中国南方树皮煤的生油潜力

中国南方晚二叠世龙潭煤系中的树皮煤主要分布在江苏南部、浙江长兴、安徽广德、江西乐平、贵州六盘水、湖南对阳等地区。将树皮煤作为烃源岩研究,对中国南方油气资源的寻找、勘查和评价具有十分重要的意义。文中通过对树皮煤的形成条件。有机质类型、演化程度以及各种显微组分对煤成烃的贡献的分析,讨论树皮煤的生烃潜力。并根据龙潭煤系生烃潜力、油气显示和生储盖的组合特征,讨论了龙潭煤系的成藏前景。     

青岛滨海地质旅游

青岛滨海旅游具有丰富的地质资源,合理地开发会使其具有专业特色,娱乐性和趣味性。滨海地质旅游将促进旅游业的发展,在向现代化国际城市中发挥作用。     

要重视海岸地区观赏植物资源的开发

列举了海岸地区常见的观赏植物群落,阐述了海岸地区观赏植物资源,对滨海旅游业如何利用海岸地区观赏植物资源提出了建议。     

Is the September 5, 2022, Luding MS6.8 earthquake an ‘unexpected’ event?

Whether the September 5, 2022, Luding M_S6.8 earthquake is an ‘expected’ event in the context of earthquake forecast? This commentary discusses this issue mainly using the recently proposed ‘earthquake nowcasting’ approach.     

不同混合层深度算法的全球适用性对比分析

混合层深度是研究海洋上层动力过程及海气相互作用的一个至关重要的物理量,准确估算混合层深度对上层海洋动力学和热力学的深入研究具有重要的科学意义。本文基于Argo实时观测剖面数据,分海域、分季节对比分析了目前常用的几种混合层深度算法的异同与优缺点。结果表明,理论上最大角度法的精确度最高,曲率法其次,然后是阈值法和最优线性拟合法。最大角度法和曲率法的结果比较接近,实测数据表明曲率法的时空适用性更广。阈值法、最优线性拟合法分别受梯度阈值和密度（或温度）梯度变化的制约,其计算的混合层深度相对较浅。各种算法的差异性随着季节跃层的增强而逐渐减小,且北半球的差异小于南半球。     

A rational method for development of limit state for liquefaction evaluation based on shear wave velocity measurements

This papers presents a new approach for developing a limit state for liquefaction evaluation based on field performance data. As an example to illustrate the new approach, a database that consists of, among many other features, in situ shear wave velocity measurements and field observations of liquefaction/non‐liquefaction in historic earthquakes is analysed. This database is first used to train a neural network to classify liquefaction/non‐liquefaction based on soil resistance parameters and load parameters. The successfully trained and tested neural network is then used to establish a limit state, a multiple dimension boundary that separates ‘zone’ of liquefaction from ‘zone’ of non‐liquefaction. The limit state yields cyclic resistance ratio for a given set of soil resistance parameters. Examination of all cases in the database show that the developed limit state has a high degree of accuracy in predicting the occurrence of liquefaction/non‐liquefaction. The developed neural network model can accurately predict the cyclic resistance ratio of soils. Copyright © 2000 John Wiley & Sons, Ltd.     

深井电极交叉供电对自然电位的影响

通过实验论证平凉地震台深井电阻率观测自然电位畸变由电极交叉供电造成,讨论分析不同电极供电对自然电位的影响。结果表明:对测量极供电,会影响自然电位,不会影响电阻率测值;单极供电对自然电位的影响表现为阶跃突跳,并以指数形态恢复,恢复时间约10 h,干扰峰值与供电电流、供电时间等有关;对观测数据进行校正,取得较好效果。     

Potential wind erosion rate response to climate and land‐use changes in the watershed of the Ningxia–Inner Mongolia reach of the Yellow River,China, 1986–2013

Climate and land‐use changes could strongly affect wind erosion and in turn cause a series of environmental problems. Thus, the objective of this study was to assess potential wind erosion rate (PWER) response to climate and land‐use changes in the watershed of the Ningxia–Inner Mongolia Reach of the Yellow River (NIMRYR), China. The watershed of NIMRYR suffers from serious wind erosion hazards, and over recent decades, wind erosion intensity and distribution has changed, following climate and land‐use changes. To understand these processes in the NIMRYR watershed, the Integrated Wind Erosion Modelling System (IWEMS) and the Revised Wind Erosion Equation (RWEQ) were used to calculate the PWER under different climate conditions and land‐use scenarios, and to assess the influences of climate and land‐use changes on the PWER. The results show the PWER in the whole watershed had a significant declining trend from 1986 to 2013. The results of the relationship among PWER, climate change, and land‐use changes showed that climate change was the dominant control on the PWER change in this watershed. Compared to the period 1986–1995, the average PWER decreased 23.32% and 64.98% as a result of climate change in the periods 1996–2005 and 2006–2013, respectively. In contrast with climate change, the effects of land‐use changes on the average PWER were much lower, and represented a change in PWER of less than 3.3% across the whole watershed. The study method we used could provide some valuable reference for wind erosion modelling, and the research results should help climate and land‐use researchers to develop strategies to reduce wind erosion. Copyright © 2017 John Wiley & Sons, Ltd.     

Temporal and spatial variations of potential evaporation and the driving mechanism over Tibet during 1961–2001

Potential evaporation (PE) is the basic component of the global hydrological cycle and energy balance. This study detected the temporal and spatial variations of PE and related driving factors in Tibet, China, for the period 1961–2001, based on observed data recorded at 22 meteorological stations. The results showed that (1) Tibet experienced a statistically significant decrease of PE between 1961 and 2001, which started mainly in the 1980s, along with accelerated warming; (2) the mean annual PE in Tibet showed an east–west increasing trend, and the annual PE at most stations presented decreasing trends; (3) an inverse correlation of mean annual PE with elevation was detected (low–high decreasing trend), and the statistical equations to estimate PE were established based on longitude, latitude and elevation; and (4) PE in Tibet can be well expressed by related meteorological variables, with vapour pressure deficit the dominant factor in determining PE.

EDITOR Z. W. Kundzewicz ASSOCIATE EDITOR not assigned     

基于LBS和深度学习的旅游景区客流量的高时频预测

为实现精准的旅游景区客流量的高时频预测,本研究构建了一套基于LBS和深度学习模型的预测方法。此方法可通过对LBS数据的转换实现预测的空间范围与时频控制,并通过方法的核心模型——基于双向循环神经网络和GRU算法构建的深度双向GRU(DBi-GRU)模型完成预测。为检验方法的有效性,研究以深圳大梅沙海滨公园为例对方法进行实验测试。实验使用拟合曲线、误差指标及DM检验3种方法评估DBi-GRU模型的预测效果。此外,实验还设置了其他五种深度学习模型作为DBi-GRU的对照模型,测试基于不同深度学习算法的模型之间的预测水平差异。实验结果表明:(1)本研究提出的DBi-GRU模型在景区客流量高时频预测中具有理想的预测效果,在高峰时段的客流量预测方面也具有较高准确性,预测效果明显优于其他深度学习模型;(2)基于双向循环网络的模型的效果普遍优于基于常规循环网络的模型。尤其是基于双向LSTM算法的模型,虽然预测的准确度略逊色于DBi-GRU模型,但在模型性能上与其的差异并不显著;(3)在相同网络参数下,GRU算法较前人采用的LSTM和RNN算法有着更高的预测准确性。本研究为客流量预测领域的研究提供了一种...