Characteristics of Fengyun-4A Satellite Atmospheric Motion Vectors and Their Impacts on Data Assimilation

The high observation efficiency,scanning speed and observation frequency of the Fengyun-4A(FY-4A)satellite indicates the progress of Chinese geostationary meteorological satellites.The characteristics of FY-4A atmospheric motion vectors(AMVs)derived from the high-level water vapor(WV-High)channel,mid-level water vapor(WV-Mid)channel,and infrared(IR)channel of FY-4A are analyzed,and their corresponding observation errors estimated.Then,the impacts of single-channel and multi-channel FY-4A AMVs on RMAPS-ST(the Rapid-refresh Multi-scale Analysis and Prediction System-Short Term)are evaluated based on one-month data assimilation cycling and forecasting experiments.Results show that the observation errors of FY-4A AMVs from the three channels have an explicit vertical structure.Results from the cycling experiments indicate that the assimilation of AMVs from WV-High produces more apparent improvement of the wind in the upper layer,while a more positive effect in the lower layer is achieved by the assimilation of AMVs from IR.Furthermore,the assimilation of AMVs from IR is more skillful for medium and moderate precipitation than from other channels owing to the good quality of data in the lower layer in the AMVs from IR.Assimilation of FY-4A AMVs from the three channels could combine the advantages of assimilation from each individual channel to improve the wind in the upper,middle and lower layers simultaneously.

Impact of Assimilating FY-4A Lightning Data with a Latent Heat Nudging Method on Short-Term Forecasts of Severe Convective Events in Eastern China

In this study,a latent heat nudging lightning data assimilation(LDA)method independent of the flash rate was developed and tested with data from the Lightning Mapping Imager(LMI)onboard the Feng-Yun-4A(FY-4A)satellite based on the Weather Research and Forecasting(WRF)model.In this LDA method,the positive temperature perturbations at the lightning location are first calculated by the difference between the moist adiabatic temperature of a lifted air parcel and the model temperature.The positive temperature perturbations in the mixed-phase region are then assimilated by a nudging method to adjust the latent heat within the convective system.Meanwhile,the water vapor mixing ratio is adapted to the temperature perturbations accordingly to constrain the relative humidity to remain unchanged.This method considers the physical nature of the convective system,in contrast with other LDA methods that establish an empirical or statistical relationship between the lightning flash rates and model variables.The impact of this LDA method on short-term(≤6 h)forecasts was evaluated using two severe convective events in eastern China:a multi-region heavy rainfall event and a thunderstorm high-wind event.The results showed that LDA could add thermodynamic information associated with the convective system to the WRF model during the nudging period,leading to a more reasonable storm environment.In the forecast fields,the simulations with LDA produced more realistic convective structures,resulting in an improvement in forecasts of precipitation and high winds.

2.5Gb/s Monolithic IC of Clock Recovery,Data Decision,and 1∶4 Demultiplexer

A high integrated monolithic IC, with functions of clock recovery, data decision, and 1 ： 4 demultiplexer,is implemented in 0.25μm CMOS process for 2.5Gb/s fiber-optic communications. The recovered and frequency divided 625MHz clock has a phase noise of -106.26dBc/Hz at 100kHz offset in response to a 2.5Gb/s PRBS input data （2^31-1）. The 2.5Gb/s PRBS data are demultiplexed to four 625Mb/s data. The 0.97mm× 0.97mm IC consumes 550mW under a single 3.3V power supply （not including output buffers）.

世界女排比赛制胜与技战术关联特征——基于DataVolley4数据考察和灰色关联分析

采用Data Volley 4和灰色关联分析方法对世界女排比赛制胜关联指标进行考察,结果显示:扣球得分与比赛制胜关联度最高,各队呈现“快强多元”与“立体高效”的进攻体系;发球凸显“战术强化”与“效率强化”,成为影响排球比赛的必然因素;拦网彰显攻防主动性,强调拦防组织的“区域协作”与“保障效力”,成为反攻环节的重要支撑;保障环节强调接发球的绝对到位率,是支撑“战术特色”和“快速多变”的基础;组织环节中二传好球数增加了比赛的难预测性,为制胜创造组织空间;自失环节中发球失误最具影响力。结合比赛制胜的关联特征,提出中国女排在巴黎奥运周期的备战策略:①树立“技术排球”理念,增强比赛各技术环节的主控性;②建立“数据排球”智库,加强对对手备战的持续追踪与数据化备赛;③坚持“靶向备战”思路,精准细化备战工作。

卵巢-附件报告和数据系统超声2022版(O-RADS US v2022)及其联合恶性风险指数4鉴别附件良、恶性肿瘤

目的观察卵巢-附件报告和数据系统超声2022版(O-RADS US v2022)及其联合恶性风险指数4(RMI4)鉴别附件良、恶性肿瘤的价值。方法回顾性分析126例手术病理诊断为附件肿瘤患者,根据O-RADS US v2022将1~3类归为良性病变、4~5类归为恶性病变,以450为RMI4分类的临界值,基于二者进行联合分类。以病理结果为金标准,绘制受试者工作特征(ROC)曲线,计算曲线下面积(AUC),评估单一O-RADS US v2022、RMI4及其联合鉴别附件良、恶性肿瘤的效能。结果126例附件肿瘤中,良性94例、恶性32例。O-RADS US v2022鉴别附件良、恶性肿瘤的敏感度、特异度、准确率及AUC分别为78.13%、80.85%和80.16%、0.795,RMI4分别为71.88%、84.04%和80.95%、0.780;二者联合的特异度及准确率(93.62%、92.06%)均高于单一O-RADS US v2022(χ^(2)=7.322、5.967,P=0.007、0.015)或RMI4(χ^(2)=4.625、5.331,P=0.032、0.021),而敏感度及AUC(87.50%、0.906)差异均无统计学意义(P均>0.05)。结论O-RADS US v2022能有效鉴别附件良、恶性肿瘤,联合RMI4可提高鉴别特异度及准确率。

Aerosol Data Assimilation Using Data from Fengyun-3A and MODIS:Application to a Dust Storm over East Asia in 2011

Aerosol optical depth （AOD） is the most basic paxalneter that describes the optical properties of atmospheric aerosols, and it can be used to indicate aerosol content. In this study, we assimilated AOD data from the Fengyun-3A （FY-3A） and MODIS meteorological satellite using the Gridpoint Statistical Interpolation three-dimensional variational data assimilation system. Experiments were conducted for a dust storm over East Asia in April 2011. Each 0600 UTC analysis initialized a 24-h Weather Research and Forecasting with Chemistry model forecast. The results generally showed that the assimilation of satellite AOD observational data can significantly improve model aerosol mass prediction skills. The AOD distribution of the analysis field was closer to the observations of the satellite after assimilation of satellite AOD data. In addition, the analysis resulting from the experiment assimilating both FY-3A/MERSI （Medium-resolution Spectral Imager） AOD data and MODIS AOD data had closer agreement with the ground-based values than the individual assimilation of the two datasets for the dust storm over East Asia. These results suggest that the Chinese FY-3A satellite aerosol products can be effectively applied to numerical models and dust weather analysis.

Fengyun-4 Geostationary Satellite-Based Solar Energy Nowcasting System and Its Application in North China

Surface solar irradiance(SSI)nowcasting(0-3 h)is an effective way to overcome the intermittency of solar energy and to ensure the safe operation of grid-connected solar power plants.In this study,an SSI estimate and nowcasting system was established using the near-infrared channel of Fengyun-4A(FY-4A)geostationary satellite.The system is composed of two key components:The first is a hybrid SSI estimation method combining a physical clear-sky model and an empirical cloudy-sky model.The second component is the SSI nowcasting model,the core of which is the derivation of the cloud motion vector(CMV)using the block-matching method.The goal of simultaneous estimation and nowcasting of global horizontal irradiance(GHI)and direct normal irradiance(DNI)is fulfilled.The system was evaluated under different sky conditions using SSI measurements at Xianghe,a radiation station in the North China Plain.The results show that the accuracy of GHI estimation is higher than that of DNI estimation,with a normalized root-mean-square error(nRMSE)of 22.4%relative to 45.4%.The nRMSE of forecasting GHI and DNI at 30-180 min ahead varied within 25.1%-30.8%and 48.1%-53.4%,respectively.The discrepancy of SSI estimation depends on cloud occurrence frequency and shows a seasonal pattern,being lower in spring-summer and higher in autumn-winter.The FY-4A has great potential in supporting SSI nowcasting,which promotes the development of photovoltaic energy and the reduction of carbon emissions in China.The system can be improved further if calibration of the empirical method is improved.

4D DATA FUSION TECHNIQUE IN URBAN WATERLOG-DRAINING DECISION SUPPORT SYSTEM

This paper studies urban waterlog_draining decision support system based on the 4D data fusion technique.4D data includes DEM,DOQ,DLG and DRG.It supplies entire databases for waterlog forecast and analysis together with non_spatial fundamental database.Data composition and reasoning are two key steps of 4D data fusion.Finally,this paper gives a real case: Ezhou Waterlog_Draining Decision Support System (EWDSS) with two application models,i.e.,DEM application model,water generating and draining model.

Use of Incremental Analysis Updates in 4D-Var Data Assimilation

The four-dimensional variational （4D-Var） data assimilation systems used in most operational and research centers use initial condition increments as control variables and adjust initial increments to find optimal analysis solutions. This approach may sometimes create discontinuities in analysis fields and produce undesirable spin ups and spin downs. This study explores using incremental analysis updates （IAU） in 4D-Var to reduce the analysis discontinuities. IAU-based 4D-Var has almost the same mathematical formula as conventional 4D-Var if the initial condition increments are replaced with time-integrated increments as control variables. The IAU technique was implemented in the NASA/GSFC 4D-Var prototype and compared against a control run without IAU. The results showed that the initial precipitation spikes were removed and that other discontinuities were also reduced, especially for the analysis of surface temperature.

Quality Assessment of FY-4A Lightning Data in Inland China

The Lightning Mapping Imager(LMI)equipped on the FY-4 A(Feng Yun-4 A)geostationary satellite achieves lightning positioning through optical imaging and has the advantages of high temporal resolution,high stability,and continuous observation.In this study,FY-4 A LMI lightning event,group and flash data from April to August 2018 are selected,and their quality are assessed through qualitative and quantitative comparison with the ground-based Advanced Time of Arrival and Direction system(ADTD)lightning observation network data and the American International Space Station(ISS)lightning imaging sensor(LIS)data.The results show that the spatial distributions of FY-4 A lightning are consistent with those of the ground-based ADTD and ISS LIS.The temporal variation in FY-4 A lightning group frequency is consistent with that of ADTD stroke,which reflects that FY-4 A LMI can capture the lightning occurrence in inland China.Quantitative statistics show that the consistency rate of FY-4 A LMI and ISS LIS events is relatively high but their consistency rate is lower in terms of lightning group and flash data.Compared with the lightning observations by the ISS LIS and the ground-based ADTD,FY-4 A LMI reports fewer lightning events in the Tibetan Plateau.The application of Tibetan Plateau lightning data requires further processing and consideration.

Assimilation of the FY-4A AGRI Clear-Sky Radiance Data in a Regional Numerical Model and Its Impact on the Forecast of the“21·7”Henan Extremely Persistent Heavy Rainfall

Assimilation of the Advanced Geostationary Radiance Imager(AGRI)clear-sky radiance in a regional model is performed.The forecasting effectiveness of the assimilation of two water vapor(WV)channels with conventional observations for the“21·7”Henan extremely heavy rainfall is analyzed and compared with a baseline test that assimilates only conventional observations in this study.The results show that the 24-h cumulative precipitation forecast by the assimilation experiment with the addition of the AGRI exceeds 500 mm,compared to a maximum value of 532.6 mm measured by the national meteorological stations,and that the location of the maximum precipitation is consistent with the observations.The results for the short periods of intense precipitation processes are that the simulation of the location and intensity of the 3-h cumulative precipitation is also relatively accurate.The analysis increment shows that the main difference between the two sets of assimilation experiments is over the ocean due to the additional ocean observations provided by FY-4A,which compensates for the lack of ocean observations.The assimilation of satellite data adjusts the vertical and horizontal wind fields over the ocean by adjusting the atmospheric temperature and humidity,which ultimately results in a narrower and stronger WV transport path to the center of heavy precipitation in Zhengzhou in the lower troposphere.Conversely,the WV convergence and upward motion in the control experiment are more dispersed;therefore,the precipitation centers are also correspondingly more dispersed.

Efficient and Effective 4D Trajectory Data Cleansing

As the rapid development of aviation industry and newly emerging crowd-sourcing projects such as Flightradar24 and FlightAware,large amount of air traffic data,particularly four-dimension(4D)trajectory data,have become available for the public.In order to guarantee the accuracy and reliability of results,data cleansing is the first step in analyzing 4D trajectory data,including error identification and mitigation.Data cleansing techniques for the 4D trajectory data are investigated.Back propagation(BP)neural network algorithm is applied to repair errors.Newton interpolation method is used to obtain even-spaced trajectory samples over a uniform distribution of each flight’s 4D trajectory data.Furthermore,a new method is proposed to compress data while maintaining the intrinsic characteristics of the trajectories.Density-based spatial clustering of applications with noise(DBSCAN)is applied to identify remaining outliers of sample points.Experiments are performed on a data set of one-day 4D trajectory data over Europe.The results show that the proposed method can achieve more efficient and effective results than the existing approaches.The work contributes to the first step of data preprocessing and lays foundation for further downstream 4D trajectory analysis.

超声O-RADS分类联合血清指标CA125及HE4诊断附件肿物良恶性的研究

目的:探讨卵巢-附件影像报告和数据系统(O-RADS)分类联合血清糖类抗原125(CA125)和人附睾分泌蛋白4(HE4)在附件肿物良恶性诊断中的应用价值。方法:回顾性分析2022年7月至2023年8月在安徽省立医院诊断并经病理证实的114例附件肿物患者,所有患者术前均行常规超声检查及血清CA125和HE4检测,以病理结果为“金标准”,将其分为良性组(87例)和恶性组(27例)。比较两组超声O-RADS分级及血清指标,采用受试者工作特征(ROC)曲线分析各项检测指标鉴别附件肿物良恶性的诊断效能。结果:良性组87例患者中超声O-RADS分类1类2例,2类22例,3类34例,4类29例,5类0例。恶性组27例患者中超声O-RADS分类1类0例,2类0例,3类2例,4类13例,5类12例。恶性组患者血清CA125中位数21.5(13.2,78.3)U/ml、HE4中位数49.0(31.3,70.5)pmol/L,其水平均高于良性组,差异有统计学意义(Z=-2.121、-2.021,P<0.05)。所有患者超声O-RADS分级、血清CA125、HE4以及联合诊断的准确率分别为71%、66%、78%和88%。经受试者工作特征(ROC)曲线分析,超声O-RADS分级、血清CA125、HE4以及联合诊断附件肿物良恶性的ROC曲线下面积(AUC)分别为0.870、0.556、0.594和0.898(95%CI:0.825~0.970)。结论:与单一的指标相比,O-RADS分类联合血清学指标CA125、HE4在附件肿物良恶性的诊断中有更高的应用价值,可提高诊断准确率。

Cross-satellite calibration of high-energy electron fluxes measured by FengYun-4A based on Arase observations

We use the High-energy Electron Experiments(HEP)instrument onboard Arase(ERG)to conduct an energy-dependent cross-satellite calibration of electron fluxes measured by the High Energy Particle Detector(HEPD)onboard FengYun-4A(FY-4A)spanning from April 1,2017,to September 30,2019.By tracing the two-dimensional magnetic positions(L,magnetic local time[MLT])of FY-4A at each time,we compare the datasets of the conjugate electron fluxes over the range of 245–894 keV in 6 energy channels for the satellite pair within different sets of L×MLT.The variations in the electron fluxes observed by FY-4A generally agree with the Arase measurements,and the percentages of the ratios of electron flux conjunctions within a factor of 2 are larger than 50%.Compared with Arase,FY-4A systematically overestimates electron fluxes at all 6 energy channels,with the corresponding calibration factors ranging from 0.67 to 0.81.After the cross-satellite calibration,the electron flux conjunctions between FY-4A and Arase show better agreement,with much smaller normalized root mean square errors.Our results provide a valuable reference for the application of FY-4A high-energy electron datasets to in-depth investigations of the Earth’s radiation belt electron dynamics.

Comparison between Google Earth KML Data and RTK Data on a Flight Planning Simulated to the Unmanned Aerial Vehicle Microdrone MD4-1000

The UAVs （unmanned aerial vehicles） and the use of graphical data files of extension KML （keyhole markup language） have become popular nowadays. The KML files are associated to the Google Earth applications. Developed by Microdrone company for planning, overflight simulation and data flight analysis, the program mdCockpit was used in this experiment. The UAV Microdrone＇s flight path was programmed in two ways： using geo referenced images from Google Earth and entering points coordinates into the program. These points have had their geographical decimal coordinates collected by GPS （global positioning system） （RTK （real time kinematic）） method. The aim here is to describe a way of evaluating the difference between the alternatives of flight planning. A flight path, defined a route with 22 points, was also simulated in the program mdCockpit. The points were collected and saved, while the images captured by the program went automatically forming a georeferenced mosaic. A comparison between the differences of coordinates to each point was made by choosing on the images and also by a RTK positioning. The result was up to 14.20 m to a 100 m flight height. There is a significant change of position and this can result in unwanted over flights in locations or even jeopardizing the safety of air activity.

一种集成DFE和CDR的56 Gbit/s PAM-4 SerDes接收机设计

基于65 nm CMOS工艺设计了一款1/4速率56 Gbit/s PAM-4 SerDes接收机,该接收机集成了可变增益放大、连续时间线性均衡(CTLE)、判决反馈均衡(DFE)、自适应阈值电压跟踪和无参考时钟数据恢复(CDR)等电路。可变增益放大技术被用来对接收信号进行幅度调节;CTLE和2抽头DFE被用来进行信道畸变补偿;自适应阈值电压跟踪技术用来确定最优的PAM-4信号判决电平;无参考时钟CDR技术则在无外部参考时钟的前提下,被用来产生最佳判决时钟,同时基于边沿检测技术有效降低了PAM-4信号非对称电平转换引起的时钟抖动。后仿真结果表明,在1.2 V电源电压下,所设计的PAM-4接收机能够实现6.75~20.75 dB的可调增益范围和高达16 dB@14 GHz的信道高频衰减补偿,且在16.1 dB@14 GHz信道下,CDR提取出的7 GHz时钟抖动峰峰值为7.21 ps。工作于56 Gbit/s速率下,接收机功耗为227 mW,能效为4.05 pJ/bit。

Application of multigrid NLS-4DVar in radar radial velocity data assimilation with WRF-ARW

The nonlinear least-squares four-dimensional variational assimilation(NLS-4DVar)method intro-duced here combines the merits of the ensemble Kalman lter and 4DVar assimilation methods.The multigrid NLS-4DVar method can be implemented without adjoint models and also corrects small-to large-scale errors with greater accuracy.In this paper,the multigrid NLS-4DVar method is used in radar radial velocity data assimilations.Observing system simulation experiments were conducted to determine the capability and efficiency of multigrid NLS-4DVar for assimilating radar radial velocity with WRF-ARW(the Advanced Research Weather Research and Forecasting model).The results show signi cant improvement in 24-h cumulative precipitation prediction due to improved initial conditions after assimilating the radar radial velocity.Additionally,the multigrid NLS-4DVar method reduces computational cost.

Toward development of the 4Dvar data assimilation system in the Bering Sea:reconstruction of the mean dynamic ocean topography

The Bering Sea circulation is derived as a variational inverse of hydrographic profiles（ temperature and salinity） , atmospheric climatologies and historical observation of ocean curents. The important result of this study is estimate of the mean climatological sea surface height （SSH） that can be used as a reference for satellite altimetry sea level anomaly data in the Bering Sea region. Numerical experiments reveal that, when combined with satellite altimetry, the obtained reference SSH effectively constrains a realistic reconstruction of the Amukta Pass circulation.

Assimilating FY-4A AGRI Radiances with a Channel-Sensitive Cloud Detection Scheme for the Analysis and Forecasting of Multiple Typhoons

This paper presents an attempt at assimilating clear-sky FY-4A Advanced Geosynchronous Radiation Imager(AGRI)radiances from two water vapor channels for the prediction of three landfalling typhoon events over the West Pacific Ocean using the 3DVar data assimilation(DA)method along with the WRF model.A channel-sensitive cloud detection scheme based on the particle filter(PF)algorithm is developed and examined against a cloud detection scheme using the multivariate and minimum residual(MMR)algorithm and another traditional cloud mask–dependent cloud detection scheme.Results show that both channel-sensitive cloud detection schemes are effective,while the PF scheme is able to reserve more pixels than the MMR scheme for the same channel.In general,the added value of AGRI radiances is confirmed when comparing with the control experiment without AGRI radiances.Moreover,it is found that the analysis fields of the PF experiment are mostly improved in terms of better depicting the typhoon,including the temperature,moisture,and dynamical conditions.The typhoon track forecast skill is improved with AGRI radiance DA,which could be explained by better simulating the upper trough.The impact of assimilating AGRI radiances on typhoon intensity forecasts is small.On the other hand,improved rainfall forecasts from AGRI DA experiments are found along with reduced errors for both the thermodynamic and moisture fields,albeit the improvements are limited.

Enhancing the vertical resolution of lunar penetrating radar data using predictive deconvolution

The Yutu-2 rover onboard the Chang’E-4 mission performed the first lunar penetrating radar detection on the farside of the Moon.The high-frequency channel presented us with many unprecedented details of the subsurface structures within a depth of approximately 50 m.However,it was still difficult to identify finer layers from the cluttered reflections and scattering waves.We applied deconvolution to improve the vertical resolution of the radar profile by extending the limited bandwidth associated with the emissive radar pulse.To overcome the challenges arising from the mixed-phase wavelets and the problematic amplification of noise,we performed predictive deconvolution to remove the minimum-phase components from the Chang’E-4 dataset,followed by a comprehensive phase rotation to rectify phase anomalies in the radar image.Subsequently,we implemented irreversible migration filtering to mitigate the noise and diminutive clutter echoes amplified by deconvolution.The processed data showed evident enhancement of the vertical resolution with a widened bandwidth in the frequency domain and better signal clarity in the time domain,providing us with more undisputed details of subsurface structures near the Chang’E-4 landing site.