对2008—2014年由气象、电离层和气候卫星联合观测系统(Constellation Observing System for Meteorology Ionosphere and Climate,COSMIC)掩星观测与最新版国际电离层参考模型IRI-2016输出得到的电离层峰值参数(峰值密度NmF2与峰值高度...对2008—2014年由气象、电离层和气候卫星联合观测系统(Constellation Observing System for Meteorology Ionosphere and Climate,COSMIC)掩星观测与最新版国际电离层参考模型IRI-2016输出得到的电离层峰值参数(峰值密度NmF2与峰值高度hmF2)在中国区域进行了比较。IRI-2016模型输出值与COSMIC掩星反演值的相关性在太阳活动高年(2011—2014年)整体上高于太阳活动低年(2008—2010年)。在低年春秋季的当地时间(local time,LT)12:00—14:00,IRI-2016相对于COSMIC掩星在30°N^55°N区域内对NmF2和hmF2分别存在低估和高估现象,在15°N^30°N区域内则恰恰相反。对于NmF2,采用IRI_CCIR和IRI_URSI两种选项的模型输出值在中午时分均存在高估,在低年高估更为显著。对于hmF2,采用IRI_CCIR和IRI_AMTB两种选项的模型输出值在低年各季节均存在高估,且IRI_AMTB选项高估更显著,冬季最突出。结果表明,在中国区域由IRI-2016模型计算NmF2和hmF2时,分别推荐使用IRI_CCIR和IRI_Shubin选项。展开更多
Follow Chen and Duda's model of spectral fall-off of ω~3, the dependence of peak parameters of ground motion, peak displacement d_m, peak velocity vin and peak acceleration a_m, upon the environment stress τ_o-v...Follow Chen and Duda's model of spectral fall-off of ω~3, the dependence of peak parameters of ground motion, peak displacement d_m, peak velocity vin and peak acceleration a_m, upon the environment stress τ_o-values are studied using near source seismic digital recordings for the sequence of the Wuding, Yunnan, M = 6.5 earthquake, in which, as a new thought, the peak parameters are assumed to be related to the medium Q-value. Three formulae for estimating the environment stress τ_o-values by the peak parameters of three types of ground motions are derived. Using these formulae, the environment stress τ_o-values are calculated for the sequence of the Wuding earthquake. The result show that τ_o-values calculated by the three formulae are constant largely, the averages of τ_o are in the range of 5.0-35 MPa for most earthquakes. It belongs to the high-stress earthquakes sequence: the high-stress values are restricted to the relatively small area closely near to the epicenter of the main shock. The fine distribu tion structure for the contours of the environment stress τ_o-values is related closely to the strong aftershocks. The analysis of spatial and temporal feature of To-values suggests that the earthquakes sequence in a rupture process generated at the specific intersection zone of seismo-tectonics under high-stress background.展开更多
文摘对2008—2014年由气象、电离层和气候卫星联合观测系统(Constellation Observing System for Meteorology Ionosphere and Climate,COSMIC)掩星观测与最新版国际电离层参考模型IRI-2016输出得到的电离层峰值参数(峰值密度NmF2与峰值高度hmF2)在中国区域进行了比较。IRI-2016模型输出值与COSMIC掩星反演值的相关性在太阳活动高年(2011—2014年)整体上高于太阳活动低年(2008—2010年)。在低年春秋季的当地时间(local time,LT)12:00—14:00,IRI-2016相对于COSMIC掩星在30°N^55°N区域内对NmF2和hmF2分别存在低估和高估现象,在15°N^30°N区域内则恰恰相反。对于NmF2,采用IRI_CCIR和IRI_URSI两种选项的模型输出值在中午时分均存在高估,在低年高估更为显著。对于hmF2,采用IRI_CCIR和IRI_AMTB两种选项的模型输出值在低年各季节均存在高估,且IRI_AMTB选项高估更显著,冬季最突出。结果表明,在中国区域由IRI-2016模型计算NmF2和hmF2时,分别推荐使用IRI_CCIR和IRI_Shubin选项。
文摘Follow Chen and Duda's model of spectral fall-off of ω~3, the dependence of peak parameters of ground motion, peak displacement d_m, peak velocity vin and peak acceleration a_m, upon the environment stress τ_o-values are studied using near source seismic digital recordings for the sequence of the Wuding, Yunnan, M = 6.5 earthquake, in which, as a new thought, the peak parameters are assumed to be related to the medium Q-value. Three formulae for estimating the environment stress τ_o-values by the peak parameters of three types of ground motions are derived. Using these formulae, the environment stress τ_o-values are calculated for the sequence of the Wuding earthquake. The result show that τ_o-values calculated by the three formulae are constant largely, the averages of τ_o are in the range of 5.0-35 MPa for most earthquakes. It belongs to the high-stress earthquakes sequence: the high-stress values are restricted to the relatively small area closely near to the epicenter of the main shock. The fine distribu tion structure for the contours of the environment stress τ_o-values is related closely to the strong aftershocks. The analysis of spatial and temporal feature of To-values suggests that the earthquakes sequence in a rupture process generated at the specific intersection zone of seismo-tectonics under high-stress background.