针对目前使用的地质灾害监测系统普遍采用的基于2G/3G/4G及其他无线技术的单点独立通信方式所存在的功耗高、信号盲区大、费用高昂等问题,该文设计一种基于远距离无线电(long range radio,LoRa)的面向山区地质灾害监测的数传节点。系统...针对目前使用的地质灾害监测系统普遍采用的基于2G/3G/4G及其他无线技术的单点独立通信方式所存在的功耗高、信号盲区大、费用高昂等问题,该文设计一种基于远距离无线电(long range radio,LoRa)的面向山区地质灾害监测的数传节点。系统基于STM32嵌入式控制器和SX1278无线通信模块,采用星型拓扑进行组网设计,实现远距离、高稳定性的传输链路,以解决山区地质灾害监测中的区域覆盖问题。通过在四川省某泥石流监测预警站的应用测试,结果表明:LoRa数传系统在泥石流监测区域的山地密林环境下信号覆盖范围良好(满足监测预警站800 m范围内的信号覆盖,丢包率低于5%),节点功耗低(电压3.6 V,平均静态工作电流0.39 mA,连续发射电流138.29 mA),能够有效解决复杂山区地质灾害监测数据的传输问题。展开更多
The flux of settling particles in the ocean has been widely explored since 1980s due to its important role in biogenic elements cycling,especially in the transport of particulate organic carbon(POC)in the deep sea.How...The flux of settling particles in the ocean has been widely explored since 1980s due to its important role in biogenic elements cycling,especially in the transport of particulate organic carbon(POC)in the deep sea.However,research in the seamount area of the oligotrophic subtropical Northwest Pacific Ocean is lacking.In this work,two sediment traps were deployed at the foot and another two at the hillside of Niulang Guyot from August2017 to July 2018.The magnitude and composition of particle fluxes were measured.The main factors influencing the spatial variations of the fluxes were evaluated.Our results indicated a low particulate flux from Niulang Guyot area in the Northwest Pacific Ocean,reflecting low primary productivity of the oligotrophic ocean.The total mass flux(TMF)decreased from 2.57 g/(m^(2)·a)to 0.56 g/(m^(2)·a)with increasing depth from 600 m to 4850 m.A clear seasonal pattern of TMF was observed,with higher flux in summer than that in winter.The peak flux of 26.52 mg/(m^(2)·d)occurred in August at 600 m,while the lowest value of 0.07 mg/(m^(2)·d)was shown in February at 4850 m.The settling particles at the deep layers had similar biochemical composition,with calcium carbonate(CaCO_(3))accounting for up to 90%,followed by organic matter and opal,characteristics of Carbonate Ocean.The POC flux decreased more rapidly in the twilight layer because of faster decomposition,remineralization,and higher temperature.A small fraction of POC was transported into the deep ocean by biological pump.Particle fluxes were mainly controlled by the calcareous ballasts besides the primary productivity of the surface water.The advection may be another important factor affecting the flux in the seamount area.The combination of settled matters rich in foraminiferal tests with topography and currents may be the reason for regulating the local abundance of benthos on seamounts.Our results will fill in the knowledge gap of sedimentation flux,improve the understanding of ecosystem in Niulang Guyot area,and eventually provide data support for the optimization of regional ecological modeling.展开更多
基金The Global Change and Air-sea Interaction II Project under contract Nos GASI-04-HYST-01 and GASI-01-NPACSTsumthe Eastern Pacific Eco-environment Monitoring and Protection Project under contract No.DY135-E2-5-02+1 种基金the Fund of COMRA-45 Cruise under contract No.DY-HC-135-45the Scientific Research Foundation of Third Institute of Oceanography,Ministry of Natural Resources of the People’s Republic of China under contract No.2017014。
文摘The flux of settling particles in the ocean has been widely explored since 1980s due to its important role in biogenic elements cycling,especially in the transport of particulate organic carbon(POC)in the deep sea.However,research in the seamount area of the oligotrophic subtropical Northwest Pacific Ocean is lacking.In this work,two sediment traps were deployed at the foot and another two at the hillside of Niulang Guyot from August2017 to July 2018.The magnitude and composition of particle fluxes were measured.The main factors influencing the spatial variations of the fluxes were evaluated.Our results indicated a low particulate flux from Niulang Guyot area in the Northwest Pacific Ocean,reflecting low primary productivity of the oligotrophic ocean.The total mass flux(TMF)decreased from 2.57 g/(m^(2)·a)to 0.56 g/(m^(2)·a)with increasing depth from 600 m to 4850 m.A clear seasonal pattern of TMF was observed,with higher flux in summer than that in winter.The peak flux of 26.52 mg/(m^(2)·d)occurred in August at 600 m,while the lowest value of 0.07 mg/(m^(2)·d)was shown in February at 4850 m.The settling particles at the deep layers had similar biochemical composition,with calcium carbonate(CaCO_(3))accounting for up to 90%,followed by organic matter and opal,characteristics of Carbonate Ocean.The POC flux decreased more rapidly in the twilight layer because of faster decomposition,remineralization,and higher temperature.A small fraction of POC was transported into the deep ocean by biological pump.Particle fluxes were mainly controlled by the calcareous ballasts besides the primary productivity of the surface water.The advection may be another important factor affecting the flux in the seamount area.The combination of settled matters rich in foraminiferal tests with topography and currents may be the reason for regulating the local abundance of benthos on seamounts.Our results will fill in the knowledge gap of sedimentation flux,improve the understanding of ecosystem in Niulang Guyot area,and eventually provide data support for the optimization of regional ecological modeling.
