Extending self-organizing maps for supervised classification of remotely sensed data

An extended self-organizing map for supervised classification is proposed in this paper. Unlike other traditional SOMs, the model has an input layer, a Kohonen layer, and an output layer. The number of neurons in the input layer depends on the dimensionality of input patterns. The number of neurons in the output layer equals the number of the desired classes. The number of neurons in the Kohonen layer may be a few to several thousands, which depends on the complexity of classification problems and the classification precision. Each training sample is expressed by a pair of vectors ： an input vector and a class codebook vector. When a training sample is input into the model, Kohonen＇s competitive learning rule is applied to selecting the winning neuron from the Kohouen layer and the weight coefficients connecting all the neurons in the input layer with both the winning neuron and its neighbors in the Kohonen layer are modified to be closer to the input vector, and those connecting all the neurons around the winning neuron within a certain diameter in the Kohonen layer with all the neurons in the output layer are adjusted to be closer to the class codebook vector. If the number of training sam- ples is sufficiently large and the learning epochs iterate enough times, the model will be able to serve as a supervised classifier. The model has been tentatively applied to the supervised classification of multispectral remotely sensed data. The author compared the performances of the extended SOM and BPN in remotely sensed data classification. The investigation manifests that the extended SOM is feasible for supervised classification.     

内蒙古区域数值预报对探空和地面观测资料的敏感性试验研究

基于内蒙古睿图预报系统的低分辨率版本和WRFDA-FSO诊断工具,评估2021年7月现有探空和地面观测对内蒙古睿图预报系统预报的影响。该方法计算代价相对低廉,并允许根据观测变量、观测类型、气压层次、地理区域等观测的子集对观测影响进行划分。代价函数为以干总能量为度量的背景场和分析场的预报误差之间的差异。结果表明:观测影响的总体总和为负,观测对预报起正贡献作用。对12 h预报误差减小贡献最大的观测来自探空观测的动力变量(U、V风分量)。而单时次单位数量平均观测影响,探空观测的贡献约为地面观测的1/2。探空观测对12 h预报误差减小从近地面层至模式层顶均保持正贡献作用,并在对流层中低层和对流层高空急流层存在两个极大值区域;地面观测在850 hPa以下低层正贡献占比明显。探空观测在被同化系统同化时均总体具有有利的影响,也反映出探空观测数据稳定、质量较高的特征;地面观测对12 h预报误差减小起正贡献作用次数最多的区域在河套地区尤为显著。同时,探讨了需进一步提高地面观测资料同化率的问题。     

松辽盆地北部三分量地震勘探方法及效果

松辽盆地北部三分量地震勘探的主要任务是检测天然气的分布范围,预测岩性油气藏。三分量地震勘探的最大难点是采集上压制随机干扰,处理上去除转换波剖面上同相轴的人为的直立错断（由于通常处理软件不佳引起）。着重介绍了三分量地震勘探的采集原理和处理方法。本次试验取得了良好的三分量剖面。     

Orbit determination by four observations

An elliptic orbit is determined from two short-arc pairs of observations at different oppositions by the angular momentum integral. Other methods for initial orbit determination than the classical do exist.     

帕米尔东北缘地区构造变形特征与盆山结构

帕米尔东北缘乌泊尔地区是正确认识帕米尔北缘盆山结构和构造变形特征非常关键的地区,本文利用连续电磁剖面(CEMP)资料和地震资料,并结合野外地质调查资料和钻井资料,对帕米尔东北缘乌泊尔地区的盆山结构和构造变形特征进行了研究。认为帕米尔东北缘及其以北地区的盆山结构表现为帕米尔造山带向北冲断和南天山向南冲断所形成的对冲结构; 帕米尔山前为基底卷入式构造,古生界—中生界沿高角度的逆冲断层推覆到新近系和第四系之上,形成山前的古生界—中生界逆冲推覆带; 北侧由受乌泊尔断裂控制的深部隐伏冲断体系和浅部的第四纪背驮盆地所构成。研究区的新生代构造变形时间开始于上新世晚期,并持续变形至今,形成了下更新统西域组（Q1x）与下伏上新统、Q2与Q1和Q3 4与Q2之间的不整合。研究区最小构造缩短量为486 km,缩短率为481％。     

顾及有效角动量与IGS超快解数据的极移预报方法

极移高精度预报对卫星实时定轨、深空探测器导航等应用至关重要.本文提出了一种联合有效角动量(Effective Angular Momentum, EAM)与国际全球卫星导航系统服务组织(International GNSS Service, IGS)提供的超快解数据进行极移预报的方法.该方法基于IGS超快解数据得到的极移第1天预报值, 对引入EAM得到的极移预报结果进行校正, 获得联合预报值.首先, 基于LS(Least Squares)+AR(Auto-Regressive)模型实现了引入EAM的极移预报, 相对国际地球自转与参考系统服务组织(International Earth Rotation and Reference Systems Service, IERS)提供的公报A数据, 在超短期(第1~10天)预报跨度可以得到更高精度的极移预报结果, 其中大气和海洋角动量发挥了主要作用.其次, 鉴于IGS超快解数据精度高、更新快的特点, 以IGS超快解为基础数据, 基于LS+AR模型可以得到极移第1天预报值, 其精度显著优于IERS公报A的极移第1天预报值.最后, 利用第1天预报值对顾及有效角动量的预报结果进行校正获得了联合预报值, 进一步提高了超短期极移预报精度(尤其是第1~5天).2020年7月24日—2022年1月30日间的联合预报结果表明: 第1~20天的预报值总体优于IERS公报A的预报值.其中, 第1~10天的预报精度显著提升, 在预报第1天, X、Y方向预报值相对公报A预报值的精度提升分别可达39.5%~62.3%和24.5%~51.9%;在预报第10天, 相对公报A预报值的精度提升分别可达28.0%~28.9%和21.9%~23.4%.

     

Stochastic model-based methods for handling uncertainty in areal interpolation

Handling of uncertainty in the estimation of values from source areas to target areas poses a challenge in areal interpolation research. Stochastic model-based methods offer a basis for incorporating such uncertainty, but to date they have not been widely adopted by the GIS community. In this article, we propose one use of such methods based in the problem of interpolating count data from a source set of zones (parishes) to a more widely used target zone geography (postcode sectors). The model developed also uses ancillary statistical count data for a third set of areas nested within both source and target zones. The interpolation procedure was implemented within a Bayesian statistical framework using Markov chain Monte Carlo methods, enabling us to take account of all sources of uncertainty included in the model. Distributions of estimated values at the target zone level are presented using both summary statistics and as individual realisations selected to illustrate the degree of uncertainty in the interpolation results. We aim to describe the use of such stochastic approaches in an accessible way and to highlight the need for quantifying estimation uncertainty arising in areal interpolation, especially given the implications arising when interpolated values are used in subsequent analyses of relationships.     

青藏高原地表反照率计算研究

根据改进的甚高分辨率扫描辐射仪（ＡＶＨＲＲ）５个观测波段的光谱特征，经多次试验，设计了一组从卫星观测的地－气系统的辐射测值中提取晴空资料的多通道门槛值判识法和提取月平均反照率的合成法；并对１９９２年ＮＯＡＡ－１２卫星获取的ＡＶＨＲＲ资料进行计算处理，分析提取晴空数据，在此基础上按卫星轨道覆盖周期合成计算得到的晴空行星反照率和地表反照率，并且计算了逐月的地表反照率。对计算结果做了初步分析和认真比较。     

测量数据可视化技术研究

介绍可视化的基本原理,阐述中视化研究的必要性,探讨测量数据可视化的技术手段,给出了可视化技术在工作形变监测及工业测量中应用情景,提出一些结论和建议。