Extensive Cold-Precipitation-Freezing Events in Southern China and Their Circulation Characteristics

Concurrence of low temperature,precipitation and freezing weather in an extensive area would cause devastating impacts on local economy and society.We call such a combination of concurrent disastrous weather“extensive coldprecipitation-freezing”events(ECPFEs).In this study,the ECPFEs in southern China(15°?35°N,102°?123°E)are objectively defined by using daily surface observational data for the period 1951?2013.An ECPFE in southern China is defined if the low temperature area,precipitation area and freezing area concurrently exceed their respective thresholds for at least three consecutive days.The identified ECPFEs are shown to be reasonable and reliable,compared with those in previous studies.The circulation anomalies in ECPFEs are characterized by a large-scale tilted ridge and trough pairing over mid-and high-latitude Eurasia,and the intensified subtropical westerlies along the southern foot of the Tibetan Plateau and the anomalous anticyclonic circulation over the subtropical western Pacific.Comparative analysis reveals that the stable cold air from the north and the warm and moist air from the south converge,facilitating a favorable environment for the concurrence of extensive low-temperature,precipitation and freezing weather.     

理想点法在矿床工业价值评价中的应用

应用理想点法的基本原理,建立了一个矿床工业价值评价的数学模型,以我国贵州省兴义市雄武地区铀矿床为实例,构造评价函数得出最优解,结果表明:理想点法能够正确评价出矿床工业价值的大小,为矿石的最优开采提供有价值的参考。     

中国地震紧急救援理论研究

如何满足国家和社会对地震应急的需求,进一步发展我国的地震应急工作,是地震界面临的课题。根据目前地震应急的现状,提出了以下2个有关地震应急理论的创新点:地震速报的基本模式,新闻媒体传播地震消息模式,地震应急预案启动模式,地震考察地区性差异,地震灾害死伤的基础数据模式,地震应急期分期模式,地震应急期救援真空模式,地震应急期黑箱、灰箱、白箱模式,地震救援队伍的后勤模式,国外地震救援队到中国参加救援法规模式,地震受灾体分类模式,新建和加固农村公共建筑提高一度模式。并且给予了论述。     

南粤古驿道历史建筑数字化保护与VR场景构建

南粤古驿道遗留了众多文化遗产,具有较高的历史、艺术、科学价值,但历史建筑损坏较为严重.为推进南粤古驿道活化利用,本文采用精细三维建模技术与虚拟现实(VR)技术实现了南粤古驿道的数字化保护.首先对南粤古驿道遗址进行了分析,然后从数据采集、点云数据处理、几何模型加工、纹理贴图等方面阐述对历史遗迹进行精细三维建模和VR场景构...     

莱州湾海水中营养盐分布与富营养化的关系

根据2001年5月和9月2个航次莱州湾海区海水营养盐等的调查资料,分析了该海域海水中5项营养盐的分布特征及时空变化,评价了水质的富营养化状况。结果表明,溶解无机氮的平均浓度为9.80μmol/dm3,2个季节中溶解无机氮以NO3-N浓度为最高,平均为7.61μmol/dm3,占总无机氮的77.65%,是莱州湾海水中的无机氮主要形式;活性磷酸盐的平均浓度为0.48μmol/dm3,活性硅酸盐的平均浓度为11.31μmol/dm3。研究发现,莱州湾海水中溶解无机氮和活性磷酸盐浓度分别是12 a前的2.03倍和3.2倍。DIN∶P,Si∶P,Si∶DIN比值分别为69.5,34.2,1.4;因此,磷酸盐为限制因素。按照营养状态指数值,莱州湾海区湾顶近岸海域划分为富营养化区,秋季一旦水文气象等条件适宜有发生赤潮的可能。     

日本海环流研究综述

日本海作为东北亚地区最大的边缘海,是西北太平洋上的重要海区。由于特殊的地理位置和复杂的地形,使得日本海的环流结构呈现独有特征,如日本海内的亚极地锋现象,复杂多变的涡旋,北部形成的深水团等。概述了日本海环流状况,着重介绍了对马海峡、郁陵海盆环流情形和日本海特征水团;总结了目前仍存在的争议问题,如对马暖流源头、对马暖流空间结构等;指出了目前日本海尚待解决的科学问题,如对马暖流流量的长期变化及其原因、东韩暖流消失现象及其机制、日本海特征水的传播路径及其影响因素、日本海的某些变化产生原因及其与全球变化的响应等。     

Preliminary seismic anisotropy in the upper crust of the south segment of Xiaojiang faults and its tectonic implications

The Xiaojiang faults,striking north-to-south(NS),and the Honghe faults,striking north-to-west(NW),are first-order block boundaries that intersect to form a concentrated stress zone at an acute angle in the southern part of the Sichuan-Yunnan rhombic block(SYB).It is also a crucial zone for material escaping from the Tibetan Plateau(TP)due to the collision between the Indian Plate and the Eurasian Plate.In December 2017,the Institute of Earthquake Forecasting of the China Earthquake Administration(CEA)deployed a linear temporary seismic broadband array,the Honghe-Xiaojiang temporary Seismic Array(HX Array),across first-order block boundaries in the southern SYB.By using the waveform data of small earthquakes recorded by stations in the HX Array across Xiaojiang faults from 2017 to 2019,and by permanent seismic stations of the China National Earthquake Networks from 2012 to 2019,this paper adopts the systematic analysis method of shear-wave splitting(SWS),SAM method,to obtain preliminary results for seismic anisotropy in the upper crust.The study area can be divided into two subzones according to the spatial distribution of the directions of polarization of the fast shear-wave(PFS)at the stations:the northern zone(zone A,where the HX Array is located)and the southern zone(zone B,to the south of the HX Array).The results show that the directions of the PFS at stations in zone A were highly consistent,dominant in the NE direction,correlated with the in-situ principal compressive stress,and were seemingly unaffected by the Xiaojiang faults.The directions of the PFS as recorded at stations in zone B were more complicated,and were dominant in the NS direction parallel to that of the regional principal compressive stress.This suggests the joint influence of complex tectonics and regional stress in this narrow wedge area.By referring to the azimuthal anisotropy derived from seismic ambient noise in the southeast margin of the TP,the NS direction of the PFS in the middle and lower crust,and its EW direction in the upper mantle,this paper concludes that azimuthal anisotropy in the upper crust differed from that in the lower crust in the south segment of Xiaojiang faults,at least beneath the observation area,and azimuthal anisotropy in the crust was different from that in the upper mantle.The results support the pattern of deformation of ductile flow in the lower crust,and the decoupling between the upper and lower crusts as well as that between the crust and the mantle in the study area.The crustal directions of the PFS appeared to be independent of the Xiaojiang faults,suggesting that the influence of the South China block on the SYB passed through the Xiaojiang faults to the Yimen region.The results of this study indicate that anisotropic studies based on data on the dense temporary seismic array can yield clearer tectonic information,and reveal the complex spatial distribution of stress and deformation in the upper crust of the south segment of Xiaojiang faults.     

GPS变形监测动态数据处理中卡尔曼滤波的应用

介绍了卡尔曼滤波的基本原理,针对常规GPS变形监测数据处理中存在着不连续、非实时的缺点,结合卡尔曼滤波的特点,运用三峡实测数据对GPS变形监测动态数据处理中卡尔曼滤波的应用进行研究。并采用各点点位位移速度图对所建立的函数模型进行验证,同时对状态方程的建立及初始值的选取进行分析总结。     

无人机载线阵摆扫CCD影像几何校正

针对无人机载线阵CCD传感器摆扫成像的技术特点,利用GPS/INS组合导航系统提供的导航遥测数据,对无人机载的线阵摆扫CCD影像建立了严格的成像模型,并设计了详细的几何校正流程。实验结果证实采用文中的成像模型和几何校正流程,可获得正确、高精度地理编码的线阵摆扫CCD正射影像。     

南海中建南盆地构造样式分析

中建南盆地是发育于南海西部陆缘我国传统疆界线附近的新生代沉积盆地,大部分区域位于我国传统疆界线内。在对盆地近万千米多道地震资料综合分析解释的基础上,对盆地的主要构造样式以及它们与油气的关系进行了分析,结果表明,盆地分布面积广,沉积厚度大,油气前景良好。盆地是属于早期断陷、后期经走滑改造而成的复合型盆地,其构造演化经历了3个阶段,不同的阶段发育不同的构造样式:早期为断陷阶段,伸展型构造样式发育;中期为断坳—压扭或走滑反转阶段,产生走滑或压扭性构造样式;晚期为区域沉降阶段,以垂向沉积为主,无明显的构造样式发育。