与澜沧大震可能相关的震磁效应——小波分析一例

用小波法分析了与1988年澜沧大震相关的通海台地磁Z分量资料。小波分析结果显示地震前“日变幅差”ΔTg(24)存在可能的异常变化;异常为正异常,异常幅度很大,异常结束后立即发生了地震。     

“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。     

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.     

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.     

3套资料中西北太平洋热带气旋活动特征的比较分析

本文使用中国气象局、美国联合台风预警中心和日本气象厅的3套热带气旋最佳路径资料(CMA资料、JTWC资料和RSMC资料)分析了1951—2016年西北太平洋热带气旋活动特征。3套资料反映的结果如下:热带气旋主要发生在10°N—25°N范围内,且1980年前其位置点在纬度上有南移的变化趋势,1980年后则相反;移速主要分布在2~6 m/s区间,在25°N左右移速明显加快,1980年前移速呈显著减小趋势;最大持续风速主要分布在10~15 m/s区间,1980年前最大持续风速有减小趋势;在风速较大的区域热带气旋最大风速半径较小,2001—2016年热带气旋和台风最大风速半径每年分别减小0.46 km和0.54 km。CMA和RSMC资料的结果高度一致,而JTWC资料结果与它们都存在一定的差异。热带气旋位置点频数和强度的变化受资料间差异的影响较大,而其位置及移速的变化则受影响较小。     

Ecological Worldview as the Central Component of Environmental Concern: Clarifying the Role of the NEP

This study examines whether an ecological worldview—operationalized by the New Ecological Paradigm (NEP) Scale--serves as the source of coherence of Environmental Concern (EC). Using data on four samples from the 1992 Gallup “Health of the Planet” Survey and the 2003 and 2010 Chinese General Social Surveys, we found that in all samples not only is the NEP the most powerful predictor of EC, but it also mediates the effects of socio-demographic variables on EC as hypothesized. The results confirm that the NEP is the source of coherence of EC, making it a meaningful construct.     

南海北部湾秋季蓝圆鲹与竹筴鱼的摄食生态及食物竞争

【目的】研究南海北部湾海域秋季蓝圆鲹与竹筴鱼的摄食生态特征和种间食物竞争。【方法】采用胃含物分析法,对2017年10月北部湾底拖网调查和港口随机取样收集的119尾蓝圆鲹(Decapterusmaruadsi)和198尾竹筴鱼(Trachurus japonicus)胃含物样品进行分析,通过肉眼直接观察或显微镜间接观察胃中残留的饵料,饵料种类鉴定、计数、称重等对食性做定量分析,以估算两种鱼类的营养级和生态位宽度,并利用生态位重叠研究两种鱼类的食物竞争关系。【结果与结论】蓝圆鲹的饵料种类19种(属),以桡足类和小型鱼类为主,优势饵料生物为布氏半棱鳀(Encrasicholinapunctifer);竹筴鱼的饵料种类18种(属),以小型鱼类和浮游甲壳类为主,优势饵料为中国毛虾(Acetes chinensis)。两种鱼类均为游泳动物食性,均存在摄食转换,随着叉长的增长,蓝圆鲹的饵料生物由小型浮游动物为主转变为小型鱼类为主,竹筴鱼的饵料生物由小型鱼类为主转变为以樱虾类和较大鱼类为主。蓝圆鲹和竹筴鱼的空胃率、竹筴鱼的平均胃饱满指数均随个体生长呈显著变化(P<0.05),但蓝圆鲹的平均胃饱满指数随个体生长无显著变化(P>0.05)。蓝圆鲹和竹筴鱼的营养级分别为3.63和3.40,营养生态位宽度分别为1.70和1.24,生态位重叠系数0.56,表明两种鱼类之间存在一定的食物竞争。     

紫金山天文台55 yr手绘黑子数据系统差分析

对紫金山天文台(简称紫台)自1954年至2011年共55 yr的手描黑子图进行了数字化.将紫台太阳黑子相对数(PRSN)和黑子群数(PGSN)与国际太阳影响数据分析中心(SIDC)中的对应数据(月平均太阳黑子相对数(IRSN)和月平均黑子群数(IGSN))进行对比研究,发现:(1)紫台黑子数据与SIDC黑子数据有很强的正相关性,说明紫台黑子数据的可靠性;(2) PRSN和IRSN、PGSN和IGSN的系统偏差分别处于7%左右、5%左右,紫台数据与SIDC数据在活动周的极小期的差异性显著大于极大期;(3)紫台的视宁度从1995年开始变差,直接导致了PRSN (PGSN)与IRSN (IGSN)的比值明显变大,表明视宁度的变化影响了紫台黑子的观测质量.     

基于压缩感知法对法拉第色散函数的重构

观测到的偏振量与法拉第色散函数之间是傅里叶变换对,而法拉第色散函数反映了辐射区域和辐射传播途径的磁场结构。如何通过这一关系精确重构出法拉第色散函数对于研究银河系及河外星系磁场具有重要的作用。目前已提出了基于压缩感知的法拉第色散函数重构方法,模拟结果要优于传统方法,然而是否具有实用性仍然未知。主要探究该方法应用于实际观测频率范围时是否依然可行,并进行了大样本统计学实验。结果表明:重构结果受多种因素的影响,具有很大的随机性,对重构结果在峰值附近再次进行最小二乘拟合后,重构的法拉第深度更接近真实值。     

天文卫星下传数据处理系统的规划

天文卫星获取的数据需要经过卫星下传数据处理系统的一系列加工,生成可以分析的数据产品,这些产品及相应软件要发布给国内外用户,同时数据处理系统还要监测载荷状态、数据质量及天体源爆发等。这样,下传数据处理系统的建设直接关系到物理成果的获取,规划该系统就变得非常有意义。从数据产品定义、子系统规划、数据流程等方面介绍卫星下传数据处理系统的规划,并提出以模块化开发方式从整体上协调各个子系统的开发,使各个系统及其软件相互配合,共同促进科学产出。