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Evaluating the Algorithm for Correction of the Bright Band Effects in QPEs with S-, C-and X-Band Dual-Polarized Radars

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Advances in Atmospheric Sciences 2019年第1期36卷 41-54页

作者： Yang CAO Debin SU Xingang FAN Hongbin CHEN key laboratory of Middle Atmosphere and Global Environment observation Institute of Atmospheric PhysicsChinese Academy of Sciences College of Electronic Engineering Chengdu University of Information Technology Sichuan meteorological Disasters Prevention Technology Center China meteorological Administration key laboratory of Atmospheric Sounding department of Geography and Geology Western Kentucky University

The bright band, a layer of enhanced radar reflectivity associated with melting ice particles, is a major source of signifi- cant overestimation in quantitative precipitation estimation （QPE） based on the Z-R （reflectivity factor-rain rate） relationship. The effects of the bright band on radar-based QPE can be eliminated by vertical profile of reflectivity （VPR） correction. In this study, we applied bright-band correction algorithms to evaluate three different bands （S-, C- and X-band） of dual-polarized radars and to reduce overestimation errors in Z-R relationship-based QPEs. After the reflectivity was corrected by the algo- rithms using average VPR （AVPR） alone and a combination of average VPR and the vertical profile of the copolar correlation coefficient （AVPR＋CC）, the QPEs were derived. The bright-band correction and resulting QPEs were evaluated in eight precipitation events by comparing to the uncorrected reflectivity and rain-gange observations, separately. The overestimation of Z-R relationship-based QPEs associated with the bright band was reduced after correction by the two schemes for which hourly rainfall was less than 5 mm. For the verification metrics of RMSE （root-mean-square error）, RMAE （relative mean absolute error） and RMB （relative mean bias） of QPEs, averaged over all eight cases, the AVPR method improved from 2.28, 0.94 and 0.78 to 1.55, 0.60 and 0.40, respectively, while the AVPR＋CC method improved to 1.44, 0.55 and 0.30, respectively. The QPEs after AVPR＋CC correction had less overestimation than those after AVPR correction, and similar conclusions were drawn for all three different bands of dual-polarized radars.

关键词： dual-polarized radar bright band QPE vertical profile of reflectivity

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Retrieving Microphysical Properties and Air Motion of Cirrus Clouds Based on the Doppler Moments Method Using Cloud Radar

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Advances in Atmospheric Sciences 2012年第3期29卷 611-622页

作者：仲凌志刘黎平邓敏周秀骥 National meteorological information Center State key laboratory of Severe Weather Chinese Academy of meteorological Sciences department of Atmospheric Science University of Wyoming

Radar parameters including radar reflectivity, Doppler velocity, and Doppler spectrum width were obtained from Doppler spectrum moments. The Doppler spectrum moment is the convolution of both the particle spectrum and the mean air vertical motion. Unlike strong precipitation, the motion of particles in cirrus clouds is quite close to the air motion around them. In this study, a method of Doppler moments was developed and used to retrieve cirrus cloud microphysical properties such as the mean air vertical velocity, mass-weighted diameter, effective particle size, and ice content. Ice content values were retrieved using both the Doppler spectrum method and classic Z-IWC （radar reflectivity-ice water content） relationships; however, the former is a more reasonable method.

关键词： radar cloud Doppler moments microphysical properties

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Ground-based and additional science support for SMILE

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Earth and Planetary Physics 2024年第1期8卷 275-298页

作者： J.A.Carter M.Dunlop C.Forsyth K.Oksavik E.Donovon A.Kavanagh S.E.Milan T.Sergienko R.C.Fear D.G.Sibeck M.Connors T.Yeoman X.Tan M.G.G.T.Taylor K.McWilliams J.Gjerloev R.Barnes D.D.Billet G.Chisham A.Dimmock M.P.Freeman D.-S.Han M.D.Hartinger S.-Y.W.Hsieh Z.-J.Hu M.K.James L.Juusola K.Kauristie E.A.Kronberg M.Lester J.Manuel J.Matzka I.McCrea Y.Miyoshi J.Rae L.Ren F.Sigernes E.Spanswick K.Sterne A.Steuwer T.Sun M.-T.Walach B.Walsh C.Wang J.Weygand J.Wild J.Yan J.Zhang Q.-H.Zhang Planetary Sciences Group School of Physics and AstronomyUniversity of LeicesterUniversity RoadLeicesterLE17RHUK Rutherford Appleton laboratory Space Science Technology Facilities CouncilOxfordshireUK School of Space and Environment Beihang UniversityBeijing 100191China key laboratory of Space Environment Monitoring and information processing Ministry of Industry and Information TechnologyBeijing 100017China department of Space and Climate Physics UCLMullard Space Science LaboratoryHolmbury St.MaryDorkingSurreyRH56NTUK Birkeland Centre for Space Science Department of Physics and Technology.University of BergenBergenNorway department of Physics and Astronomy University of Calgary2500 University DriveCalgaryAlbertaCanada T2N 1N4 British Antarctic Survey CambridgeUK Swedish Institute of Space Physics KirunaSweden West Highfield Campus University of SouthamptonUniversity RoadSO171BJUK Goddard Space Flight Center NASAGreenbeltMarylandUSA Athabasca University AthabascaCanada ESTEC European Space AgencyNetherlands University of Saskatchewan SaskatoonCanada The Johns Hopkins University Applied Physics laboratory LaurelMarylandUSA Swedish Institude of Space Physics UppsalaSE 75121Sweden Tongji University Shanghai 200092China Center for Space Plasma Physics Space Science Institute4765 Walnut Street Suite BBoulderColorado80301USA Polar Research Institute of China Shanghai 200136China Finnish meteorological Institute(FMI) Finland department of Earth and Environmental Sciences(Geophysics) Ludwig Maximilian University of Munich(LMU)MunichTheresienstr.41MunichD-80333Germany Canadian Space Agency MontrealCanada GFZ German Research Centre for Geosciences PotsdamGermany Nagoya University Institute for Space Earth Environment ResearchCenter for Integrated Data ScienceNagoyaAichiJP 464-8601 Northumbria University Newcastle upon TyneTyne and WearUK NE18ST National Space Science Center Chinese Academy SciencesBeijing 100190China Arctic Geophysics University Centre in Svalbard

The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field conditions,and simultaneously monitor the auroral response of the Northern Hemisphere *** these large-scale responses with medium and fine-scale measurements at a variety of cadences by additional ground-based and space-based instruments will enable a much greater scientific impact beyond the original goals of the SMILE ***,we describe current community efforts to prepare for SMILE,and the benefits and context various experiments that have explicitly expressed support for SMILE can offer.A dedicated group of international scientists representing many different experiment types and geographical locations,the Ground-based and Additional Science Working Group,is facilitating these *** include constructing an online SMILE Data Fusion Facility,the discussion of particular or special modes for experiments such as coherent and incoherent scatter radar,and the consideration of particular observing strategies and spacecraft *** anticipate growing interest and community engagement with the SMILE mission,and we welcome novel ideas and insights from the solar-terrestrial community.

关键词： magnetosphere ionosphere magnetosphere-ionosphere coupling ground-based experimentation SMILE conjunctions missions

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Initial results of China's GNSS-R airborne campaign: soil moisture retrievals

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Science Bulletin 2015年第10期60卷 964-971,I0008页

作者：万玮白伟华赵利民龙笛孙越强孟祥广谌华崔喜爱洪阳 State key laboratory of Hydroscience and Engineering Tsinghua University department of Hydraulic Engineering Tsinghua University Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences meteorological observation Center China Meteorological Administration

The global navigation satellite system reflectometry （GNSS-R） technique has been proven to be a powerful tool for retrieving geophysical parameters of ocean and land/hydrology processes. The ultimate goal for such GNSS-R applications is to achieve large-scale, all- weather, and full-time mapping using spaceborne platforms. In order to ensure both GNSS-R receiver and algorithm meet the requirements of spaceborne observations, airborne experimental campaigns need to be first carried out for early testing and validation purposes. This paper presents a first comprehensive overview of China＇s airborne GNSS-R campaign conducted on May 30, 2014. There were two objectives for this campaign：（l） to examine the capability of the GNSS-R receiver developed by the National Space Science Center, Chinese Academy of Sciences, for airborne observations and （2） to study algo-rithms for soil moisture and altimetry retrievals. In this paper, initial results of soil moisture retrievals are pre- sented. The left-hand circularly polarized-predominant satellite information was successfully used to retrieval soil moisture over the cropland. The right-hand circularly polarized components of the reflected signals were also received and examined. The GPS-derived soil moisture results, on the one hand, correctly represented the spatial variations of the soil moisture along the tracking of the flight; on the other hand, the results underestimated the ground-truth. Errors from the retrieval model and from the positioning and effects from the vegetation layer and from the atmospheric water vapor were the primary causes of the uncertainties in soil moisture retrievals using the airborne GNSS-R data. This airborne experimental campaign firstly investigate that China has the capability to perform airborne GNSS-R observation using the self-developed receiver, although the receiver developed by the NSSC needs to be further examined for its capability for spaceborne observation. The early findings of th

关键词： GNSS-R Soil moisture - Airborne campaign The Yellow River GPS

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Simulation of Extreme Updrafts in the Tropical Cyclone Eyewall

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Advances in Atmospheric Sciences 2020年第7期37卷 781-792页

作者： Yan ZHENG Liguang WU Haikun ZHAO Xingyang ZHOU Qingyuan LIU key laboratory of meteorological Disaster of Ministry of Education Nanjing University of Information Science and TechnologyNanjing 210044China State key laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200433China jiangsu Institute of meteorological Sciences Nanjing 210009China

Strong vertical motion(>10 m s-1)has profound implications for tropical cyclone(TC)structure changes and *** extreme updrafts in the TC are occasionally observed in real TCs,the associated small-scale features remain *** on an analysis of the extreme eyewall updrafts in two numerical experiments conducted with the Advanced Research version of the Weather Research and Forecasting(WRF)model,in which the large-eddy simulation(LES)technique was used with the finest grid spacings of 37 and 111 m,for the first time this study demonstrates that the simulated extreme updrafts that occur mainly in the enhanced eyewall convection on the down-shear left side are comparable to available *** simulated extreme updraft exhibits relatively high frequencies in the lower(750 m),middle(6.5 km)and upper(13 km)troposphere,which are associated with different types of small-scale *** the lower-level extreme updraft is mainly related to the tornado-scale vortex,the extreme updraft at upper levels is closely associated with a pair of counter-rotating horizontal rolls oriented generally along the TC tangential flow,which are closely associated with the enhanced eyewall *** extreme updraft at middle levels is related to relatively complicated small-scale *** study suggests that extreme updrafts can be simulated when the grid spacing is about 100 m or less in the WRF-LES framework,although the simulated small-scale features need further verification in both observation and simulation.

关键词： cyclone extreme troposphere

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Adaptive stochastic resonance method for weak signal detection based on particle swarm optimization

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Instrumentation 2015年第2期2卷 3-10页

作者： XING Hongyan ZHANG Qiang LU Chunxia Collaborative Innovation Center on Forecast and Evaluation of meteorological Disasters Nanjing University of Information Science & Technology key laboratory of meteorological observation and information processing of jiangsu Province Nanjing University of Information Science & Technology

In order to solve the parameter adjustment problems of adaptive stochastic resonance system in the areas of weak signal detection,this article presents a new method to enhance the detection efficiency and availability in the system of two-dimensional Duffing based on particle swarm ***,the influence of different parameters on the detection performance is analyzed *** correlation between parameter adjustment and stochastic resonance effect is also discussed and converted to the problem of multi-parameter ***,the experiments including typical system and sea clutter data are conducted to verify the effect of the proposed *** show that the proposed method is highly effective to detect weak signal from chaotic background,and enhance the output SNR greatly.

关键词： Adaptive stochastic resonance two-dimensional Duffing oscillator weak signal detection particle swarm optimization

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Hybrid inversion method for equivalent electric charge of thunder cloud based on multi-station atmospheric electric field

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Instrumentation 2015年第3期2卷 3-11页

作者： XING Hongyan ZHANG Qiang JI Xinyuan XU wei Collaborative Innovation Center on Forecast and Evaluation of meteorological Disasters Nanjing University of Information Science & Technology key laboratory of meteorological observation and information processing of jiangsu Province Nanjing University of Information Science & Technology

This article proposes the hybrid method to inverse the equivalent electric charge of thunder cloud based on the data of multi-station atmospheric electric field. Firstly,the method combines the genetic algorithm( GA) and New ton method through the mosaic hybrid structure. In addition,the thunder cloud equivalent charge is inversed based on the forw ard modeling results by giving the parameters of the thunder cloud charge structure. Then an ideal model is built to examine the performance compared to the nonlinear least squares method. Finally,a typical thunderstorms process in Nanjing is analyzed by Genetic-New ton algorithm with the help of weather radar. The results show the proposed method has the strong global searching capability so that the problem of initial value selection can be solved effectively,as well as gets the better inversion results. Furthermore,the mosaic hybrid structure can absorb the advantages of tw o algorithms better,and the inversion position is consistent with the strongest radar *** inversion results find the upper negative charge is small and can be ignored,w hich means the triple-polarity charge structure is relatively scientific,w hich could give some references to the research like lightning forecasting,location tracking.

关键词： inversion of thunder cloud equivalent charge atmospheric electric field genetic algorithm new ton method

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Frequency modulated weak signal detection based on stochastic resonance and genetic algorithm

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Instrumentation 2016年第1期3卷 41-49页

作者： XING Hongyan LU Chunxia ZHANG Qiang Collaborative Innovation Center on Forecast and Evaluation of meteorological Disasters Nanjing University of Information Science & Technology key laboratory of meteorological observation and information processing of jiangsu Province Nanjing University of Information Science & Technology

Stochastic resonance system is subject to the restriction of small frequency parameter in weak signal detection,in order to solve this problem,a frequency modulated weak signal detection method based on stochastic resonance and genetic algorithm is presented in this paper. The frequency limit of stochastic resonance is eliminated by introducing carrier signal,which is multiplied with the measured signal to be injected in the stochastic resonance system,meanwhile,using genetic algorithm to optimize the carrier signal frequency,which determine the generated difference-frequency signal in the lowfrequency range,so as to achieve the stochastic resonance weak signal detection. Results showthat the proposed method is feasible and effective,which can significantly improve the output SNR of stochastic resonance,in addition,the system has the better self-adaptability,according to the operation result and output phenomenon,the unknown frequency of the signal to be measured can be obtained,so as to realize the weak signal detection of arbitrary frequency.

关键词： stochastic resonance two-dimension Duffing oscillator frequency modulated genetic algorithm

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Modeling and Analysis of the Impacts of Temporal-Spatial Variant Troposphere on Ground-Based SAR Imaging of Asteroids

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Journal of Beijing Institute of Technology 2023年第6期32卷 727-739页

作者： Tingting Fu Yuanhao Li Zhiyang Chen Zheng Wu Cheng Hu Radar Research laboratory School of Information and ElectronicsBeijing Institute of TechnologyBeijing 100081China Beijing key laboratory of Embedded Real-time information processing Technology the Chongqing Institute of meteorological Sciences Chongqing 401147China

The near-Earth asteroid collisions could cause catastrophic disasters to humanity and the Earth,so it is crucial to monitor ***-based synthetic aperture radar(SAR)is an observation technique for high resolution imaging of *** ground-based SAR requires a long integration time to achieve a large synthetic aperture,and the echo signal will be seriously affected by temporal-spatial variant *** spatiotemporal freezing tropospheric models are *** cope with this,this paper models and analyses the impacts of temporal-spatial variant troposphere on ground-based SAR imaging of *** the background tropo-sphere,a temporal-spatial variant ray tracing method is proposed to trace the 4D(3D spatial+temporal)refractive index network provided by the numerical weather model,and calculate the error of the background *** the tropospheric turbulence,the Andrew power spectral model is used in conjunction with multiphase screen theory,and varying errors are obtained by tracking the changing position of the pierce point on the phase *** simulation,the impact of temporal-spatial variant tropospheric errors on image quality is analyzed,and the simulation results show that the X-band echo signal is seriously affected by the troposphere and the echo signal must be compensated.

关键词： near-Earth asteroids ground-based SAR troposphere ray tracing

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An observational Analysis of the Oceanic and Atmospheric Structure of Global-Scale Multi-decadal Variability

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Advances in Atmospheric Sciences 2014年第2期31卷 316-330页

作者： Peng LIU Chung-Hsiung SUI key laboratory of meteorological Disaster of Ministry of Education Nanjing University of Information Science & Technology department of Atmospheric Sciences NTU Taipei 10617

The aim of the present study was to identify multi-decadal variability （MDV） relative to the current centennial global warming trend in available observation *** centennial global wanning trend was first identified in the global mean surface temperature （STgm） *** MDV was identified based on three sets of climate variables,including sea surface temperature （SST）,ocean temperature from the surface to 700 m,and the NCEP and ERA40 reanalysis datasets,*** variables were detrended and low-pass *** three independent EOF analyses of the filtered variables,all results consistently showed two dominant modes,with their respective temporal variability resembling the Pacific Decadal Oscillation/Inter-decadal Pacific Oscillation （PDO/IPO） and the Atlantic Multi-decadal Oscillation （AMO）.The spatial structure of the PDO-like oscillation is characterized by an ENSO-like structure and hemispheric symmetric *** structure associated with the AMO-like oscillation exhibits hemispheric asymmetric features with anomalous warm air over Eurasia and warm SST in the Atlantic and Pacific basin north of 10°S,and cold SST over the southern *** Pacific and Atlantic MDV in upper-ocean temperature suggest that they are mutually *** also found that the PDO-like and AMO-like oscillations are almost equally important in global-scale MDV by EOF *** the period 1975-2005,the evolution of the two oscillations has given rise to strong temperature trends and has contributed almost half of the STgm ***,in the next decade,the two oscillations are expected to slow down the global warming trends.

关键词： global-scale multi-decadal variation global mean surface temperature PDO-like oscillation AMO-like oscillation

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