By using monitoring data of lightning locating system in Hebei during 1999- 2010 and lightning disaster data in Hebei during 2002- 2010,temporal-spatial distribution characteristics of ground flash and lightning disas...By using monitoring data of lightning locating system in Hebei during 1999- 2010 and lightning disaster data in Hebei during 2002- 2010,temporal-spatial distribution characteristics of ground flash and lightning disaster in Hebei Province were analyzed. Annual,monthly and daily changes of ground flash,lightning current intensity and ground flash density in Hebei were analyzed,and we compared ground flash with lightning disaster distribution.展开更多
The problems in calculating parameters of equivalent collection area,earth resistivity and lightning protection category as well as their effects on lightning disaster risk assessment were analyzed,and practical examp...The problems in calculating parameters of equivalent collection area,earth resistivity and lightning protection category as well as their effects on lightning disaster risk assessment were analyzed,and practical examples proved the effects of those differences on lightning protection identification,intercept efficiency calculation in evaluating lightning disaster risk. In the meantime,several new concepts,such as the height of buildings for lightning protection were defined,and a fixed radius value was set to the ground flash density for calculation,establishing the ground flash density formula to solve the problems in parameter calculation,which would be beneficial to promote the standardization of lightning disaster risk assessment.展开更多
Based on the relationship between lightning flash density and radar echoes and a statistical analysis using satellite and radar observations,a scheme was introduced into the mesoscale model GRAPES（Global and Regional...Based on the relationship between lightning flash density and radar echoes and a statistical analysis using satellite and radar observations,a scheme was introduced into the mesoscale model GRAPES（Global and Regional Assimilation and PrEdiction System）to forecast the cloud to ground（CC）flash activities.Because the relationship is a necessary but not sufficient condition for lightning,an additional constraint condition related to temperature of cloud top is added into the scheme to determine whether the lightning activity really occurs.Only if the lightning activity meets the criterion to occur,the CG flash density in a grid is considered to be valid.This was proved to be necessary for reducing the false prediction.Two cases that occurred on the edge of the subtropical high in coastal regions of South China were simulated to examine the efficiency of the scheme.The results showed that the scheme was capable of forecasting lightning activities in South China.The simulated lightning areas agreed with the CG flash observations,and the CG flash density forecast by the model was also consistent with observational results in magnitude.In consideration of the forecast aging of the explicit cloud microphysical scheme in GRAPES,lightning activities can now be forecast accurately within 6 h.展开更多
文摘By using monitoring data of lightning locating system in Hebei during 1999- 2010 and lightning disaster data in Hebei during 2002- 2010,temporal-spatial distribution characteristics of ground flash and lightning disaster in Hebei Province were analyzed. Annual,monthly and daily changes of ground flash,lightning current intensity and ground flash density in Hebei were analyzed,and we compared ground flash with lightning disaster distribution.
文摘The problems in calculating parameters of equivalent collection area,earth resistivity and lightning protection category as well as their effects on lightning disaster risk assessment were analyzed,and practical examples proved the effects of those differences on lightning protection identification,intercept efficiency calculation in evaluating lightning disaster risk. In the meantime,several new concepts,such as the height of buildings for lightning protection were defined,and a fixed radius value was set to the ground flash density for calculation,establishing the ground flash density formula to solve the problems in parameter calculation,which would be beneficial to promote the standardization of lightning disaster risk assessment.
基金Supported by the National Science & Technology Pillar Program of Ministry of Finance under Grant No.2008BAC36B04the National Natural Science Foundation of China under Grant No.40875003the Basic Scientific Research and Operation Fund of Chinese Academy of Meteorological Sciences under Grant No.2008Y003
文摘Based on the relationship between lightning flash density and radar echoes and a statistical analysis using satellite and radar observations,a scheme was introduced into the mesoscale model GRAPES（Global and Regional Assimilation and PrEdiction System）to forecast the cloud to ground（CC）flash activities.Because the relationship is a necessary but not sufficient condition for lightning,an additional constraint condition related to temperature of cloud top is added into the scheme to determine whether the lightning activity really occurs.Only if the lightning activity meets the criterion to occur,the CG flash density in a grid is considered to be valid.This was proved to be necessary for reducing the false prediction.Two cases that occurred on the edge of the subtropical high in coastal regions of South China were simulated to examine the efficiency of the scheme.The results showed that the scheme was capable of forecasting lightning activities in South China.The simulated lightning areas agreed with the CG flash observations,and the CG flash density forecast by the model was also consistent with observational results in magnitude.In consideration of the forecast aging of the explicit cloud microphysical scheme in GRAPES,lightning activities can now be forecast accurately within 6 h.
