2017年9月2日宁夏固原4.6级地震震例分析     

李文君  曾宪伟  卫定军  李国斌  罗国富 《地震地磁观测与研究》2019,41(1):40-47

2017年9月2日宁夏固原市原州区发生4.6级地震。通过对此次地震的回顾和总结,得到以下结论：①固原4.6级地震为孤立型地震;余震主要分布在主震震中西南侧,结合震源机制节面解,初步判定NW向节面应为此次地震的发震断层面,震源错动方式为左旋走滑兼具逆冲;震源机制解最佳拟合深度为9 km;震源机制解参数为节面Ⅰ：走向34°、倾角62°、滑动角174°,节面Ⅱ：走向127°、倾角85°、滑动角28°;②固原4.6级地震前存在前震活动、小震调制异常以及固原地震窗异常;③海原小山钻孔应变异常变化与固原4.6级地震有关,且与该测项预测指标已有的研究结果较吻合,但此次地震震级比预计震级偏大;④固原地震台地电阻率和地磁谐波振幅比异常期间发生了3次中强地震,其中,2017年5月17—20日,固原地震台地电阻率EW向出现快速下降,之后呈低值变化;固原地震台地磁谐波振幅比NS向从2014年开始经历下降—转折—回升过程,具有良好的映震效能。  相似文献   

WGS84与ITRS基准转换参数估计及长期演化特性分析     

张清华  隋立芬  甘雨  肖国锐  戚国宾 《武汉大学学报(信息科学版)》2015,40(3):395-400

针对在轨运行的GPS卫星,利用由NGA提供的WGS84框架下精密星历以及IGS提供的ITRS框架下的精密星历,采用7参数布尔沙模型,并结合不同卫星的星载原子钟的稳定性,在最小二乘准则下求取WGS84和ITRS之间的转换参数。在此基础上,为了得到较长时间尺度上转换参数的演化特性,首先采用EMD算法进行去噪,以使得数据更能反映参数变化的本质特性,然后在消除趋势项的基础上,对转换参数的时间序列进行谱分析,以探索其周期特性。利用NGA和IGS提供的2009-01-01~2012-06-30共1306d的精密星历,求取每天一组的坐标转换参数,分析其长期演化特性后发现:3个平移参数分别具有345d,690d和345d的周期项,3个旋转参数分别具有459d,172d和459d的周期项,尺度参数则不具有明显的周期项。  相似文献   

Impacts of climate change under CMIP5 RCP scenarios on streamflow in the Huangnizhuang catchment   总被引：1，自引：0，他引：1  

Fen Ouyang  Yonghua Zhu  Guobin Fu  Haishen Lü  Aijing Zhang  Zhongbo Yu  Xi Chen 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(7):1781-1795

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敦煌莫高窟大气颗粒物中水溶性离子变化及来源解析   总被引：1，自引：0，他引：1  

杨小菊  武发思  徐瑞红  贺东鹏  张国彬  康世昌  李潮流  汪万福 《高原气象》2021,40(2):436-447

为探明莫高窟大气颗粒物污染特征,采集了2014年4-12月第16窟及72窟外环境中大气颗粒物PM2.5和PM10～2.5样品,对比分析了样品中水溶性离子变化及影响因素,通过主成分分析法解析了其主要来源.结果表明:(1)窟区主风向为南风,起沙风频率仅为0.01％,不利于污染物的扩散;(2)窟外PM2.5和PM10～2.5...  相似文献   

一种新的混合迭代UKF     

常国宾  许江宁  胡柏青  纪兵 《武汉大学学报(信息科学版)》2012,37(6):701-703

从统计线性回归的角度对无味变换(unscented transformation,UT)进行分析,推导了迭代无味卡尔曼滤波(iterated unscented Kalman filter,IUKF)。针对IUKF计算量大的问题,结合弦线迭代法和IUKF,得到了一种新的混合迭代无味卡尔曼滤波器。数值仿真的结果表明,新滤波算法的精度优于扩展卡尔曼滤波、迭代扩展卡尔曼滤波和无味卡尔曼滤波,并可以有效降低IUKF的计算量。  相似文献   

The change in values for ecological footprint indices following land-use change in a Loess Plateau watershed in China     

Ping Zhou  Guobin Liu 《Environmental Earth Sciences》2009,59(3):529-536

Sustainability was defined as the continuous support of human quality of life within a region’s ecological carrying capacity. Ecological footprint was a quantitatively measuring indicator to analyze the sustainable use of natural resources and had been widely used to evaluate whether the development of a certain region was within the range of the capacity of natural ecosystem. In the present study, production data, consumption data and statistics communique of Zhifanggou watershed were analyzed to determine per capita ecological footprint, biological carrying capacity and related indices. On the basis of theory a model was applied that showed the biologically productive land area required by a defined population—ecological footprint model before and after grain for green policy. Result showed that after introducing the grain for green policy, per capita ecological footprint was reduced from 0.733 to 0.650 hm² cap⁻¹ and biological capacity was increased from 1.559 to 1.567 hm² cap⁻¹. There was a surplus of ecosystem resources both before and after the grain for green policy and this increased as a result of the policy. The related ecological footprint indices analysis showed that 10,000 RMB of GDP of ecological footprint was reduced, but ecological efficiency, ecological footprint index, bio-diversity of ecological footprint and system development ability increased Results demonstrated that conditions in this watershed improved and development potential was enhanced. Meanwhile, the sensitive index of forestland was strengthened more than other biological productive areas after introducing the policy. In adjusting and improving the land use structure created a resource-saving mode, forming resource-saving increase mode gradually, and triggering sustained consumption which will improve the ecological environment of zhifanggou watershed in the future.  相似文献   

Evaluation of various root transformations of daily precipitation amounts fitted with a normal distribution for Australia     

Guobin Fu  Neil R. Viney  Stephen P. Charles 《Theoretical and Applied Climatology》2010,99(1-2):229-238

This paper evaluates the various root transformations (2/3, 7/12, 1/2, 5/12, 1/3, and 1/4) of daily precipitation amounts fitted with a truncated normal distribution model for 189 stations across Australia. The results indicate that all stations used in this study can be identified to have a specific root transformation resulting in a “good” fit with a normal distribution and the minimum correlation coefficients (r) fitted with a normal distribution is 0.9925. The 5/12 power transformation leads to the “best” fit with a normal distribution in 47% of stations across Australia. This conclusion could extend the applications of many statistical testing techniques and methods on daily precipitation studies.  相似文献   

影响莫高窟小气候的环境因子对比分析   总被引：2，自引：0，他引：2  

李红寿  汪万福  张国彬  邱飞  詹洪涛 《干旱气象》2008,26(2):25-30

应用不同时空尺度对莫高窟的小气候进行对比分析,发现莫高窟的地形地貌、水系统、植被等环境因子对其小气候有重要影响。莫高窟的小地形结构和水系统对其风速、湿度、太阳辐射等有显著影响。2005年4—12月窟前与窟顶月平均相比,太阳辐射总量降低411．21MJ／m^2,地表温度降低2．7℃,相对湿度增大9％,风速降低3．7m／s。窟前月较差小于戈壁0．9℃。但对于气温而言,主要受较大尺度因素的控制,窟前、窟顶、戈壁均处于同一温度层。2004年莫高窟日较差比敦煌小4．8℃。莫高窟的环境因子使莫高窟周边形成了更为稳定的小气候,非常有利于文物保护,这也是千年莫高窟保存至今的一个重要原因。  相似文献   

Vegetation responses to integrated water management in the Ejina basin,northwest China   总被引：1，自引：0，他引：1  

Yichi Zhang  Jingjie Yu  Ping Wang  Guobin Fu 《水文研究》2011,25(22):3448-3461

The Ejina basin, which is located in arid and semi‐arid areas of northwest China, has experienced severe environmental deterioration in the past several decades, and an exploratory project was launched by the Chinese Government in 2001 to restore this degraded ecosystem. In this study, multi‐scale remotely sensed data and field investigations were used to quantify the responses of vegetation to the implementation of integrated water management under this project. In terms of the seasonal accumulated Normalized Difference Vegetation Index (SAN) variation, (1) the vegetation in 80·4% of the oasis regions showed an increasing or recovering trend, and increasing SAN trends with a magnitude greater than 0·14 a^?1 mainly resulted from cultivated land reclamation; (2) the vegetation in 91·5% of the desert regions presented an increasing trend, and the statistically significant trends mainly appeared in the middle and lower Ejina basin; (3) the vegetation in 19·6% of oasis and 5·1% of desert regions showed a decreasing or degrading trend, mainly where rivers diminished and along artificial concrete canals; and (4) opposite signs of vegetation trends occurred simultaneously along some natural rivers experiencing water reduction, with a decreasing trend generally appearing in the high SAN regions, whereas an increasing trend was seen in the low SAN regions. The broad vegetation recovery observed was due to the comprehensive improvement of the water environment, which was attributed to both the increase in runoff entering the Ejina basin and the adoption of engineering measures. Vegetation degradation in the area mainly resulted from deterioration of the local water environment, which was closely related to the problems of water management. The results of this study can be used as a reference for adjusting the current water resource management strategy to effectively restore this ecosystem. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

近45a重庆暴雨气候变化特征分析     

刘毅  孙俊  周国兵  王欢  林建 《湖北气象》2020,39(3):306-311

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