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Reproducing past subduction and mantle flow using high-resolution global convection models 被引量:11
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作者 JiaShun Hu LiJun Liu Quan Zhou 《Earth and Planetary Physics》 2018年第3期189-207,共19页
Plate subduction drives both the internal convection and the surface geology of the solid Earth.Despite the rapid increase of computational power,it remains challenging for geodynamic models to reproduce the history o... Plate subduction drives both the internal convection and the surface geology of the solid Earth.Despite the rapid increase of computational power,it remains challenging for geodynamic models to reproduce the history of Earth-like subduction and associated mantle flow.Here,based on an adaptive approach of sequential data assimilation,we present a high-resolution global model since the mid-Mesozoic.This model incorporates the thermal structure and surface kinematics of tectonic plates based on a recent plate reconstruction to reproduce the observed subduction configuration and Earth-like convection.Introduction of temperature-and composition-dependent rheology allows for incorporation of many natural complexities,such as initiation of subduction zones,reversal of subduction polarity,and detailed plate-boundary dynamics.The resultant present-day slab geometry well matches Benioff zones and seismic tomography at depths < 1500 km,making it possible to hindcast past subduction dynamics and mantle flow.For example,the model produces a flat Farallon slab beneath North America during the Late Cretaceous to Early Cenozoic,a feature that has been geodynamically challenging to reproduce.This high-resolution model can also capture details of the 4-D evolution of slabs and the ambient mantle,such as temporally and spatially varying mantle flow associated with evolving slab geometry and buoyancy flux,as well as the formation of shallow slab tears due to subduction of young seafloors and the resulting complex mantle deformation.Such a geodynamic framework serves to further constrain uncertain plate reconstruction in the geological past,and to better understand the origin of enigmatic mantle seismic features. 展开更多
关键词 GLOBAL SUBDUCTION model data ASSIMILATION earth-like SUBDUCTION Farallon flat SLAB MANTLE flow
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基于平坦地球模型的电磁态势仿真
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作者 刘琳 李炜 《舰船电子对抗》 2015年第6期62-64,共3页
随着现代通信技术的不断发展,电磁态势仿真在军事战争中具有重要意义。通过计算机模拟预测电磁态势可以起到优化战场武器装备布局的作用。基于平坦地球方法,以Java为开发语言,实现了基于平坦地球模型的电磁态势仿真系统。通过与美国的... 随着现代通信技术的不断发展,电磁态势仿真在军事战争中具有重要意义。通过计算机模拟预测电磁态势可以起到优化战场武器装备布局的作用。基于平坦地球方法,以Java为开发语言,实现了基于平坦地球模型的电磁态势仿真系统。通过与美国的高级折射效应预测系统比较,证明了本系统有很高的反应速度及精确度。 展开更多
关键词 电磁态势 平坦地球模型 JAVA语言
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根据非同步卫星移动地面站和陆地移动电台频率共享的干涉概率分析
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作者 罗有灿 《黑龙江八一农垦大学学报》 2005年第6期72-75,共4页
非静止轨道卫星移动通信服务(MMS)利用VHF带频率共享已有的陆地移动通信服务(LMS)和频率。它提示了在MMS和LMS之间共享VHF带频率时预测干涉影响的方法。标准电波传播模型定为flatearthmodel,NES则把Poisson分布定为在分布均匀的条件下... 非静止轨道卫星移动通信服务(MMS)利用VHF带频率共享已有的陆地移动通信服务(LMS)和频率。它提示了在MMS和LMS之间共享VHF带频率时预测干涉影响的方法。标准电波传播模型定为flatearthmodel,NES则把Poisson分布定为在分布均匀的条件下同时传送的MES数。利用上述内容求出能超过干涉标准的概率,并提示了其结果。 展开更多
关键词 非同步移动卫星业务 低轨移动卫星服务 基站 陆地移动服务 移动站 传播模型
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