2021年6—9月全球火山活动简报     

顾国辉  康建红  贾若  关升 《中国地震》2021,37(4):924-928

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吉林省龙岗火山岩区早更新世粗面玄武岩地球化学特征及构造意义     

徐智涛  李萌萌  盘晓东  孙景贵  顾国辉  刘宏岩  马飞 《地震地磁观测与研究》2021,42(2):160-161

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反射地震在胶东西北部变质岩区深部构造探测中的应用     

王怀洪  朱裕振  孙超  王秀东  田思清  巩固 《地球物理学进展》2021,36(1):267-273

焦家、三山岛、招平作为胶东西北部三大主要控矿断裂带,控制了胶西北地区近80％以上的金矿储量.金矿主要沿断裂倾角变化的平缓部位和陡、缓转折部位富集,构成了"阶梯式"分布型式.在复杂的区域地质构造背景下,如何清晰准确地预测控矿构造陡缓相间的倾角变化规律,成为金矿深部勘查必须要解决的问题.为了查明胶西北深部构造变化特征,本文应用地震方法进行了探索尝试.结合研究区以往地质、物探资料,构建了本区薄层反射地质模型,通过正演模拟研究,分析了采集参数,指导采集并获得了较高质量数据;针对变质岩区地震资料信噪比低、构造倾角大等特点,通过组合去噪、时频反褶积等技术手段,提高了地震信噪比;分析了该区地震反射波特征,以断面或蚀变带反射波直接进行断裂构造解释.明确了主要控矿构造在纵向上整体具有上陡下缓的"铲式"的特点,构造倾角30°～50°,局部达70°以上,呈倾角陡、缓相间阶梯式展布形态,且南东倾向断裂规模较北西倾向大.根据解释结果,预测了断裂带深度,指导了钻孔布设并获得了验证.  相似文献   

Generation of realistic synthetic catchments to explore fine continental surface processes     

Raphaël Bunel  Nicolas Lecoq  Yoann Copard  Eric Guérin  Marco Van de Wiel  Nicolas Massei 《地球表面变化过程与地形》2021,46(3):593-610

Understanding, analysing, and predicting the erosion mechanisms and sedimentary flows produced by catchments plays a key role in environmental conservation and restoration management and policies. Numerical case-testing studies are generally undertaken to analyse the sensitivity of flood and soil erosion processes to the physical characteristics of catchments. Most analyses are conducted on simple virtual catchments with physical characteristics that, unlike real catchments, are perfectly controlled. Virtual catchments generally correspond to V-shaped valley catchments. However, although these catchments are suitable for methodical analysis of the results, they do not provide a realistic representation of the spatial structures of the landscape and field conditions. They can, therefore, lead to potential modelling errors and can make it difficult to extend or generalize their results. Our proposed method bridges the gap between real and traditional virtual catchments by creating realistic virtual catchments with perfectly controllable physical characteristics. Our approach represents a real alternative to traditional test case procedures and provides a new framework for geomorphological and hydrological communities. It combines a field procedural generation approach, geographic information system processing procedures, and the CAESAR-Lisflood landscape evolution model. We illustrate how each of these components acts in the process of generating virtual catchments. Five physical parameters were adjusted and tested for each virtual catchment: drainage density, hypsometric integral, mean slope of the main channel, granulometry, and land use. One of our virtual catchments is compared with a real catchment and a virtual catchment produced by a standard method. This comparison indicates that our approach can produce more realistic virtual catchments than those produced by more traditional methods, while a high degree of controllability is maintained. This new method of generating virtual catchments therefore offers significant research potential to identify the impacts of the physical characteristics of catchments on hydro-sedimentary dynamics and responses.  相似文献   

区域经济增长中的产业结构变动效应——以广西为例     

王洪涛  顾江 《地域研究与开发》2014,(5)

基于产业结构贡献统计的多部门经济模型,分析1951—2012年广西产业结构变动对经济增长贡献的时间差异和2002—2012年广西各地区产业结构变动对区域经济增长贡献的空间差异。受计划经济和市场经济下不同政策手段与方式的影响,在时间上广西产业结构变动对经济增长贡献呈两阶段波动收敛,在空间上三大经济区呈自西向东梯度推移的规律性变化,因受二产不断增加因素的影响,14个城市间产业结构变动过程差异显著,且三大经济区和14个城市的经济政策使产业结构变动与区域经济增长呈反向变化。后工业社会和市场经济条件下,完善开放统一要素市场,促进要素资源流动,构建分工合理与布局科学的产业体系,逐步以间接调控方式并遵循市场规律来推动产业结构优化和升级,应成为国家从宏观层面制定产业结构调整政策时需要考量的重点。  相似文献   

兰江流域近43年气候变化及对水资源的影响   总被引：5，自引：0，他引：5  

康丽莉  顾骏强  樊高峰 《气象》2007,33(2):70-75

利用累积距平法对兰江流域近43年（1961-2003年）气温、降水量和径流量资料进行分析，研究兰江流域气候变化及其气候变化对水资源的影响。结果显示：兰江流域近43年来气温、降水量总的趋势是上升的；1990年代是兰江流域气温上升和降水增加最显著的时段，主要表现在冬春气温明显上升，夏季降水量明显增加：兰江流域年径流深与年降水量基本保持同步变化。兰江流域过去43年的气候变化对流域内水资源产生了较大的影响，而且由于兰江流域内水资源空间分布差异较大，致使流域内人均水资源占有量较少的金华地区易受气候变化影响而出现供水紧张。  相似文献   

柴北缘西端冷湖盐场北山辉长岩地球化学及年代学研究   总被引：2，自引：0，他引：2       下载免费PDF全文

董增产  辜平阳  焦和  查显锋  陈锐明  张海迪 《地质科学》2014,49(4):1132-1149

柴北缘冷湖盐场北山镍铜矿区发育辉长岩和角闪辉长岩;属亚碱性岩石系列。球粒陨石、 原始地幔标准化曲线呈两组特征;但配分型式基本一致;反映其来自同一源区。稀土标准化曲线表现为弱右倾型;Eu基本无异常;说明斜长石分离结晶作用不明显。Rb、 Nb、 Zr、Cr等微量元素丰度及比值具有近似平行部分熔融的演化趋势。结合岩体Mg^#值和岩体固结指数（SI）高等特点;揭示原始岩浆具有幔源原生玄武岩浆特征;认为其成因与俯冲板片流体交代地幔楔源区的部分熔融有关;而且;Nb、 Zr、 Y元素丰度表明辉长岩源区为过渡型地幔。另外;两类岩体强烈亏损Nb、 Ta、 Zr、 Hf、 Ti等高场强元素（HFSE）;富集Ba、 Th、 U、 Pb等大离子亲石元素;反映明显的消减带和岛弧环境岩浆岩典型特征。LA-ICPMS锆石U-Pb测年结果表明辉长岩形成于254±3 Ma;结合该时期区域地质构造背景;认为柴北缘晚二叠世处于俯冲作用之下的岛弧构造环境;具有活动大陆边缘性质。  相似文献   

北京良乡井水温动态初析     

赵文忠  乔振瑛  谷庭瑶  牟凤香 《地震地磁观测与研究》2006,27(4):113-117

简要介绍了北京市良乡井水温动态的观测条件与环境,系统分析了水温年月日动态特征,认识了水温的正常动态变化规律与干扰因素,研究了典型震例,发现了同震异常与远兆异常等现象。  相似文献   

Sources,transport, and sinks of SO<Subscript>2</Subscript> over the equatorial Pacific during the Pacific Atmospheric Sulfur Experiment     

Burton Alonza Gray  Yuhang Wang  Dasa Gu  Alan Bandy  Lee Mauldin  Antony Clarke  Becky Alexander  Douglas D. Davis 《Journal of Atmospheric Chemistry》2011,68(1):27-53

The Pacific Atmospheric Sulfur Experiment (PASE) is the first sulfur-budget field experiment to feature simultaneous flux measurements of DMS marine emissions and SO₂ deposition to the ocean surface. We make use of these data to constrain a 1-D chemical transport model to study the production and loss pathways for DMS and SO₂ over the equatorial Pacific. Model results suggest that OH is the main sink for DMS in the boundary layer (BL), and the average DMS-to-SO₂ conversion efficiency is ~73%. In an exploratory run involving the addition of 1 pptv of BrO as a second oxidant, a 14% increase in the DMS flux is needed beyond that based on OH oxidation alone. This BrO addition also reduces the DMS-to-SO₂ conversion efficiency from 73% to 60%. The possibility of non-DMS sources of marine sulfur influencing the estimated conversion efficiency was explored and found to be unconvincing. For BL conditions, SO₂ losses consist of 48% dry deposition, while transport loss to the BuL and aerosol scavenging each account for another 19%. The conversion of SO₂ to H₂SO₄ consumes the final 14%. In the BuL, cloud scavenging removes 85% of the SO₂, thus resulting in a decreasing vertical profile for SO₂. The average SO₂ dry deposition velocity from direct measurements (i.e., 0.36 cm sec⁻¹) is approximately 50% of what is calculated from the 1-D model and the global GEOS-Chem model. This suggests that the current generation of global models may be significantly overestimating SO₂ deposition rates over some tropical marine areas. Although the specific mechanism cannot be determined, speculation here is that the dry deposition anomalous results may point to the presence of a micro-surface chemical phenomenon involving partial saturation with either S(IV) and/or S(VI) DMS oxidation products. This could also appear as a pH drop in the ocean’s surface microfilm layer in this region. Finally, we propose that the enhanced SO₂ level observed in the lower free troposphere versus that in the upper BuL during PASE is most likely the result of transported DMS/SO₂-rich free-tropospheric air parcels from the east of the PASE sampling area, rather than an inadequate representation in the model of local convection.  相似文献   

Development of a Downscaling Method in China Regional Summer Precipitation Prediction   总被引：1，自引：0，他引：1       下载免费PDF全文

GU Weizong  CHEN Lijuan  LI Weijing  CHEN Deliang 《Acta Meteorologica Sinica》2011,25(3):303-315

A downscaling method taking into account of precipitation regionalization is developed and used in the regional summer precipitation prediction (RSPP) in China. The downscaling is realized by utilizing the optimal subset regression based on the hindcast data of the Coupled Ocean-Atmosphere General Climate Model of National Climate Center (CGCM/NCC), the historical reanalysis data, and the observations. The data are detrended in order to remove the influence of the interannual variations on the selection of predictors for the RSPP. Optimal predictors are selected through calculation of anomaly correlation coe±cients (ACCs) twice to ensure that the high-skill areas of the CGCM/NCC are also those of observations, with the ACC value reaching the 0.05 significant level. One-year out cross-validation and independent sample tests indicate that the downscaling method is applicable in the prediction of summer precipitation anomaly across most of China with high and stable accuracy, and is much better than the direct CGCM/NCC prediction. The predictors used in the downscaling method for the RSPP are independent and have strong physical meanings, thus leading to the improvements in the prediction of regional precipitation anomalies.  相似文献