatiotemporal variability of eco-hydrological characteristics of the rivers in the Longitudinal Range-Gorge Region and their driving forces

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Science Bulletin 2007年第S2期 122-133页

作者： HU Bo CUI BaoShan WEI GuoLiang ZHAI HongJuan REN HuaLi State Key Joint Laboratory of Environmental Simulation and Pollution Control,School of Environment,Beijing Normal University,Beijing 100875,China

Taking two typical rivers in high mountains and steep gorge areas as example,this paper analyzes the spetiotemporal variability of the eco-hydrological characteristics and the driving forces leading to changes.Firstly,based on the species-environmental data processing,this paper adopts canonical correspondence analysis(CCA)method to identify the environmental factors influencing the distribu- tion of river bank vegetation.Secondly,this study uses the ecological diversity Index to represent the spatiotemporel variability of ecological characteristics.Thirdly,this paper uses the multiple correlation method to analyze the relationship between the hydrological factors and meteorological factors,and to identify the key factors leading to the hydrological regime changes.At last,based on the analysis of basin water quality data,this paper analyzes the regularity of spatiotemporal variability and its driving forces.By the systematic analysis on the outcome,we could get that the spatiotemporel distribution of eco-hydrological characteristics shows the regular changes from the upstream to downstream(from the north to the south),and the spatiotemporal variability of eco-hydrological characteristics is typical from the east to the west.Altitude,aspect and water distribution are the primary natural driving forces leading to the spatiotemporel variability of eco-hydrological characteristics;and exploitation and op- eration of hydroelectric power station,construction of road on the river bank,and basin land utilization are the main human driving forces.

关键词： Longitudinal Range-Gorge Region Lancang River Yuanjiang River driving forces eco-hydrology spatiotemporal variability environmental factors

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Spatial variability of soil hydraulic and physical properties in erosive sloping agricultural fields

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Water Science and Engineering 2023年第1期16卷 57-66页

作者： Deepak Singh Alok Kumar Mishra Sridhar Patra Sankar Mariappan Nisha Singh Saswat Kumar Kar ICAR-Indian Institute of Soil and Water Conservation Dehradun 248195India Sam Higginbottom University of Agriculture Technology and SciencesPrayagraj 211007India Hemvati Nandan Bahuguna Garhwal University Srinagar(Garhwal)246174India

It is essential to minimize soil quality degradation in sloping agricultural fields through stabilization and improvement of soil hydraulic properties using sustainable soil management.This study aimed to analyze the impact of different tillage practices,including conventional tillage(CT),minimum tillage(MT),and zero tillage(ZT),on soil hydraulic conductivity in a sloping agricultural field under maizeewheat rotation.The results showed that the highest runoff volume(257.40 m3),runoff coefficient(42.84%),and soil loss(11.3 t)were observed when the CT treatment was applied.In contrast,the lowest runoff volume(67.95 m3),runoff coefficient(11.35%),and soil loss(1.05 t)were observed when the ZT treatment was adopted.The soil organic carbon and aggregate mean weight diameter were found to be significantly greater(with mean values of 0.79%and 1.19 mm,respectively)with the ZT treatment than with the CT treatment.With the tilled treatments(CT and MT),substantial changes in the saturated soil hydraulic conductivity(ks),near-saturated soil hydraulic conductivity(k),and water-conducting porosity(ε)were observed between two crop seasons.These three soil parameters were significantly higher in the period after maize harvesting than in the wheat growing period.In contrast,no significant difference in these soil parameters was found when the untilled treatment(ZT)was carried out.With regard to the slope positions,ks,k,andεshowed different behaviors under different treatments.The toe slope position showed significantly lower ks andεvalues than the summit and middle slope positions.Of the evaluated tillage practices,ZT was found to be the most promising means to improve the soil hydro-physical properties and effectively reduce surface runoff and soil erosion.

关键词： Hydraulic conductivity Macropore Conservation tillage spatiotemporal variability Soil erosion

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spatiotemporal Changes in Soil Nutrients:A Case Study in Taihu Region of China

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Journal of Integrative Agriculture 2014年第1期13卷 187-194页

作者： LIU Lei-lei ZHU Yan LIU Xiao-jun CAO Wei-xing XU Mao WANG Xu-kui WANG En-li National Engineering and Technology Center for Information Agriculture/Jiangsu Key Laboratory for Information Agriculture/Nanjing Agricultural University Soil and Fertilizer Station of Jiangsu Agricultural Department CSRIO Sustainable Agricultural Flagship CSIRO Land and Water

The accurate assessment of the spatiotemporal changes in soil nutrients influenced by agricultural production provides the basis for development of management strategies to maintain soil fertility and balance soil nutrients. In this paper, we combined spatial measurements from 2 157 soil samples and geostatistical analysis to assess the spatiotemporal changes in soil organic carbon （SOC）, total nitrogen （TN）, available phosphorus （AP） and available potassium content （AK） from the first soil survey （in the 1980s） to the second soil survey （in the 2000s） in the Taihu region of Jiangsu Province in China. The results showed that average soil nutrients in three soil types all exhibited the increased levels in the 2000s （except for AK in the yellow brown soil）. The standard deviation of soil nutrient contents increased （except for TN in the paddy soil）. Agricultural production in the 20 years led to increases in SOC, TN, AP and AK by 74, 82, 89 and 65%, respectively, of the Taihu areas analyzed. From the 1980s to 2000s all the nugget/sill ratios of soil nutrients indices were between 25 and 75% （except for AK in the yellow brown soil in the 2000s）, indicating moderate spatial dependence. The ratio of AP in the yellow brown soil in the 2000s was 88.74%, showing weak spatial dependence. The spatial correlation range values for SOC, TN, AP and AK in the 2000s all decreased. The main areas showing declines in SOC, TN and AP were in the northwest. For AK, the main region with declining levels was in the east and middle of western areas. Apparently, the increase in soil nutrients in the Taihu region can be mainly attributed to the large increase in fertilizer inputs, change in crop systems and enhanced residues management since the 1980s. Future emphasis should be placed on avoiding excess fertilizer inputs and balancing the effects of the fertilizers in soils.

关键词： soil fertility spatiotemporal variability soil organic carbon total nitrogen phosphorus potassium

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spatiotemporal changes in forest loss and its linkage to burned areas in China

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Journal of Forestry Research 2020年第6期31卷 2525-2536页

作者： Zhiwei Wu Saijia Yan Lei He Yanlong Shan Key Laboratory of Poyang Lake Wetland and Watershed Research Ministry of EducationJiangxi Normal UniversityNanchang 330022People’s Republic of China School of Geography and Environment Jiangxi Normal UniversityNanchang 330022People’s Republic of China Jiangxi Provincial Key Laboratory of Poyang Lake Comprehensive Management and Resource Development Jiangxi Normal UniversityNanchang 330022People’s Republic of China Forestry College Beihua UniversityJilin 132013People’s Republic of China

Fire-induced forest loss has substantially increased worldwide over the last decade.In China,the connection between forest loss and frequent fi res on a national scale remains largely unexplored.In this study,we used a data set for a time-series of forest loss from the Global Forest Watch and for a MODIS-derived burned area for 2003–2015 to ascertain variations in forest loss and to explore its relationship with forest fi res(represented by burned areas)at the country-and forest-zone levels.We quantifi ed trends in forest loss during 2003–2015 using linear regression analysis and assessed the relation between forest loss and burned areas using Spearman’s correlation.Forest loss increased signifi cantly(264.8 km 2 a−1;R 2=0.54,p<0.01)throughout China,with an average annual increase of 11.4%during 2003–2015.However,the forest loss trend had extensive spatial heterogeneity.Forest loss increased mainly in the subtropical evergreen broadleaf forest zone(315.0 km 2 a−1;R 2=0.69,p<0.01)and tropical rainforest zone(38.8 km 2 a−1;R 2=0.66,p<0.01),but the loss of forest decreased in the cold temperate deciduous coniferous forest zone(−70.8 km 2 year−1;R 2=0.75,p<0.01)and the temperate deciduous mixed broadleaf and coniferous forest zone(−14.4 km 2 a−1;R 2=0.45,p<0.05).We found that 1.0%of China’s area had a signifi cant positive correlation(r≥0.55,p<0.05)with burned areas and 0.3%had a signifi cant negative correlation(r≤−0.55,p<0.05).In particular,forest loss had a signifi cant positive relationship with the burned area in the cold temperate deciduous coniferous forest zone(16.9% of the lands)and the subtropical evergreen broadleaf forest zone(7.8%).These results provide a basis for future predictions of fi re-induced forest loss in China.

关键词： Forest loss Forest fire Burned area spatiotemporal variability Correlation analysis

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