土壤与水评估工具(soil and water assessment tool,SWAT)作为一种广泛用于农业非点源(non-point source,NPS)污染模拟的分布式水文模型,虽在许多地区取得成效,但因参数化和水文响应不足,在干旱地区模拟中仍存在不确定性。为解决这一难...土壤与水评估工具(soil and water assessment tool,SWAT)作为一种广泛用于农业非点源(non-point source,NPS)污染模拟的分布式水文模型,虽在许多地区取得成效,但因参数化和水文响应不足,在干旱地区模拟中仍存在不确定性。为解决这一难题,该研究提出一种“物理约束+数据驱动”的混合建模策略:基于SWAT模型与卷积神经网络-长短期记忆网络(convolutional neural network-the long short term memory network,CNN-LSTM)的耦合方法,并引进改进型粒子群优化算法(improved particle swarm optimization,IPSO)应用于耦合框架中。该方法既同步优化了耦合模型的网络结构与超参数,又将每日输出结果的加权融合权重纳入同一优化向量。通过自适应惯性权重与扰动机制,实现对SWAT模型的误差校正。该研究通过分析单一SWAT模型的局限性,比较了SWAT模型与耦合模型在日尺度模拟精度上的差异,并探讨了IPSO与其他9种元启发式算法在超参数优化中的表现。最终以黄河宁夏段为研究区域,分析耦合模型在模拟总氮(total nitrogen,TN)和总磷(total phosphorus,TP)污染中的性能提升,并对流域NPS污染进行多尺度解析。结果表明,耦合模型在TN和TP模拟中显著优于单一的SWAT模型。TN的决定系数(determination coefficient,R^(2))、纳什效率系数(Nash-Sutcliffe efficiency,NSE)、百分比偏差(percent bias,PBIAS)和中心均方根误差(centered root mean square error,CRMSE)分别提高了14.1%、14.5%、38.6%和32.5%;TP的R^(2)、NSE、PBIAS和CRMSE分别提高了10.7%、12.0%、65.3%和40.7%。基于耦合模型的流域NPS污染时空分异分析显示,丰水期的峰值主要由降水和施肥协同作用导致,枯水期受宁夏冬灌影响。南部子流域的污染主要受降水径流驱动,北部灌区则由农业集约化主导。水系区间NPS污染贡献排名中,引黄灌区贡献31%~37%的TN和TP排放,红柳沟和苦水河水系受集约型农牧业影响,单位面积输出强度较高。研究表明,SWAT-IPSO-CNN-LSTM耦合方法有效降低了SWAT在干旱区站点率定的不确定性,并通过误差修正机制显著提升了氮磷模拟的精度与鲁棒性,为干旱区水环境管理提供了更可靠的技术支持。展开更多
With the definition and adoption of the Global Stratotype Section and Point （GSSP） for base of the Visean in China, the newly synthesized zonations and correlation of some significant fossil groups： foraminifera, c...With the definition and adoption of the Global Stratotype Section and Point （GSSP） for base of the Visean in China, the newly synthesized zonations and correlation of some significant fossil groups： foraminifera, conodont, coral and brachiopoda near the Tournaisian-Visean boundary beds are reviewed, which help in the recognition of the boundary in various sedimentary facies. The occurrence of two physical events, one pre- and one post- the Tournaisian-Visean boundary is emphasized, which allows for recognition of the position close to the Tournaisian-Visean boundary in the field. The regional correlation in southern China and international correlation throughout Eurasia around the Tournaisian-Visean boundary beds with the GSSP is proposed.展开更多
Scientific research and productive practice for earth history are inseparable from the accurate stratigraphic framework and time framework. Establishing the globally unified, precise and reliable chronostratigraphic s...Scientific research and productive practice for earth history are inseparable from the accurate stratigraphic framework and time framework. Establishing the globally unified, precise and reliable chronostratigraphic series and geological time series is the major goal of the International Commission on Stratigraphy （ICS）. Under the leadership of the ICS, the countries around the world have carried out research on the Global Standard Stratotype-section and Points （GSSPs） for the boundaries of chronostratigraphic systems. In the current International Chronostratigraphic Chart （ICC）, 65 GSSPs have been erected in the Phanerozoic Eonothem, and one has yet been erected in the Precambrian Eonothem. Based on the progress of research on stratigraphy especially that from its subcommissions, the ICS is constantly revising the ICC, and will publish a new International Stratigraphic Guide in 2020. After continual efforts and broad international cooperation of Chinese stratigraphers, 10 GSSPs within the Phanerozoic Eonothem have been approved and ratified to erect in China by the ICS and IUGS. To establish the standards for strafigraphic division and correlation of China, with the support from the Ministry of Science and Technology, the National Natural Science Foundation of China and the China Geological Survey, Chinese stratigraphers have carried out research on the establishment of Stages in China. A total of 102 stages have been defined in the ＂Regional Chronostratigraphic Chart of China （geologic time）＂, in which 59 stages were studied in depth. In 2014, the ＂Stratigraphic Chart of China＂ was compiled, with the essential contents as follows： the correlation between international chronostratigraphy and regional chronostratigraphy of China （geologic time）, the distributive status of lithostratigraphy, the characteristics of geological ages, the biostratigraphic sequence, the magnetostratigraphy, the geological events and eustatic sea-level change during every geological stage. The ＂Stratigraphical Guide of China and its Explanation （2014）＂ was also published. Chinese stratigraphers have paid much attention to stratigraphic research in south China, northeast China, north China and northwest China and they have made great achievements in special research on stratigraphy, based on the 1：1000000, 1：250000, 1：200000 and 1：50000 regional geological survey projects. Manifold new stratigraphic units were discovered and established by the regional geological surveys, which are helpful to improve the regional chronostratigraphic series of China. On the strength of the investigation in coastal and offshore areas, the status of marine strata in China has been expounded. According to the developing situation of international stratigraphy and the characteristics of Chinese stratigraphic work, the contrast relation between regional stratigraphic units of China and GSSPs will be established in the future, which will improve the application value of GSSPs and the standard of regional stratigraphic division and correlation. In addition, the study of stratigraphy of the Precambrian, terrestrial basins and orogenic belts will be strengthened, the Stratigraphic Chart of China will be improved, the typical stratigraphic sections in China will be protected and the applied study of stratigraphy in the fields of oil and gas, solid minerals, etc. will be promoted. On the ground of these actions, stratigraphic research will continue to play a great role in the social and economic development of China.展开更多
文摘土壤与水评估工具(soil and water assessment tool,SWAT)作为一种广泛用于农业非点源(non-point source,NPS)污染模拟的分布式水文模型,虽在许多地区取得成效,但因参数化和水文响应不足,在干旱地区模拟中仍存在不确定性。为解决这一难题,该研究提出一种“物理约束+数据驱动”的混合建模策略:基于SWAT模型与卷积神经网络-长短期记忆网络(convolutional neural network-the long short term memory network,CNN-LSTM)的耦合方法,并引进改进型粒子群优化算法(improved particle swarm optimization,IPSO)应用于耦合框架中。该方法既同步优化了耦合模型的网络结构与超参数,又将每日输出结果的加权融合权重纳入同一优化向量。通过自适应惯性权重与扰动机制,实现对SWAT模型的误差校正。该研究通过分析单一SWAT模型的局限性,比较了SWAT模型与耦合模型在日尺度模拟精度上的差异,并探讨了IPSO与其他9种元启发式算法在超参数优化中的表现。最终以黄河宁夏段为研究区域,分析耦合模型在模拟总氮(total nitrogen,TN)和总磷(total phosphorus,TP)污染中的性能提升,并对流域NPS污染进行多尺度解析。结果表明,耦合模型在TN和TP模拟中显著优于单一的SWAT模型。TN的决定系数(determination coefficient,R^(2))、纳什效率系数(Nash-Sutcliffe efficiency,NSE)、百分比偏差(percent bias,PBIAS)和中心均方根误差(centered root mean square error,CRMSE)分别提高了14.1%、14.5%、38.6%和32.5%;TP的R^(2)、NSE、PBIAS和CRMSE分别提高了10.7%、12.0%、65.3%和40.7%。基于耦合模型的流域NPS污染时空分异分析显示,丰水期的峰值主要由降水和施肥协同作用导致,枯水期受宁夏冬灌影响。南部子流域的污染主要受降水径流驱动,北部灌区则由农业集约化主导。水系区间NPS污染贡献排名中,引黄灌区贡献31%~37%的TN和TP排放,红柳沟和苦水河水系受集约型农牧业影响,单位面积输出强度较高。研究表明,SWAT-IPSO-CNN-LSTM耦合方法有效降低了SWAT在干旱区站点率定的不确定性,并通过误差修正机制显著提升了氮磷模拟的精度与鲁棒性,为干旱区水环境管理提供了更可靠的技术支持。
基金supported by the Ministry of Science and Technology (Grant No. 2006FY120300-7)the National Commission on Stratigraphy of China (No. 2006CB80640)the China Geological Survey (No. 1212010916059)
文摘With the definition and adoption of the Global Stratotype Section and Point （GSSP） for base of the Visean in China, the newly synthesized zonations and correlation of some significant fossil groups： foraminifera, conodont, coral and brachiopoda near the Tournaisian-Visean boundary beds are reviewed, which help in the recognition of the boundary in various sedimentary facies. The occurrence of two physical events, one pre- and one post- the Tournaisian-Visean boundary is emphasized, which allows for recognition of the position close to the Tournaisian-Visean boundary in the field. The regional correlation in southern China and international correlation throughout Eurasia around the Tournaisian-Visean boundary beds with the GSSP is proposed.
基金supported by the Ministry of Science and Technology(Grant No.2015FY310100)the National Natural Science Foundation of China(Grant Nos.41472030)the China Geological Survey(Grant Nos.DD20160120-04,DD20160120-02,DD20160345,1212011120427,12120114026701)
文摘Scientific research and productive practice for earth history are inseparable from the accurate stratigraphic framework and time framework. Establishing the globally unified, precise and reliable chronostratigraphic series and geological time series is the major goal of the International Commission on Stratigraphy （ICS）. Under the leadership of the ICS, the countries around the world have carried out research on the Global Standard Stratotype-section and Points （GSSPs） for the boundaries of chronostratigraphic systems. In the current International Chronostratigraphic Chart （ICC）, 65 GSSPs have been erected in the Phanerozoic Eonothem, and one has yet been erected in the Precambrian Eonothem. Based on the progress of research on stratigraphy especially that from its subcommissions, the ICS is constantly revising the ICC, and will publish a new International Stratigraphic Guide in 2020. After continual efforts and broad international cooperation of Chinese stratigraphers, 10 GSSPs within the Phanerozoic Eonothem have been approved and ratified to erect in China by the ICS and IUGS. To establish the standards for strafigraphic division and correlation of China, with the support from the Ministry of Science and Technology, the National Natural Science Foundation of China and the China Geological Survey, Chinese stratigraphers have carried out research on the establishment of Stages in China. A total of 102 stages have been defined in the ＂Regional Chronostratigraphic Chart of China （geologic time）＂, in which 59 stages were studied in depth. In 2014, the ＂Stratigraphic Chart of China＂ was compiled, with the essential contents as follows： the correlation between international chronostratigraphy and regional chronostratigraphy of China （geologic time）, the distributive status of lithostratigraphy, the characteristics of geological ages, the biostratigraphic sequence, the magnetostratigraphy, the geological events and eustatic sea-level change during every geological stage. The ＂Stratigraphical Guide of China and its Explanation （2014）＂ was also published. Chinese stratigraphers have paid much attention to stratigraphic research in south China, northeast China, north China and northwest China and they have made great achievements in special research on stratigraphy, based on the 1：1000000, 1：250000, 1：200000 and 1：50000 regional geological survey projects. Manifold new stratigraphic units were discovered and established by the regional geological surveys, which are helpful to improve the regional chronostratigraphic series of China. On the strength of the investigation in coastal and offshore areas, the status of marine strata in China has been expounded. According to the developing situation of international stratigraphy and the characteristics of Chinese stratigraphic work, the contrast relation between regional stratigraphic units of China and GSSPs will be established in the future, which will improve the application value of GSSPs and the standard of regional stratigraphic division and correlation. In addition, the study of stratigraphy of the Precambrian, terrestrial basins and orogenic belts will be strengthened, the Stratigraphic Chart of China will be improved, the typical stratigraphic sections in China will be protected and the applied study of stratigraphy in the fields of oil and gas, solid minerals, etc. will be promoted. On the ground of these actions, stratigraphic research will continue to play a great role in the social and economic development of China.
