Spatial Sciences on Ice: 50 years of Australian activities on the Amery Ice Shelf,East Antarctica     

Volker Janssen  Rachael Hurd 《The Australian geographer》2008,39(4):389-408

The Antarctic climate system involves many complex interactions between the atmosphere, oceans and ice and is sensitive to variations in these components. Ice shelves represent the ice–ocean–atmosphere interface of the Antarctic continent and are therefore very important indicators of climate change in the region. The Amery Ice Shelf is the largest ice shelf in East Antarctica and has been the focus of many scientific research projects over the past 50 years. This paper presents a history of the use of spatial science techniques from basic survey equipment to satellite systems in Australian research projects based on the Amery Ice Shelf (and surrounding glaciers) since 1955. The application of these spatial data to projects based primarily in the fields of geodesy, glaciology, climatology, and oceanography has allowed the measurement and monitoring of the physical, dynamic and environmental characteristics of this large and remote region. This new information provides scientists with a better understanding of the ice shelf/ocean/atmosphere system allowing future monitoring to observe the effects of global climate change.  相似文献   

Development of gullies and sediment production in the black soil region of northeastern China   总被引：11，自引：0，他引：11  

Yongqiu Wu  Qiuhong Zheng  Yongguang Zhang  Baoyuan Liu  Hong Cheng  Yanzai Wang 《Geomorphology》2008,101(4):683-691

Gully erosion is an important environmental hazard in the black soil region of northeastern China. It is a primary sediment source in the region which needs appropriate soil conservation practices. Gully incision in rolling hills typical of this region was monitored using real-time kinematic GPS to assess the rates of gully development and the resultant sediment production. From 2002 to 2005, gully heads in the study area retreated between 15.4 and 33.5 m, giving an average retreat rate of 8.4 m yr^− 1. Field measurements showed that total sediment production due to gully erosion during the three years ranged between 257 and 1854 m³ yr^− 1, which is equivalent to 326 to 2355 t yr^− 1, with gully-head retreat accounting for 0 to 21.7% (4.4% in average). The sediment delivery ratio was especially high during the summer rainy season (56% in average). Sediment production by ephemeral gullies and permanent gullies was 1.5 times greater than that from surface erosion. Gully heads retreated faster in the spring freeze–thaw period than in the summer. The stage of gully development could be identified based on short-term changes in the gully erosion rate.  相似文献   

基于GPS的华北地区地壳水平形变特征研究   总被引：1，自引：0，他引：1  

党学会  郭炳辉  吕健 《华北地震科学》2015,33(1)

利用中国大陆构造环境监测网络2009、2011年2期的GPS数据资料,计算得到华北地区相对于稳定的欧亚板块的区域水平速度场。根据水平速度场,基于连续变形假说,采用三角形方法计算了区域应变场特征值,并用GMT绘制了其分布图像。结合地震地质资料对该区的地壳水平形变特征进行分析研究,得出了有意义的结论:(1)水平相对运动与应变率场分布显示,板块交界处的断裂带及其附近区域地壳运动差异显著,应变率量值较为突出;(2)山西断陷带的活动方式与地质结果具有差异性;(3)区内最大剪应变、面膨胀的高值区主要位于环渤海的京津唐地区、山西断陷带中南部及郯庐断裂带中南段。  相似文献   

地壳形变测项概论     

秦家林 《东北地震研究》2015,(1)

回顾了地壳形变观测工作的发展历程,详细阐述了地壳形变观测手段、方法的变化,以及观测台网的布局,最后分析了测量误差。  相似文献   

Heterogeneous strain regime in the eastern margin of Tibetan Plateau and its tectonic implications     

Guojie Meng  Xiaoning Su  Weiwei Wu  Jinwei Ren  Yonglin Yang  Jicang Wu  Chieh-Hung Chen  Nikolay V. Shestakov 《地震科学（英文版）》2015,28(1):1-10

The eastern margin of Tibetan Plateau is one of the most active zones of tectonic deformation and seismicity in China. To monitor strain buildup and benefit seismic risk assessment, we constructed 14 survey-mode global position system(GPS) stations throughout the northwest of Longmenshan fault. A new GPS field over 1999–2011 is derived from measurements of the newly built and pre-existing stations in this region. Sequentially,two strain rate fields, one preceding and the other following the 2008 MW7.9 Wenchuan earthquake, are obtained using the Gausian weighting approach. Strain field over1999–2007 shows distinct strain partitioning prior to the2008 MW7.9 Wenchuan earthquake, with compression spreading over around Longmenshan area. Strain field derived from the two measurements in 2009 and 2011 shows that the area around Longmenshan continues to be under striking compression, as the pattern preceding the Wenchuan earthquake, implying a causative factor of the sequent of 2013 MW6.7 Lushan earthquake. Our GPSderived dilatation shows that both the Wenchuan and Lushan earthquakes occurred within the domain of pronounced contraction. The GPS velocities demonstrate that the Longriba fault underwent slight motion with the faultnormal and-parallel rates at 1.0 ± 2.5 mm and 0.3 ± 2.2 mm/a; the Longmenshan fault displayed slow activity, with a fault-normal rate at 0.8 ± 2.5 mm/a, and a fault-parallel rate at 1.8 ± 1.7 mm/a. Longriba fault is on a par with Longmenshan fault in strain partitioning to accommodate the southeastward motion of eastern margin of the Tibetan Plateau. Integrated analysis of principal strain tensors, mean principal stress, and fast directions of mantle anisotropy shows that west of Sichuan is characterized as mechanically strong crust-mantle coupling.  相似文献   

日本MW 9.0级大地震前后华北和东北地区现今构造应力作用调整过程与研究意义探讨     

谭成轩  胡秋韵  张鹏  丰成君  秦向辉 《地学前缘》2015,22(1):345-359

为了探讨日本M_W 9.0级大地震前后华北和东北地区现今构造应力作用调整过程与研究意义,对华北和东北地区进行原位现今地应力绝对测量与实时监测、GPS测量,结果表明：日本大地震在山东半岛、华北北部地区和东北地区所诱发同震位移引起的张性效应调整周期分别约为6个月(即调整结束时间大约在2011年9月)、15个月(即调整结束时间大约在2012年6月)和26个月(即调整结束时间大约在2013年5月),张性效应调整周期与同震位移大小成正比。在这种调整过程中,往往表现出区域现今构造应力作用方式和构造应力场转换,并可能伴随重大地质事件(如地震等)的发生。2012年5月28日和29日、6月18日、8月26日及2013年1月11日在唐山及其周围地区分别发生的4.8级、3.2级、4.0级、3.3级和3.0级地震与华北北部地区构造应力作用方式和构造应力场转换有关,而2013年10月31日以来在吉林省松原市发生的地震群应与东北地区构造应力作用方式和构造应力场转换有关,而非一个大地震前的小震群。  相似文献   

南北地震带近期地壳水平运动变化分析   总被引：3，自引：0，他引：3  

蒋锋云  张晓亮  张希  王伟 《地震研究》2015,38(2):229-236

对2009、2011及2013年3期陆态网络流动GPS观测资料进行了处理,获得了2009~2011及2011~2013年两个时间段南北地震带地壳水平运动速度图像。参考1999~2007年网络工程流动GPS速度场结果,分析了南北地震带近期地壳水平运动场与应变场变化特征,认为近期地壳运动变化受汶川地震震后影响较大。2013年芦山7.0级地震和岷县漳县6.6级地震是2008年汶川8.0级地震震后应力场调整触发的结果。  相似文献   

北斗+GPS组合单点定位精度评价与分析   总被引：2，自引：0，他引：2  

魏二虎  刘学习  刘经南 《测绘通报》2017,(5):1-5

北斗系统现在已经进入了全球组网的阶段。本文详细推导了北斗/GPS组合单点定位的数学模型;设计了两种方案,利用Multi-GNSS Experiment（MGEX）网的实测数据,分别从单个测站和亚太及其周边地区的12个测站来全面地进行北斗、GPS单系统,以及北斗+GPS组合单点定位的精度评价与分析;验证了组合单点定位的数学模型,得出了组合系统单点定位的精度和稳定性均优于单系统的结论,以期为北斗系统的应用推广提供参考。  相似文献   

BDS+GPS技术支持下的超高层建筑施工投点监测分析     

王勇  林财荣  郭际明  尹超凡  章迪 《测绘通报》2017,(6):5-8

超高层建筑施工中常采用激光投点仪向上传递地面控制点作为测量基准。为了避免投点误差过大,本文采用BDS+GPS技术进行组网监测其投点精度,给出了超高层建筑BDS+GPS监测相应的数据处理策略,对比分析了BDS、GPS及组合BDS+GPS 3系统之间,以及与激光投点前地面点坐标之间的差异。结果表明,GPS和BDS+GPS组合系统定位精度相当,BDS定位性能稍差,但满足超高层监测精度要求,利用北斗技术进行超高层建筑基准传递工作具有一定可行性。  相似文献   

联合区域叠加滤波法与小波变换去除GPS站坐标时间序列噪声     

马俊  周晓慧  朱兆涵 《测绘通报》2017,(12):6-11

GPS站坐标时间序列中存在的周期性与非周期性误差严重影响了对测站运动特征的分析及其非线性变化的物理机制解释。因此,为削弱噪声的影响,本文首先利用区域叠加滤波法去除了南加利福尼亚地区16个测站时间序列的共模误差,以此削弱时间序列中存在的包括周年和半周年误差在内的周期性误差。为去除滤波后残留的噪声,对滤波后的信号进行静态离散小波变换,提取了周期为半周年以上的信号。结果表明,联合区域叠加滤波法与小波变换对GPS站坐标时间序列进行处理,既能够削弱周期性误差对信号的影响,又能较好地提取测站的非线性运动信号。  相似文献