The Eurasian teleconnection pattern （EU） is an important low-frequency pattern with well-known impacts on climate anomalies in Eurasia. The difference of low-level v-winds in several regions in the Eurasian mid-high...The Eurasian teleconnection pattern （EU） is an important low-frequency pattern with well-known impacts on climate anomalies in Eurasia. The difference of low-level v-winds in several regions in the Eurasian mid-high latitudes is defined as the EU index （EUIv）. In this study, the relationship between the winter EUIv and precipitation in the following summer over China is investigated. Results show that there is a significant positive （negative） correlation between the winter EUIv and the following summer precipitation over North China （the Yangtze River-Huaihe River basins）. Meanwhile, an interdecadal variability exists in the interannual relationship, and the correlation has become significantly enhanced since the early 1980s. Thus, the proposed EUIv may have implications for the prediction of summer precipitation anomalies over China. In positive winter EUIv years, three cyclonic circulation anomalies are observed--over the Ural Mountains, the Okhotsk Sea, and the subtropical western North Pacific. That is, the Ural blocking and Okhotsk blocking are inactive, zonal circulation prevails in the mid-high latitudes, and the western Pacific subtropical high tends to be weaker and locates to the north of its normal position in the following summer. This leads to above-normal moisture penetrating into the northern part of East China, and significant positive （negative） precipitation anomalies over North China （the Yangtze River-Huaihe River basins）, and vice versa. Further examination shows that the SST anomalies over the Northwest Pacific and subtropical central North Pacific may both contribute to the formation of EUIv-related circulation anomalies over the western North Pacific.展开更多
Based on the Late Paleozoic geological background and the latest exploration achievements of the Ordos Basin and North China platform, it is concluded that during the sedimentary period of Permian He 8 Member, the are...Based on the Late Paleozoic geological background and the latest exploration achievements of the Ordos Basin and North China platform, it is concluded that during the sedimentary period of Permian He 8 Member, the area in concern had multiple material sources, multiple river systems, flat terrain, shallow sedimentary water, widely distributed fluvial facies sand body and no continuous lake area, so alluvial river sedimentary system developed in the whole region. Based on stratigraphic correlation and division, and a large number of drilling and outcrop data, a comprehensive analysis of lithofacies and sedimentary facies types and distribution was carried out to reconstruct the ancient geographic pattern of the He 8 Member sedimentary period. The results of paleogeography restoration show that the area of Ordos Basin was the "runoff area" in the sedimentary slope in the western part of the North China platform during the sedimentary period of He 8 Member, the whole region was mainly alluvial plain sedimentation featuring alternate fluvial facies, flood plain facies and flood-plain lake facies. According to the results of flume deposition simulation experiment, a new sedimentary model of "alluvial river & flood-plain lake" is established, which reveals the genesis of large area gravel sand body in He 8 Member of this area and provides geological basis for the exploration of tight gas in the south of the basin.展开更多
Baseflow is one of the major pathways of runoff in hilly areas,and its contributions to surface water resources and pollutant loads cannot be ignored.In this study,based on water quantity and quality data from 1988 to...Baseflow is one of the major pathways of runoff in hilly areas,and its contributions to surface water resources and pollutant loads cannot be ignored.In this study,based on water quantity and quality data from 1988 to 2019 in hilly and low rainfall watersheds,we focused on the impact of long-term baseflow on nitrogen load using the load allocation based on the baseflow separation method.We also constructed a nitrogen balance model for the Chaohe River Basin of China from 2012 to 2021 to analyze the nitrogen accumulation in the basin.We used the baseflow nitrogen load lag analysis method to study the lag characteristics of the baseflow discharge process and analyzed the response and periodicity of baseflow nitrogen to precipitation and soil accumulation using time delay analysis.The res-ults showed that the contribution rate of baseflow nitrogen reached 69%and showed a slight increasing trend from 1988 to 2019.The ef-fects of changes in precipitation and nitrogen accumulation on the baseflow contribution was observed after 1-2 and 2 yr,respectively.After nitrogen accumulation,it entered the river channel through baseflow,which was already the main and continuous source of nitro-gen in rivers in hilly areas.展开更多
Multivariate statistical techniques, including cluster analysis (CA), principal component analysis (PCA), factor analysis (FA) and discriminant analysis (DA), were used to evaluate temporal and spatial variations and ...Multivariate statistical techniques, including cluster analysis (CA), principal component analysis (PCA), factor analysis (FA) and discriminant analysis (DA), were used to evaluate temporal and spatial variations and to interpret a large and complex water quality data sets collected from the Songhua River Basin. The data sets, which contained 14 parameters, were generated during the 7-year (1998-2004) monitoring program at 14 different sites along the rivers. Three significant sampling locations (less polluted sites, moderately polluted sites and highly polluted sites) were detected by CA method, and five latent factors (organic, inor-ganic, petrochemical, physiochemical, and heavy metals) were identified by PCA and FA methods. The re-sults of DA showed only five parameters (temperature, pH, dissolved oxygen, ammonia nitrogen, and nitrate nitrogen) and eight parameters (temperature, pH, dissolved oxygen, biochemical oxygen demand, ammonia nitrogen, nitrate nitrogen, volatile phenols and total arsenic) were necessarily in temporal and spatial varia-tions analysis, respectively. Furthermore, this study revealed the major causes of water quality deterioration were related to inflow of effluent from domestic and industrial wastewater disposal.展开更多
农业的起源和传播强化了人类适应和改造自然环境的能力,对全球生态系统产生了深刻的影响,并促进了人类文化的发展以及文明的起源。华北地区是粟作农业起源的核心地带,新石器时代以来的考古遗迹众多,文化序列完整,是研究早期作物起源及...农业的起源和传播强化了人类适应和改造自然环境的能力,对全球生态系统产生了深刻的影响,并促进了人类文化的发展以及文明的起源。华北地区是粟作农业起源的核心地带,新石器时代以来的考古遗迹众多,文化序列完整,是研究早期作物起源及农业演化的理想区域。本研究在淇河流域植物大遗存分析的基础上,收集了华北地区中全新世9~3 ka B.P.期间粟(Setaria italica)、黍(Panicum miliaceum)、水稻(Oryza sativa)、小麦(Triticum aestivum)和大豆(Glycine max)5种农作物数据,并结合气候、地貌等信息系统分析了淇河流域中全新世农业结构演化及其对环境的适应过程。研究表明,淇河流域农业经济结构演化特征与整个华北地区相比具有同步性。中全新世以来,适宜的气候环境为农业的发展和传播提供了有利的自然条件,水稻不断向北传播,在6.3 ka B.P.前后已经进入淇河流域,形成以粟、黍、水稻为主的混合农业体系;5.5 ka B.P.前后,随着气候的波动以及湿地的衰退,水稻逐渐退出淇河流域,农业结构演变为以粟、黍为主的旱作农业;3.5 ka B.P.前后随着小麦的传入,该地区形成以粟、黍、小麦为主的传统旱作农业体系。此外,华北地区中全新世以来农业结构的演化与气候环境及地貌之间存在显著的相关性,气候的周期性变化导致生业模式及农作物组合特征适时调整。地貌类型对农业也有着一定的影响和制约作用,对史前聚居点的分布、农业结构都产生了显著影响。展开更多
The interactions among the Asian-Pacific monsoon subsystems have significant impacts on the climatic regimes in the monsoon region and even the whole world. Based on the domestic and foreign related research, an analy...The interactions among the Asian-Pacific monsoon subsystems have significant impacts on the climatic regimes in the monsoon region and even the whole world. Based on the domestic and foreign related research, an analysis is made of four different teleconnection modes found in the Asian-Pacific monsoon region, which reveal clearly the interactions among the Indian summer monsoon （ISM）, the East Asian summer monsoon （EASM）, and the western North Pacific summer monsoon （WNPSM）. The results show that： （1） In the period of the Asian monsoon onset, the date of ISM onset is two weeks earlier than the beginning of the Meiyu over the Yangtze River Basin, and a teleconnection mode is set up from the southwestern India via the Bay of Bengal （BOB） to the Yangtze River Basin and southern Japan, i.e., the ＂southern＂ teleconnection of the Asian summer monsoon. （2） In the Asian monsoon culmination period, the precipitation of the Yangtze River Basin is influenced significantly by the WNPSM through their teleconnection relationship, and is negatively related to the WNPSM rainfall, that is, when the WNPSM is weaker than normal, the precipitation of the Yangtze River Basin is more than normal. （3） In contrast to the rainfall over the Yangtze River Basin, the precipitation of northern China （from the 4th pentad of July to the 3rd pentad of August） is positively related to the WNPSM. When the WNPSM is stronger than normal, the position of the western Pacific subtropical high （WPSH） becomes farther northeast than normal, the anomalous northeastward water vapor transport along the southwestern flank of WPSH is converged over northern China, providing adequate moisture for more rainfalls than normal there. （4） The summer rainfall in northern China has also a positive correlation with the ISM. During the peak period of ISM, a teleconnection pattern is formed from Northwest India via the Tibetan Plateau to northern China, i.e., the ＂northern＂ teleconnection of the Asian summer monsoon. The above four kinds of teleconnections reflect the links among the Asian monsoon subsystems of ISM, EASM, and WNPSM during the northward advancing march of the Asian summer monsoons.展开更多
以潮白河为研究区域,探讨了与模型参数及模型模拟性能有关的多参数灵敏度及不确定性分析方法(Multi-Parameter Sensitivity and Uncertainty Analysis,MPSUA)。基于MonteCarlo模拟的多参数灵敏度分析,可以评价模型中多个参数的相对重要...以潮白河为研究区域,探讨了与模型参数及模型模拟性能有关的多参数灵敏度及不确定性分析方法(Multi-Parameter Sensitivity and Uncertainty Analysis,MPSUA)。基于MonteCarlo模拟的多参数灵敏度分析,可以评价模型中多个参数的相对重要性。GLUE不确定性分析则能对模型性能进行量化评估。实例研究表明,通过MPSUA方法,可以减少优化参数的个数。而且,在没有对模型进行参数优化之前,基于MPSUA就可以确定模型的模拟精度。例如同样的模型在潮河可以获得比在白河更高的模拟精度。这种同一模型在不同流域所体现的差异性,一方面是源于模型结构本身的不完善,另一方面则与用于建模的数据误差有关。SCE-UA参数优化结果与MPSUA结果几乎一致,说明本文的参数灵敏度与模型总体性能评估方法比较合理。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.41505061,41530531 and 41405092)the National Basic Research Program of China(Grant Nos.2012CB955902 and 2013CB430204)
文摘The Eurasian teleconnection pattern （EU） is an important low-frequency pattern with well-known impacts on climate anomalies in Eurasia. The difference of low-level v-winds in several regions in the Eurasian mid-high latitudes is defined as the EU index （EUIv）. In this study, the relationship between the winter EUIv and precipitation in the following summer over China is investigated. Results show that there is a significant positive （negative） correlation between the winter EUIv and the following summer precipitation over North China （the Yangtze River-Huaihe River basins）. Meanwhile, an interdecadal variability exists in the interannual relationship, and the correlation has become significantly enhanced since the early 1980s. Thus, the proposed EUIv may have implications for the prediction of summer precipitation anomalies over China. In positive winter EUIv years, three cyclonic circulation anomalies are observed--over the Ural Mountains, the Okhotsk Sea, and the subtropical western North Pacific. That is, the Ural blocking and Okhotsk blocking are inactive, zonal circulation prevails in the mid-high latitudes, and the western Pacific subtropical high tends to be weaker and locates to the north of its normal position in the following summer. This leads to above-normal moisture penetrating into the northern part of East China, and significant positive （negative） precipitation anomalies over North China （the Yangtze River-Huaihe River basins）, and vice versa. Further examination shows that the SST anomalies over the Northwest Pacific and subtropical central North Pacific may both contribute to the formation of EUIv-related circulation anomalies over the western North Pacific.
基金Supported by the China National Science and Technology Major Project(2011ZX05044,2011ZX05007-004)
文摘Based on the Late Paleozoic geological background and the latest exploration achievements of the Ordos Basin and North China platform, it is concluded that during the sedimentary period of Permian He 8 Member, the area in concern had multiple material sources, multiple river systems, flat terrain, shallow sedimentary water, widely distributed fluvial facies sand body and no continuous lake area, so alluvial river sedimentary system developed in the whole region. Based on stratigraphic correlation and division, and a large number of drilling and outcrop data, a comprehensive analysis of lithofacies and sedimentary facies types and distribution was carried out to reconstruct the ancient geographic pattern of the He 8 Member sedimentary period. The results of paleogeography restoration show that the area of Ordos Basin was the "runoff area" in the sedimentary slope in the western part of the North China platform during the sedimentary period of He 8 Member, the whole region was mainly alluvial plain sedimentation featuring alternate fluvial facies, flood plain facies and flood-plain lake facies. According to the results of flume deposition simulation experiment, a new sedimentary model of "alluvial river & flood-plain lake" is established, which reveals the genesis of large area gravel sand body in He 8 Member of this area and provides geological basis for the exploration of tight gas in the south of the basin.
基金Under the auspices of the National Natural Science Foundation of China(No.52221003,42277044)。
文摘Baseflow is one of the major pathways of runoff in hilly areas,and its contributions to surface water resources and pollutant loads cannot be ignored.In this study,based on water quantity and quality data from 1988 to 2019 in hilly and low rainfall watersheds,we focused on the impact of long-term baseflow on nitrogen load using the load allocation based on the baseflow separation method.We also constructed a nitrogen balance model for the Chaohe River Basin of China from 2012 to 2021 to analyze the nitrogen accumulation in the basin.We used the baseflow nitrogen load lag analysis method to study the lag characteristics of the baseflow discharge process and analyzed the response and periodicity of baseflow nitrogen to precipitation and soil accumulation using time delay analysis.The res-ults showed that the contribution rate of baseflow nitrogen reached 69%and showed a slight increasing trend from 1988 to 2019.The ef-fects of changes in precipitation and nitrogen accumulation on the baseflow contribution was observed after 1-2 and 2 yr,respectively.After nitrogen accumulation,it entered the river channel through baseflow,which was already the main and continuous source of nitro-gen in rivers in hilly areas.
文摘Multivariate statistical techniques, including cluster analysis (CA), principal component analysis (PCA), factor analysis (FA) and discriminant analysis (DA), were used to evaluate temporal and spatial variations and to interpret a large and complex water quality data sets collected from the Songhua River Basin. The data sets, which contained 14 parameters, were generated during the 7-year (1998-2004) monitoring program at 14 different sites along the rivers. Three significant sampling locations (less polluted sites, moderately polluted sites and highly polluted sites) were detected by CA method, and five latent factors (organic, inor-ganic, petrochemical, physiochemical, and heavy metals) were identified by PCA and FA methods. The re-sults of DA showed only five parameters (temperature, pH, dissolved oxygen, ammonia nitrogen, and nitrate nitrogen) and eight parameters (temperature, pH, dissolved oxygen, biochemical oxygen demand, ammonia nitrogen, nitrate nitrogen, volatile phenols and total arsenic) were necessarily in temporal and spatial varia-tions analysis, respectively. Furthermore, this study revealed the major causes of water quality deterioration were related to inflow of effluent from domestic and industrial wastewater disposal.
文摘农业的起源和传播强化了人类适应和改造自然环境的能力,对全球生态系统产生了深刻的影响,并促进了人类文化的发展以及文明的起源。华北地区是粟作农业起源的核心地带,新石器时代以来的考古遗迹众多,文化序列完整,是研究早期作物起源及农业演化的理想区域。本研究在淇河流域植物大遗存分析的基础上,收集了华北地区中全新世9~3 ka B.P.期间粟(Setaria italica)、黍(Panicum miliaceum)、水稻(Oryza sativa)、小麦(Triticum aestivum)和大豆(Glycine max)5种农作物数据,并结合气候、地貌等信息系统分析了淇河流域中全新世农业结构演化及其对环境的适应过程。研究表明,淇河流域农业经济结构演化特征与整个华北地区相比具有同步性。中全新世以来,适宜的气候环境为农业的发展和传播提供了有利的自然条件,水稻不断向北传播,在6.3 ka B.P.前后已经进入淇河流域,形成以粟、黍、水稻为主的混合农业体系;5.5 ka B.P.前后,随着气候的波动以及湿地的衰退,水稻逐渐退出淇河流域,农业结构演变为以粟、黍为主的旱作农业;3.5 ka B.P.前后随着小麦的传入,该地区形成以粟、黍、小麦为主的传统旱作农业体系。此外,华北地区中全新世以来农业结构的演化与气候环境及地貌之间存在显著的相关性,气候的周期性变化导致生业模式及农作物组合特征适时调整。地貌类型对农业也有着一定的影响和制约作用,对史前聚居点的分布、农业结构都产生了显著影响。
基金Supported by the National Science and Technology Support Program (2007BAC03A01)the National Plan on Key Basic Research and Development (2006CB403604).
文摘The interactions among the Asian-Pacific monsoon subsystems have significant impacts on the climatic regimes in the monsoon region and even the whole world. Based on the domestic and foreign related research, an analysis is made of four different teleconnection modes found in the Asian-Pacific monsoon region, which reveal clearly the interactions among the Indian summer monsoon （ISM）, the East Asian summer monsoon （EASM）, and the western North Pacific summer monsoon （WNPSM）. The results show that： （1） In the period of the Asian monsoon onset, the date of ISM onset is two weeks earlier than the beginning of the Meiyu over the Yangtze River Basin, and a teleconnection mode is set up from the southwestern India via the Bay of Bengal （BOB） to the Yangtze River Basin and southern Japan, i.e., the ＂southern＂ teleconnection of the Asian summer monsoon. （2） In the Asian monsoon culmination period, the precipitation of the Yangtze River Basin is influenced significantly by the WNPSM through their teleconnection relationship, and is negatively related to the WNPSM rainfall, that is, when the WNPSM is weaker than normal, the precipitation of the Yangtze River Basin is more than normal. （3） In contrast to the rainfall over the Yangtze River Basin, the precipitation of northern China （from the 4th pentad of July to the 3rd pentad of August） is positively related to the WNPSM. When the WNPSM is stronger than normal, the position of the western Pacific subtropical high （WPSH） becomes farther northeast than normal, the anomalous northeastward water vapor transport along the southwestern flank of WPSH is converged over northern China, providing adequate moisture for more rainfalls than normal there. （4） The summer rainfall in northern China has also a positive correlation with the ISM. During the peak period of ISM, a teleconnection pattern is formed from Northwest India via the Tibetan Plateau to northern China, i.e., the ＂northern＂ teleconnection of the Asian summer monsoon. The above four kinds of teleconnections reflect the links among the Asian monsoon subsystems of ISM, EASM, and WNPSM during the northward advancing march of the Asian summer monsoons.
文摘以潮白河为研究区域,探讨了与模型参数及模型模拟性能有关的多参数灵敏度及不确定性分析方法(Multi-Parameter Sensitivity and Uncertainty Analysis,MPSUA)。基于MonteCarlo模拟的多参数灵敏度分析,可以评价模型中多个参数的相对重要性。GLUE不确定性分析则能对模型性能进行量化评估。实例研究表明,通过MPSUA方法,可以减少优化参数的个数。而且,在没有对模型进行参数优化之前,基于MPSUA就可以确定模型的模拟精度。例如同样的模型在潮河可以获得比在白河更高的模拟精度。这种同一模型在不同流域所体现的差异性,一方面是源于模型结构本身的不完善,另一方面则与用于建模的数据误差有关。SCE-UA参数优化结果与MPSUA结果几乎一致,说明本文的参数灵敏度与模型总体性能评估方法比较合理。
