1013号台风“鲶鱼”的台风环流分离方法比较

台风系统为中α尺度系统,接近大尺度系统.为了研究环境气流与台风的相互作用,需要将台风从环境风场中分离出来.分别采用时间滤波、空间滤波和动力学方法将2010年第13号（1013号）超强台风“鲶鱼”（Megi）从环境风场中分离出来,对比分离得到的台风环境场,结果表明：时间滤波和空间滤波具有相对的随机性,容易留下台风风场的残留,同时也会减弱环境风场,而采用动力学方法可以将台风“Megi”较好地分离出来.3种方法各有优缺点,采用时间滤波可以使风场、高度场和温度场很好地平衡,但是需要较长的时间序列;空间滤波方法,仅采用一个时刻的时间,方法相对简单易用,但是由于台风风场、高度场和温度场的尺度并不相同,采用同一尺度对台风滤波容易造成风场、高度场和温度场的不平衡;动力学滤波方法分离效果较好,但是相对复杂,在低层也容易产生不平衡的现象.     

相控阵雷达扫描方式对回波强度测量的影响

有源数字阵列雷达的波束设计非常灵活,可变的波束宽度和多波束模式不仅可以满足不同任务的观测需求,还可有效节约扫描时间,但阵列天线参数随波位改变的特性对相控阵天气雷达回波强度的精确定标提出了挑战。2013年4—6月,中国气象科学研究院与安徽四创电子股份有限公司联合研发的X波段一维有源相控阵天气雷达 (X-PAR) 进行了装配后的首次测试观测。对比该雷达与相同位置的C波段双线偏振雷达 (C-POL) 观测资料发现,X-PAR不同宽度的扫描波束均能取得较合理的观测资料。但由于各模式的雷达方程及其标定方法不尽相同,并受到阵列天线照射体积、展宽波束和发射增益的影响,造成X-PAR回波强度存在一定的测量偏差。结合天线参数分析和实际数据统计将测量偏差订正至±1 dB内,为雷达的进一步调试和改进提供了依据。     

Applications of wavelet analysis in differential propagation phase shift data de-noising

Using numerical simulation data of the forward differential propagation shift （ΦDP） of polarimetric radar,the principle and performing steps of noise reduction by wavelet analysis are introduced in detail.Profiting from the multiscale analysis,various types of noises can be identified according to their characteristics in different scales,and suppressed in different resolutions by a penalty threshold strategy through which a fixed threshold value is applied,a default threshold strategy through which the threshold value is determined by the noise intensity,or a ΦDP penalty threshold strategy through which a special value is designed for ΦDP de-noising.Then,a hard-or soft-threshold function,depending on the de-noising purpose,is selected to reconstruct the signal.Combining the three noise suppression strategies and the two signal reconstruction functions,and without loss of generality,two schemes are presented to verify the de-noising effect by dbN wavelets：（1） the penalty threshold strategy with the soft threshold function scheme （PSS）; （2） the ΦDP penalty threshold strategy with the soft threshold function scheme （PPSS）.Furthermore,the wavelet de-noising is compared with the mean,median,Kalman,and finite impulse response （FIR） methods with simulation data and two actual cases.The results suggest that both of the two schemes perform well,especially when ΦDP data are simultaneously polluted by various scales and types of noises.A slight difference is that the PSS method can retain more detail,and the PPSS can smooth the signal more successfully.     

Web Service for extracting stream networks from DEM data

This paper describes the implementation of a morphology based algorithm for extracting stream networks from data as a Web Service within the framework of GeoBrain, an open, interoperable, distributed, standard-compliant, multi-tier web-based geospatial information services and knowledge building system. Unlike standard out-of-the-box GIS software, which uses the flow direction based algorithm and often produces streams that are spatially uniform, streams extracted with this Web Service correctly reflect spatial variability in dissection patterns. In addition, this Web Service is free and can be accessed from anywhere provided that there is an Internet connection and a standard Web browser.     

四川省冕宁县大顶山磁铁矿床成因探讨

大顶山磁铁矿床位于泸沽花岗岩体外接触带,铁矿体赋存于中元古界登相营群夕卡岩化大理岩中,呈似层状、透镜状产出,矿体与夕卡岩化大理岩关系密切;大顶山磁铁矿床是泸沽花岗岩体侵位过程中沿层交代的产物,其矿床成因属接触交代型矿床.     

对我国政府在全球采掘业透明倡议中应持立场的思考和建议

历经10余年的发展,采掘业透明倡议已经发生了巨大变化,西方发达国家开始积极介入,主动宣布试点或计划实施。形势的变化要求我国及时调整以往所持立场。本文简要介绍了全球采掘业透明倡议的组织架构及运作、实施现状,深入分析了各利益相关方的动机,对其未来发展加以研判,并结合我国涉及采掘业透明倡议的情况,提出了新形势下我国短期内不宜实施,但须及时调整立场;鼓励金融机构和企业介入EITI和其他反腐败倡议;政府应考虑成为EITI的正式支持国。     

美国内政部四轮战略规划的发展趋势及特点分析

美国内政部的战略规划是该部施政纲领的集中体现。四轮战略规划的目标从2003年强调资源保护、利用与休闲娱乐的平衡,到2007年增加全球经济、环境、政治和其他因素对内政部战略规划的影响,直至2014年强调资源的娱乐、人文观赏价值,并重视培养下一代的管理责任。内政部战略定位逐渐清晰。资源保护、经济发展、休闲娱乐的相对关系发生变化,从强调三者平衡到强调资源的休闲、文化等景观价值。     

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An Review of International Climate Change Conference and Analysis on Recent Hot Issues

The international climate change negotiation has been carried out over 20 years. The issue of climate change has shifted from a scientific question into a complex political matter which is related to the sustainable development of mankind. Based on the overview of major processes and stages of international climate conferences, this paper analyzed the key measures that major countries have taken to address climate change, as well as the primary tasks of Paris climate conference and recent international actions. The recent international climate policy issues were also analyzed in order to provide suggestions for China’s activel participation in the development of a new round of international climate change system.     

大气CO2浓度时空变化卫星遥感监测的应用潜力分析

GOSAT卫星观测反演大气CO2浓度精度已经提高到了1—2 ppm,而卫星数据能否准确地揭示全球和区域大气CO2浓度变化特征还缺乏充分的评价与分析。本文针对已经连续运行观测3年的GOSAT卫星,收集了来自美国NASA-OCO团队(ACOS)和日本环境研究所GOSAT团队(NIES)基于各自算法反演的两套大气CO2柱浓度数据,描述并分析了全球大气CO2时空变化特征。分析结果表明,从XCO2反演的绝对值结果来看ACOS总体上比NIES的高出约2 ppm左右,但从时空的相对变化上它们揭示了相近的大气CO2浓度时空变化特征。两套数据显示出全球平均大气CO2浓度在2010年—2012年的3年期间年增量分别为1.8 ppm和2.0 ppm;季节变化幅度,北半球最大4—6 ppm,南半球最大约2 ppm,这与地面观测结果基本一致。进一步将EDGAR 4.2人为排放总量格网化数据与GOSAT卫星观测反演的CO2浓度进行相关统计分析,结果指出两套数据对人为排放量有着微弱的响应。本文结果指出目前GOSAT卫星观测反演的XCO2可以检测出全球和区域大气CO2浓度的年变化、季节变化和区域空间变化的特征;GOSAT卫星10.5 km空间分辨率的观测虽难于检测出点源的浓度变化,但从区域上对人为排放的累积效应的监测显示了一定的应用潜力。