Using the data of the Lightning Location System( LLS) over Hubei Province,through the analysis of the distribution characteristics of CG( Cloud-to-Ground) flash density in 2015,it was found that the layout of the dete...Using the data of the Lightning Location System( LLS) over Hubei Province,through the analysis of the distribution characteristics of CG( Cloud-to-Ground) flash density in 2015,it was found that the layout of the detection station had influence on the spatial distribution of lightning.Grid CG flash density data were used to characterize the spatial distribution of the CG flash,and station distance factor was used to characterize the detection station layout. The result showed that there existed negative correlation between density and factor,significant correlation between the density component and the factor for the lightning current amplitude of 5 to 30 kA,and insignificant correlation between >30 kA of density component and factor. So it is necessary to revise the density to eliminate the influence of the station layout. On the basis of the linear regression method and its residual theory,the revision model of the grid CG flash density and the statistical model of relative detection efficiency were established. The result consistency of segment and non-segmented revision of the density was verified. Through the contrastive analysis of theoretical detection efficiency and relative detection efficiency,the feasibility for revision method of CG flash density and the statistical method of relative detection efficiency was also verified.展开更多
Based on the monitoring data of cloud-to-ground( CG) lightning positioning network and Doppler weather radar as well as MICAPS1°× 1° objective analysis field,a squall line process outside of the subtrop...Based on the monitoring data of cloud-to-ground( CG) lightning positioning network and Doppler weather radar as well as MICAPS1°× 1° objective analysis field,a squall line process outside of the subtropical high in low-latitude plateau on May 7,2010 was analyzed. The results showed that wind direction shear between low and high levels and low-level convergence zones provided favorable circulation background for the strong thunderstorm process,while high energy and high humidity,strong thermal instability and ascending motion at low and middle levels offered beneficial environmental conditions for the formation of the thunderstorm. 9 620 return strokes of cloud-to-ground lightning were monitored by the lightning positioning network,and cloud-to-ground lightning was distributed like bands between 584 and 586 hP a. The occurrence of cloud-to-ground lightning was mainly related to echo top and echo intensity at-10 ℃ stratification height,and it mainly appeared in zones where echo top height was larger than 13 km and echo intensity at-10 ℃ stratification height was 35-40 dB Z. Wind convergence and maintaining of high radial velocity were favorable for the development of convective echoes and occurrence of cloud-to-ground lightning.展开更多
There were three hailstorms in Shandong Province, caused by a same northeast cold eddy situation on 1 June 2002. Cloud-to-ground （CG） flashes occurring in the weather event were observed by Shandong Lightning Detect...There were three hailstorms in Shandong Province, caused by a same northeast cold eddy situation on 1 June 2002. Cloud-to-ground （CG） flashes occurring in the weather event were observed by Shandong Lightning Detection Network （SLDN）, which consists of 10 sensors covering all over Shandong Province. The temporal and spatial distributions of CG lightning are investigated for the three hailstorms by using the data from SLDN, Doppler radar and satellite. The results show that different thunderstorms present different lightning features even if under the same synoptic situation. The percentage of positive CG lightning is very high during the period of hail falling. CG flashes mainly occurred in the region with a cloud top brightness temperature lower than -50℃. Negative CG flashes usually clustered in the lower temperature region and tended to occur in the region with maximum temperature gradient, while the positive ones usually spread discretely. Negative CG flashes usually occurred in intense echo regions with reflectivity greater than 50 dBz, while the positive CG flashes often occurred in weak and stable echo regions （10-30 dBz） or cloud anvils, although they can be observed in strong convective regions sometimes. Almost all haft falling took place in the stage with active positive flashes, and the peak positive flash rate is a little prior to the hail events. The thunderstorm could lead to disastrous weather when positive CG lightning activities occur in cluster. Severe thunderstorms sometimes present a low flash rate at its vigorous stage, which is probably caused by the ＂mechanism of chargeregion lift＂ through investigating the reflectivity evolution. Combined with the total lightning （intracloud and CG） data obtained by LIS onboard TRMM, the phenomenon of high ratio of intracloud flash to CG flash in severe hailstorm has been discussed. The competition of the same charge sources between different lightning types can also be helpful for explaining the cause of low CG lightning activities in severe storms.展开更多
基于河北省电力部门2005—2014年16站闪电定位资料,对京津冀地区地闪频次和雷电流强度的时空分布特征进行统计分析。结果表明,京津冀地区正地闪占地闪总数的7.33%,该比率高于河南的3.16%,低于内蒙古高原的9.60%。地闪主要出现在夏季,占...基于河北省电力部门2005—2014年16站闪电定位资料,对京津冀地区地闪频次和雷电流强度的时空分布特征进行统计分析。结果表明,京津冀地区正地闪占地闪总数的7.33%,该比率高于河南的3.16%,低于内蒙古高原的9.60%。地闪主要出现在夏季,占全年的90.0%;春、秋两季,正地闪所占比率高于地闪频繁的夏季。地闪主要出现在15:00—19:00,最大值出现在16:00,其中正地闪的峰值比负地闪晚1 h。该地区50%以上的地闪雷电流强度集中在20~45 k A之间,其中负地闪与正地闪的平均雷电流强度分别为40.46 k A、74.16 k A,正地闪的平均雷电流强度是负地闪的1.8倍。3月的平均雷电流强度最大;上午的平均雷电流强度大于下午。地闪高密度区主要集中在燕山南麓和太行山东麓迎风坡面的山区与平原过渡区、下垫面水汽充足的水体和湿地区域以及人口相对集中的城市中心区;雷电流强度>80 k A的闪电主要分布在京津冀地区的东部沿海、河北中东部平原、张家口西北部以及承德北部,且闪电强度较大的地区闪电密度较小。唐山、保定、沧州地区处于地闪密度和地闪雷电流强度的高值区,该区域在建设工程的选址和防雷装置设计中应充分重视并加强对雷电灾害的防御措施。展开更多
通过对比分析2008年北京及其周边地区SAFIR(Surveillance et Alerte Foudre par Interferometrie Radiometrique)和ADTD(Advanced TOA and Direction system)两套闪电定位系统观测的地闪资料,结果显示:SAFIR系统探测的正地闪次数、负地...通过对比分析2008年北京及其周边地区SAFIR(Surveillance et Alerte Foudre par Interferometrie Radiometrique)和ADTD(Advanced TOA and Direction system)两套闪电定位系统观测的地闪资料,结果显示:SAFIR系统探测的正地闪次数、负地闪次数均比ADTD系统偏少,但二者探测到正地闪和负地闪的日变化、月变化特征基本一致。SAFIR系统探测的正地闪百分比ADTD高。SAFIR系统的地闪高值区主要在偏南部,而ADTD系统的正地闪电流强度高值区流高值区主要在偏北部,地闪低值区分布基本一致。SAFIR系统探测的正地闪、负地闪电流强度小于ADTD系统的观测值,前者探测的正地闪电流强度日分布中整体比后者小约25 k A,负地闪电流强度日分布则小约10 k A。二者观测的电流强度日变化、月变化变化特征基本一致。ADTD负地闪电流累积概率分布整体和IEEE工作组给出范围较为接近。SAFIR系统探测的正地闪电流强度高值区空间分布较集中,而ADTD系统的空间分布相对较均匀分散。整体而言,两者探测的闪电时间分布特征较为接近,而闪电次数和强度分布特征有差别,对于出现差别的原因有待进一步研究。展开更多
文摘Using the data of the Lightning Location System( LLS) over Hubei Province,through the analysis of the distribution characteristics of CG( Cloud-to-Ground) flash density in 2015,it was found that the layout of the detection station had influence on the spatial distribution of lightning.Grid CG flash density data were used to characterize the spatial distribution of the CG flash,and station distance factor was used to characterize the detection station layout. The result showed that there existed negative correlation between density and factor,significant correlation between the density component and the factor for the lightning current amplitude of 5 to 30 kA,and insignificant correlation between >30 kA of density component and factor. So it is necessary to revise the density to eliminate the influence of the station layout. On the basis of the linear regression method and its residual theory,the revision model of the grid CG flash density and the statistical model of relative detection efficiency were established. The result consistency of segment and non-segmented revision of the density was verified. Through the contrastive analysis of theoretical detection efficiency and relative detection efficiency,the feasibility for revision method of CG flash density and the statistical method of relative detection efficiency was also verified.
基金Supported by National Natural Science Foundation of China(No.41305002)Science and Technology Project of Yunnan Province(No.2014RA002,2016RA096)
文摘Based on the monitoring data of cloud-to-ground( CG) lightning positioning network and Doppler weather radar as well as MICAPS1°× 1° objective analysis field,a squall line process outside of the subtropical high in low-latitude plateau on May 7,2010 was analyzed. The results showed that wind direction shear between low and high levels and low-level convergence zones provided favorable circulation background for the strong thunderstorm process,while high energy and high humidity,strong thermal instability and ascending motion at low and middle levels offered beneficial environmental conditions for the formation of the thunderstorm. 9 620 return strokes of cloud-to-ground lightning were monitored by the lightning positioning network,and cloud-to-ground lightning was distributed like bands between 584 and 586 hP a. The occurrence of cloud-to-ground lightning was mainly related to echo top and echo intensity at-10 ℃ stratification height,and it mainly appeared in zones where echo top height was larger than 13 km and echo intensity at-10 ℃ stratification height was 35-40 dB Z. Wind convergence and maintaining of high radial velocity were favorable for the development of convective echoes and occurrence of cloud-to-ground lightning.
基金Supported by the National Natural Science Foundation of China under Grant Nos.40505001 and 40325013,and Meteorological Foundation of Shandong Province (2005sdqxj01).
文摘There were three hailstorms in Shandong Province, caused by a same northeast cold eddy situation on 1 June 2002. Cloud-to-ground （CG） flashes occurring in the weather event were observed by Shandong Lightning Detection Network （SLDN）, which consists of 10 sensors covering all over Shandong Province. The temporal and spatial distributions of CG lightning are investigated for the three hailstorms by using the data from SLDN, Doppler radar and satellite. The results show that different thunderstorms present different lightning features even if under the same synoptic situation. The percentage of positive CG lightning is very high during the period of hail falling. CG flashes mainly occurred in the region with a cloud top brightness temperature lower than -50℃. Negative CG flashes usually clustered in the lower temperature region and tended to occur in the region with maximum temperature gradient, while the positive ones usually spread discretely. Negative CG flashes usually occurred in intense echo regions with reflectivity greater than 50 dBz, while the positive CG flashes often occurred in weak and stable echo regions （10-30 dBz） or cloud anvils, although they can be observed in strong convective regions sometimes. Almost all haft falling took place in the stage with active positive flashes, and the peak positive flash rate is a little prior to the hail events. The thunderstorm could lead to disastrous weather when positive CG lightning activities occur in cluster. Severe thunderstorms sometimes present a low flash rate at its vigorous stage, which is probably caused by the ＂mechanism of chargeregion lift＂ through investigating the reflectivity evolution. Combined with the total lightning （intracloud and CG） data obtained by LIS onboard TRMM, the phenomenon of high ratio of intracloud flash to CG flash in severe hailstorm has been discussed. The competition of the same charge sources between different lightning types can also be helpful for explaining the cause of low CG lightning activities in severe storms.
文摘基于河北省电力部门2005—2014年16站闪电定位资料,对京津冀地区地闪频次和雷电流强度的时空分布特征进行统计分析。结果表明,京津冀地区正地闪占地闪总数的7.33%,该比率高于河南的3.16%,低于内蒙古高原的9.60%。地闪主要出现在夏季,占全年的90.0%;春、秋两季,正地闪所占比率高于地闪频繁的夏季。地闪主要出现在15:00—19:00,最大值出现在16:00,其中正地闪的峰值比负地闪晚1 h。该地区50%以上的地闪雷电流强度集中在20~45 k A之间,其中负地闪与正地闪的平均雷电流强度分别为40.46 k A、74.16 k A,正地闪的平均雷电流强度是负地闪的1.8倍。3月的平均雷电流强度最大;上午的平均雷电流强度大于下午。地闪高密度区主要集中在燕山南麓和太行山东麓迎风坡面的山区与平原过渡区、下垫面水汽充足的水体和湿地区域以及人口相对集中的城市中心区;雷电流强度>80 k A的闪电主要分布在京津冀地区的东部沿海、河北中东部平原、张家口西北部以及承德北部,且闪电强度较大的地区闪电密度较小。唐山、保定、沧州地区处于地闪密度和地闪雷电流强度的高值区,该区域在建设工程的选址和防雷装置设计中应充分重视并加强对雷电灾害的防御措施。
文摘通过对比分析2008年北京及其周边地区SAFIR(Surveillance et Alerte Foudre par Interferometrie Radiometrique)和ADTD(Advanced TOA and Direction system)两套闪电定位系统观测的地闪资料,结果显示:SAFIR系统探测的正地闪次数、负地闪次数均比ADTD系统偏少,但二者探测到正地闪和负地闪的日变化、月变化特征基本一致。SAFIR系统探测的正地闪百分比ADTD高。SAFIR系统的地闪高值区主要在偏南部,而ADTD系统的正地闪电流强度高值区流高值区主要在偏北部,地闪低值区分布基本一致。SAFIR系统探测的正地闪、负地闪电流强度小于ADTD系统的观测值,前者探测的正地闪电流强度日分布中整体比后者小约25 k A,负地闪电流强度日分布则小约10 k A。二者观测的电流强度日变化、月变化变化特征基本一致。ADTD负地闪电流累积概率分布整体和IEEE工作组给出范围较为接近。SAFIR系统探测的正地闪电流强度高值区空间分布较集中,而ADTD系统的空间分布相对较均匀分散。整体而言,两者探测的闪电时间分布特征较为接近,而闪电次数和强度分布特征有差别,对于出现差别的原因有待进一步研究。
