The Carnian Pluvial Episode(CPE)fingerprints global environmental perturbations and biological extinction on land and oceans and is potentially linked to the Wrangellia Large Igneous Province(LIP).However,the correlat...The Carnian Pluvial Episode(CPE)fingerprints global environmental perturbations and biological extinction on land and oceans and is potentially linked to the Wrangellia Large Igneous Province(LIP).However,the correlation between terrestrial environmental changes and Wrangellia volcanism in the Ordos Basin during the CPE remains poorly understood.Records of negative carbon isotopic excursions(NCIEs),mercury(Hg),Hg/TOC,and Hg enrichment factor(HgEF)from oil shales in a large-scale terrestrial Ordos Basin in the Eastern Tethys were correlated with marine and other terrestrial successions.The three significant NCIEs in the study section were consistently correlated with those in the CPE successions of Europe,the UK,and South and North China.The U-Pb geochronology indicates a Ladinian-Carnian age for the Chang 7 Member.A comprehensive overview of the geochronology,NCIE correlation,and previous bio-and chronostratigraphic frameworks shows that the Ladinian-Carnian boundary is located in the lower part of Chang 7 in the Yishicun section.HgEF may be a more reliable proxy for tracing volcanic eruptions than the Hg/TOC ratio because the accumulation rates of TOC content largely vary in terrestrial and marine successions.The records of Hg,Hg/TOC,HgEF,and NCIEs in the Ordos Basin aligned with Carnian successions worldwide and were marked by similar anomalies,indicating a global response to the Wrangellia LIP during the CPE.Anoxia,a warm-humid climate,enhancement of detrital input,and NCIEs are synchronous with the CPE interval in the Ordos Basin,which suggests that the CPE combined with the regional Qinling Orogeny should dominate the enhanced rate of terrigenous input and paleoenvironmental evolution in the Ordos Basin.展开更多
Desert-fringe vegetation growing over bright, sandy soils reduces the surface albedo from above 0.4 to well below 0.3. Called desert-scrub, these shrubs form a predominantly vertical clumps protruding from the soil-le...Desert-fringe vegetation growing over bright, sandy soils reduces the surface albedo from above 0.4 to well below 0.3. Called desert-scrub, these shrubs form a predominantly vertical clumps protruding from the soil-level, thereby significantly increasing the coefficient of turbulent heat transfer from the surface. The impact on global and desert-belt climate of changes in these two surface characteristics was simulated by a multi-layer energy balance tnodel. Evaluated only as a forcing to a further climatic change (that is, without accounting for any possible feedbacks) the results are: if vegetation (such as apparently existed under the warmer climate of 6,000 BP ) grows over large areas in the arid, currently bare-soil regions, the annual Northern Hemisphere surface temperature increases by 0.7t (by 0.6'C in July ), the surface temperature over land in the 20-30°N zone increases by 0.9℃ in both the annual and the July means, and the land-ocean annual temperature contrast in this zone increases by 0.25℃(0.2° in July). These results represent the combined influence of the reduction in the surface albedo and of the increase in the coefficient of turbulent heat transfer. In the desert-belt zones, the increase in the transfer coefficient sharply reduces the land temperature and the land-ocean temperature contrast from the values produced by the albedo change alone. This reduction must be attributed to the increased land-to-ocean circulation (which our model does not evaluate explicitly). Considering that a stronger circulation (resulting from land-ocean temperature contrast) generally forces a higher rainfall, the vegetation which emerged in the arid regions during the post-glacial optimum should be considered a significant positive feedback towards a still warmer, and also a more pluvial, climate. Our study may have implications for the 21st century, if the global warming expected from the enhanced greenhouse effects is accompanied by increased precipitation over the continents.展开更多
Is GI(Green Infrastructure)viable to mitigate urban pluvial flood caused by extreme storm events?Limited research and planning have been undertaken in recent years,but little practice has been found in the real world....Is GI(Green Infrastructure)viable to mitigate urban pluvial flood caused by extreme storm events?Limited research and planning have been undertaken in recent years,but little practice has been found in the real world.This retrospective study provides an example of mitigating pluvial flood by LID(Low Impact Development)principal and practices and transforming an old,ultra-dense low-income community into a climate change resilient community.The key findings include keeping flood control in mind when designing GI in the beginning;mimicking the sites’hydrologic characteristics as much as possible;outreaching to residences for maintenance issues from the beginning and monitoring the performance of GI facilities continuously.Technically,bioretention growing media with higher infiltration rate is specified that must be great than 150 mm/h in short term and 80 mm/h for long term;this paper chose low maintenance permeable pavement products avoiding clogging;and increasing parking space without compromising the design goals.展开更多
Increasing urban pluvial flood disasters due to climate change and rapid urbanisation have been a great challenge worldwide.Timely and effective emergency evacuation is important for reducing casualties and losses.Thi...Increasing urban pluvial flood disasters due to climate change and rapid urbanisation have been a great challenge worldwide.Timely and effective emergency evacuation is important for reducing casualties and losses.This has become a bottleneck for emergency management.This study aimed to develop a commonly used Agent-Based Mode(ABM)for pluvial flood emergency evacuation at the city scale,exploring the cascading impacts of pluvial flooding on human behaviour and emergency evacuation.The July 2021 pluvial flood event in Zhengzhou,Henan Province,claiming 380 lives and 40.9 billion yuan in direct losses,was selected as this case study.A raster-based hydraulic model(ECNU Flood-Urban)was used to predict flood inundation(extent and depth)during an event in Zhengzhou’s centre.Moreover,a comparative analysis of emergency evacuations was conducted before and after the pluvial flood event.The results showed that crowd behaviour plays an important role in an emergency evacuation,and extensive flooding leads to an 11-83%reduction in the number of evacuees.This study highlights the importance of risk education and contingency plans in emergency response.The ABM model developed in this study is proven to be effective and practical and will provide support for decision-making in urban flood emergency management.展开更多
This article describes a new method of urban pluvial flood modeling by coupling the 1D storm water management model(SWMM)and the 2D flood inundation model(ECNU Flood-Urban).The SWMM modeling results(the overflow of th...This article describes a new method of urban pluvial flood modeling by coupling the 1D storm water management model(SWMM)and the 2D flood inundation model(ECNU Flood-Urban).The SWMM modeling results(the overflow of the manholes)are used as the input boundary condition of the ECNU Flood-Urban model to simulate the rainfall–runoff processes in an urban environment.The analysis is applied to the central business district of East Nanjing Road in downtown Shanghai,considering 5-,10-,20-,50-,and 100-year return period rainfall scenarios.The results show that node overflow,water depth,and inundation area increase proportionately with the growing return periods.Water depths are mostly predicted to be shallow and surface flows generally occur in the urban road network due to its low-lying nature.The simulation result of the coupled model proves to be reliable and suggests that urban surface water flooding could be accurately simulated by using this methodology.Adaptation measures(upgrading of the urban drainage system)can then be targeted at specific locations with significant overflow and flooding.展开更多
Based on station precipitation observations,radar quantitative precipitation estimates(QPE), and radar fusion data during Typhoon Fitow(2013), the influence of multisource precipitation data on multiscale urban typhoo...Based on station precipitation observations,radar quantitative precipitation estimates(QPE), and radar fusion data during Typhoon Fitow(2013), the influence of multisource precipitation data on multiscale urban typhoon pluvial flood modeling is studied. Using Shanghai, China,as the study area, a simplified 2D hydrodynamic model is applied to simulations. Combined with actual flood incidents reported by the public and soil moisture data, we perform multiscale verifications and determine the applicability of three precipitation datasets in the modeling. The results are as follows:(1) At the city scale, although QPE have higher spatial resolution, these estimates are lower than station observations. Radar fusion data have both high accuracy and high spatial resolution. For flood depths above 5 cm, the radar fusion precipitation scenario can improve the matching probability by 6%.(2) At the neighborhood scale, the radar fusion precipitation scenario can effectively mitigate the problems of an uneven spatial distribution of stations and a weak QPE to accurately capture pluvial details.(3)One fixed-point assessment shows that different precipitation data have little influence on the temporal characteristics of the modeling result-all three types of data can accurately reflect flood occurrence times. This work can provide a scientific basis for constructing effective urban pluvial flood monitoring systems.展开更多
Deep learning models demonstrate impressive performance in rapidly predicting urban floods,but there are still limitations in enhancing physical connectivity and interpretability.This study proposed an innovative mode...Deep learning models demonstrate impressive performance in rapidly predicting urban floods,but there are still limitations in enhancing physical connectivity and interpretability.This study proposed an innovative modeling approach that integrates convolutional neural networks with weighted cellular automaton(CNN-WCA)to achieve the precise and rapid prediction of urban pluvial flooding processes and enhance the physical connectivity and reliability of modeling results.The study began by generating a rainfall-inundation dataset using WCA and LISFLOOD-FP,and the CNN-WCA model was trained using outputs from LISFLOOD-FP and WCA.Subsequently,the pre-trained model was applied to simulate the flood caused by the 20 July 2021 rainstorm in Zhengzhou City.The predicted inundation spatial distribution and depth by CNN-WCA closely aligned with those of LISFLOOD-FP,with the mean absolute error concentrated within 5 mm,and the prediction time of CNN-WCA was only 0.8%that of LISFLOOD-FP.The CNN-WCA model displays a strong capacity for accurately predicting changes in inundation depths within the study area and at susceptible points for urban flooding,with the Nash-Sutcliffe e fficiency values of most flood-prone points exceeding 0.97.Furthermore,the physical connectivity of the inundation distribution predicted by CNN-WCA is better than that of the distribution obtained with a CNN.The CNN-WCA model with additional physical constraints exhibits a reduction of around 34%in instances of physical discontinuity compared to CNN.Our results prove that the CNN model with multiple physical constraints has signifi cant potential to rapidly and accurately simulate urban flooding processes and improve the reliability of prediction.展开更多
Nature-based solutions(NBS)involve the sustainable maintenance,management,and restoration of natural or modified ecosystems.Flooding is a major problem in Phnom Penh,Cambodia,and has significant social and economic ra...Nature-based solutions(NBS)involve the sustainable maintenance,management,and restoration of natural or modified ecosystems.Flooding is a major problem in Phnom Penh,Cambodia,and has significant social and economic ramifications.This study tries to suggest creative solutions that support human welfare and biodiversity while simultaneously resolving social problems by adopting NBS.An online survey using convenience and snowball sampling was conducted to assess the openness of Phnom Penh residents to adopting NBS for flood mitigation in their homes or buildings.The survey investigated perceptions of NBS effectiveness based on previous knowledge and flood risk perception.Results revealed a strong correlation between perceived efficacy and willingness to adopt NBS.Specifically,flood risk perception and prior knowledge significantly influenced the perceived effectiveness of NBS.Key findings indicate that high installation and maintenance costs,lack of awareness,limited space,cultural factors,and perceived ineffectiveness are primary barriers to NBS adoption.Additionally,specific regional factors contribute to reluctance in certain areas of Phnom Penh.To overcome these barriers,the study recommends that the Cambodian government and other stakeholders invest in public education campaigns to raise awareness about the benefits of NBS.Financial incentives and subsidies should be provided to reduce the economic burden on residents.Furthermore,integrating NBS into urban planning and infrastructure development is crucial to enhance community resilience against floods.展开更多
为研究卡尼期雨幕事件在鄂尔多斯盆地南部的响应,对该盆地ZH2钻孔延长组进行孢粉化石、有机碳同位素、草莓状黄铁矿和主量元素分析。孢粉化石由下至上划分出Punctatisporites-Verrucosisporites-Osmundacidites组合Ⅰ和Asseretospora-Ap...为研究卡尼期雨幕事件在鄂尔多斯盆地南部的响应,对该盆地ZH2钻孔延长组进行孢粉化石、有机碳同位素、草莓状黄铁矿和主量元素分析。孢粉化石由下至上划分出Punctatisporites-Verrucosisporites-Osmundacidites组合Ⅰ和Asseretospora-Apiculatisporis组合Ⅱ,地质年代分别为中三叠世拉丁期和晚三叠世卡尼期。在孢粉组合Ⅱ下部张家滩页岩中总有机碳富集、有机碳同位素发生负漂移,漂移量为4.88‰,同时草莓状黄铁矿指标指示着该层位形成于贫氧的环境,Al_(2)O_(3)/MgO比值和化学蚀变指数(chemical index of alteration,CIA)值在该层位均处于高值,指示着高温、湿润、强化学风化的环境。以上特征表明卡尼期雨幕事件在鄂尔多斯盆地造成了显著影响。进一步分析显示这些指标在张家滩页岩中可划分为4个独立的高温、湿润、缺氧、有机碳富集片段,指示了卡尼期雨幕事件(Carnian pluvial event,CPE)在鄂尔多斯盆地的4次气候波动,分别命名为:CPEⅠ、CPEⅡ、CPEⅢ、CPEⅣ。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42172109,41872113,42172108)China National Petroleum Corporation-China University of Petroleum(Beijing)Strategic Cooperation Science and Technology Project(Grant No.ZLZX2020-02)+1 种基金State's Key Project of Research and Development Plan(Grant No.2018YFA0702405)Science Foundation of China University of Petroleum(Beijing)(Grant Nos.2462020BJRC002,2462020YXZZ020)。
文摘The Carnian Pluvial Episode(CPE)fingerprints global environmental perturbations and biological extinction on land and oceans and is potentially linked to the Wrangellia Large Igneous Province(LIP).However,the correlation between terrestrial environmental changes and Wrangellia volcanism in the Ordos Basin during the CPE remains poorly understood.Records of negative carbon isotopic excursions(NCIEs),mercury(Hg),Hg/TOC,and Hg enrichment factor(HgEF)from oil shales in a large-scale terrestrial Ordos Basin in the Eastern Tethys were correlated with marine and other terrestrial successions.The three significant NCIEs in the study section were consistently correlated with those in the CPE successions of Europe,the UK,and South and North China.The U-Pb geochronology indicates a Ladinian-Carnian age for the Chang 7 Member.A comprehensive overview of the geochronology,NCIE correlation,and previous bio-and chronostratigraphic frameworks shows that the Ladinian-Carnian boundary is located in the lower part of Chang 7 in the Yishicun section.HgEF may be a more reliable proxy for tracing volcanic eruptions than the Hg/TOC ratio because the accumulation rates of TOC content largely vary in terrestrial and marine successions.The records of Hg,Hg/TOC,HgEF,and NCIEs in the Ordos Basin aligned with Carnian successions worldwide and were marked by similar anomalies,indicating a global response to the Wrangellia LIP during the CPE.Anoxia,a warm-humid climate,enhancement of detrital input,and NCIEs are synchronous with the CPE interval in the Ordos Basin,which suggests that the CPE combined with the regional Qinling Orogeny should dominate the enhanced rate of terrigenous input and paleoenvironmental evolution in the Ordos Basin.
文摘Desert-fringe vegetation growing over bright, sandy soils reduces the surface albedo from above 0.4 to well below 0.3. Called desert-scrub, these shrubs form a predominantly vertical clumps protruding from the soil-level, thereby significantly increasing the coefficient of turbulent heat transfer from the surface. The impact on global and desert-belt climate of changes in these two surface characteristics was simulated by a multi-layer energy balance tnodel. Evaluated only as a forcing to a further climatic change (that is, without accounting for any possible feedbacks) the results are: if vegetation (such as apparently existed under the warmer climate of 6,000 BP ) grows over large areas in the arid, currently bare-soil regions, the annual Northern Hemisphere surface temperature increases by 0.7t (by 0.6'C in July ), the surface temperature over land in the 20-30°N zone increases by 0.9℃ in both the annual and the July means, and the land-ocean annual temperature contrast in this zone increases by 0.25℃(0.2° in July). These results represent the combined influence of the reduction in the surface albedo and of the increase in the coefficient of turbulent heat transfer. In the desert-belt zones, the increase in the transfer coefficient sharply reduces the land temperature and the land-ocean temperature contrast from the values produced by the albedo change alone. This reduction must be attributed to the increased land-to-ocean circulation (which our model does not evaluate explicitly). Considering that a stronger circulation (resulting from land-ocean temperature contrast) generally forces a higher rainfall, the vegetation which emerged in the arid regions during the post-glacial optimum should be considered a significant positive feedback towards a still warmer, and also a more pluvial, climate. Our study may have implications for the 21st century, if the global warming expected from the enhanced greenhouse effects is accompanied by increased precipitation over the continents.
文摘Is GI(Green Infrastructure)viable to mitigate urban pluvial flood caused by extreme storm events?Limited research and planning have been undertaken in recent years,but little practice has been found in the real world.This retrospective study provides an example of mitigating pluvial flood by LID(Low Impact Development)principal and practices and transforming an old,ultra-dense low-income community into a climate change resilient community.The key findings include keeping flood control in mind when designing GI in the beginning;mimicking the sites’hydrologic characteristics as much as possible;outreaching to residences for maintenance issues from the beginning and monitoring the performance of GI facilities continuously.Technically,bioretention growing media with higher infiltration rate is specified that must be great than 150 mm/h in short term and 80 mm/h for long term;this paper chose low maintenance permeable pavement products avoiding clogging;and increasing parking space without compromising the design goals.
基金supported by the National Natural Science Foundation of China(Grant No.41871164)the National Key Research and Development Program of China(Grant No.2018YFC1508803)+2 种基金the Major Program of National Social Science Fund of China(Grant No.18ZDA105)the Shanghai Philosophy and Social Science Planning Program(Grant No.2021XRM005)the Fundamental Research Funds for the Central Universities(Grant No.2022ECNU-XWK-XK001)。
文摘Increasing urban pluvial flood disasters due to climate change and rapid urbanisation have been a great challenge worldwide.Timely and effective emergency evacuation is important for reducing casualties and losses.This has become a bottleneck for emergency management.This study aimed to develop a commonly used Agent-Based Mode(ABM)for pluvial flood emergency evacuation at the city scale,exploring the cascading impacts of pluvial flooding on human behaviour and emergency evacuation.The July 2021 pluvial flood event in Zhengzhou,Henan Province,claiming 380 lives and 40.9 billion yuan in direct losses,was selected as this case study.A raster-based hydraulic model(ECNU Flood-Urban)was used to predict flood inundation(extent and depth)during an event in Zhengzhou’s centre.Moreover,a comparative analysis of emergency evacuations was conducted before and after the pluvial flood event.The results showed that crowd behaviour plays an important role in an emergency evacuation,and extensive flooding leads to an 11-83%reduction in the number of evacuees.This study highlights the importance of risk education and contingency plans in emergency response.The ABM model developed in this study is proven to be effective and practical and will provide support for decision-making in urban flood emergency management.
基金supported by the National Key Research and Development Program of China(Grant Nos.2018YFC1508803,2017YFE0107400,2017YFE0100700)the National Natural Science Foundation of China(Grant Nos.41871164,51761135024)+3 种基金the National Social Science Fund of China(Grant No.18ZDA105)the Humanities and Social Sciences Project of the Ministry of Education of China(Grant No.17YJAZH111)the Key Project of Soft Science Research of Shanghai(Grant No.19692108100)the Fundamental Research Funds for the Central Universities(Grant Nos.2018ECNU-QKT001,2017ECNUKXK013)。
文摘This article describes a new method of urban pluvial flood modeling by coupling the 1D storm water management model(SWMM)and the 2D flood inundation model(ECNU Flood-Urban).The SWMM modeling results(the overflow of the manholes)are used as the input boundary condition of the ECNU Flood-Urban model to simulate the rainfall–runoff processes in an urban environment.The analysis is applied to the central business district of East Nanjing Road in downtown Shanghai,considering 5-,10-,20-,50-,and 100-year return period rainfall scenarios.The results show that node overflow,water depth,and inundation area increase proportionately with the growing return periods.Water depths are mostly predicted to be shallow and surface flows generally occur in the urban road network due to its low-lying nature.The simulation result of the coupled model proves to be reliable and suggests that urban surface water flooding could be accurately simulated by using this methodology.Adaptation measures(upgrading of the urban drainage system)can then be targeted at specific locations with significant overflow and flooding.
基金This study was sponsored by the National Natural Science Foundation of China(Grant Nos.41871164,41806046)the Shanghai Sailing Program(Grant No.21YF1456900)+1 种基金the Shanghai Philosophy and Social Science Planning Program(Grant No.2021XRM005)the Fundamental Research Funds for the Central Universities(Grant No.2022ECNU-XWK-XK001).
文摘Based on station precipitation observations,radar quantitative precipitation estimates(QPE), and radar fusion data during Typhoon Fitow(2013), the influence of multisource precipitation data on multiscale urban typhoon pluvial flood modeling is studied. Using Shanghai, China,as the study area, a simplified 2D hydrodynamic model is applied to simulations. Combined with actual flood incidents reported by the public and soil moisture data, we perform multiscale verifications and determine the applicability of three precipitation datasets in the modeling. The results are as follows:(1) At the city scale, although QPE have higher spatial resolution, these estimates are lower than station observations. Radar fusion data have both high accuracy and high spatial resolution. For flood depths above 5 cm, the radar fusion precipitation scenario can improve the matching probability by 6%.(2) At the neighborhood scale, the radar fusion precipitation scenario can effectively mitigate the problems of an uneven spatial distribution of stations and a weak QPE to accurately capture pluvial details.(3)One fixed-point assessment shows that different precipitation data have little influence on the temporal characteristics of the modeling result-all three types of data can accurately reflect flood occurrence times. This work can provide a scientific basis for constructing effective urban pluvial flood monitoring systems.
基金supported by the General Program of National Natural Science Foundation of China(Grant No.42377467)。
文摘Deep learning models demonstrate impressive performance in rapidly predicting urban floods,but there are still limitations in enhancing physical connectivity and interpretability.This study proposed an innovative modeling approach that integrates convolutional neural networks with weighted cellular automaton(CNN-WCA)to achieve the precise and rapid prediction of urban pluvial flooding processes and enhance the physical connectivity and reliability of modeling results.The study began by generating a rainfall-inundation dataset using WCA and LISFLOOD-FP,and the CNN-WCA model was trained using outputs from LISFLOOD-FP and WCA.Subsequently,the pre-trained model was applied to simulate the flood caused by the 20 July 2021 rainstorm in Zhengzhou City.The predicted inundation spatial distribution and depth by CNN-WCA closely aligned with those of LISFLOOD-FP,with the mean absolute error concentrated within 5 mm,and the prediction time of CNN-WCA was only 0.8%that of LISFLOOD-FP.The CNN-WCA model displays a strong capacity for accurately predicting changes in inundation depths within the study area and at susceptible points for urban flooding,with the Nash-Sutcliffe e fficiency values of most flood-prone points exceeding 0.97.Furthermore,the physical connectivity of the inundation distribution predicted by CNN-WCA is better than that of the distribution obtained with a CNN.The CNN-WCA model with additional physical constraints exhibits a reduction of around 34%in instances of physical discontinuity compared to CNN.Our results prove that the CNN model with multiple physical constraints has signifi cant potential to rapidly and accurately simulate urban flooding processes and improve the reliability of prediction.
文摘Nature-based solutions(NBS)involve the sustainable maintenance,management,and restoration of natural or modified ecosystems.Flooding is a major problem in Phnom Penh,Cambodia,and has significant social and economic ramifications.This study tries to suggest creative solutions that support human welfare and biodiversity while simultaneously resolving social problems by adopting NBS.An online survey using convenience and snowball sampling was conducted to assess the openness of Phnom Penh residents to adopting NBS for flood mitigation in their homes or buildings.The survey investigated perceptions of NBS effectiveness based on previous knowledge and flood risk perception.Results revealed a strong correlation between perceived efficacy and willingness to adopt NBS.Specifically,flood risk perception and prior knowledge significantly influenced the perceived effectiveness of NBS.Key findings indicate that high installation and maintenance costs,lack of awareness,limited space,cultural factors,and perceived ineffectiveness are primary barriers to NBS adoption.Additionally,specific regional factors contribute to reluctance in certain areas of Phnom Penh.To overcome these barriers,the study recommends that the Cambodian government and other stakeholders invest in public education campaigns to raise awareness about the benefits of NBS.Financial incentives and subsidies should be provided to reduce the economic burden on residents.Furthermore,integrating NBS into urban planning and infrastructure development is crucial to enhance community resilience against floods.
文摘为研究卡尼期雨幕事件在鄂尔多斯盆地南部的响应,对该盆地ZH2钻孔延长组进行孢粉化石、有机碳同位素、草莓状黄铁矿和主量元素分析。孢粉化石由下至上划分出Punctatisporites-Verrucosisporites-Osmundacidites组合Ⅰ和Asseretospora-Apiculatisporis组合Ⅱ,地质年代分别为中三叠世拉丁期和晚三叠世卡尼期。在孢粉组合Ⅱ下部张家滩页岩中总有机碳富集、有机碳同位素发生负漂移,漂移量为4.88‰,同时草莓状黄铁矿指标指示着该层位形成于贫氧的环境,Al_(2)O_(3)/MgO比值和化学蚀变指数(chemical index of alteration,CIA)值在该层位均处于高值,指示着高温、湿润、强化学风化的环境。以上特征表明卡尼期雨幕事件在鄂尔多斯盆地造成了显著影响。进一步分析显示这些指标在张家滩页岩中可划分为4个独立的高温、湿润、缺氧、有机碳富集片段,指示了卡尼期雨幕事件(Carnian pluvial event,CPE)在鄂尔多斯盆地的4次气候波动,分别命名为:CPEⅠ、CPEⅡ、CPEⅢ、CPEⅣ。
