Aiming at the needs of mechanism analysis of rainstorms and development of numerical prediction models in south China, the Guangzhou Institute of Tropical and Marine Meteorology of China Meteorological Administration ...Aiming at the needs of mechanism analysis of rainstorms and development of numerical prediction models in south China, the Guangzhou Institute of Tropical and Marine Meteorology of China Meteorological Administration and the Chinese Academy of Meteorological Sciences jointly set up the Longmen Cloud Physics Field Experiment Base,China Meteorological Administration. This paper introduces the instruments and field experiments of this base, provides an overview of the recent advances in retrieval algorithms of microphysical parameters, improved understanding of microphysical characteristics, as well as the formation mechanisms and numerical prediction of heavy rainfalls in south China based on the field experiments dataset.展开更多
利用基于中尺度数值模式WRF(Weather Research and Forecast)的集合卡尔曼滤波(EnKF,Ensemble Kalman Filter)同化系统直接同化广东地区雷达反射率资料,对2017年台风“天鸽”(1713,Hato)近海发展以及降水预报效果进行数值模拟分析研究...利用基于中尺度数值模式WRF(Weather Research and Forecast)的集合卡尔曼滤波(EnKF,Ensemble Kalman Filter)同化系统直接同化广东地区雷达反射率资料,对2017年台风“天鸽”(1713,Hato)近海发展以及降水预报效果进行数值模拟分析研究。结果显示,直接同化雷达反射率资料后,台风的回波强度和范围有了明显改善,可更好地调整水汽场、水凝物和温度场。当台风风场和水汽场调整后,进入台风主体部分的水汽量显著增加,使得台风强度增强,台风中心最低海平面气压降低,与实况更接近。同化雷达反射率资料后,6 h和24 h降水强度和落区预报效果有显著改善,尤其是能提高大暴雨和特大暴雨量级的TS评分,此外地面2 m温度和2 m相对湿度的预报效果也有改进。展开更多
The objective of this research was to acquire a raindrop size distribution(DSDs)retrieved from C-band polarimetric radar observations scheme for the first time in south China.An observation period of the precipitation...The objective of this research was to acquire a raindrop size distribution(DSDs)retrieved from C-band polarimetric radar observations scheme for the first time in south China.An observation period of the precipitation process was selected,and the shape-slope(μ-Λ)relationship of this region was statistically analyzed using the raindrop sample observations from the two-dimensional video disdrometer(2DVD)at Xinfeng Station,Guangdong Province.Simulated data of the C-band polarimetric radar reflectivity ZHHand differential reflectivity ZDRwere obtained through scattering simulation.The simulation data were combined with DSD fitting to determine the ZDR-Λand log10(ZHH/N0)-Λrelationships.Using Xinfeng C-band polarimetric radar observations ZDRand ZHH,the raindrop Gamma size distribution parametersμ,Λ,and N0were retrieved.A scheme for using C-band polarimetric radar to retrieve the DSDs was developed.This research revealed that during precipitation process,the DSDs obtained using the C-band polarimetric radar retrieval scheme are similar to the 2DVD observations,the precipitation characteristics of rainfall intensity(R),mass-weighted mean diameter(Dm)and intercept parameter(Nw)with time obtained by radar retrieval are basically consistent with the observational results of the 2DVD.This scheme establishes the relationship between the observations of the C-band polarimetric radar and the physical quantities of the numerical model.This method not only can test the prediction of the model data assimilation system on the convective scale and determine error sources,but also can improve the microphysical precipitation processes analysis and radar quantitative precipitation estimation.The present research will facilitate radar data assimilation in the future.展开更多
The clinical efficacy was compared between 3D navigation-assisted percutaneous iliosacral screw(3DPS)and minimally invasive reconstruction plate(MIRP)in treating sacroiliac complex injury and the surgical procedures o...The clinical efficacy was compared between 3D navigation-assisted percutaneous iliosacral screw(3DPS)and minimally invasive reconstruction plate(MIRP)in treating sacroiliac complex injury and the surgical procedures of 3DPS were introduced.A retrospective analysis was performed on 49 patients with sacroiliac complex injury from March 2013 to May 2017.Twenty-one cases were treated by 3DPS,and 28 cases by MIRP.Intraoperative indexes as operative time,blood loss,incision length,length of hospital stay and postoperative complications were respectively documented.Quality of reduction was postoperatively evaluated by Matta radiological criteria,and clinical effect was assessed by Majeed scoring criteria at the last followup.Operative time and hospital stay were significantly shortened,and blood loss,and incision length were significantly reduced in 3DPS group as compared with those in MIRP group(P<0.05).No statistically significant difference was found between 3DPS group and MIRP group in the assessment of reduction and function(P>0.05).It was concluded that both 3DPS and MIRP can effectively treat the sacroiliac complex injury,and 3DPS can provide an accurate,safe and minimally invasive fixation with shorter operative time and hospital stay.展开更多
To the Editor:Lumbar spinal canal stenosis(LSCS)is a common disease among older individuals.Hypertrophic lumbar ligamentum flavum(LLF)plays a vital role in the pathogenesis of LSCS.The physiological LLF is a kind of d...To the Editor:Lumbar spinal canal stenosis(LSCS)is a common disease among older individuals.Hypertrophic lumbar ligamentum flavum(LLF)plays a vital role in the pathogenesis of LSCS.The physiological LLF is a kind of dense connective tissue with thickness of 2 to 4mm,which is mainly composed of fibroblasts and extracellular matrix(ECM).ECM contains elastic,collagen fibers and ground substances.The distribution characteristics of fibers show that a large number of elastic fibers are mixed with a small amount of the collagen fibers;mainly type I and type III collagen fibers.These fibers are arranged tightly and regularly along the direction of column’s axis.The LLF is located in the dorsal part of the dura mater of the spinal canal,and it attaches to the upper border and lower parts of anterior surfaces of the laminas.The hypotrophy of LLF is the consequence of several factors such as aging,inflammatory process,stress loading and genetic predisposition.展开更多
基金National Natural Science Foundation of China(U22422203,42030610,41975138,41975046,42075086,42275008)the High-level Science and Technology Journals Projects of Guangdong Province(214040990009)+1 种基金National Key Research and Development Program of China under Grant(2017YFC1501701,2017YFC1501703)Science and Technology Foundation of CAMS(2020KJ021)。
文摘Aiming at the needs of mechanism analysis of rainstorms and development of numerical prediction models in south China, the Guangzhou Institute of Tropical and Marine Meteorology of China Meteorological Administration and the Chinese Academy of Meteorological Sciences jointly set up the Longmen Cloud Physics Field Experiment Base,China Meteorological Administration. This paper introduces the instruments and field experiments of this base, provides an overview of the recent advances in retrieval algorithms of microphysical parameters, improved understanding of microphysical characteristics, as well as the formation mechanisms and numerical prediction of heavy rainfalls in south China based on the field experiments dataset.
文摘利用基于中尺度数值模式WRF(Weather Research and Forecast)的集合卡尔曼滤波(EnKF,Ensemble Kalman Filter)同化系统直接同化广东地区雷达反射率资料,对2017年台风“天鸽”(1713,Hato)近海发展以及降水预报效果进行数值模拟分析研究。结果显示,直接同化雷达反射率资料后,台风的回波强度和范围有了明显改善,可更好地调整水汽场、水凝物和温度场。当台风风场和水汽场调整后,进入台风主体部分的水汽量显著增加,使得台风强度增强,台风中心最低海平面气压降低,与实况更接近。同化雷达反射率资料后,6 h和24 h降水强度和落区预报效果有显著改善,尤其是能提高大暴雨和特大暴雨量级的TS评分,此外地面2 m温度和2 m相对湿度的预报效果也有改进。
基金National Key R&D Program of China(2018YFC1507401)Science and Technology Planning Project of Guangdong Province(2017B020244002)+1 种基金National Natural Science Foundation of China(41975138,41705020)Natural Science Foundation of Guangdong Province(2019A1515010814)。
文摘The objective of this research was to acquire a raindrop size distribution(DSDs)retrieved from C-band polarimetric radar observations scheme for the first time in south China.An observation period of the precipitation process was selected,and the shape-slope(μ-Λ)relationship of this region was statistically analyzed using the raindrop sample observations from the two-dimensional video disdrometer(2DVD)at Xinfeng Station,Guangdong Province.Simulated data of the C-band polarimetric radar reflectivity ZHHand differential reflectivity ZDRwere obtained through scattering simulation.The simulation data were combined with DSD fitting to determine the ZDR-Λand log10(ZHH/N0)-Λrelationships.Using Xinfeng C-band polarimetric radar observations ZDRand ZHH,the raindrop Gamma size distribution parametersμ,Λ,and N0were retrieved.A scheme for using C-band polarimetric radar to retrieve the DSDs was developed.This research revealed that during precipitation process,the DSDs obtained using the C-band polarimetric radar retrieval scheme are similar to the 2DVD observations,the precipitation characteristics of rainfall intensity(R),mass-weighted mean diameter(Dm)and intercept parameter(Nw)with time obtained by radar retrieval are basically consistent with the observational results of the 2DVD.This scheme establishes the relationship between the observations of the C-band polarimetric radar and the physical quantities of the numerical model.This method not only can test the prediction of the model data assimilation system on the convective scale and determine error sources,but also can improve the microphysical precipitation processes analysis and radar quantitative precipitation estimation.The present research will facilitate radar data assimilation in the future.
文摘The clinical efficacy was compared between 3D navigation-assisted percutaneous iliosacral screw(3DPS)and minimally invasive reconstruction plate(MIRP)in treating sacroiliac complex injury and the surgical procedures of 3DPS were introduced.A retrospective analysis was performed on 49 patients with sacroiliac complex injury from March 2013 to May 2017.Twenty-one cases were treated by 3DPS,and 28 cases by MIRP.Intraoperative indexes as operative time,blood loss,incision length,length of hospital stay and postoperative complications were respectively documented.Quality of reduction was postoperatively evaluated by Matta radiological criteria,and clinical effect was assessed by Majeed scoring criteria at the last followup.Operative time and hospital stay were significantly shortened,and blood loss,and incision length were significantly reduced in 3DPS group as compared with those in MIRP group(P<0.05).No statistically significant difference was found between 3DPS group and MIRP group in the assessment of reduction and function(P>0.05).It was concluded that both 3DPS and MIRP can effectively treat the sacroiliac complex injury,and 3DPS can provide an accurate,safe and minimally invasive fixation with shorter operative time and hospital stay.
基金supported by the grants from the Scientific Research Grant of Health and Family Planning Commission of Wuhan Municipality(No.WX19B06)the Health Commission of Hubei Province Scientific Research Project(No.WJ2019H429).
文摘To the Editor:Lumbar spinal canal stenosis(LSCS)is a common disease among older individuals.Hypertrophic lumbar ligamentum flavum(LLF)plays a vital role in the pathogenesis of LSCS.The physiological LLF is a kind of dense connective tissue with thickness of 2 to 4mm,which is mainly composed of fibroblasts and extracellular matrix(ECM).ECM contains elastic,collagen fibers and ground substances.The distribution characteristics of fibers show that a large number of elastic fibers are mixed with a small amount of the collagen fibers;mainly type I and type III collagen fibers.These fibers are arranged tightly and regularly along the direction of column’s axis.The LLF is located in the dorsal part of the dura mater of the spinal canal,and it attaches to the upper border and lower parts of anterior surfaces of the laminas.The hypotrophy of LLF is the consequence of several factors such as aging,inflammatory process,stress loading and genetic predisposition.
