准噶尔盆地玛湖凹陷三叠系源上砂砾岩扇—断—压三控大面积成藏模式   总被引：1，自引：0，他引：1  

瞿建华  杨荣荣  唐勇 《地质学报》2019,93(4):915-927

准噶尔盆地玛湖富烃凹陷下三叠统百口泉组新近发现了我国首个源上大面积连续型砂砾岩油藏群,是对全球"连续型"油气藏研究的新补充,但其成藏机理和模式并不很清楚。为加强对其的理论认识,并为下步勘探提供参考,基于油气生、储、盖、圈、运、保等基础石油地质条件,并结合油气藏特征,进行了成藏条件与成藏模式的综合研究。结果表明,优质充足的下二叠统风城组碱湖油气来源、规模有效的扇三角洲前缘砂砾岩储层、多重组合的扇三角洲平原致密砾岩、泥岩和断裂封盖保存、沟通良好的高角度断裂输导体系、平缓连续的构造背景奠定了大面积连续成藏的地质基础。在此背景下,高成熟的风城组所生成油气,在切穿烃源灶和储层的高角度压扭性断裂沟通下,优先充注物性相对好的扇三角洲前缘水下河道砂岩和砂质细砾岩,并且在地层异常高压促进下,控制着油气富集程度,使得油气成藏表现为大型缓坡浅水扇三角洲沉积控制下的源上扇-断-压三控大面积"连续型"。百口泉组油气藏具有的油质轻且含气、微裂缝广泛发育,以及异常高压等,决定了砾岩储层虽总体低孔低渗,但依旧能够高产。在油源断裂沟通的斜坡区上倾方向,叠合地层异常高压以及扇三角洲前缘水下河道砂砾岩的区域是下步有利勘探方向。  相似文献   

Rainstorm-generated sediment yield model based on soil moisture proxies (SMP)     

Sushindra Kumar Gupta  Pushpendra K. Singh  Jaivir Tyagi  Gunwant Sharma  Ajay Singh Jethoo 《水文研究》2020,34(16):3448-3463

This study develops improved Soil Moisture Proxies (SMP) based suspended sediment yield (SMPSY) models corresponding to three antecedent moisture conditions (AMCs) (i.e., AMC-I-AMC-III) by coupling the improved initial abstraction (I_a-λ) model, the SMA procedure and the SMP concept for modelling the rainfall generated suspended sediment yield. The SMPSY models specifically incorporate a watershed storage index (S) model to accentuate the transformation from storm to storm and to avoid the sudden jumps in sediment yield computation. The workability of the SMPSY models is tested using a large dataset of rainfall and sediment yield (98 storm events) from twelve small watersheds and a comparison has been made with the existing MSY model. The goodness-of-fit (GOF) statistics is evaluated in terms of the Nash Sutcliffe efficiency (NSE), and error indices, i.e., root mean square error (RMSE), normalized root mean square error (nRMSE), standard error (SE), mean absolute error (MAE), and RMSE-observations standard deviation ratio (RSR). The NSE values vary from 74.31% to 96.57% and from 75.21% to 91.78%, respectively for the SPMSY and MSY model. The NSE statistics indicate that the SMPSY model has lower uncertainty in simulating sediment yield as compared to the MSY model. The error indices are lower for the SMPSY model than the MSY model for most of the watersheds. These results show that the SMPSY model has less uncertainty and performs better than the MSY model. A sensitivity analysis of the SMPSY model shows that the parameter β is most sensitive followed by parameter S, α and A. Overall, the results show that the characterization of soil moisture variability in terms of SMPs and incorporation of improved delivery ratio and runoff coefficient relationship improves the simulation of the erosion and sediment yield generation process.  相似文献   

中国大陆GNSS连续站观测噪声的时空分布     

金涛  占伟  王洪栋 《测绘科学》2017,42(10)

为了全面分析我国大陆及其周边GNSS连续站噪声的空间分布规律,该文基于陆态网络260个GNSS连续站和周边区域10个IGS站的观测数据,利用GAMIT/GLOBK软件进行解算,得到各站的坐标值及其N、E、U 3分量误差值,制定筛选标准,依据该标准剔除质量差的测站,剔除异常值;利用Matlab软件,按照东向(E分量)、北向(N分量)、垂向(U分量)3个方向进行拟合,并提取各测站单日解的最大误差值出现的年积日,绘制其在我国大陆的空间分布图,得到中国大陆GNSS连续站最大单日误差值的时空分布特性图。发现大部分GNSS连续站单日最大误差值集中在夏季(7月居多)并分析了原因。  相似文献   

Mapping cropping intensity trends in China during 1982–2013     

《Applied geography (Sevenoaks, England)》2017

Long range continuous monitoring information of cropping intensity is useful for sustainable agricultural management but still limited. This study filled this information gap through delivering spatiotemporal continuous datasets of cropping intensity in China during the past 30 years. Cropping intensity data were derived by a wavelet features-based method based on the long-term weekly global EVI2 (Enhance Vegetation Index with two bands) at 0.05° spatial resolution (5 km) from 1982 to 1999 and 8-day composite 500 m Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance products from 2001 to 2013. The remote-sensing estimated images in 2013 agreed well with field survey data (overall accuracy = 91.63%) and the national agricultural census data (r² = 0.89). Results revealed that the cropping intensity remarkably increased during 1982–1999 but slightly declined during 2001–2013. The overall cropping intensity increased from 1.34 in the 1980s to 1.41 in the 1990s, and then dropped to an average of 1.36 after 2000. From 1982 to 1999, approximately 93,225 km² single-cropped areas changed to double-cropping, primarily those located in the North China plain. However, 39,883 km² double-cropped areas were turned back into single-cropping areas from 2001 to 2013, principally located in the North China plain, the Middle-lower Yangtze River plain, and the hill regions of the southern Yangtze River. This reverse trend of cropping intensity was due to combined effects from the corresponding reverse variations in agricultural population, increasing agricultural mechanical power, positive agricultural policy. The agricultural duty free policy has only immediate effects on stabilizing cropping intensity in croplands with more favorable biophysical conditions.  相似文献   

中国大宗商品期货交割库空间布局及影响因素   总被引：1，自引：1，他引：0  

陈超  马春光 《地理科学》2017,37(1):125-129

运用核密度估计、空间自相关分析、地理探测器等方法,分析了中国大宗商品期货交割库的空间分布与聚类特征及其影响因素,结果表明：大宗商品期货交割库数量呈现不均匀分布态势,主要分布于东南沿海地区;大宗商品期货交割库核密度空间分布存在显著的差异,核密度高值分布区主要集中在东部沿海地区,而西北部地区则呈现极低密度状态;大宗商品期货交割库存在明显的空间集聚分布特征,主要在安徽、浙江、福建一带呈明显的集聚效应;大宗商品期货交割库空间分异的主要影响因素为区域综合运输能力和进出口总额。  相似文献   

日本虎杖覆盖对连作的影响——日本西阿瓦陡坡土地农业系统传统耕作评价     

INAGAKI Hidehiro  UNNO Nahoko  SAKAKIBARA Takumi  KUBOTA Sakiko  HASEGAWA Kana 《资源与生态学报(英文版)》2021,12(2):254-259

禾本科物种(例如银草、芦苇)在日本传统的地膜覆盖农业中普遍使用,西阿瓦地区是全球重要的农业遗产系统(GIAHS)所在地。传统上,这里的农民使用银草覆盖农业土壤。但当地农民从长期的经验中了解到,日本虎杖覆盖更适合该地区茄科作物的种植。目前尚不清楚日本虎杖覆盖物为何对茄科作物的种植有益。在本项研究中,我们假设日本虎杖覆盖物可能会有效避免连续种植马铃薯的危害。因为过去每年都会种植两次本地马铃薯,因此,我们调查了日本虎杖覆盖对连续种植马铃薯以及番茄种植后对马铃薯产量的影响。在2018年进行的田间试验中,我们首先在连续马铃薯栽培的土壤和未耕种的土壤中比较了日本虎杖覆盖、银草覆盖和无草覆盖(对照)对马铃薯产量的影响,结果表明日本虎杖覆盖减少了马铃薯产量的降低程度。其次,我们比较了番茄种植后的土壤和未耕种的土壤中的虎杖覆盖和无草覆盖对马铃薯产量的影响,结果再次表明了日本虎杖覆盖减少了马铃薯生长和产量下降的程度。这些发现表明用日本虎杖覆盖有助于避免连续种植马铃薯的风险。  相似文献   

Random encounters in probabilistic time geography   总被引：1，自引：0，他引：1  

Zhang-Cai Yin  Stephan Winter  Li-Fu Hu  Jie-Jun Huang 《International journal of geographical information science》2018,32(5):1026-1042

Probabilistic time geography considers the encounter of moving agents to be random; therefore, a quantitative time geography analysis must consider the actual encounter probability. The existing algorithm of encounter probability is oriented over a discrete space and is sensitive to the unit definition of a virtual grid; thus, it is not suitable for continuous space. For this reason, a new method is presented in this paper for the encounter of two moving agents in continuous space. When the encounters are less than a specified distance threshold apart, an encounter event occurs based on the probability of the product, which is calculated by their respective probability density functions over their respective potential location areas. This probability provides a quantitative basis for predicting the likelihood of two agents meeting, as well as the location of this meeting point. Finally, the validity of the proposed model is verified by an experiment, which uses tracking data to calculate the encounter probabilities of three zebras and analyse the distribution characteristics of these probabilities over time and space.  相似文献   

那曲市历年冰雹日数变化特征及冰雹、雷暴环境条件分析     

达瓦泽仁  央美  王秀明  等. 《气象与环境科学》2018,41(4):84-91

利用那曲市7个国家气象观测站建站至2015年的冰雹日数资料,分析了那曲市冰雹日数时空分布特征及气候突变情况,并分析了2012—2016年色尼区单站冰雹日、雷雨日个例,揭示了色尼区冰雹、雷暴发生前的环境条件。结果表明:那曲市年平均冰雹日数呈减少趋势,减少趋势最明显的是申扎县,每10 a减少4. 9天,减少趋势最弱的为色尼区和班戈县,每10 a减少1. 9天,减少趋势均通过了0. 01的显著性检验;不同区域各代表站均显示减少趋势且出现突变现象;那曲市冰雹天气具有明显的季节特征,大多集中在6—9月;降雹时间多集中在14—20时,占全天的78%。对那曲市色尼区冰雹日和雷雨(无降雹)日个例分析表明,高原较强对流发生在0℃层高度低(多在1.5 km高度以下)、CAPE值小(多在500 J·kg~(-1)以下)、风垂直切变弱的环境下,与平原地区大冰雹环境差异显著,因而高原冰雹绝大部分为直径5 mm以下的小冰雹,严格意义上应称为霰;雷雨天气低层较雹日的更暖湿,其温度露点差略小于雹日的,露点比雹日的高,因而雹日抬升凝结高度高于雷雨日的。  相似文献   

面向自然连续面群边线的协同化简方法     

张付兵  孙群  朱新铭  马京振 《地球信息科学学报》2022,24(4):631-642

自然连续面群边线化简是地形图中自然面状要素和地理国情普查数据中自然图斑自动制图综合的重要实施步骤。现有面要素边线化简算法大多以线化简算法为基础,未有效化简弯曲特征、保持面积平衡和满足图面视觉清晰性要求,且化简结果存在共享边界不一致、边线自相交和边线之间相交的拓扑问题。为此,结合自然连续面群表达特点和化简要求,本文提出一种面向自然连续面群边线的协同化简方法。首先将自然连续面群转换为拓扑数据结构组织,以待化简弧段及其相邻弧段为基础构建约束Delaunay三角网,标识化简区域;其次利用弧段双侧层次多叉树模型渐进式退化条带状弯曲、化简细小弯曲;最后自适应夸大狭窄“瓶颈”,实现边线的协同化简。以河南省某区域1:5万地形图中的植被与土质面要素进行化简实验,相较于对比方法,该方法能够有效保持自然连续面群边线化简前后的拓扑一致性、要素之间的面积平衡,充分化简目标尺度下的局部不清晰细节,化简结果精度高。  相似文献   

用连续小波变换分析探地雷达回波信号   总被引：5，自引：1，他引：4  

詹毅  李修忠  梁昌洪  岳元俊 《物探与化探》1999,23(6):443-447,453

脉冲探地雷达回波信号是典型的非平稳、非线性信号.本文通过连续小波变换,对地下圆柱目标实测结果进行分析,得到了目标冲击响应的典型波形特征.分析结果证明,这种方法可以有效地用于目标检测,时延估计等脉冲探地雷达信号处理中的关键问题  相似文献