Analysis of a variational Bayesian adaptive cubature Kalman filter tracking loop for high dynamic conditions

GPS Solutions - Under high dynamic conditions, a robust tracking loop is essential for accuracy positioning with the global position system. In previous studies, the extended Kalman filter...     

基于BP神经网络的浙北夏季降尺度降水预报方法的应用

利用NCEP提供的全球空间分辨率为2.5°×2.5°、2007—2012年6—8月日平均500 h Pa高度场再分析格点资料和浙北地区158个站点观测资料,研究了不同大气环流型下局地降水与大尺度降水场之间的关系,以4种不同环流型下的预报对象和预报因子分别采用BP神经网络方法对观测资料进行逼近,得到4种空间降尺度的预报模型,分析对比4种预报模型158站逐日的降水量的预报。结果表明:神经网络模型的隐层节点数为2时,对降水的拟合效果最好;对降水的极值拟合效果中,环流分型中NW型和C型的效果优于SW型和SE型;从4种分型下的误差空间分布来看,浙北地区沿海的宁波、舟山一带的误差小于浙北其他区域;把雨量分等级后进行预测,发现模型对暴雨的预测能力最好。     

中国极地考察站广域网通信建设与服务现状及展望

通过中国极地考察"十五"能力南极两站卫星通信网络系统项目的建设,我国南极考察站的广域网通信能力和站区网络通信能力已经有了很大提高。系统阐述南极两站的广域网通信现状,内容包括南极两站卫星通信链路的建设情况、考察站计算机网络系统建设情况以及该系统所提供的服务情况,涉及卫星通信、局域网以及VOIP等技术;对未来几年极地考察通信中可能会采用的通信技术建设提出建议。     

失地民众的征地拆迁满意度研究——以湖北咸宁市嘉通高速公路征地拆迁为例

结合国内征地拆迁的现状和特点,构建失地民众征地拆迁满意度模型,利用湖北省嘉通高速公路沿线村落的调查数据,采用基于PLS法的结构方程模型对征地拆迁民众满意度进行了实证分析。研究表明:失地民众对征地拆迁满意度不高,主要与民众对补偿款的满意程度、就业扶持力度以及信息是否公开透明等影响因素有关,此外,民众除了重视物质方面的补偿,还同等看重信息透明度、政策公平度等“无形”补偿。根据研究结果,建议政府与开发商合作提高就业扶持力度,利用新媒体平台拓展信息覆盖程度,完善纠纷解决机制。     

Climate change and glacier area variations in China during the past half century

Glacier variations in the Tibetan Plateau and surrounding mountain ranges in China affect the livelihood of over one billion people who depend on water from the Yellow, Yangtze, Brahmaputra, Ganges and Indus rivers originating in these areas. Based on the results of the present study and published literature, we found that the glaciers shrank 15.7% in area from 1963 to 2010 with an annual area change of -0.33%. The shrinkage generally decreased from peripheral mountain ranges to the interior of Tibet.The linear trends of annual air temperature and precipitation at 147 stations were 0.36°C(10a)~(-1) and 8.96 mm(10a)~(-1) respectively from 1961 to 2010. The shrinkage of glaciers was well correlated with the rising temperature and the spatial patterns of the shrinkage were influenced by other factors superimposed on the rising temperature such as glacier size, type, elevation, debris cover and precipitation.     

卡拉库姆盆地晚二叠世-三叠纪的构造属性讨论

卡拉库姆盆地位于中亚地区图兰地台南部,北西走向,是中亚地区最重要的含油气盆地之一。对于盆地晚二叠世-三叠纪的构造属性一直都存在着很多争论,我们根据钻井、地球物理及露头资料,认为卡拉库姆盆地是以增生杂岩为基底形成的一个沉积盆地,晚二叠世-三叠纪具有弧后裂谷的性质。卡拉库姆盆地前侏罗纪的构造演化分为4个阶段:1)石炭纪之前古特提斯洋壳开始俯冲增生; 2)石炭纪-早二叠世形成丝路弧; 3)晚二叠世-三叠纪马什哈德-北帕米尔弧形成,卡拉库姆盆地处于弧后拉张的位置; 4)晚三叠世末伊朗等地块与欧亚大陆碰撞,卡拉库姆盆地进入短暂的周缘前陆盆地阶段。其晚二叠世-三叠纪的沉积中心在北阿姆河坳陷,木尔加布坳陷和科佩特山前坳陷,沉积环境主要为陆相,三叠纪发生海侵,部分地区接受海相沉积。岩石类型主要为陆源碎屑岩、火山岩及少量灰岩。     

毛乌素沙漠东南缘滴哨沟湾剖面DGS1层段粒度特征及其指示的全新世气候变化

分析滴哨沟湾剖面全新统DGS1段的粒度数据,认为流动沙丘砂、泥炭、砂质古土壤、古固定-半固定沙丘砂到湖沼相和次生黄土的颗粒总体上变细,分选变差。结合腹足类动物化石和湖沼相地层中石英砂粒表面电镜扫描,认为DGS1粒度结果实际上是全新世以来多次冬夏季风的交互演替过程的气候-地质记录。据此,将DGS1粒度信号记录的全新世气候分为4个阶段——全新世早期好转期、全新世鼎盛期、大暖期向寒冷期转变波动期和降温不稳定的沙漠化频繁变化时期。     

Petrology and Geochemistry of the Banded Iron Formation of the Kuluketage Block,Xinjiang, NW China: Implication for BIF Depositional Setting

The Kuluketage block, located in the northeast Tarim craton, is one of the largest Precambrian blocks in the Xinjiang province. Recently, many banded iron formation (BIF)‐type (Superior‐type) deposits have been discovered in the western part of the Kuluketage block. These deposits occurred in the Paleoproterozoic Shayiti Formation, Xingditage Group, which has a nearly E–W distribution in the southern Xinger and Xingdi faults. Tremolite biotite schist and quartzite are the main wall rocks. The geochemical characteristics of schist indicate that the BIFs occurred in a passive continental margin environment. The LA–ICP–MS zircon ²⁰⁶Pb/²³⁸U ages of BIF and late syenite are 1945 ± 10 Ma(MSWD = 0.77) (weighted average age) and 1974 ± 27 Ma(MSWD = 1.05) (upper intercept age), respectively, indicating that the BIFs occurred in the Paleoproterozoic. In addition, the approximately 1.9 Ga magmatic and metamorphic events are consistent with the global‐scale 2.1–1.8 Ga collisional orogen events which are associated with the assembly of the Columbia supercontinent. The geochemical characteristics show that magnetite and quartz are dominant components (total content, 91.65–98.22 wt.%), and the Zr(Nb) and TiO₂, Zr(Nb) and Al₂O₃ and Zr and Y/Ho display strongly positive correlations, illustrating the addition of crustal materials into the chemical precipitate of the original BIFs. The higher Zr, Nb and Al₂O₃ contents and a lower Y/Ho ratio of the Kuluketage BIFs indicate a higher terrigenous detrital component contaminant compared to BIFs of North China Craton (NCC). The rare earth and yttrium (REY) distribution patterns show a slight LREE enrichment and weak Eu positive anomaly features, indicating that the source of Fe and Si of the Kuluketage BIFs is mainly from the contribution of low‐temperature hydrothermal alteration of the oceanic crust. In addition, along with the decreasing BIF depositional age, the declining of Eu anomaly values reflects the increasing importance of low‐temperature hydrothermal solutions relative to high‐temperature hydrothermal solutions. Moreover, no Ce anomalies in studied BIFs, NCC and Xinyu BIFs are attributed to relative reducing environmental condition when the original BIFs precipitated.