Ecosystem services,which include water yield services,have been incorporated into decision processes of regional land use planning and sustainable development.Spatial pattern characteristics and identification of fact...Ecosystem services,which include water yield services,have been incorporated into decision processes of regional land use planning and sustainable development.Spatial pattern characteristics and identification of factors that influence water yield are the basis for decision making.However,there are limited studies on the driving mechanisms that affect the spatial heterogeneity of ecosystem services.In this study,we used the Hengduan Mountain region in southwest China,with obvious spatial heterogeneity,as the research site.The water yield module in the InVEST software was used to simulate the spatial distribution of water yield.Also,quantitative attribution analysis was conducted for various geomorphological and climatic zones in the Hengduan Mountain region by using the geographical detector method.Influencing factors,such as climate,topography,soil,vegetation type,and land use type and pattern,were taken into consideration for this analysis.Four key findings were obtained.First,water yield spatial heterogeneity is influenced most by climate-related factors,where precipitation and evapotranspiration are the dominant factors.Second,the relative importance of each impact factor to the water yield heterogeneity differs significantly by geomorphological and climatic zones.In flat areas,the influence of evapotranspiration is higher than that of precipitation.As relief increases,the importance of precipitation increases and eventually,it becomes the most influential factor.Evapotranspiration is the most influential factor in a plateau climate zone,while in the mid-subtropical zone,precipitation is the main controlling factor.Third,land use type is also an important driving force in flat areas.Thus,more attention should be paid to urbanization and land use planning,which involves land use changes,to mitigate the impact on water yield spatial pattern.The fourth finding was that a risk detector showed that Primarosol and Anthropogenic soil areas,shrub areas,and areas with slope<5°and 250-350 should be recognized as water yield important zones,while the corresponding elevation values are different among different geomorphological and climatic zones.Therefore,the spatial heterogeneity and influencing factors in different zones should be fully con-sidered while planning the maintenance and protection of water yield services in the Hengduan Mountain region.展开更多
Studying runoff characteristics and quantifying human activities’impact on northern Shaanxi,a crucial mineral resource area in China,is crucial to alleviate water resource contradictions.In this study,hydrological el...Studying runoff characteristics and quantifying human activities’impact on northern Shaanxi,a crucial mineral resource area in China,is crucial to alleviate water resource contradictions.In this study,hydrological element trends were analyzed using theβ-z-h three-parameter indication method.The Mann-Kendall,Pettitt,moving T,and Yamamoto methods were used to test the mutation point of hydrological elements.The Budyko framework was used to quantitatively assess the impacts of climate change and multiple human activities on runoff reduction.The results showed that(1):Precipitation(PRE),potential evapotranspiration(E0),and temperature(TEM)showed increasing trends;runoff in the Huangfuchuan,Gushanchuan,Kuye River,Tuwei River,Wuding River,Qingjian River,and Yanhe River catchments showed decreasing trends(HFC,GSC,KYR,TWR,WDR,QJR,YR);whereas runoff in the Jialu River(JLR)catchment showed a“V-shaped”trend from 1980 to2020.(2)Runoff was positively correlated with PRE and negatively correlated with E0and the subsurface index(n),with the elasticity coefficients of PRE,E0,and n showing an increasing trend in the change period.(3)Human activities were a key factor in runoff reduction,although the impact of different human activities showed spatial variations.This study provides a scientific foundation for achieving the sustainable development of water resources in mining areas.展开更多
The downward shortwave radiation(DSR)is a key input parameter for land surface models and climate models.Based on the daily averaged Global Land Surface Satellite downward shortwave radiation(GLASS-DSR)dataset over th...The downward shortwave radiation(DSR)is a key input parameter for land surface models and climate models.Based on the daily averaged Global Land Surface Satellite downward shortwave radiation(GLASS-DSR)dataset over the Yunnan-Kweichow Plateau(YKP)from 1984 to 2018,this paper analyzes variation trend and breakpoints of DSR.The results show that:annual averaged DSR decreases at a decreasing rate of-1.84 W·m^(-2)·decade^(-1) over the YKP from 1984 to 2018;the overall distribution of interannual averaged DSR shows higher in the mid-west,and gradually decreasing from west to northeast over the YKP;the estimated averaged DSR is larger in spring than in summer due to the influence of the monsoon;monthly averaged DSR reaches its maximum in May and its minimum in December;breakpoints are found in the seasonal and trend components of daily averaged DSR.Eleven driving factors are examined for their effects on DSR variation,including annual average temperature,precipitation,10 m wind speed,aerosol optical thickness(AOT),total cloud cover,elevation,slope,aspect,longitude,latitude,and climate zones.According to thefindings,AOT predominates in the spatio-temporal distribution of DSR over the YKP.This study will contribute to studies related to climate change and highland radiation.展开更多
Climate change and human activities are primary drivers of runoff variations,significantly impacting the hydrological balance of river basins.In recent decades,the Yellow River Basin,China has experienced a marked dec...Climate change and human activities are primary drivers of runoff variations,significantly impacting the hydrological balance of river basins.In recent decades,the Yellow River Basin,China has experienced a marked decline in runoff,posing challenges to the sustainable development of regional water resources and ecosystem stability.To enhance the understanding of runoff dynamics in the basin,we selected the Dahei River Basin,a representative tributary in the upper reaches of the Yellow River Basin as the study area.A comprehensive analysis of runoff trends and contributing factors was conducted using the data on hydrology,meteorology,and water resource development and utilization.Abrupt change years of runoff series in the Dahei River Basin was identified by the Mann-Kendall and Pettitt tests:1999 at Dianshang,Qixiaying,and Meidai hydrological stations and 1995 at Sanliang hydrological station.Through hydrological simulations based on the Variable Infiltration Capacity(VIC)model,we quantified the factors driving runoff evolution in the Dahei River Basin,with climate change contributing 9.92%–22.91%and human activities contributing 77.09%–90.08%.The Budyko hypothesis method provided similar results,with climate change contributing 13.06%–20.89%and human activities contributing 79.11%–86.94%.Both methods indicated that human activities,particularly water consumption,were dominant factors in the runoff variations of the Dahei River Basin.The integration of hydrological modeling with attribution analysis offers valuable insights into runoff evolution,facilitating adaptive strategies to mitigate water scarcity in arid and semi-arid areas.展开更多
A simple and facile gas chromatography-mass spectrometer （GC-MS） fingerprint of Su-He-Xiang-Wan （SHXW） was developed, the similarity analysis was conducted, and attribution of the major characteristic peaks was id...A simple and facile gas chromatography-mass spectrometer （GC-MS） fingerprint of Su-He-Xiang-Wan （SHXW） was developed, the similarity analysis was conducted, and attribution of the major characteristic peaks was identified for SHXW quality control. GC-MS analysis was performed on a QP2010 instrument （Shimadzu, Japan） equipped with a capillary column of RTX-5MS. The column temperature was initiated at 50℃, held for 5 min, increased at the rate of 3 ℃/min to 120 ℃, held for 2 min, and then increased at the rate of 4 ℃/min to 220℃, held for 10 min. Helium carrier gas was used at a constant flow rate of 1.3 mL/min. Mass conditions were ionization voltage, 70 eV; injector temperature, 250℃; ion source temperature, 250 ℃; splitting ratio, 30：1; full scan mode in the 40-500 Da mass ranges with rate of 0.2 s per scan. Attribution of the major characteristic peaks was identified for SHXW by comparing the chemical standards, references of Chinese herbal medicines and the negative controls of prescription samples （NC） of SHXW. With the help of the temperature-programmed retention indices （PTRIs） used together with mass spectra and chemical standards, 25 major characteristic peaks have been identified. Nine volatile medicinal materials were identified in the prescription of SHXW by attributing to the 27 major characteristic peaks. The results demonstrate that the proposed method is a powerful approach to quality control of complex herbal medicines.展开更多
Analysing runoff changes and how these are affected by climate change and human activities is deemed crucial to elucidate the ecological and hydrological response mechanisms of rivers.The Indicators of Hydrologic Alte...Analysing runoff changes and how these are affected by climate change and human activities is deemed crucial to elucidate the ecological and hydrological response mechanisms of rivers.The Indicators of Hydrologic Alteration and the Range of Variability Approach(IHA-RVA)method,as well as the ecological indicator method,were employed to quantitatively assess the degree of hydrologic change and ecological response processes in the Yellow River Basin from 1960 to 2020.Using Budyko's water heat coupling balance theory,the relative contributions of various driving factors(such as precipitation,potential evapotranspiration,and underlying surface)to runoff changes in the Yellow River Basin were quantitatively evaluated.The results show that the annual average runoff and precipitation in the Yellow River Basin had a downwards trend,whereas the potential evapotranspiration exhibited an upwards trend from 1960 to 2020.In approximately 1985,it was reported that the hydrological regime of the main stream underwent an abrupt change.The degree of hydrological change was observed to gradually increase from upstream to downstream,with a range of 34.00%-54.00%,all of which are moderate changes.However,significant differences have been noted among different ecological indicators,with a fluctuation index of 90.00%at the outlet of downstream hydrological stations,reaching a high level of change.After the mutation,the biodiversity index of flow in the middle and lower reaches of the Yellow River was generally lower than that in the base period.The research results also indicate that the driving factor for runoff changes in the upper reach of the Yellow River Basin is mainly precipitation,with a contribution rate of 39.31%-54.70%.Moreover,the driving factor for runoff changes in the middle and lower reaches is mainly human activities,having a contribution rate of 63.70%-84.37%.These results can serve as a basis to strengthen the protection and restoration efforts in the Yellow River Basin and further promote the rational development and use of water resources in the Yellow River.展开更多
Using the Moderate Resolution Imaging Spectroradiometer-normalized difference vegetation index(NDVI) dataset,we investigated the patterns of spatiotemporal variation in vegetation coverage and its associated driving f...Using the Moderate Resolution Imaging Spectroradiometer-normalized difference vegetation index(NDVI) dataset,we investigated the patterns of spatiotemporal variation in vegetation coverage and its associated driving forces in the Qinling-Daba(Qinba) Mountains in 2000–2014.The Sen and Mann–Kendall models and partial correlation analysis were used to analyze the data,followed by calculation of the Hurst index to analyze future trends in vegetation coverage.The results of the study showed that(1) NDVI of the study area exhibited a significant increase in 2000–2014(linear tendency,2.8%/10a).During this period,a stable increase was detected before 2010(linear tendency,4.32%/10a),followed by a sharp decline after 2010(linear tendency,–6.59%/10a).(2) Spatially,vegetation cover showed a "high in the middle and a low in the surroundings" pattern.High values of vegetation coverage were mainly found in the Qinba Mountains of Shaanxi Province.(3) The area with improved vegetation coverage was larger than the degraded area,being 81.32% and 18.68%,respectively,during the study period.Piecewise analysis revealed that 71.61% of the total study area showed a decreasing trend in vegetation coverage in 2010–2014.(4) Reverse characteristics of vegetation coverage change were stronger than the same characteristics on the Qinba Mountains.About 46.89% of the entire study area is predicted to decrease in the future,while 34.44% of the total area will follow a continuously increasing trend.(5) The change of vegetation coverage was mainly attributed to the deficit in precipitation.Moreover,vegetation coverage during La Nina years was higher than that during El Nino years.(6) Human activities can induce ambiguous effects on vegetation coverage: both positive effects(through implementation of ecological restoration projects) and negative effects(through urbanization) were observed.展开更多
Quantification of the impacts of environmental changes on runoff in the transitional area from the Tibetan Plateau to the Loess Plateau is of critical importance for regional water resources management.Trends and abru...Quantification of the impacts of environmental changes on runoff in the transitional area from the Tibetan Plateau to the Loess Plateau is of critical importance for regional water resources management.Trends and abrupt change points of the hydro-climatic variables in the Tao River Basin were investigated during 1956-2015.It also quantitatively separates the impacts of climate change and human activities on runoff change in the Tao River by using RCC-WBM model.Results indicate that temperature presented a significant rising trend(0.2℃per decade)while precipitation exhibited an insignificant decreasing trend(3.8 mm per decade)during 1956-2015.Recorded runoff in the Tao River decreased significantly with a magnitude of-13.7 mm per decade and abrupt changes in 1968 and 1986 were identified.Relative to the baseline period(1956-1968),runoff in the two anthropogenic disturbed periods of 1969-1986 and 1987-2015 decreased by 27.8 mm and 76.5 mm,respectively,which can be attributed to human activities(accounting for 69%)and climate change(accounting for 31%).Human activities are the principal drivers of runoff reduction in the Tao River Basin.However,the absolute influences on runoff reductions by the both drivers tend to increase,from 7.7 mm in 1969-1986 to 24.4 mm in 1987-2015 by climate change and from 20.2 mm to 52.2 mm by human activities.展开更多
Yanhu Lake basin(YHB)is a typical alpine lake on the northeastern Tibetan Plateau(TP).Its continuous expansion in recent years poses serious threats to downstream major projects.As a result,studies of the mechanisms u...Yanhu Lake basin(YHB)is a typical alpine lake on the northeastern Tibetan Plateau(TP).Its continuous expansion in recent years poses serious threats to downstream major projects.As a result,studies of the mechanisms underlying lake expansion are urgently needed.The elasticity method within the Budyko framework was used to calculate the water balance in the Yanhu Lake basin(YHB)and the neighboring Tuotuo River basin(TRB).Results show intensification of hydrological cycles and positive trends in the lake area,river runoff,precipitation,and potential evapotranspiration.Lake expansion was significant between 2001 and 2020 and accelerated between 2015 and 2020.Precipitation increase was the key factor underlying the hydrological changes,followed by glacier meltwater and groundwater.The overflow of Yanhu Lake was inevitable because it was connected to three other lakes and the water balance of all four lakes was positive.The high salinity lake water diverted downstream will greatly impact the water quality of the source area of the Yangtze River and the stability of the permafrost base of the traffic corridor.展开更多
Toward solving the actual operation problems of cascade hydropower stations under hydrologic uncertainty, this paper presents the process of extraction of statistical characteristics from long-term optimal cascade ope...Toward solving the actual operation problems of cascade hydropower stations under hydrologic uncertainty, this paper presents the process of extraction of statistical characteristics from long-term optimal cascade operation, and proposes a monthly operation function algorithm for the actual operation of cascade hydropower stations through the identification, processing, and screening of available information during long-term optimal operation. Applying the operation function to the cascade hydropower stations on the Jinshajiang-Yangtze River system, the modeled long-term electric generation is shown to have high precision and provide benefits. Through comparison with optimal operation, the simulation results show that the operation function proposed retains the characteristics of optimal operation. Also, the inadequacies and attribution of the algorithm are discussed based on case study, providing decision support and reference information for research on large-scale cascade operation work.展开更多
Small structures in coal mine working face is one of the main hidden dangers of safe and effi cient production in coal mine.Currently,seismic exploration is often used as the main method for detecting such structures....Small structures in coal mine working face is one of the main hidden dangers of safe and effi cient production in coal mine.Currently,seismic exploration is often used as the main method for detecting such structures.However,limited by the accuracy of seismic data processing and interpretation,the interpreted location of small structures is often deviated.Ground-penetrating radar(GPR)can detect small structures accurately,but the exploration depth is shallow.The combination of the two methods can improve the exploration accuracy of small structures in coal mine.Aiming at the 1226#working face of Shuguang coal mine,we propose a method of seismic-attributes based small-structure prediction error correction using GPR data.First,we extract the coherence,curvature,and dip attributes from seismic data,that are sensitive to small structures,then by considering factors such as the eff ective detection range of GPR and detection environment,we select two structures from the prediction results of seismic attributes for GPR detection.Finally,based on the relationship between the positions of small structures predicted by the two methods,we use statistical methods to determine the overall off set distance and azimuth of the small structures in the entire study area and use the results as a standard for correcting each structure position.The results show that the GPR data can be used to correct the horizontal position errors of small structures predicted by seismic attribute analysis.The accuracy of the prediction results is greatly improved,with the error controlled within 5 m and reduced by more than 80%.Therefore,the feasibility of the method proposed in this study is verified.展开更多
By examining field outcrops, drilling cores and seismic data, it is concluded that the Middle and Late Permian “Emeishan basalts” in Western Sichuan Basin were developed in two large eruption cycles, and the two set...By examining field outcrops, drilling cores and seismic data, it is concluded that the Middle and Late Permian “Emeishan basalts” in Western Sichuan Basin were developed in two large eruption cycles, and the two sets of igneous rocks are in unconformable contact. The lower cycle is dominated by overflow volcanic rocks;while the upper cycle made up of pyroclastic flow volcanic breccia and pyroclastic lava is typical explosive facies accumulation. With high-quality micro-dissolution pores and ultra-fine dissolution pores, the upper cycle is a set of high-quality porous reservoir. Based on strong heterogeneity and great differences of pyroclastic flow subfacies from surrounding rocks in lithology and physical properties, the volcanic facies and volcanic edifices in Western Sichuan were effectively predicted and characterized by using seismic attribute analysis method and instantaneous amplitude and instantaneous frequency coherence analysis. The pyroclastic flow volcanic rocks are widely distributed in the Jianyang area. Centering around wells YT1, TF2 and TF8, the volcanic rocks in Jianyang area had 3edifice groups and an area of about 500 km^(2), which is the most favorable area for oil and gas exploration in volcanic rocks.展开更多
Objective To estimate the lung cancer burden that may be attributable to ambient fine particulate matter （PM2.5） pollution in Guangzhou city in China from 2005 to 2013. Methods The data regarding PM2.5 exposure were...Objective To estimate the lung cancer burden that may be attributable to ambient fine particulate matter （PM2.5） pollution in Guangzhou city in China from 2005 to 2013. Methods The data regarding PM2.5 exposure were obtained from the ＆#39;Ambient air pollution exposure estimation for the Global Burden of Disease 2013＇ dataset at 0.1° ×0.1° spatial resolution. Disability-adjusted life years （DALYs） were estimated based on the information of mortality and incidence of lung cancer. Comparative risk analysis and integrated exposure-response function were used to estimate attributed disease burden. Results The population-weighted average concentration of PM2.5 was increased by 34.6% between 1990 and 2013, from 38.37 μg/m3 to 51.31 μg/m^3. The lung cancer DALYs in both men and women were increased by 36.2% from 2005 to 2013. The PM2.5 attributed lung cancer DALYs increased from 12105.0 （8181.0 for males and 3924.0 for females） in 2005 to 16489.3 （11291.7 for males and 5197.6 for females） in 2013. An average of 23.1% lung cancer burden was attributable to PM2.5 pollution in 2013. Conclusion PM2.5 has caused serious but under-appreciated public health burden in Guangzhou and the trend deteriorates. Effective strategies are needed to tackle this major public health problem.展开更多
Submarine seep plumes are a natural phenomenon in which different types of gases migrate through deep or shallow subsurface sediments and leak into seawater in pressure gradient.When detected using acoustic data,the l...Submarine seep plumes are a natural phenomenon in which different types of gases migrate through deep or shallow subsurface sediments and leak into seawater in pressure gradient.When detected using acoustic data,the leaked gases frequently exhibit a flame-like structure.We numerically modelled the relationship between the seismic response characteristic and bubble volume fraction to establish the bubble volume fraction in the submarine seep plume.Results show that our models are able to invert and predict the bubble volume fraction from field seismic oceanography data,by which synthetic seismic sections in different dominant frequencies could be numerically simulated,seismic attribute sections(e.g.,instantaneous amplitude,instantaneous frequency,and instantaneous phase)extracted,and the correlation between the seismic attributes and bubble volume fraction be quantitatively determined with functional equations.The instantaneous amplitude is positively correlated with bubble volume fraction,while the instantaneous frequency and bubble volume fraction are negatively correlated.In addition,information entropy is introduced as a proxy to quantify the relationship between the instantaneous phase and bubble volume fraction.As the bubble volume fraction increases,the information entropy of the instantaneous phase increases rapidly at the beginning,followed by a slight upward trend,and finally stabilizes.Therefore,under optimal noise conditions,the bubble volume fraction of submarine seep plumes can be inverted and predicted based on seismic response characteristics in terms of seismic attributes.展开更多
Well Shuangyushi 1 and Well Nanchong l deployed in the NW and central Sichuan Basin have obtained a high-yield industrial gas flow in the dolomite and karst reservoirs of the Middle Permian Maokou Formation,showing go...Well Shuangyushi 1 and Well Nanchong l deployed in the NW and central Sichuan Basin have obtained a high-yield industrial gas flow in the dolomite and karst reservoirs of the Middle Permian Maokou Formation,showing good exploration prospects of the Maokou Formation.In order to identify the sequence stratigraphic features of the Maokou Formation,its sequence stratigraphy was divided and a unified sequence stratigraphic framework applicable for the entire basin was established to analyze the stratigraphic denudation features within the sequence framework by using the spectral curve trend attribute analysis,together with drilling and outcrop data.On this basis,the controls of sequence on source rocks and reservoirs were analyzed.In particular,the Maokou Formation was divided into two third-order sequences e SQ1 and SQ2.SQ1 was composed of members Mao 1 Member and Mao 3,while SQ2 was composed of Mao 4 Member.Sequence stratigraphic correlation indicated that the Maokou Formation within the basin had experienced erosion to varying extent,forming“three intense and two weak”denuded regions,among which,the upper part of SQ2 was slightly denuded in the two weak denuded regions(SW Sichuan Basin and locally Eastern Sichuan Basin),while SQ2 was denuded out in the three intense denuded regions(Southern Sichuan BasineCentral Sichuan Basin,NE and NW Sichuan Basin).The development of source rocks and reservoirs within sequence stratigraphic framework was significantly affected by sequence boundary;the grain banks that can form effective reservoir were predominately distributed in SQ1 highstand systems tract(HST),while effective source rocks were predominately distributed in SQ1 transgressive system tract(TST).It is concluded that the sequence division method is objective and reasonable,which can effectively guide oil and gas exploration in this region.展开更多
Lake surface temperature(LST)is a key parameter in regulating regional water-carbon cycles and biological processes,playing a critical role in the energy and mass balance of lakes.The Tibetan Plateau(TP)is home to tho...Lake surface temperature(LST)is a key parameter in regulating regional water-carbon cycles and biological processes,playing a critical role in the energy and mass balance of lakes.The Tibetan Plateau(TP)is home to thousands of lakes and is highly sensitive to climate change.Therefore,the response of these lakes to a warming climate is crucial for the water security and ecological stability of the“Asian Water Tower”.However,the long-term trend of LST and its driving factors on the TP over the past two decades remain unclear.Here,we employ an all-weather land surface temperature dataset and a representative lake method to investigate the interannual trend of LST on the TP from 2000 to 2022.The analysis uses temperature data from 519 to 581 lakes with interannual dynamic changes in surface area.The results show that lakes on the TP exhibit an overall warming trend,with an average rate of 0.10±0.27℃(10 a)^(-1).Among the representative lakes,61%show a warming trend.The most significant warming occurs in autumn,with 91%of the representative lakes showing an increase in LST(0.47±0.30℃(10 a)^(-1)).The warming rate in spring is about half of that in autumn.In winter,the LST trend exhibits a polarized pattern:although some lakes experience significant warming,more than half show intense cooling.In summer,the trend of LST change is more moderate than that in other seasons.The positive feedback from the reduction in lake ice duration drives the LST trend on the TP.The lake ice duration reduces every 10-day,the annual LST increases 0.4℃.Additionally,altitude and lake expansion can also influence LST changes.Lakes at lower altitudes generally experience higher warming trends.Lake expansion can exacerbate lake warming in autumn by enhancing thermal inertia and delaying lake freeze-up.展开更多
Changes in global climate intensify the hydrological cycle, directly influence precipitation, evaporation, runoff, and cause the re-distribution of water resources in time and space. The aridity index （AI）, defined ...Changes in global climate intensify the hydrological cycle, directly influence precipitation, evaporation, runoff, and cause the re-distribution of water resources in time and space. The aridity index （AI）, defined as the ratio of annual precipitation to annual potential evapotranspiration, is a widely used numerical indicator to quantify the degree of dryness at a given location. This study examined the effects of climate change on Al in China during 1961-2015. The results showed that the nationally averaged AI experienced a notable interdecadal transition in 1993, characterized by increasing AI （wetter） between 1961 and 1993, and decreasing AI （drier） after 1993. Overall, the decreased solar radiation （solar dimming） was the main factor affected the nationally averaged AI during 1961-1993, while the relative humidity dominated the variations of nationally averaged AI during 1993-2015. However, the roles of individual factors on the changes in AI vary in different subregions. Precipitation is one of the important contributing factors for the changes orAl in almost all subregions, except the Mid-Lower Yangtze and Huaihe basins. Solar radiation has been significantly decreased during 1961-1993 in South China, Southwest China, Mid-Lower Yangtze and Huaihe basins, and the Tibetan Plateau. Therefore, it dominated the trends of AI in these subregions. The relative humidity mainly affected the Mid-Lower Yangtze and Huaihe basins, Southwest China, and the Tibetan Plateau during 1993-2015, hence dominated the trends of Al in these subregions. The changes of temperature and wind speed, however, played a relatively weak role in the variations of AI.展开更多
The Songhua River Basin(SRB),ranking third largest in China in terms of both runoff volume and basin area,has experi-enced frequent disasters and drastic changes in runoff since the early 20th century.Many studies hav...The Songhua River Basin(SRB),ranking third largest in China in terms of both runoff volume and basin area,has experi-enced frequent disasters and drastic changes in runoff since the early 20th century.Many studies have analyzed the causes of runoff re-duction;however,the spatiotemporal differences in runoff contributions and their underlying mechanisms remain poorly understood,which are crucial for regional water resources management and effective utilization.This study used the Mann-Kendall rank correlation trend test,continuous wavelet analysis,cumulative anomaly,and the slope change ratio of cumulative quantities(SCRCQ)method to explore the runoff changes characteristics and spatiotemporal differences of the contributions of climate change and human activities to runoff changes across three sub-basins of the SRB.The results show that:1)runoff from 1955 to 2022 in all the three sub-basins exhibit a statistically significant decreasing trend at 0.05 significant level.2)Four abrupt change points in runoff were detected in Nenjiang River Basin(NRB)and the mainstream of the SRB(MSRB),whereas only two change points in the Second Songhua River(SSRB).3)Runoff and precipitation series of the NRB and MSRB exhibit similar multi-timescale cycle characteristics with the most dominated cycles of 45-58 yr.In contrast,it is 12-18 yr for SSRB.4)Anthropogenic activities are the primary factor leading to in the reduction of runoff in NRB(74.33%-91.67%)and MSRB(50.11%-102.12%),whereas it is only 5.38%-33.12%in SSRB.This is attributed to the uneven distribution of regional climate and human activities in the entire SRB.5)With the growing demand for water diversion for agri-cultural irrigation,anthropogenic activities in the NRB and MSRB have increased.However,the opposite is found in SSR,where the in-creased influence of precipitation on runoff and water conservation policies are identified.展开更多
Electrofacies are used to determine reservoir rock properties,especially permeability,to simulate fluid flow in porous media.These are determined based on classification of similar logs among different groups of loggi...Electrofacies are used to determine reservoir rock properties,especially permeability,to simulate fluid flow in porous media.These are determined based on classification of similar logs among different groups of logging data.Data classification is accomplished by different statistical analysis such as principal component analysis,cluster analysis and differential analysis.The aim of this study is to predict 3D FZI(flow zone index)and Electrofacies(EFACT)volumes from a large volume of 3D seismic data.This study is divided into two parts.In the first part of the study,in order to make the EFACT model,nuclear magnetic resonance(NMR)log parameters were employed for developing an Electrofacies diagram based on pore size distribution and porosity variations.Then,a graph-based clustering method,known as multi resolution graph-based clustering(MRGC),was employed to classify and obtain the optimum number of Electrofacies.Seismic attribute analysis was then applied to model each relaxation group in order to build the initial 3D model which was used to reach the final model by applying Probabilistic Neural Network(PNN).In the second part of the study,the FZI 3D model was created by multi attributes technique.Then,this model was improved by three different artificial intelligence systems including PNN,multilayer feed-forward network(MLFN)and radial basis function network(RBFN).Finally,models of FZI and EFACT were compared.Results obtained from this study revealed that the two models are in good agreement and PNN method is successful in modeling FZI and EFACT from 3D seismic data for which no Stoneley data or NMR log data are available.Moreover,they may be used to detect hydrocarbon-bearing zones and locate the exact place for producing wells for the future development plans.In addition,the result provides a geologically realistic spatial FZI and reservoir facies distribution which helps to understand the subsurface reservoirs heterogeneities in the study area.展开更多
Accurately identifying the spatial differences in the response of regional runoff to climate and land use changes can clarify the mechanism of regional runoff changes and provide a scientific basis for adopting the ap...Accurately identifying the spatial differences in the response of regional runoff to climate and land use changes can clarify the mechanism of regional runoff changes and provide a scientific basis for adopting the appropriate water resource protection policies.In this study,based on the Budyko theory,we quantitatively evaluated the spatial differences in the response of runoff to climate and land use changes in the Yiluo River Basin after 2000;calculated the sensitivity of runoff changes to precipitation(P),potential evapotranspiration(E_(0))and land use changes;and quantified the contributions of those three factors to runoff changes.The findings revealed that with decreasing elevation,precipitation gradually decreases,potential evapotranspiration gradually increases,and runoff gradually decreases in the Yiluo River basin.Influenced by the population density,both cultivated land and construction land are widely distributed with the middle and lower reaches of the basin,while the upper reaches are dominated by forest land.Compared with the base period(1985-1989),precipitation and potential evapotranspiration in the watershed during the change period(2000-2017)basically showed decreasing and increasing trends,respectively,with obvious spatial differentiation.P increased significantly in the upper reaches of the Yi River,with an average of 35.2 mm(-83.8-84.7 mm),while P increased and decreased in the other five subbasins,but the decreasing trend was more prominent.Among the subbasins,the upper and middle reaches of the Luo River showed the largest reductions in P,with an average of-34.2 mm(-145.9-20.6 mm),whereas the middle reaches of the Yi River showed the smallest reduction in P,with an average of-10.9 mm(-84.2-59.5 mm).The E_(0)in the different regions during the change period showed an increasing trend,and the increase in E_(0)gradually decreased from the upper reaches to the lower reaches.The E_(0)in the upper reaches of the Luo River showed the largest change,with an average of 45.3 mm(38.2-48.3 mm),while the lower reaches of the Yiluo River showed the smallest change,with an average of 7.3 mm(-3.2-17.1 mm).Land use changes were primarily from cultivated to construction land in the middle and lower reaches.Runoff changes were positively correlated with precipitation changes and negatively correlated with potential evapotranspiration and land use changes.The absolute values of the sensitivity coefficients of runoff to these environmental factors decreased with lower altitude,indicating a reduced responsiveness of the basin runoff under a warming and drying climate trend.Reductions in precipitation and changes in potential evapotranspiration have led to reductions in runoff ranging from 4.7 to 17.4 mm and from 0.7 to 9.1 mm,respectively,while land use changes led to corresponding runoff reductions of 23.0 to 46.5 mm,suggesting that land use changes are more likely to trigger runoff changes in the basin than climatic fluctuations.Given the dominance of cultivated land,especially in the middle and lower reaches,and the region’s high susceptibility to human activities,there has been a significant reduction in runoff in recent years.The contribution of land use change to the runoff reduction in the Yiluo River Basin was greater at lower elevations,up to 86.1%,while climatic effects were more significant at higher elevations,up to 27.8%.Therefore,promoting the implementation of projects such as water ecological restoration and returning farmland to forests are of great significance to curb the over-exploitation of groundwater,to formulate scientific management and scheduling policies in order to realize the transformation of the water balance in the river basin from a non-steady state to a steady state,and to promote the integrity of the ecosystem of the lower reaches of the Yellow River and ensure its sustainable development.展开更多
基金National Basic Research Program of China,No.2015CB452702National Natural Science Foundation of China,No.41571098.No.41530749+1 种基金National Key R&D Program of China,No.2017YFC1502903Major Consulting Project of Strategic Development Institute,Chinese Academy of Sciences,No.Y02015001。
文摘Ecosystem services,which include water yield services,have been incorporated into decision processes of regional land use planning and sustainable development.Spatial pattern characteristics and identification of factors that influence water yield are the basis for decision making.However,there are limited studies on the driving mechanisms that affect the spatial heterogeneity of ecosystem services.In this study,we used the Hengduan Mountain region in southwest China,with obvious spatial heterogeneity,as the research site.The water yield module in the InVEST software was used to simulate the spatial distribution of water yield.Also,quantitative attribution analysis was conducted for various geomorphological and climatic zones in the Hengduan Mountain region by using the geographical detector method.Influencing factors,such as climate,topography,soil,vegetation type,and land use type and pattern,were taken into consideration for this analysis.Four key findings were obtained.First,water yield spatial heterogeneity is influenced most by climate-related factors,where precipitation and evapotranspiration are the dominant factors.Second,the relative importance of each impact factor to the water yield heterogeneity differs significantly by geomorphological and climatic zones.In flat areas,the influence of evapotranspiration is higher than that of precipitation.As relief increases,the importance of precipitation increases and eventually,it becomes the most influential factor.Evapotranspiration is the most influential factor in a plateau climate zone,while in the mid-subtropical zone,precipitation is the main controlling factor.Third,land use type is also an important driving force in flat areas.Thus,more attention should be paid to urbanization and land use planning,which involves land use changes,to mitigate the impact on water yield spatial pattern.The fourth finding was that a risk detector showed that Primarosol and Anthropogenic soil areas,shrub areas,and areas with slope<5°and 250-350 should be recognized as water yield important zones,while the corresponding elevation values are different among different geomorphological and climatic zones.Therefore,the spatial heterogeneity and influencing factors in different zones should be fully con-sidered while planning the maintenance and protection of water yield services in the Hengduan Mountain region.
基金Department of Water Resources of Shaanxi Province of China,No.2023slkj-8National Natural Science Foundation of China,No.51779209。
文摘Studying runoff characteristics and quantifying human activities’impact on northern Shaanxi,a crucial mineral resource area in China,is crucial to alleviate water resource contradictions.In this study,hydrological element trends were analyzed using theβ-z-h three-parameter indication method.The Mann-Kendall,Pettitt,moving T,and Yamamoto methods were used to test the mutation point of hydrological elements.The Budyko framework was used to quantitatively assess the impacts of climate change and multiple human activities on runoff reduction.The results showed that(1):Precipitation(PRE),potential evapotranspiration(E0),and temperature(TEM)showed increasing trends;runoff in the Huangfuchuan,Gushanchuan,Kuye River,Tuwei River,Wuding River,Qingjian River,and Yanhe River catchments showed decreasing trends(HFC,GSC,KYR,TWR,WDR,QJR,YR);whereas runoff in the Jialu River(JLR)catchment showed a“V-shaped”trend from 1980 to2020.(2)Runoff was positively correlated with PRE and negatively correlated with E0and the subsurface index(n),with the elasticity coefficients of PRE,E0,and n showing an increasing trend in the change period.(3)Human activities were a key factor in runoff reduction,although the impact of different human activities showed spatial variations.This study provides a scientific foundation for achieving the sustainable development of water resources in mining areas.
基金supported in part by the Platform Construction Project of High Level Talent in KUSTn part by the National Natural Science Foundation of China[grant number 42230109 and 41961053].
文摘The downward shortwave radiation(DSR)is a key input parameter for land surface models and climate models.Based on the daily averaged Global Land Surface Satellite downward shortwave radiation(GLASS-DSR)dataset over the Yunnan-Kweichow Plateau(YKP)from 1984 to 2018,this paper analyzes variation trend and breakpoints of DSR.The results show that:annual averaged DSR decreases at a decreasing rate of-1.84 W·m^(-2)·decade^(-1) over the YKP from 1984 to 2018;the overall distribution of interannual averaged DSR shows higher in the mid-west,and gradually decreasing from west to northeast over the YKP;the estimated averaged DSR is larger in spring than in summer due to the influence of the monsoon;monthly averaged DSR reaches its maximum in May and its minimum in December;breakpoints are found in the seasonal and trend components of daily averaged DSR.Eleven driving factors are examined for their effects on DSR variation,including annual average temperature,precipitation,10 m wind speed,aerosol optical thickness(AOT),total cloud cover,elevation,slope,aspect,longitude,latitude,and climate zones.According to thefindings,AOT predominates in the spatio-temporal distribution of DSR over the YKP.This study will contribute to studies related to climate change and highland radiation.
基金supported by the National Key Research and Development Program of China(2022YFC3204401)the National Natural Science Foundation of China(U23A2001,U2243234)+2 种基金the Major Science and Technology Projects of Inner Mongolia Autonomous Region(KCX2024013-1,2022EEDSKJXM005)the Inner Mongolia Autonomous Region Science and Technology Leading Talent Team(2022LJRC0007)the Inner Mongolia Agricultural University Basic Research Business Expenses Project(BR221012,BR221204).
文摘Climate change and human activities are primary drivers of runoff variations,significantly impacting the hydrological balance of river basins.In recent decades,the Yellow River Basin,China has experienced a marked decline in runoff,posing challenges to the sustainable development of regional water resources and ecosystem stability.To enhance the understanding of runoff dynamics in the basin,we selected the Dahei River Basin,a representative tributary in the upper reaches of the Yellow River Basin as the study area.A comprehensive analysis of runoff trends and contributing factors was conducted using the data on hydrology,meteorology,and water resource development and utilization.Abrupt change years of runoff series in the Dahei River Basin was identified by the Mann-Kendall and Pettitt tests:1999 at Dianshang,Qixiaying,and Meidai hydrological stations and 1995 at Sanliang hydrological station.Through hydrological simulations based on the Variable Infiltration Capacity(VIC)model,we quantified the factors driving runoff evolution in the Dahei River Basin,with climate change contributing 9.92%–22.91%and human activities contributing 77.09%–90.08%.The Budyko hypothesis method provided similar results,with climate change contributing 13.06%–20.89%and human activities contributing 79.11%–86.94%.Both methods indicated that human activities,particularly water consumption,were dominant factors in the runoff variations of the Dahei River Basin.The integration of hydrological modeling with attribution analysis offers valuable insights into runoff evolution,facilitating adaptive strategies to mitigate water scarcity in arid and semi-arid areas.
基金Foundation item： Projects（21275164, 21075138） supported by the National Natural Science Foundation of China
文摘A simple and facile gas chromatography-mass spectrometer （GC-MS） fingerprint of Su-He-Xiang-Wan （SHXW） was developed, the similarity analysis was conducted, and attribution of the major characteristic peaks was identified for SHXW quality control. GC-MS analysis was performed on a QP2010 instrument （Shimadzu, Japan） equipped with a capillary column of RTX-5MS. The column temperature was initiated at 50℃, held for 5 min, increased at the rate of 3 ℃/min to 120 ℃, held for 2 min, and then increased at the rate of 4 ℃/min to 220℃, held for 10 min. Helium carrier gas was used at a constant flow rate of 1.3 mL/min. Mass conditions were ionization voltage, 70 eV; injector temperature, 250℃; ion source temperature, 250 ℃; splitting ratio, 30：1; full scan mode in the 40-500 Da mass ranges with rate of 0.2 s per scan. Attribution of the major characteristic peaks was identified for SHXW by comparing the chemical standards, references of Chinese herbal medicines and the negative controls of prescription samples （NC） of SHXW. With the help of the temperature-programmed retention indices （PTRIs） used together with mass spectra and chemical standards, 25 major characteristic peaks have been identified. Nine volatile medicinal materials were identified in the prescription of SHXW by attributing to the 27 major characteristic peaks. The results demonstrate that the proposed method is a powerful approach to quality control of complex herbal medicines.
基金supported by the Basic Research Project of Key Scientific Research Projects of Colleges and Universities of Henan Province,China(23ZX012).
文摘Analysing runoff changes and how these are affected by climate change and human activities is deemed crucial to elucidate the ecological and hydrological response mechanisms of rivers.The Indicators of Hydrologic Alteration and the Range of Variability Approach(IHA-RVA)method,as well as the ecological indicator method,were employed to quantitatively assess the degree of hydrologic change and ecological response processes in the Yellow River Basin from 1960 to 2020.Using Budyko's water heat coupling balance theory,the relative contributions of various driving factors(such as precipitation,potential evapotranspiration,and underlying surface)to runoff changes in the Yellow River Basin were quantitatively evaluated.The results show that the annual average runoff and precipitation in the Yellow River Basin had a downwards trend,whereas the potential evapotranspiration exhibited an upwards trend from 1960 to 2020.In approximately 1985,it was reported that the hydrological regime of the main stream underwent an abrupt change.The degree of hydrological change was observed to gradually increase from upstream to downstream,with a range of 34.00%-54.00%,all of which are moderate changes.However,significant differences have been noted among different ecological indicators,with a fluctuation index of 90.00%at the outlet of downstream hydrological stations,reaching a high level of change.After the mutation,the biodiversity index of flow in the middle and lower reaches of the Yellow River was generally lower than that in the base period.The research results also indicate that the driving factor for runoff changes in the upper reach of the Yellow River Basin is mainly precipitation,with a contribution rate of 39.31%-54.70%.Moreover,the driving factor for runoff changes in the middle and lower reaches is mainly human activities,having a contribution rate of 63.70%-84.37%.These results can serve as a basis to strengthen the protection and restoration efforts in the Yellow River Basin and further promote the rational development and use of water resources in the Yellow River.
基金Major Project of High-resolution Earth Observation SystemBeijing Natural Science Foundation,No.8144052
文摘Using the Moderate Resolution Imaging Spectroradiometer-normalized difference vegetation index(NDVI) dataset,we investigated the patterns of spatiotemporal variation in vegetation coverage and its associated driving forces in the Qinling-Daba(Qinba) Mountains in 2000–2014.The Sen and Mann–Kendall models and partial correlation analysis were used to analyze the data,followed by calculation of the Hurst index to analyze future trends in vegetation coverage.The results of the study showed that(1) NDVI of the study area exhibited a significant increase in 2000–2014(linear tendency,2.8%/10a).During this period,a stable increase was detected before 2010(linear tendency,4.32%/10a),followed by a sharp decline after 2010(linear tendency,–6.59%/10a).(2) Spatially,vegetation cover showed a "high in the middle and a low in the surroundings" pattern.High values of vegetation coverage were mainly found in the Qinba Mountains of Shaanxi Province.(3) The area with improved vegetation coverage was larger than the degraded area,being 81.32% and 18.68%,respectively,during the study period.Piecewise analysis revealed that 71.61% of the total study area showed a decreasing trend in vegetation coverage in 2010–2014.(4) Reverse characteristics of vegetation coverage change were stronger than the same characteristics on the Qinba Mountains.About 46.89% of the entire study area is predicted to decrease in the future,while 34.44% of the total area will follow a continuously increasing trend.(5) The change of vegetation coverage was mainly attributed to the deficit in precipitation.Moreover,vegetation coverage during La Nina years was higher than that during El Nino years.(6) Human activities can induce ambiguous effects on vegetation coverage: both positive effects(through implementation of ecological restoration projects) and negative effects(through urbanization) were observed.
基金the National Key Research and Development Programs of China(2016YFA0601501)the National Natural Science Foundation of China(41830863,51879162,41601025)the Belt and Road Fund on Water and Sustainability of the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering(2019).
文摘Quantification of the impacts of environmental changes on runoff in the transitional area from the Tibetan Plateau to the Loess Plateau is of critical importance for regional water resources management.Trends and abrupt change points of the hydro-climatic variables in the Tao River Basin were investigated during 1956-2015.It also quantitatively separates the impacts of climate change and human activities on runoff change in the Tao River by using RCC-WBM model.Results indicate that temperature presented a significant rising trend(0.2℃per decade)while precipitation exhibited an insignificant decreasing trend(3.8 mm per decade)during 1956-2015.Recorded runoff in the Tao River decreased significantly with a magnitude of-13.7 mm per decade and abrupt changes in 1968 and 1986 were identified.Relative to the baseline period(1956-1968),runoff in the two anthropogenic disturbed periods of 1969-1986 and 1987-2015 decreased by 27.8 mm and 76.5 mm,respectively,which can be attributed to human activities(accounting for 69%)and climate change(accounting for 31%).Human activities are the principal drivers of runoff reduction in the Tao River Basin.However,the absolute influences on runoff reductions by the both drivers tend to increase,from 7.7 mm in 1969-1986 to 24.4 mm in 1987-2015 by climate change and from 20.2 mm to 52.2 mm by human activities.
基金funded by the National Natural Science Foundation of China(42002264)the China Geological Survey Program(DD20230537)the Fundamental Research Funds for the Central Public Research Institutes(SK202006).
文摘Yanhu Lake basin(YHB)is a typical alpine lake on the northeastern Tibetan Plateau(TP).Its continuous expansion in recent years poses serious threats to downstream major projects.As a result,studies of the mechanisms underlying lake expansion are urgently needed.The elasticity method within the Budyko framework was used to calculate the water balance in the Yanhu Lake basin(YHB)and the neighboring Tuotuo River basin(TRB).Results show intensification of hydrological cycles and positive trends in the lake area,river runoff,precipitation,and potential evapotranspiration.Lake expansion was significant between 2001 and 2020 and accelerated between 2015 and 2020.Precipitation increase was the key factor underlying the hydrological changes,followed by glacier meltwater and groundwater.The overflow of Yanhu Lake was inevitable because it was connected to three other lakes and the water balance of all four lakes was positive.The high salinity lake water diverted downstream will greatly impact the water quality of the source area of the Yangtze River and the stability of the permafrost base of the traffic corridor.
基金supported by the National Natural Science Foundation of China (Grant No. 40971300)the Fundamental Research Funds for the Central Universities (Grant No.10QX43)
文摘Toward solving the actual operation problems of cascade hydropower stations under hydrologic uncertainty, this paper presents the process of extraction of statistical characteristics from long-term optimal cascade operation, and proposes a monthly operation function algorithm for the actual operation of cascade hydropower stations through the identification, processing, and screening of available information during long-term optimal operation. Applying the operation function to the cascade hydropower stations on the Jinshajiang-Yangtze River system, the modeled long-term electric generation is shown to have high precision and provide benefits. Through comparison with optimal operation, the simulation results show that the operation function proposed retains the characteristics of optimal operation. Also, the inadequacies and attribution of the algorithm are discussed based on case study, providing decision support and reference information for research on large-scale cascade operation work.
基金This study work is supported by the Directly Managed Scientifi c Research Project of Huainan Mining(Group)Co.Ltd.(No.HNKYJTJS(2018)181),the Major Project of Shaanxi Coal and Chemical Industry Group Co.Ltd.(No.2018SMHKJ-A-J-03),China Energy Investment Corporation 2030 Pilot Project(No.GJNY2030XDXM-19-03.2),State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology(Beijing).I also would like to thank the editorial department and the review experts for their valuable comments and suggestions,and thank the Compagnie Générale de Géophysique(CGG)for the Jason software support.
文摘Small structures in coal mine working face is one of the main hidden dangers of safe and effi cient production in coal mine.Currently,seismic exploration is often used as the main method for detecting such structures.However,limited by the accuracy of seismic data processing and interpretation,the interpreted location of small structures is often deviated.Ground-penetrating radar(GPR)can detect small structures accurately,but the exploration depth is shallow.The combination of the two methods can improve the exploration accuracy of small structures in coal mine.Aiming at the 1226#working face of Shuguang coal mine,we propose a method of seismic-attributes based small-structure prediction error correction using GPR data.First,we extract the coherence,curvature,and dip attributes from seismic data,that are sensitive to small structures,then by considering factors such as the eff ective detection range of GPR and detection environment,we select two structures from the prediction results of seismic attributes for GPR detection.Finally,based on the relationship between the positions of small structures predicted by the two methods,we use statistical methods to determine the overall off set distance and azimuth of the small structures in the entire study area and use the results as a standard for correcting each structure position.The results show that the GPR data can be used to correct the horizontal position errors of small structures predicted by seismic attribute analysis.The accuracy of the prediction results is greatly improved,with the error controlled within 5 m and reduced by more than 80%.Therefore,the feasibility of the method proposed in this study is verified.
基金Supported by the Scientific and Technological Major Project of the Southwest Oil and Gas Field Company (2019ZD01-03)。
文摘By examining field outcrops, drilling cores and seismic data, it is concluded that the Middle and Late Permian “Emeishan basalts” in Western Sichuan Basin were developed in two large eruption cycles, and the two sets of igneous rocks are in unconformable contact. The lower cycle is dominated by overflow volcanic rocks;while the upper cycle made up of pyroclastic flow volcanic breccia and pyroclastic lava is typical explosive facies accumulation. With high-quality micro-dissolution pores and ultra-fine dissolution pores, the upper cycle is a set of high-quality porous reservoir. Based on strong heterogeneity and great differences of pyroclastic flow subfacies from surrounding rocks in lithology and physical properties, the volcanic facies and volcanic edifices in Western Sichuan were effectively predicted and characterized by using seismic attribute analysis method and instantaneous amplitude and instantaneous frequency coherence analysis. The pyroclastic flow volcanic rocks are widely distributed in the Jianyang area. Centering around wells YT1, TF2 and TF8, the volcanic rocks in Jianyang area had 3edifice groups and an area of about 500 km^(2), which is the most favorable area for oil and gas exploration in volcanic rocks.
基金supported by the Centre for Health Statistics Information,National Health and Family Planning Commission of the People’s Republic of China
文摘Objective To estimate the lung cancer burden that may be attributable to ambient fine particulate matter （PM2.5） pollution in Guangzhou city in China from 2005 to 2013. Methods The data regarding PM2.5 exposure were obtained from the ＆#39;Ambient air pollution exposure estimation for the Global Burden of Disease 2013＇ dataset at 0.1° ×0.1° spatial resolution. Disability-adjusted life years （DALYs） were estimated based on the information of mortality and incidence of lung cancer. Comparative risk analysis and integrated exposure-response function were used to estimate attributed disease burden. Results The population-weighted average concentration of PM2.5 was increased by 34.6% between 1990 and 2013, from 38.37 μg/m3 to 51.31 μg/m^3. The lung cancer DALYs in both men and women were increased by 36.2% from 2005 to 2013. The PM2.5 attributed lung cancer DALYs increased from 12105.0 （8181.0 for males and 3924.0 for females） in 2005 to 16489.3 （11291.7 for males and 5197.6 for females） in 2013. An average of 23.1% lung cancer burden was attributable to PM2.5 pollution in 2013. Conclusion PM2.5 has caused serious but under-appreciated public health burden in Guangzhou and the trend deteriorates. Effective strategies are needed to tackle this major public health problem.
基金Supported by the Natural Science Foundation of Shandong Province(No.ZR2022MD074)the Laboratory for Marine Mineral Resources+3 种基金Qingdao National Laboratory for Marine Science and Technology(No.MMRKF201810)the National Natural Science Foundation of China(No.41606077)the National Key R&D Program of China:HighPrecision Characterization Technology of Gas Hydrate Reservoir(No.2017YFC0307406-03)supported by the Shandong Province Taishan Scholar Construction Project。
文摘Submarine seep plumes are a natural phenomenon in which different types of gases migrate through deep or shallow subsurface sediments and leak into seawater in pressure gradient.When detected using acoustic data,the leaked gases frequently exhibit a flame-like structure.We numerically modelled the relationship between the seismic response characteristic and bubble volume fraction to establish the bubble volume fraction in the submarine seep plume.Results show that our models are able to invert and predict the bubble volume fraction from field seismic oceanography data,by which synthetic seismic sections in different dominant frequencies could be numerically simulated,seismic attribute sections(e.g.,instantaneous amplitude,instantaneous frequency,and instantaneous phase)extracted,and the correlation between the seismic attributes and bubble volume fraction be quantitatively determined with functional equations.The instantaneous amplitude is positively correlated with bubble volume fraction,while the instantaneous frequency and bubble volume fraction are negatively correlated.In addition,information entropy is introduced as a proxy to quantify the relationship between the instantaneous phase and bubble volume fraction.As the bubble volume fraction increases,the information entropy of the instantaneous phase increases rapidly at the beginning,followed by a slight upward trend,and finally stabilizes.Therefore,under optimal noise conditions,the bubble volume fraction of submarine seep plumes can be inverted and predicted based on seismic response characteristics in terms of seismic attributes.
基金Special and Significant Project of National Science and Technology“Study on oil and gas resources potential of marine carbonate rocks and formation conditions and distribution of giant oil and gas fields”(No.2011ZX05004-001).
文摘Well Shuangyushi 1 and Well Nanchong l deployed in the NW and central Sichuan Basin have obtained a high-yield industrial gas flow in the dolomite and karst reservoirs of the Middle Permian Maokou Formation,showing good exploration prospects of the Maokou Formation.In order to identify the sequence stratigraphic features of the Maokou Formation,its sequence stratigraphy was divided and a unified sequence stratigraphic framework applicable for the entire basin was established to analyze the stratigraphic denudation features within the sequence framework by using the spectral curve trend attribute analysis,together with drilling and outcrop data.On this basis,the controls of sequence on source rocks and reservoirs were analyzed.In particular,the Maokou Formation was divided into two third-order sequences e SQ1 and SQ2.SQ1 was composed of members Mao 1 Member and Mao 3,while SQ2 was composed of Mao 4 Member.Sequence stratigraphic correlation indicated that the Maokou Formation within the basin had experienced erosion to varying extent,forming“three intense and two weak”denuded regions,among which,the upper part of SQ2 was slightly denuded in the two weak denuded regions(SW Sichuan Basin and locally Eastern Sichuan Basin),while SQ2 was denuded out in the three intense denuded regions(Southern Sichuan BasineCentral Sichuan Basin,NE and NW Sichuan Basin).The development of source rocks and reservoirs within sequence stratigraphic framework was significantly affected by sequence boundary;the grain banks that can form effective reservoir were predominately distributed in SQ1 highstand systems tract(HST),while effective source rocks were predominately distributed in SQ1 transgressive system tract(TST).It is concluded that the sequence division method is objective and reasonable,which can effectively guide oil and gas exploration in this region.
基金supported by the National Natural Science Foundation of China(Grant Nos.52479024&W2412158)。
文摘Lake surface temperature(LST)is a key parameter in regulating regional water-carbon cycles and biological processes,playing a critical role in the energy and mass balance of lakes.The Tibetan Plateau(TP)is home to thousands of lakes and is highly sensitive to climate change.Therefore,the response of these lakes to a warming climate is crucial for the water security and ecological stability of the“Asian Water Tower”.However,the long-term trend of LST and its driving factors on the TP over the past two decades remain unclear.Here,we employ an all-weather land surface temperature dataset and a representative lake method to investigate the interannual trend of LST on the TP from 2000 to 2022.The analysis uses temperature data from 519 to 581 lakes with interannual dynamic changes in surface area.The results show that lakes on the TP exhibit an overall warming trend,with an average rate of 0.10±0.27℃(10 a)^(-1).Among the representative lakes,61%show a warming trend.The most significant warming occurs in autumn,with 91%of the representative lakes showing an increase in LST(0.47±0.30℃(10 a)^(-1)).The warming rate in spring is about half of that in autumn.In winter,the LST trend exhibits a polarized pattern:although some lakes experience significant warming,more than half show intense cooling.In summer,the trend of LST change is more moderate than that in other seasons.The positive feedback from the reduction in lake ice duration drives the LST trend on the TP.The lake ice duration reduces every 10-day,the annual LST increases 0.4℃.Additionally,altitude and lake expansion can also influence LST changes.Lakes at lower altitudes generally experience higher warming trends.Lake expansion can exacerbate lake warming in autumn by enhancing thermal inertia and delaying lake freeze-up.
基金partially supported by the National Natural Science Foundation of China (41790424 and 41505043)
文摘Changes in global climate intensify the hydrological cycle, directly influence precipitation, evaporation, runoff, and cause the re-distribution of water resources in time and space. The aridity index （AI）, defined as the ratio of annual precipitation to annual potential evapotranspiration, is a widely used numerical indicator to quantify the degree of dryness at a given location. This study examined the effects of climate change on Al in China during 1961-2015. The results showed that the nationally averaged AI experienced a notable interdecadal transition in 1993, characterized by increasing AI （wetter） between 1961 and 1993, and decreasing AI （drier） after 1993. Overall, the decreased solar radiation （solar dimming） was the main factor affected the nationally averaged AI during 1961-1993, while the relative humidity dominated the variations of nationally averaged AI during 1993-2015. However, the roles of individual factors on the changes in AI vary in different subregions. Precipitation is one of the important contributing factors for the changes orAl in almost all subregions, except the Mid-Lower Yangtze and Huaihe basins. Solar radiation has been significantly decreased during 1961-1993 in South China, Southwest China, Mid-Lower Yangtze and Huaihe basins, and the Tibetan Plateau. Therefore, it dominated the trends of AI in these subregions. The relative humidity mainly affected the Mid-Lower Yangtze and Huaihe basins, Southwest China, and the Tibetan Plateau during 1993-2015, hence dominated the trends of Al in these subregions. The changes of temperature and wind speed, however, played a relatively weak role in the variations of AI.
基金Under the auspices of National Natural Science Foundation of China(No.42271125)Jilin Province Foreign Expert Project(No.L202322)Doctoral Research Initiation Project of Jilin Normal University(No.0420237)。
文摘The Songhua River Basin(SRB),ranking third largest in China in terms of both runoff volume and basin area,has experi-enced frequent disasters and drastic changes in runoff since the early 20th century.Many studies have analyzed the causes of runoff re-duction;however,the spatiotemporal differences in runoff contributions and their underlying mechanisms remain poorly understood,which are crucial for regional water resources management and effective utilization.This study used the Mann-Kendall rank correlation trend test,continuous wavelet analysis,cumulative anomaly,and the slope change ratio of cumulative quantities(SCRCQ)method to explore the runoff changes characteristics and spatiotemporal differences of the contributions of climate change and human activities to runoff changes across three sub-basins of the SRB.The results show that:1)runoff from 1955 to 2022 in all the three sub-basins exhibit a statistically significant decreasing trend at 0.05 significant level.2)Four abrupt change points in runoff were detected in Nenjiang River Basin(NRB)and the mainstream of the SRB(MSRB),whereas only two change points in the Second Songhua River(SSRB).3)Runoff and precipitation series of the NRB and MSRB exhibit similar multi-timescale cycle characteristics with the most dominated cycles of 45-58 yr.In contrast,it is 12-18 yr for SSRB.4)Anthropogenic activities are the primary factor leading to in the reduction of runoff in NRB(74.33%-91.67%)and MSRB(50.11%-102.12%),whereas it is only 5.38%-33.12%in SSRB.This is attributed to the uneven distribution of regional climate and human activities in the entire SRB.5)With the growing demand for water diversion for agri-cultural irrigation,anthropogenic activities in the NRB and MSRB have increased.However,the opposite is found in SSR,where the in-creased influence of precipitation on runoff and water conservation policies are identified.
文摘Electrofacies are used to determine reservoir rock properties,especially permeability,to simulate fluid flow in porous media.These are determined based on classification of similar logs among different groups of logging data.Data classification is accomplished by different statistical analysis such as principal component analysis,cluster analysis and differential analysis.The aim of this study is to predict 3D FZI(flow zone index)and Electrofacies(EFACT)volumes from a large volume of 3D seismic data.This study is divided into two parts.In the first part of the study,in order to make the EFACT model,nuclear magnetic resonance(NMR)log parameters were employed for developing an Electrofacies diagram based on pore size distribution and porosity variations.Then,a graph-based clustering method,known as multi resolution graph-based clustering(MRGC),was employed to classify and obtain the optimum number of Electrofacies.Seismic attribute analysis was then applied to model each relaxation group in order to build the initial 3D model which was used to reach the final model by applying Probabilistic Neural Network(PNN).In the second part of the study,the FZI 3D model was created by multi attributes technique.Then,this model was improved by three different artificial intelligence systems including PNN,multilayer feed-forward network(MLFN)and radial basis function network(RBFN).Finally,models of FZI and EFACT were compared.Results obtained from this study revealed that the two models are in good agreement and PNN method is successful in modeling FZI and EFACT from 3D seismic data for which no Stoneley data or NMR log data are available.Moreover,they may be used to detect hydrocarbon-bearing zones and locate the exact place for producing wells for the future development plans.In addition,the result provides a geologically realistic spatial FZI and reservoir facies distribution which helps to understand the subsurface reservoirs heterogeneities in the study area.
基金The National Natural Science Foundation of China(52130907)。
文摘Accurately identifying the spatial differences in the response of regional runoff to climate and land use changes can clarify the mechanism of regional runoff changes and provide a scientific basis for adopting the appropriate water resource protection policies.In this study,based on the Budyko theory,we quantitatively evaluated the spatial differences in the response of runoff to climate and land use changes in the Yiluo River Basin after 2000;calculated the sensitivity of runoff changes to precipitation(P),potential evapotranspiration(E_(0))and land use changes;and quantified the contributions of those three factors to runoff changes.The findings revealed that with decreasing elevation,precipitation gradually decreases,potential evapotranspiration gradually increases,and runoff gradually decreases in the Yiluo River basin.Influenced by the population density,both cultivated land and construction land are widely distributed with the middle and lower reaches of the basin,while the upper reaches are dominated by forest land.Compared with the base period(1985-1989),precipitation and potential evapotranspiration in the watershed during the change period(2000-2017)basically showed decreasing and increasing trends,respectively,with obvious spatial differentiation.P increased significantly in the upper reaches of the Yi River,with an average of 35.2 mm(-83.8-84.7 mm),while P increased and decreased in the other five subbasins,but the decreasing trend was more prominent.Among the subbasins,the upper and middle reaches of the Luo River showed the largest reductions in P,with an average of-34.2 mm(-145.9-20.6 mm),whereas the middle reaches of the Yi River showed the smallest reduction in P,with an average of-10.9 mm(-84.2-59.5 mm).The E_(0)in the different regions during the change period showed an increasing trend,and the increase in E_(0)gradually decreased from the upper reaches to the lower reaches.The E_(0)in the upper reaches of the Luo River showed the largest change,with an average of 45.3 mm(38.2-48.3 mm),while the lower reaches of the Yiluo River showed the smallest change,with an average of 7.3 mm(-3.2-17.1 mm).Land use changes were primarily from cultivated to construction land in the middle and lower reaches.Runoff changes were positively correlated with precipitation changes and negatively correlated with potential evapotranspiration and land use changes.The absolute values of the sensitivity coefficients of runoff to these environmental factors decreased with lower altitude,indicating a reduced responsiveness of the basin runoff under a warming and drying climate trend.Reductions in precipitation and changes in potential evapotranspiration have led to reductions in runoff ranging from 4.7 to 17.4 mm and from 0.7 to 9.1 mm,respectively,while land use changes led to corresponding runoff reductions of 23.0 to 46.5 mm,suggesting that land use changes are more likely to trigger runoff changes in the basin than climatic fluctuations.Given the dominance of cultivated land,especially in the middle and lower reaches,and the region’s high susceptibility to human activities,there has been a significant reduction in runoff in recent years.The contribution of land use change to the runoff reduction in the Yiluo River Basin was greater at lower elevations,up to 86.1%,while climatic effects were more significant at higher elevations,up to 27.8%.Therefore,promoting the implementation of projects such as water ecological restoration and returning farmland to forests are of great significance to curb the over-exploitation of groundwater,to formulate scientific management and scheduling policies in order to realize the transformation of the water balance in the river basin from a non-steady state to a steady state,and to promote the integrity of the ecosystem of the lower reaches of the Yellow River and ensure its sustainable development.
