分形方法在苏北盆地金湖凹陷石油资源评价中的应用

成熟勘探区剩余资源量的多少倍受关注。根据金湖凹陷的油藏规模分布特征,应用分形方法估计该区的石油地质资源。石油地质资源总量为12284×10⁴t,分布在507个油藏中;其中未发现的具有经济价值的石油地质资源量为2740×10⁴t,分布在126个油藏中。这反映了该区的油气勘探程度较高,但仍有一定的勘探潜力,大量中-小油藏是今后勘探的主攻目标。分形方法作为油气资源评价的一种新途径,计算过程简便,结果可靠,应用前景广阔。     

华北陆块东南缘凤台组时代的讨论

华北陆块东南缘凤台组归属于震旦系或寒武系尚无定论,影响了对华北陆块震旦纪与寒武纪转折时期的古构造、古地理和古生物的重大质变事件的探讨。本文根据下震旦统顶部与凤台组之间裂离不整合的发现及其意义的讨论,以及凤台组夹层粉砂质泥岩620Ma的Pb-Pb等时线年龄,基本厘定出凤台组时代为晚震旦世。     

金沙江美姑河牛牛坝水电站库区泥石流对工程影响分析

金沙江美姑河牛牛坝水电站库区泥石流沟分布面积广、发生频率高;调查表明库区现有不同类型泥石流沟31条,其中属于高度危险的泥石流沟4条,中度危险的泥石流沟15条;这些泥石流不会造成严重的堵河问题。在施工期泥石流对水电站工程的影响突出,特别是靠近库首的泥石流对工程的安全构成威胁。水库蓄水后,库区泥石流对水电站工程影响有所降低,但位于大坝下游区的泥石流对水电站正常运行仍有较大的影响。     

“一带一路”建设背景下重庆与东盟国家贸易格局演变和影响因素分析

“贸易畅通”是“一带一路”建设的重要内容,重庆作为中国西部地区内陆开放高地,贸易发展优势明显。运用贸易强度指数和HM指数,分析2001—2017年重庆与东盟国家贸易格局和贸易依赖程度,并分析影响重庆与东盟国家贸易格局的影响因素。结果表明：①重庆与东盟国家贸易联系紧密,增长速度快,贸易总额在“一带一路”沿线六大区域中始终保持领先地位;②马来西亚和泰国成为重庆与东盟国家中最重要的贸易伙伴,越南、新加坡、菲律宾和印度尼西亚紧随其后,而与缅甸、柬埔寨、老挝和文莱的贸易总额较少;③在进口方面,形成以马来西亚、泰国和越南为首的多元进口格局,泰国和越南进口伙伴地位上升。在出口方面,形成以马来西亚为首的多元出口新格局,越南出口地位下降;④在市场相互依赖程度方面,重庆出口对东盟国家特别是马来西亚和新加坡贸易市场的重要性程度上升,而对东盟国家市场依赖程度较小;⑤产业结构、贸易通道、文化交流和政策等是影响重庆与东盟国家贸易格局的重要影响因素。     

Lidar-aided analysis of boreal forest backscatter at Ku band

This paper analyzes the backscatter of the microwave signal in a boreal forest environment based on a Ku -band airborne Frequency-Modulated Continuous Waveform (FMCW) profiling radar—Tomoradar. We selected a half-managed boreal forest in the southern part of Finland for a field test. By decomposing the waveform collected by the Tomoradar, the vertical canopy structure was achieved. Based on the amplitude of the waveform, the Backscattered Energy Ratio of Canopy-to-Total (BERCT) was calculated. Meanwhile, the canopy fraction was derived from the corresponding point cloud recorded by a Velodyne VLP-16 LiDAR mounted on the same platform. Lidar-derived canopy fraction was obtained by counting the number of the first/ the strongest returns versus the total amount of returns. Qualitative and quantitative analysis of radar-derived BERCT on lidar-derived canopy fraction and canopy height are investigated. A fitted model is derived to describe the Ku-band microwave backscatter in the boreal forest to numerically analyze the proportion contributed by four factors: lidar-derived canopy fraction, radar-derived canopy height, the radar-derived distance between trees and radar sensor and other factors, from co-polarization Tomoradar measurements. The Root Mean Squared Error (RMSE) of the proposed model was 0.0958, and the coefficient of determination R2 was 0.912. The fitted model reveals that the correlation coefficient between radar-derived BERCT and lidar-derived canopy fraction is 0.84, which illustrates that lidar surface reflection explains the majority of the profiling /waveform radar response. Thus, vertical canopy structure derived from lidar can be used for the benefit of radar analysis.     

Tree species identification within an extensive forest area with diverse management regimes using airborne hyperspectral data

Information on tree species composition is crucial in forest management and can be obtained using remote sensing. While the topic has been addressed frequently over the last years, the remote sensing-based identification of tree species across wide and complex forest areas is still sparse in the literature. Our study presents a tree species classification of a large fraction of the Białowieża Forest in Poland covering 62 000 ha and being subject to diverse management regimes. Key objectives were to obtain an accurate tree species map and to examine if the prevalent management strategy influences the classification results. Tree species classification was conducted based on airborne hyperspectral HySpex data. We applied an iterative Support Vector Machine classification and obtained a thematic map of 7 individual tree species (birch, oak, hornbeam, lime, alder, pine, spruce) and an additional class containing other broadleaves. Generally, the more heterogeneous the area was, the more errors we observed in the classification results. Managed forests were classified more accurately than reserves. Our findings indicate that mapping dominant tree species with airborne hyperspectral data can be accomplished also over large areas and that forest management and its effects on forest structure has an influence on classification accuracies and should be actively considered when progressing towards operational mapping of tree species composition.     

热带西太平洋海洋上层热含量的分布特征及其年际变化的分析

选用海面至20℃等温线所处深度水层的平均温度来表征研究海域海洋上层热含量。利用这一特征值，分析1986—1990年期间热带西太平洋边缘海域海洋上层热含量在秋季的分布特征和年际变化。结果表明：（1）热含量呈南高北低分布，在7．5－22．1°N范围内。以130°E断面为代表，热含量的平均递减率为0．179（℃／纬度）；（2）热含量的分布主要取决于环流系统，其等值线因受黑潮和棉兰老海流的影响而由纬向分布转向经向分布。某些区域因受暖涡及冷涡的影响而呈封闭状分布；（3）热含量的年际变化与E1Nino事件存在着很好的相关性，在E1Nino事件发生期间，热含量变得很低，高热含量（大于26．5℃）海区的分布范围明显缩小。     

渤、黄、东海三维潮波运动数值模拟

采用POM三维海流数值模式模拟渤、黄、东海潮波运动。所得潮汐调和常数与77个测站的观测值的平均绝对误差：m1振幅1．92cm,迟角4．39°;M2振幅4．70cm,迟角5．08°。模拟结果显示M2分潮流共存在8个圆流点,m1岁潮流共存在9个圆流点。其中,M2分潮流在舟山群岛附近与m1分潮流在黄海北部和台湾海峡谷存在一个圆流点,这三个圆流点是本文数值模拟所首次显示的,需进一步的观测验证它们实际存在与否。模式还得出湍流涡动系数分布。     

黄河三角洲潮滩潮沟体系的分维特征

利用分形分维方法对黄河三角洲潮滩和潮沟的地貌特征进行了定量研究。结果表明，潮滩和潮沟的分维值可以较好地反映潮滩潮沟的发育演化规律。随着时间的推移和潮沟潮滩的进一步发育，黄河三角洲潮沟的分维值呈逐渐增大的趋势，而潮滩的分维值则呈逐渐减小的趋势，两者在分维值的变化上存在着负相关关系。该研究为黄河三角洲潮滩发育时空谱系的建立和深入研究提出了一种新方法和新的定量指标。     

长江和长江口高含量无机氮的主要控制因素

根据1998－1998年长江和长江口河水和雨水的现场调查、历史资料以及相关文献，定量分析长江流域无机氮的主要来源和输送调查。估算表明，降水无机氮、农业非点源氮（化肥和土壤流失的氮）和点源污水氮的输入分别占长江口无机氮输出通量的62．3％、18．5％和14．4％。氮的降水输入是长江口高含量无机氮的主要来源，进入长江的降水氮仅仅大约占长江流域全部降水氮的36．8％。降水米要受控于化肥气态损失、化石燃料及动植物过程中释放的物质等。实际上，化肥N的气态损失和农业非点源流失大约占长江流域年化肥N使用量的60％，这是控制长江口高含量无机氮的关键因素。