无线定位技术是第三代移动通信系统中一个非常有前景的技术。文章首先对无线定位技术的网络构架进行了描述,并阐述了各个关键的网络元素的功能,然后分析研究了目前在3G P P标准中的几种定位方法以及各个定位方法的信令流程,最后对3G中...无线定位技术是第三代移动通信系统中一个非常有前景的技术。文章首先对无线定位技术的网络构架进行了描述,并阐述了各个关键的网络元素的功能,然后分析研究了目前在3G P P标准中的几种定位方法以及各个定位方法的信令流程,最后对3G中无线定位技术的应用前景进行了展望。展开更多
The method for surface modelling of land cover scenarios(SMLCS)has been improved to simulate the scenarios of land cover in Eurasia.On the basis of the observation monthly climatic data observed from 2127 weather stat...The method for surface modelling of land cover scenarios(SMLCS)has been improved to simulate the scenarios of land cover in Eurasia.On the basis of the observation monthly climatic data observed from 2127 weather stations in Eurasia during 1981-2010,the climatic scenarios data of RCP26,RCP45 and RCP85 scenarios released by CMIP5,and the land cover current data of Eurasia in 2010,the land cover scenarios of Eurasia were respectively simulated.The results show that most land cover types would generally have similar changing trends in the future,but with some difference in different periods under the three scenarios of RCP26,RCP45 and RCP85.Deciduous needleleaf forest,mixed forest,shrub land,wetlands and snow and ice would generally decrease in Eurasia during 2010-2100.Snow and ice would have the fastest decreasing rate that would decrease by 37.42%on average.Shrub land would have the slowest decreasing rate that would decrease by 5.65%on average.Water bodies would have the fastest increasing rate that would increase by 28.78%on average.Barren or sparsely vegetated land would have the slowest increasing rate that would increase by 0.76%.Moreover,the simulated results show that climate change would directly impact on land cover change in Eurasia.展开更多
基金National Key R&D Program of China,No.2017YFA0603702,No.2018YFC0507200National Natural Science Foundation of China,No.41421001,No.41271406Innovation Project of LREIS,N0.O88RA6OOYA。
文摘The method for surface modelling of land cover scenarios(SMLCS)has been improved to simulate the scenarios of land cover in Eurasia.On the basis of the observation monthly climatic data observed from 2127 weather stations in Eurasia during 1981-2010,the climatic scenarios data of RCP26,RCP45 and RCP85 scenarios released by CMIP5,and the land cover current data of Eurasia in 2010,the land cover scenarios of Eurasia were respectively simulated.The results show that most land cover types would generally have similar changing trends in the future,but with some difference in different periods under the three scenarios of RCP26,RCP45 and RCP85.Deciduous needleleaf forest,mixed forest,shrub land,wetlands and snow and ice would generally decrease in Eurasia during 2010-2100.Snow and ice would have the fastest decreasing rate that would decrease by 37.42%on average.Shrub land would have the slowest decreasing rate that would decrease by 5.65%on average.Water bodies would have the fastest increasing rate that would increase by 28.78%on average.Barren or sparsely vegetated land would have the slowest increasing rate that would increase by 0.76%.Moreover,the simulated results show that climate change would directly impact on land cover change in Eurasia.
