An objective prediction model for typhoon rainstorm using particle swarm optimization: neural network ensemble

A nonlinear ensemble prediction model for typhoon rainstorm has been developed based on particle swarm optimization-neural network (PSO-NN). In this model, PSO algorithm is employed for optimizing the network structure and initial weight of the NN with creating multiple ensemble members. The model input of the ensemble member is the high correlated grid point factors selected from the rainfall forecast field of Japan Meteorological Agency numerical prediction products using the stepwise regression method, and the model output is the future 24 h rainfall forecast of the 89 stations. Results show that the objective prediction model is more accurate than the numerical prediction model which is directly interpolated into the stations, so it can better been implemented for the interpretation and application of numerical prediction products, indicating a potentially better operational weather prediction.     

基于KPCA的台风强度神经网络集合预报方法研究

针对影响台风强度前期预报因子较多以及因子的非线性变化特点,首先采用逐步回归方法筛选出部分预报因子,再利用核主成分分析方法在剩余的预报因子中提取包含了原数据较多信息的核主成分与前期选入的预报因子共同作为模型输入.进一步考虑到神经网络集合预报中个体的准确性和差异性的权衡问题,在不同的初始条件下生成若干组神经网络,分别选择每组中性能最优的个体,建立了一种新的非线性神经网络集合预报模型.最后以西北太平洋海域2001-2010年5-10月的台风强度为研究对象进行了预报试验.结果表明,这种神经网络集合预报模型的预报结果符合实际应用的要求,其预报平均绝对误差明显小于同等条件下的神经网络方法和逐步回归预报方法.     

Measuring the Magnetic-Field Strength of the Quiet Solar Corona Using “EIT Waves”

Variations in the propagation of globally propagating disturbances (commonly called “EIT waves”) through the low solar corona offer a unique opportunity to probe the plasma parameters of the solar atmosphere. Here, high-cadence observations of two “EIT wave” events taken using the Atmospheric Imaging Assembly (AIA) instrument onboard the Solar Dynamics Observatory (SDO) are combined with spectroscopic measurements from the Extreme ultraviolet Imaging Spectrometer (EIS) onboard the Hinode spacecraft and used to examine the variability of the quiet coronal magnetic-field strength. The combination of pulse kinematics from SDO/AIA and plasma density from Hinode/EIS is used to show that the magnetic-field strength is in the range ≈?2?–?6 G in the quiet corona. The magnetic-field estimates are then used to determine the height of the pulse, allowing a direct comparison with theoretical values obtained from magnetic-field measurements from the Helioseismic and Magnetic Imager (HMI) onboard SDO using global-scale PFSS and local-scale extrapolations. While local-scale extrapolations predict heights inconsistent with prior measurements, the agreement between observations and the PFSS model indicates that “EIT waves” are a global phenomenon influenced by global-scale magnetic field.     

应用型本科人才专业能力指标的构建

建立包括专业能力类型、专业能力指标分级、专业能力项目名称、专业能力描述和专业能力评价标准等要素的专业能力指标体系,通过专业能力分析,确定相关专业的各项专业能力指标,形成相应的能力指标内涵表,可为该专业应用型本科人才专业能力培养提供培养标准和检验标准,提高专业能力培养质量,满足社会经济发展对应用型本科人才应具有的专业能力水平的需要.     

利用RD模型和DEM数据的高分辨率机载SAR图像模拟

本文提出一种利用DEM数据基于RD模型的SAR图像模拟方法.该方法选择了Muhleman后向散射系数模型模拟SAR图像的辐射特性,引入SAR成像中的RD模型直接进行几何变换和灰度重采样模拟出SAR图像的几何特征.实验结果分析表明:模拟的SAR图像和真实SAR图像在图像纹理和几何关系上是一致的,而且几何关系可以精确配准到均方根误差为1.3个像素.     

利用ArcGIS转换HPD源数据库中航海物标空间数据

我国海事测绘部门自2008年开始引进CARIS HPD海道产品数据库系统,其空间数据共享转换方法一直是无法解决的难题。本文从CARIS HPD物标源数据库和Shapefile文件数据存储结构入手,详细阐述了CARIS HPD航海物标源数据空间信息获取方法和ArcGIS Shapefile文件生成方式,并提出将物标空间数据从HPD源数据库转换至Shapefile文件的解决方案。     

菲律宾Ms≥7级地震活动规律及未来趋势

通过可公度信息提取方法、蝴蝶结构图、震中时空迁移特征分析近50年菲律宾Ms≥7级中、浅源地震,发现2013、2014年Ms≥7级地震信号强,2014年最强;22年地震主周期明显,其中可划出活跃期与平静期;2012年为菲律宾新地震周期及活跃期的开始;菲律宾Ms≥7级地震震中时空交替迁移规律明显,未来震中向西北部迁移.菲律宾Ms≥7级地震与太阳黑子活动22年双周期关系密切,多发生在太阳黑子活动偶数周期极大年附近及其下降段.目前,太阳黑子活动处于第24周期极大年附近,2013～2014年Ms≥7级地震发生的可能性很大,与可公度分析结果一致.     

Application of an analytical hierarchical process approach for landslide susceptibility mapping in A Luoi district,Thua Thien Hue Province,Vietnam

A Luoi is a Vietnamese–Laotian border district situated in the western part of Thua Thien Hue province, central Vietnam, where landslides occur frequently and seriously affect local living conditions. This study focuses on the spatial analysis of landslide susceptibility in this 263-km² area. To analyze landslide manifestation in the study area, causative factor maps are derived of slope angle, weathering, land use, geomorphology, fault density, geology, drainage distance, elevation, and precipitation. The analytical hierarchical process approach is used to combine these maps for landslide susceptibility mapping. A landslide susceptibility zonation map with four landslide susceptibility classes, i.e. low, moderate, high, and very high susceptibility for landsliding, is derived based on the correspondence with an inventory of observed landslides. The final map indicates that about 37% of the area is very highly susceptible for landsliding and about 22% is highly susceptible, which means that more than half of the area should be considered prone to landsliding.     

深埋煤层应力松弛状态演化试验与动力学分析

应用Lyapunov指数法,对试验得到的深埋煤层应力松弛系统演化对应于各级应变水平的时间序列进行分析,科学重构相空间,得到了每一递进应变水平的相轨迹均不重复地围绕各自对应的历史应力中值而顺次演化。采用分形几何学方法进行时间序列分析,定量揭示出煤样应力松弛系统演化的各层次间自相似性,并部分反映了经典力学与非线性科学间的关系。得到了对应各级应变水平系统演化时间序列的非线性动力学评价指标,并判定深埋煤层应力松弛系统为复杂系统且具有典型混沌特征。深埋煤层应力松弛系统演化的混沌程度及复杂程度呈下降规律,煤体内部力学性质弱化因素与强化因素之间竞争最为激烈的阶段,其混沌程度最高,而宏观破坏后系统伴随最低的混沌程度及复杂程度。     

GPS动态变形分析中的傅里叶级数恒星日滤波

针对恒星日滤波中计算GPS卫星轨道运行周期提前时间的问题,提出一种基于傅里叶级数曲线拟合的提前时间估计方法。根据跨度达8 526 d的广播星历计算每天中所有可用卫星运行周期相对于前1 d的平均提前时间,将此平均提前时间作为采样点,以8阶三角函数形式展开的傅里叶级数进行曲线拟合,将卫星运行周期的提前时间拟合成关于时间的单一变量函数,免去了繁琐的计算步骤。实验结果表明,傅里叶级数恒星日滤波法缩小了监测点N、E、U三个方向坐标残差序列的均方根值,有效消除了GPS动态变形监测分析中的多路径影响,提高了复杂工程环境下动态变形监测中变形信息提取的能力。