This study utilizes data from a 3D lightning location system,polarimetric radar,and current measurements from channels of triggered lightning flashes(TLFs)to analyze the structural characteristics of the parent thunde...This study utilizes data from a 3D lightning location system,polarimetric radar,and current measurements from channels of triggered lightning flashes(TLFs)to analyze the structural characteristics of the parent thunderstorms associated with negative TLFs in South China.The triggered-flash region(TFR)displays distinct stratiform cloud characteristics,including lower radar reflectivity heights and a predominance of ice crystals and dry snow above the 0℃ layer.In contrast,the thunderstorm convection core region(CCR)tends to have more graupel particles in the mixed-phase layers and exhibits an ice-water content peak approximately 3.4 times that of the TFR.The charge regions involved in discharges in TFRs exhibit a dipolar charge structure,with the-5℃ layer roughly dividing the upper positive and lower negative charge regions.Conversely,the CCRs feature a typical tripolar charge structure.The dominant dipole charge structure in the TFR results in an increase in the negative charge field below the negative charge region with height,providing a necessary condition for successfully triggering negative TLFs.Furthermore,the horizontal extent of TLFs is positively correlated with their duration and charge transfer.Regions where TLF channels with larger charge transfers propagate tend to have greater maximum radar reflectivity but lower average radar reflectivity compared to regions with TLFs with smaller charge transfer.展开更多
Based on the lightning monitoring data, automatic and routine weather station observation data in spring （March-May） of 2013 of Sichuan Province, the corresponding relationship between the spatial distribution and t...Based on the lightning monitoring data, automatic and routine weather station observation data in spring （March-May） of 2013 of Sichuan Province, the corresponding relationship between the spatial distribution and the different regions, and the characteristics of atmospheric circulation and evolution of influence the sys- tem were analyzed and summarized. The results show that： the lightning and thunderstorm showed great regional differences in the spring of 2013 in Sichuan Province and the thunderstorm activity period was not the same in different areas. Because of the change of atmospheric circulation, the influence system from March to May corresponding to the thunderstorms in Sichuan tended to be volatile, also.展开更多
By dint of natural orthogonal function(EOF) decomposition,correlation and trend analysis methods,the temporal and spatial variation characteristics of thunderstorms in recent 46 years in Henan Province were analyzed.T...By dint of natural orthogonal function(EOF) decomposition,correlation and trend analysis methods,the temporal and spatial variation characteristics of thunderstorms in recent 46 years in Henan Province were analyzed.The result showed that the thunderstorms in Henan Province decreased gradually from the northwest region to the southeast region and the frequency of thunderstorms in the southeast area was relatively high.The thunderstorm intensity area was in its horizontal distribution.Thunderstorms acted relative actively in 60s and tended to dwindle in the end of 80s.While in recent years,the thunderstorms tended to increase and started act frequently.Since March to August in every year,thunderstorms multiplied in each region and decreased after September.The period between 16:00 to 20:00 was the high peak hours of thunderstorms every year.Thunderstorms distribution in Henan Province had pretty good consistence,increasing and decreasing at the same time.The annual variation of thunderstorms showed an unobvious decreasing tendency.展开更多
Three summer thunderstorms in the eastern region of China were analyzed in detail using multiple data, including Doppler radar, lightning location network, TRMM （Tropical Rainfall Measuring Mission）, MT- SAT （Multi...Three summer thunderstorms in the eastern region of China were analyzed in detail using multiple data, including Doppler radar, lightning location network, TRMM （Tropical Rainfall Measuring Mission）, MT- SAT （Multi-Function Transport Satellite） images, NCEP （National Centers for Environmental Prediction） Reanalysis, and radiosonde. Two of the three storms were sprite-producing and the other was non-sprite- producing. The two sprite-producing storms occurred on 1 2 August and 2~28 July 2007, producing 16 and one sprite, respectively. The non-sprite-producing storm occurred on 29-30 July 2007. The major ob- jective of the study was to try to find possible differences between sprite-producing and non-sprite producing storms using the multiple datasets. The results showed that the convection in the 1-2 August storm was the strongest compared with the other storms, and it produced the largest number of sprites. Precipitation ice, cloud ice and cloud water content in the convective regions in the 1-2 August storm were larger than in the other two storms, but the opposite was true in the weak convective regions. The storm microphysical prop- erties along lines through parent CG （cloud-to-ground lightning） locations showed no special characteristics related to sprites. The flash rate evolution in the 1-2 August storm provided additional confirmation that major sprite activity coincides with a rapid decrease in the negative CG flash rate. However, the evolution curve of the CG flash rate was erratic in the sprite-producing storm on 27-28 July, which was significantly different from that in the 1 2 August storm. The average positive CG peak current in sprite-producing storms was larger than that in the non-sprite-producing one.展开更多
The Tibetan Plateau, with an average altitude above 4000 m, is the highest and largest plateau in the world. The frequency of thunderstorms in this region is extremely high. Many indices are used in operational foreca...The Tibetan Plateau, with an average altitude above 4000 m, is the highest and largest plateau in the world. The frequency of thunderstorms in this region is extremely high. Many indices are used in operational forecasting to assess the stability of the atmosphere and predict the probability of severe thunderstorm development. One of the disadvantages of many of these indices is that they are mainly based on observations from plains. However, considering the Plateau＇s high elevation, most convective parameters cannot be applied directly, or their application is ineffective. The pre-convective environment on thunderstorm days in this region is investigated based on sounding data obtained throughout a five-year period（2006–10）.Thunderstorms occur over the Tibetan Plateau under conditions that differ strikingly from those in plains. On this basis,stability indices, such as the Showalter index（including SI and SICCL）, and the K index are improved to better assess the thunderstorm environments on the Plateau. Verification parameters, such as the true-skill statistic（TSS） and Heidke skill score（HSS）, are adopted to evaluate the optimal thresholds and relative forecast skill for each modified index. Lastly, the modified indices are verified with a two-year independent dataset（2011–12）, showing satisfactory results for the modified indices. For determining whether or not a thunderstorm day is likely to occur, we recommend the modified SICCLindex.展开更多
基金funded by the Natural Science Foundation of China(Grant No.U2342215)Key Laboratory of South China Sea Meteorological Disaster Prevention and Mitigation of Hainan Province(Grant No.SCSF202302)。
文摘This study utilizes data from a 3D lightning location system,polarimetric radar,and current measurements from channels of triggered lightning flashes(TLFs)to analyze the structural characteristics of the parent thunderstorms associated with negative TLFs in South China.The triggered-flash region(TFR)displays distinct stratiform cloud characteristics,including lower radar reflectivity heights and a predominance of ice crystals and dry snow above the 0℃ layer.In contrast,the thunderstorm convection core region(CCR)tends to have more graupel particles in the mixed-phase layers and exhibits an ice-water content peak approximately 3.4 times that of the TFR.The charge regions involved in discharges in TFRs exhibit a dipolar charge structure,with the-5℃ layer roughly dividing the upper positive and lower negative charge regions.Conversely,the CCRs feature a typical tripolar charge structure.The dominant dipole charge structure in the TFR results in an increase in the negative charge field below the negative charge region with height,providing a necessary condition for successfully triggering negative TLFs.Furthermore,the horizontal extent of TLFs is positively correlated with their duration and charge transfer.Regions where TLF channels with larger charge transfers propagate tend to have greater maximum radar reflectivity but lower average radar reflectivity compared to regions with TLFs with smaller charge transfer.
文摘Based on the lightning monitoring data, automatic and routine weather station observation data in spring （March-May） of 2013 of Sichuan Province, the corresponding relationship between the spatial distribution and the different regions, and the characteristics of atmospheric circulation and evolution of influence the sys- tem were analyzed and summarized. The results show that： the lightning and thunderstorm showed great regional differences in the spring of 2013 in Sichuan Province and the thunderstorm activity period was not the same in different areas. Because of the change of atmospheric circulation, the influence system from March to May corresponding to the thunderstorms in Sichuan tended to be volatile, also.
基金Supported by Scientific Research Special Fund for Public Welfare Industry (GYHY 200806014)Nanjing University of Information Science & Technology Program (E30JG0730)
文摘By dint of natural orthogonal function(EOF) decomposition,correlation and trend analysis methods,the temporal and spatial variation characteristics of thunderstorms in recent 46 years in Henan Province were analyzed.The result showed that the thunderstorms in Henan Province decreased gradually from the northwest region to the southeast region and the frequency of thunderstorms in the southeast area was relatively high.The thunderstorm intensity area was in its horizontal distribution.Thunderstorms acted relative actively in 60s and tended to dwindle in the end of 80s.While in recent years,the thunderstorms tended to increase and started act frequently.Since March to August in every year,thunderstorms multiplied in each region and decreased after September.The period between 16:00 to 20:00 was the high peak hours of thunderstorms every year.Thunderstorms distribution in Henan Province had pretty good consistence,increasing and decreasing at the same time.The annual variation of thunderstorms showed an unobvious decreasing tendency.
基金supported jointly by Strategic Priority Research Program on Space Science(Grant No.XDA04072400)Project Supported by the Specialized Research Fund for State Key Laboratories,Youth Innovation Promotion Association,CAS,National Basic Research Program of China(973 Program,Grant No.2010CB428602)+2 种基金the Special Fund for Public Welfare Industry(GYHY201006005-07)National Natural Science Foundation of China(Grant Nos.41374153,40930949,40804028)Beijing Natural Science Foundation
文摘Three summer thunderstorms in the eastern region of China were analyzed in detail using multiple data, including Doppler radar, lightning location network, TRMM （Tropical Rainfall Measuring Mission）, MT- SAT （Multi-Function Transport Satellite） images, NCEP （National Centers for Environmental Prediction） Reanalysis, and radiosonde. Two of the three storms were sprite-producing and the other was non-sprite- producing. The two sprite-producing storms occurred on 1 2 August and 2~28 July 2007, producing 16 and one sprite, respectively. The non-sprite-producing storm occurred on 29-30 July 2007. The major ob- jective of the study was to try to find possible differences between sprite-producing and non-sprite producing storms using the multiple datasets. The results showed that the convection in the 1-2 August storm was the strongest compared with the other storms, and it produced the largest number of sprites. Precipitation ice, cloud ice and cloud water content in the convective regions in the 1-2 August storm were larger than in the other two storms, but the opposite was true in the weak convective regions. The storm microphysical prop- erties along lines through parent CG （cloud-to-ground lightning） locations showed no special characteristics related to sprites. The flash rate evolution in the 1-2 August storm provided additional confirmation that major sprite activity coincides with a rapid decrease in the negative CG flash rate. However, the evolution curve of the CG flash rate was erratic in the sprite-producing storm on 27-28 July, which was significantly different from that in the 1 2 August storm. The average positive CG peak current in sprite-producing storms was larger than that in the non-sprite-producing one.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41275128, 41375063 and 41206163)the Chengdu Institute of Plateau Meteorology Foundation
文摘The Tibetan Plateau, with an average altitude above 4000 m, is the highest and largest plateau in the world. The frequency of thunderstorms in this region is extremely high. Many indices are used in operational forecasting to assess the stability of the atmosphere and predict the probability of severe thunderstorm development. One of the disadvantages of many of these indices is that they are mainly based on observations from plains. However, considering the Plateau＇s high elevation, most convective parameters cannot be applied directly, or their application is ineffective. The pre-convective environment on thunderstorm days in this region is investigated based on sounding data obtained throughout a five-year period（2006–10）.Thunderstorms occur over the Tibetan Plateau under conditions that differ strikingly from those in plains. On this basis,stability indices, such as the Showalter index（including SI and SICCL）, and the K index are improved to better assess the thunderstorm environments on the Plateau. Verification parameters, such as the true-skill statistic（TSS） and Heidke skill score（HSS）, are adopted to evaluate the optimal thresholds and relative forecast skill for each modified index. Lastly, the modified indices are verified with a two-year independent dataset（2011–12）, showing satisfactory results for the modified indices. For determining whether or not a thunderstorm day is likely to occur, we recommend the modified SICCLindex.
