空间互联网将是由各种区域网构成的复杂异构网络,为了使其能够逐步实现自动化运行,网络效益得到最大程度的发挥,须做好网络互联的顶层规划与设计,并开发具体的标准技术。根据近年CCSDS(Consultative Committee for Space Data Systems,...空间互联网将是由各种区域网构成的复杂异构网络,为了使其能够逐步实现自动化运行,网络效益得到最大程度的发挥,须做好网络互联的顶层规划与设计,并开发具体的标准技术。根据近年CCSDS(Consultative Committee for Space Data Systems,空间数据系统咨询委员会)发布的建议书,以及相关工作组的项目规划情况,介绍了SSI(Solar System Internetwork,太阳系互联网)体系结构、IPoC(IP over CCSDS space links,在CCSDS空间链路之上承载IP),以及DTN(Delay Tolerant Networking,容延迟网络)等标准项目。从CCSDS空间网络互联技术的发展历程不难得出结论:我国未来空间网络互联应注重区域网之间互联的顶层设计;区域网内部各子网之间的互联技术应选择以航天任务需求牵引为主;DTN将在区域网之间互联以及区域网从简单到复杂发展中都发挥重要作用。展开更多
In summer 2020,extreme rainfall occurred throughout the Yangtze River basin,Huaihe River basin,and southern Yellow River basin,which are defined here as the central China(CC)region.However,only a weak central Pacific(...In summer 2020,extreme rainfall occurred throughout the Yangtze River basin,Huaihe River basin,and southern Yellow River basin,which are defined here as the central China(CC)region.However,only a weak central Pacific(CP)El Niño happened during winter 2019/20,so the correlations between the El Niño–Southern Oscillation(ENSO)indices and ENSO-induced circulation anomalies were insufficient to explain this extreme precipitation event.In this study,reanalysis data and numerical experiments are employed to identify and verify the primary ENSO-related factors that cause this extreme rainfall event.During summer 2020,unusually strong anomalous southwesterlies on the northwest side of an extremely strong Northwest Pacific anticyclone anomaly(NWPAC)contributed excess moisture and convective instability to the CC region,and thus,triggered extreme precipitation in this area.The tropical Indian Ocean(TIO)has warmed in recent decades,and consequently,intensified TIO basinwide warming appears after a weak El Niño,which excites an extremely strong NWPAC via the pathway of the Indo-western Pacific Ocean capacitor(IPOC)effect.Additionally,the ENSO event of 2019/20 should be treated as a fast-decaying CP El Niño rather than a general CP El Niño,so that the circulation and precipitation anomalies in summer 2020 can be better understood.Last,the increasing trend of tropospheric temperature and moisture content in the CC region after 2000 is also conducive to producing heavy precipitation.展开更多
针对星地、星间复杂空间链路之间的高效数据传输需求,融合国际空间数据系统咨询委员会(Consultative Committee for Space Date System, CCSDS)与传输控制协议(Transmission Control Protocol, TCP)/互联网协议(Internet Protocol, IP)...针对星地、星间复杂空间链路之间的高效数据传输需求,融合国际空间数据系统咨询委员会(Consultative Committee for Space Date System, CCSDS)与传输控制协议(Transmission Control Protocol, TCP)/互联网协议(Internet Protocol, IP),基于物理层、数据链路层、网络层、传输层、应用层协议模型,提出了空间链路统一传输协议总体设计方案。针对不同空间链路协议差异导致的数据交互复杂问题,数据链路层采用统一空间数据链路协议,实现异构空间链路多业务混合传输;网络层采用封装数据包和IPoC(IP over CCSDS)协议承载IP数据,便于统一寻址;应用层采用空间数据包协议。通过数据链路层传输帧信道复用、网络层IP数据包复用与聚合、应用层空间数据包聚合,在不同通信协议层面实现了不同应用数据的融合传输。在地面测试系统中模拟星地、星间通信场景,验证了所提出的空间链路网络协议格式和数据传输服务的有效性。展开更多
文摘空间互联网将是由各种区域网构成的复杂异构网络,为了使其能够逐步实现自动化运行,网络效益得到最大程度的发挥,须做好网络互联的顶层规划与设计,并开发具体的标准技术。根据近年CCSDS(Consultative Committee for Space Data Systems,空间数据系统咨询委员会)发布的建议书,以及相关工作组的项目规划情况,介绍了SSI(Solar System Internetwork,太阳系互联网)体系结构、IPoC(IP over CCSDS space links,在CCSDS空间链路之上承载IP),以及DTN(Delay Tolerant Networking,容延迟网络)等标准项目。从CCSDS空间网络互联技术的发展历程不难得出结论:我国未来空间网络互联应注重区域网之间互联的顶层设计;区域网内部各子网之间的互联技术应选择以航天任务需求牵引为主;DTN将在区域网之间互联以及区域网从简单到复杂发展中都发挥重要作用。
基金This study was jointly supported by grants from the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(Grant No.XDB40000000)the CAS(Grant No.QYZDJ-SSW-DQC021)+3 种基金the National Natural Science Foundation of China(Grant No.41630531)the State Key Laboratory of Loess and Quaternary GeologyWe thank the supercomputer center of the Pilot Qingdao National Laboratory for Marine Science and Technology and Beijing Super Cloud Computing Center,who offered computing servicesWe also thank Dr.X.Z.LI,H.LIU,and L.LIU from the Institute of Earth Environment,CAS,who offered suggestions for our numerical experiments.
文摘In summer 2020,extreme rainfall occurred throughout the Yangtze River basin,Huaihe River basin,and southern Yellow River basin,which are defined here as the central China(CC)region.However,only a weak central Pacific(CP)El Niño happened during winter 2019/20,so the correlations between the El Niño–Southern Oscillation(ENSO)indices and ENSO-induced circulation anomalies were insufficient to explain this extreme precipitation event.In this study,reanalysis data and numerical experiments are employed to identify and verify the primary ENSO-related factors that cause this extreme rainfall event.During summer 2020,unusually strong anomalous southwesterlies on the northwest side of an extremely strong Northwest Pacific anticyclone anomaly(NWPAC)contributed excess moisture and convective instability to the CC region,and thus,triggered extreme precipitation in this area.The tropical Indian Ocean(TIO)has warmed in recent decades,and consequently,intensified TIO basinwide warming appears after a weak El Niño,which excites an extremely strong NWPAC via the pathway of the Indo-western Pacific Ocean capacitor(IPOC)effect.Additionally,the ENSO event of 2019/20 should be treated as a fast-decaying CP El Niño rather than a general CP El Niño,so that the circulation and precipitation anomalies in summer 2020 can be better understood.Last,the increasing trend of tropospheric temperature and moisture content in the CC region after 2000 is also conducive to producing heavy precipitation.
文摘针对星地、星间复杂空间链路之间的高效数据传输需求,融合国际空间数据系统咨询委员会(Consultative Committee for Space Date System, CCSDS)与传输控制协议(Transmission Control Protocol, TCP)/互联网协议(Internet Protocol, IP),基于物理层、数据链路层、网络层、传输层、应用层协议模型,提出了空间链路统一传输协议总体设计方案。针对不同空间链路协议差异导致的数据交互复杂问题,数据链路层采用统一空间数据链路协议,实现异构空间链路多业务混合传输;网络层采用封装数据包和IPoC(IP over CCSDS)协议承载IP数据,便于统一寻址;应用层采用空间数据包协议。通过数据链路层传输帧信道复用、网络层IP数据包复用与聚合、应用层空间数据包聚合,在不同通信协议层面实现了不同应用数据的融合传输。在地面测试系统中模拟星地、星间通信场景,验证了所提出的空间链路网络协议格式和数据传输服务的有效性。
