The Global Precipitation Measurement(GPM)dual-frequency precipitation radar(DPR)products(Version 07A)are employed for a rigorous comparative analysis with ground-based operational weather radar(GR)networks.The reflect...The Global Precipitation Measurement(GPM)dual-frequency precipitation radar(DPR)products(Version 07A)are employed for a rigorous comparative analysis with ground-based operational weather radar(GR)networks.The reflectivity observed by GPM Ku PR is compared quantitatively against GR networks from CINRAD of China and NEXRAD of the United States,and the volume matching method is used for spatial matching.Additionally,a novel frequency correction method for all phases as well as precipitation types is used to correct the GPM Ku PR radar frequency to the GR frequency.A total of 20 GRs(including 10 from CINRAD and 10 from NEXRAD)are included in this comparative analysis.The results indicate that,compared with CINRAD matched data,NEXRAD exhibits larger biases in reflectivity when compared with the frequency-corrected Ku PR.The root-mean-square difference for CINRAD is calculated at 2.38 d B,whereas for NEXRAD it is 3.23 d B.The mean bias of CINRAD matched data is-0.16 d B,while the mean bias of NEXRAD is-2.10 d B.The mean standard deviation of bias for CINRAD is 2.15 d B,while for NEXRAD it is 2.29 d B.This study effectively assesses weather radar data in both the United States and China,which is crucial for improving the overall consistency of global precipitation estimates.展开更多
在无线传感器网络中,延迟是影响实时服务质量的重要因素.为了减少分组在转发过程中的排队延迟,提出一种基于动态优先级的实时分组调度机制(Dynamic Priority Based Real-time Packet Scheduling简写DPRS).在DPRS中,节点的队列被分为三...在无线传感器网络中,延迟是影响实时服务质量的重要因素.为了减少分组在转发过程中的排队延迟,提出一种基于动态优先级的实时分组调度机制(Dynamic Priority Based Real-time Packet Scheduling简写DPRS).在DPRS中,节点的队列被分为三个优先级队列,分别存放紧急分组、延误分组以及普通分组,DPRS在三个队列之间采取优先级调度机制,且根据当前队列的拥塞程度在每个队列内部采取先到先服务(First Come First Service简写FCFS)或后到先服务(Last Come First Service简写LCFS)的调度机制.理论分析和实验对比验证结果表明DPRS能够提高无线传感器网络的实时性.展开更多
The North Pacific storm track(NPST)is a high-frequency area of extratropical cyclones and an important channel for water vapor and energy transfer between low and mid–high latitudes.Previous weather and dynamic studi...The North Pacific storm track(NPST)is a high-frequency area of extratropical cyclones and an important channel for water vapor and energy transfer between low and mid–high latitudes.Previous weather and dynamic studies in this region have made significant progress,but due to the lack of ocean surface rainfall observation data,there is a lack of statistical research on precipitation in this area.In this study,statistical research on the spatiotemporal distribution characteristics of NPST rainfall was conducted based on GPM DPR(Global Precipitation Measurement Dual-frequency Precipitation Radar)observation data and ERA5 atmospheric parameters,and analysis and explanations are provided based on the atmospheric parameters.The study found that,compared to low-pressure systems,pressure gradients have a greater impact on cyclone activity and rainfall distribution.This feature,along with the meridional distribution of high atmospheric water vapor in the North Pacific Ocean and low in the north,collectively leads to the offset of high-frequency rainfall areas relative to storm tracks.The distribution of sea surface temperatures in the North Pacific Ocean affects the zonal distribution of storm tracks,causing weather disturbances and precipitation along the storm tracks to exhibit a northward extension from west to east.This study deepens our understanding of the role of NPST in global-scale water vapor and energy balance,and is of great significance for improving the prediction accuracy of climate models with respect to rainfall generated by extratropical cyclones.展开更多
基金funded by the National Key Research and Development Program of China(Grant No.2023YFB3907500)the National Natural Science Foundation(Grant No.42330602)the“Fengyun Satellite Remote Sensing Product Validation and Verification”Youth Innovation Team of the China Meteorological Administration(Grant No.CMA2023QN12)。
文摘The Global Precipitation Measurement(GPM)dual-frequency precipitation radar(DPR)products(Version 07A)are employed for a rigorous comparative analysis with ground-based operational weather radar(GR)networks.The reflectivity observed by GPM Ku PR is compared quantitatively against GR networks from CINRAD of China and NEXRAD of the United States,and the volume matching method is used for spatial matching.Additionally,a novel frequency correction method for all phases as well as precipitation types is used to correct the GPM Ku PR radar frequency to the GR frequency.A total of 20 GRs(including 10 from CINRAD and 10 from NEXRAD)are included in this comparative analysis.The results indicate that,compared with CINRAD matched data,NEXRAD exhibits larger biases in reflectivity when compared with the frequency-corrected Ku PR.The root-mean-square difference for CINRAD is calculated at 2.38 d B,whereas for NEXRAD it is 3.23 d B.The mean bias of CINRAD matched data is-0.16 d B,while the mean bias of NEXRAD is-2.10 d B.The mean standard deviation of bias for CINRAD is 2.15 d B,while for NEXRAD it is 2.29 d B.This study effectively assesses weather radar data in both the United States and China,which is crucial for improving the overall consistency of global precipitation estimates.
文摘在无线传感器网络中,延迟是影响实时服务质量的重要因素.为了减少分组在转发过程中的排队延迟,提出一种基于动态优先级的实时分组调度机制(Dynamic Priority Based Real-time Packet Scheduling简写DPRS).在DPRS中,节点的队列被分为三个优先级队列,分别存放紧急分组、延误分组以及普通分组,DPRS在三个队列之间采取优先级调度机制,且根据当前队列的拥塞程度在每个队列内部采取先到先服务(First Come First Service简写FCFS)或后到先服务(Last Come First Service简写LCFS)的调度机制.理论分析和实验对比验证结果表明DPRS能够提高无线传感器网络的实时性.
基金funded by the National Natural Science Foundation of China(Grant Nos.42275140,42230612,91837310,41675041,and 92037000)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(Grant No.2019QZKK0104)。
文摘The North Pacific storm track(NPST)is a high-frequency area of extratropical cyclones and an important channel for water vapor and energy transfer between low and mid–high latitudes.Previous weather and dynamic studies in this region have made significant progress,but due to the lack of ocean surface rainfall observation data,there is a lack of statistical research on precipitation in this area.In this study,statistical research on the spatiotemporal distribution characteristics of NPST rainfall was conducted based on GPM DPR(Global Precipitation Measurement Dual-frequency Precipitation Radar)observation data and ERA5 atmospheric parameters,and analysis and explanations are provided based on the atmospheric parameters.The study found that,compared to low-pressure systems,pressure gradients have a greater impact on cyclone activity and rainfall distribution.This feature,along with the meridional distribution of high atmospheric water vapor in the North Pacific Ocean and low in the north,collectively leads to the offset of high-frequency rainfall areas relative to storm tracks.The distribution of sea surface temperatures in the North Pacific Ocean affects the zonal distribution of storm tracks,causing weather disturbances and precipitation along the storm tracks to exhibit a northward extension from west to east.This study deepens our understanding of the role of NPST in global-scale water vapor and energy balance,and is of great significance for improving the prediction accuracy of climate models with respect to rainfall generated by extratropical cyclones.
