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151.
“数字地球”科学工程 总被引:10,自引:0,他引:10
“数字地球”是集科学、技术和工程于一体的一项宏伟的科学体系。“数字地球”由基础研究、技术支撑和科学工程三部分组成,其中科学工程是“数字地球”的核心和目标。文章在我国“数字地球”科学工程现状分析的基础上,结合国情,对我国“数字地球”科学工程的发展提出了建议。 相似文献
152.
153.
GIS-based hazard mapping and zonation of debris flows in Xiaojiang Basin,southwestern China 总被引:11,自引:0,他引:11
Y.?P.?HeEmail author H.?Xie P.?Cui F.?Q.?Wei D.?L.?Zhong J.?S.?Gardner 《Environmental Geology》2003,45(2):286-293
Debris flow sites were identified at 140 locations in the Xiaojiang Basin in Yunnan province, southwestern China. Their spatial distribution and catchment characteristics are described in detail on the basis of previous research, air photo interpretation, field investigation and mapping using Geographical Information Systems (GIS). Using a statistical approach, a quantitative model of hazards assessment and zonation was developed through synthesis analysis of basin areas, gradients, and the relative reliefs of these debris flow sites. In terms of debris flow hazard assessment, areas within the Xiaojiang Basin can be classified as severe, heavy and light hazard regions. 相似文献
154.
Cui W 《The Astrophysical journal》2000,536(1):L31-L34
We here investigate the possibility that the ultra-high-energy cosmic-ray (UHECR) events observed above the Greisen-Zatsepin-Kuzmin (GZK) limit are mostly protons accelerated in reconnection sites just above the magnetosphere of newborn millisecond pulsars that are originated by accretion-induced collapse (AIC). We formulate the requirements for the acceleration mechanism and show that AIC pulsars with surface magnetic fields 1012 G/=10(20) eV. Because the expected rate of AIC sources in our Galaxy is very small ( approximately 10(-5) yr(-1)), the corresponding contribution to the flux of UHECRs is negligible and the total flux is given by the integrated contribution from AIC sources produced by the distribution of galaxies located within the distance that is unaffected by the GZK cutoff ( approximately 50 Mpc). We find that reconnection should convert a fraction xi greater, similar0.1 of magnetic energy into UHECRs in order to reproduce the observed flux. 相似文献
155.
移动式测绘系统(MMS)已在交通管理、城市规划、地图更新、工程勘测、精准农业、战场测绘等领域广泛应用。本文在简要叙述MMS基本概念和主要功能的基础上,探讨了MMS的发展现状和应用方向,进而提出了当前发展MMS需要解决的关键技术,仅供参考。 相似文献
156.
西北地区近期地壳水平运动与构造变形特征 总被引:3,自引:0,他引:3
利用截止2004年的西北地区GPS和跨祁连-龙首山构造带的红外测距观测资料,借助最小二乘配置、弹性块体边界负位错模型及单一力源反演,研究昆仑山口西8.1级大震前后西北地区水平形变应变场的动态演化特征;尤其是大震3年后,即当前的构造形变与应力场态势;获取活动块体及其边界断裂上可能反映中强以上孕震背景的高应变能积累区、段,以及可能的潜在震源。结果表明:青藏块体北缘地区经8.1级大震后的短期松弛和调整,目前正在恢复印度板块北东向碰撞推挤背景场的主控作用。而北天山构造带中段及其与西段的交汇区、南天山构造带中西段及其与西昆仑构造带的交汇区、阿尔金断裂中段、祁连山构造带中东段及其与海原断裂的交汇区、西秦岭北缘断裂与庄浪河断裂东南延伸线的交汇区域等具有相对高应变能积累背景;临泽与海原这两个地区也反映一定程度的应变能积累状态。 相似文献
157.
158.
Cui Xingfu Li Hongbing Hu Ying Liang Hong Qi Li 《应用地球物理》2007,4(2):94-100
When topography and low velocity zone differences vary greatly, conventional vertical static time shifts will cause wavefield distortion and influence wave equation seismic imaging for seismic data acquired on a complex near surface. In this paper, we propose an approach to datum correction that combines a joint tomography inversion with wavefield continuation to solve the static problem for seismic data on rugged acquisition topography. First, the near surface model is obtained by refracted wave tomography inversion. Second, the wavefield of sources and receivers are continued downward and upward to accomplish datum correction starting from a flat surface and locating the datum above topography. Based on the reciprocal theorem, Huygens' and Fresnel principles, the location of sources and receivers, and regarding the recorded data on the surface as a secondary emission, the sources and receivers are upward-continued to the datum above topography respectively. Thus, the datum correction using joint tomography inversion and wavefield continuation with the condition of a complex near surface is accomplished. 相似文献
159.
Summary Cloud microphysical properties in tropical convective and stratiform regions are examined based on hourly zonal-mean data
from a two-dimensional cloud-resolving simulation. The model is integrated for 21 days with the imposed large-scale vertical
velocity, zonal wind and horizontal advections obtained from Tropical Ocean Global Atmosphere Coupled Ocean-atmosphere Response
Experiment (TOGA COARE). Time-mean cloud microphysical budgets are analyzed in raining stratiform regions, convective regions,
and non-raining stratiform regions, respectively. In raining stratiform regions, ice water path (IWP) and liquid water path
(LWP) have similar magnitudes. The collection process contributes slightly more to the growth of raindrops than the melting
processes do, and surface rain rate is higher than the raindrop-related microphysical rate, indicating that the hydrometeor
convergence from the convective regions plays a role in surface rainfall processes. In convective regions, IWP is much smaller
than LWP, the collection process is dominant in producing raindrops, and surface rain rate is lower than the raindrop-related
microphysical rate. In non-raining stratiform regions, IWP is much larger than LWP, and the melting processes are important
in maintaining the raindrop budget. The statistical analysis of hourly data suggests that the slopes of linear regression
equations between IWP and LWP in three regions are different. Rain producing processes in convective regions are associated
with the water cloud processes regardless of convection intensity. 相似文献
160.
基于融媒体技术的地震专业知识服务系统是服务社会工程科技、地震及相关行业的专业信息平台,具有信息集成、科学技术创新、集管理与决策于一体的特点。本文论述了该服务系统的设计模式特点、服务内容及对象、系统技术架构和功能,并对其未来应用及发展方向进行讨论。 相似文献