夏季选择北太平洋安全航线的方法研究

根据多年平均流场和卫星云图分析,提出了一种夏季北太平洋上中国至北症状,中美洲远洋船舶安全航行的航线选择区,它位于２００ｈＰａ副热带高压脊线附近至其南部对流层上部槽以北广阔地区,并以实例作了较充分讨论。     

SLR应用展望——伽利略计划和非合作目标跟踪

随着SLR精度的提高和数据量的增大,SLR现已广泛应用于大地测量和相关科学中。论述了SLR在非合作目标的跟踪等新领域中的应用及SLR在伽利略计划中的作用,并展望了SLR技术的发展方向。     

Role of Antarctic ice mass balance in present-day sea-level change

The Antarctic ice sheet is arguably the most critical in terms of future sea-level rise, primarily because it contains 70% of the world's fresh water. While there exists evidence of accelerated ice-sheet ablation during the past decade, the possibility that the ice sheets contributed little to 20th century sea-level rise could result in Antarctica becoming the largest contributor to sea-level rise during the 21st century. Here we review the findings of studies published following the 2007 Intergovernmental Panel for Climate Change (IPCC) study, focusing on the role of Antarctica in present-day (1992–2006) sea-level rise. We show that the choice of glacial isostatic adjustment (GIA) model significantly affects GRACE-estimated Antarctic mass loss, adding 0.25–0.45 mm/yr to the estimate of sea-level rise. The current estimate of Antarctica's contribution to sea-level rise has a wide range: from −0.12 to +0.52 mm/yr. The discrepancy between observed sea-level trend of 1.8 mm/yr and those estimated from various geophysical sources (2.10 ± 0.99 mm/yr) is 0.30 mm/yr. The role of Antarctica in sea-level rise might be better constrained by lengthening satellite observations, using long-term GPS data to discriminate subglacial vertical motion from ice mass balance, and detecting the sea-level signal due to elastic loading from the melting ice-sheets.     

北斗卫星技术在数字地质调查系统中的集成开发与应用

在深入了解"北斗一号"导航卫星系统技术特点的基础上,结合地质调查工作流程,研究"北斗一号"导航卫星系统与数字地质调查系统集成的关键技术和实现方式以及系统的应用推广模式。研究表明,基于"北斗一号"卫星系统与GPS的双模式位置报送机制,可以为野外地质调查人员提供稳定的位置服务;北斗终端与手机的短信互通,在无手机网络的艰险地区也可与外界保持实时沟通。基于北斗导航卫星的DGSInfo系统可实现驻地实时监控和指挥,有助于野外应急事件的快速响应和处置,在中心节点可实现全局监控,为管理部门指挥调度和决策提供依据。GSIGrid野外地质调查管理服务与安全保障系统可在固定节点实现对移动节点的移动轨迹和通讯信息实时监控,并能与野外驻地和移动目标进行互动通讯,为野外地质调查人员提供查询服务,为突发事件应急处置的管理与决策提供数据支持。集成系统在东昆仑1:50000区调项目示范应用中取得了良好效果。      

A comparison of GOCE gravitational models with EGM2008

Four new gravity field models from GOCE, two of them combined with GRACE, are compared here with EGM2008. The objectives are to look into the differences in consecutive ranges of the spherical harmonic expansion globally as well as in selected geographical regions and in the regions of the various data sources used for EGM2008. In general, GOCE is able to contribute to improved global gravity models in the spherical harmonic range between 120 and 200 (and above). The agreement between EGM2008 and the GOCE models is very good in well-surveyed regions such as North America, Europe and Australia, with geoid RMS-differences on the order of 4–6 cm. In other regions, where the surface gravity data available for the development of EGM2008 were poor, such as South America, Africa, South-East Asia or China the RMS-differences are on a level of 30 cm. Here GOCE leads to a significant improvement. These findings are confirmed by the analysis of the areas of the various EGM2008 data sources. In the regions of the so-called “fill-in” data of EGM2008 RMS-geoid height differences are high. In Antarctica GOCE also gives important improvements in terms of spatial resolution and accuracy. In general, the agreement between EGM2008 and the GOCE-models up to degree and order (d/o) 200 is good, with a global (excluding the polar gaps of GOCE orbits, throughout) geoid difference RMS of 11 cm, in the ocean areas 8 cm and 20 cm in the continental areas. GOCE models are better suited for ocean circulation studies because no prior ocean information enters into the data reduction process, as it is the case when deducing gravity anomalies from an altimetric mean sea surface. On the other hand, the good consistency between GOCE-models and EGM2008 in ocean areas very likely indicates that the influence of ocean circulation information on EGM2008 is rather small. The four tested GOCE models behave similarly except at the highest latitudes where GOCE lacks data due to its orbit inclination of 96.5° and some form of regularization which has to be applied.     

地震应急卫星通信系统远端小站的故障诊断与处理

本文对地震应急卫星通信系统进行了简要介绍.针对系统运行过程中遇到的远端小站的各类故障进行了诊断分析.文中主要通过介绍设备状态及链路层状态两方面,来对如何解决此类故障问题提出了处理方案.     

中间层顶变化的SABER/TIMED卫星观测

本文利用TIMED卫星搭载的SABER探测仪对全球中间层顶信息进行了研究,包括中间层顶的高度、温度及其季节和纬度变化,并对双中间层顶现象进行了分析.中间层顶的温度约在160～180K之间变化,高度在85～100km内变化,温度和高度都是冬季高夏季低,有着较为一致的变化趋势.中间层顶高纬呈现显著年变化,而低纬和赤道呈现弱的半年变化,南北半球的中间层顶信息有着不对称性.高纬地区的双中间层顶现象十分显著,中间层顶一般会从100km附近迅速降低至85km附近.根据长时间范围内平均的结果显示,北半球的双中间层顶现象在20°N—30°N的中纬范围开始发生,证实了北半球双中间层顶现象不再仅限于极区和中高纬地区.而南半球则仍是在50°S才显著发生双中间层顶现象.我们统计了中高纬地区夏季所有的单个观测剖面并且与当年冬季的平均背景剖面相比较,数据显示,较低的夏季第二中间层顶高度绝大多数比冬季中间层顶低12～16km.     

中国大陆地壳地震震中分布的卫星磁异常约束

陆壳中的地震更危险,但其分布更具有弥散性,尤其在中国大陆地区;因此可靠且易用的地震警示信息显得非常重要.目前这类信息主要来自历史地震目录,大地测量及构造等资料,还需要补充其它的地学资料.本文提出一种来自卫星地壳磁场的约束.对于中国大陆的壳内地震(M_S≥5.0),研究表明其大都(80％以上)位于卫星地壳磁场的垂向磁感应强度分量的零等值线上或附近,并且理论上可以用一作用于半无限磁弹性平面中的集中力所产生的磁场分布来进行相应解释.尽管存在许多不确定因素,这种新的独立于传统资料的约束,提供了更为详细的地震警示性信息.同时,在缺少历史地震目录,大地测量及构造资料的地区,这种约束可作为一种先导性的监测信息加以使用.     

河北三河台数字电扰动异常分析

从2013年12月17日开始,三河台数字电扰动观测的NS和EW两测道交替出现了背景值增大的高值异常,现场调查和分析表明,这种高值脉冲异常主要是受仪表厂的供电干扰所致,仪器本身的工作正常;对观测系统数据采集软件的数据存储格式进行研究后发现,如果出现缺数,可能造成两个测道的数据出现互换的现象,应尽快改进数据采集软件,把两个测道采集的数据改为两个数据文件;同时,模拟观测的对比结果表明,同时间段模拟观测未出现异常;通过更换东西向线路和电极,观测数据恢复正常。综合分析认为,三河台数字电扰动出现的高值异常是干扰造成的,并非震兆异常。     

联合GNSS/LEO卫星观测数据的区域电离层建模与精度评估

高精度的电离层模型对于提高导航卫星系统的定位精度具有重要意义.低轨卫星的快速发展为建立高精度的电离层模型提供了新的契机.基于仿真数据模拟获得2017年1月1日-30日LEO (low earth orbit)和GNSS(global navigation satellite system)卫星观测数据,星座类型包括60...