Volume 37,Issue 6,2009 Table of Contents
2009, 37(6):641-645.
Abstract:
The Secondgeneration Sourcestrength Inversed Model 2 (SSIM2) is introduced, which depends on the meteorological background field supplied by MM5, and estimates the initial distribution of air pollutant sources by using the Avalue method of atmospheric environmental capacity, then calculates the concentration of air pollutants, and corrects the estimated distribution of air pollutant sources repeatedly until the distribution satisfies that the deviation between simulated and target concentrations is less than 5 percent on each grid point of the model domain. The verification by the air pollutant emission inventory of Changzhi in Shanxi province shows that the inversed distribution of air pollutants is much closer to the real one. The application of SSIM2 to the atmospheric environmental impact assessment for the urban planning of Tianjing and Suzhou shows that SSIM2 can provide a scientific basis for the allocation plan of air pollutant sources and the construction planning of new urban development zones.
The Secondgeneration Sourcestrength Inversed Model 2 (SSIM2) is introduced, which depends on the meteorological background field supplied by MM5, and estimates the initial distribution of air pollutant sources by using the Avalue method of atmospheric environmental capacity, then calculates the concentration of air pollutants, and corrects the estimated distribution of air pollutant sources repeatedly until the distribution satisfies that the deviation between simulated and target concentrations is less than 5 percent on each grid point of the model domain. The verification by the air pollutant emission inventory of Changzhi in Shanxi province shows that the inversed distribution of air pollutants is much closer to the real one. The application of SSIM2 to the atmospheric environmental impact assessment for the urban planning of Tianjing and Suzhou shows that SSIM2 can provide a scientific basis for the allocation plan of air pollutant sources and the construction planning of new urban development zones.
2009, 37(6):646-650.
Abstract:
A summary is made of studies about acetate and formate in precipitation across the world. Some details of sample preparation and experimental methods used in the analysis of organic acids in rainwater are given. The spatialtemporal distributions of acetic and formic acids are summarized. The observed levels of these acids, together with their theoretical contributions at different levels of pH value, indicate that these acids are important contributors to the acidity of precipitation. The sources of the two organic acids, which can be categorized as natural, anthropogenic, and chemical sources, and their meaning to the other organic acid researches are discussed.
A summary is made of studies about acetate and formate in precipitation across the world. Some details of sample preparation and experimental methods used in the analysis of organic acids in rainwater are given. The spatialtemporal distributions of acetic and formic acids are summarized. The observed levels of these acids, together with their theoretical contributions at different levels of pH value, indicate that these acids are important contributors to the acidity of precipitation. The sources of the two organic acids, which can be categorized as natural, anthropogenic, and chemical sources, and their meaning to the other organic acid researches are discussed.
2009, 37(6):651-655.
Abstract:
A survey is made of the quality of purified water used in the in the Acid Rain Monitoring Network of China Meteorological Administration (CMA) based on the station reports from 2006 to 2008. Statistics show that the quality of purified water has been improved gradually since the enforcement of the Standard Operation Manual (SOP) for Acid Rain Monitoring issued by CMA in 2005. Averagely, for the three years, the quality of purified water for 95% of stations meets the threshold requirement (conductivity less than 10 μS·cm-1) of SOP, and that for 83% of stations reaches the target requirement (conductivity less than 5 μS·cm-1). The sources of purified water can be roughly classified into four categories, i.e., selfmade distillated water at station, commercialavailable purified drinking water, distillated water from hospitals, and purified/distillated water from different factories/agencies. The percentage of commercialavailable purified drinking water in the total tends to increase in the last three years, and that of distillated water from hospitals decreasing accordingly. Among the four categories of purified water sources, the quality of the commercial available purified drinking water and that of the distillated water from hospitals are relatively good, and that of the selfmade distillated water is relatively poor as expected.
A survey is made of the quality of purified water used in the in the Acid Rain Monitoring Network of China Meteorological Administration (CMA) based on the station reports from 2006 to 2008. Statistics show that the quality of purified water has been improved gradually since the enforcement of the Standard Operation Manual (SOP) for Acid Rain Monitoring issued by CMA in 2005. Averagely, for the three years, the quality of purified water for 95% of stations meets the threshold requirement (conductivity less than 10 μS·cm-1) of SOP, and that for 83% of stations reaches the target requirement (conductivity less than 5 μS·cm-1). The sources of purified water can be roughly classified into four categories, i.e., selfmade distillated water at station, commercialavailable purified drinking water, distillated water from hospitals, and purified/distillated water from different factories/agencies. The percentage of commercialavailable purified drinking water in the total tends to increase in the last three years, and that of distillated water from hospitals decreasing accordingly. Among the four categories of purified water sources, the quality of the commercial available purified drinking water and that of the distillated water from hospitals are relatively good, and that of the selfmade distillated water is relatively poor as expected.
2009, 37(6):656-659.
Abstract:
The continuing heavy pollution cases from 2004 to 2008 in Beijing are calculated, and the weather patterns without duststorm weather during the continuing heavy pollution episodes are analyzed. It is concluded that continuing heavy pollution processes exhibit distinct seasonality, including mainly sand/dust pollution in spring and nonsand/dust pollution in falltowinter season; during continuing heavy pollution episodes, the nonsand/dust continuing pollution processes correspond with lowvisibility weather, such as heavy fog, light fog, haze and smoke, etc.; in the later periods, pollution processes correspond with gale or precipitation weather, especially the longtime heavy pollution events frequently occurring during heavy fog weather. The circulation characteristics during continuing pollution episodes without sand/dust weather are: there is zonal circulation in the upper air, a warm ridge at 850 hPa, a weak pressure field on the ground; serious pollution is often found under the saddlefield pattern; continuing heavy pollution days are frequently related with regional pollution.
The continuing heavy pollution cases from 2004 to 2008 in Beijing are calculated, and the weather patterns without duststorm weather during the continuing heavy pollution episodes are analyzed. It is concluded that continuing heavy pollution processes exhibit distinct seasonality, including mainly sand/dust pollution in spring and nonsand/dust pollution in falltowinter season; during continuing heavy pollution episodes, the nonsand/dust continuing pollution processes correspond with lowvisibility weather, such as heavy fog, light fog, haze and smoke, etc.; in the later periods, pollution processes correspond with gale or precipitation weather, especially the longtime heavy pollution events frequently occurring during heavy fog weather. The circulation characteristics during continuing pollution episodes without sand/dust weather are: there is zonal circulation in the upper air, a warm ridge at 850 hPa, a weak pressure field on the ground; serious pollution is often found under the saddlefield pattern; continuing heavy pollution days are frequently related with regional pollution.
2009, 37(6):660-664.
Abstract:
The urban heat island effect in Lanzhou is analyzed using the average temperature and daily maximum/minimum temperature data from 1956 to 2005. The tendencies and contribution rates of heat island intensity are calculated using the temperature tendencies of the three temperatures of Lanzhou and the suburbs. Results show that the differences of the three temperatures between Lanzhou and the suburbs all exhibit increasing trends. The tendencies of average temperature，maximum temperature and minimum temperature are 0.371 ℃/10a, 0.169 ℃/10a and 0.654 ℃/10a， respectively, with minimum temperature increasing most obviously. In recent 50 years，the temperatures increased mainly in the later 25 years (1981 to 2005), and the tendencies of average temperature，maximum temperature and minimum temperature of Lanzhou are 0.789 ℃/10a， 0.997 ℃/10a, and 0.625 ℃/10a，while those of the suburbs are 0.395 ℃/10a,0.188 ℃/10a, and 0.674 ℃/10a, respectively. The heat island contribution rates of three temperatures are 87.0%，49.6%, and 100%,respectively. In winter, the tendencies of average temperature and minimum temperature are the greatest in both urban and suburb areas，but the heat island contribution rates of the temperatures are not the largest，which may be mainly related with the severe air pollution in winter in Lanzhou，because it can hold back the urban heat island effect in some extent. In the later 25 years， the urban heat island effect of Lanzhou is becoming stronger, but the contribution rates of average temperature and maximum temperature are declining.
The urban heat island effect in Lanzhou is analyzed using the average temperature and daily maximum/minimum temperature data from 1956 to 2005. The tendencies and contribution rates of heat island intensity are calculated using the temperature tendencies of the three temperatures of Lanzhou and the suburbs. Results show that the differences of the three temperatures between Lanzhou and the suburbs all exhibit increasing trends. The tendencies of average temperature，maximum temperature and minimum temperature are 0.371 ℃/10a, 0.169 ℃/10a and 0.654 ℃/10a， respectively, with minimum temperature increasing most obviously. In recent 50 years，the temperatures increased mainly in the later 25 years (1981 to 2005), and the tendencies of average temperature，maximum temperature and minimum temperature of Lanzhou are 0.789 ℃/10a， 0.997 ℃/10a, and 0.625 ℃/10a，while those of the suburbs are 0.395 ℃/10a,0.188 ℃/10a, and 0.674 ℃/10a, respectively. The heat island contribution rates of three temperatures are 87.0%，49.6%, and 100%,respectively. In winter, the tendencies of average temperature and minimum temperature are the greatest in both urban and suburb areas，but the heat island contribution rates of the temperatures are not the largest，which may be mainly related with the severe air pollution in winter in Lanzhou，because it can hold back the urban heat island effect in some extent. In the later 25 years， the urban heat island effect of Lanzhou is becoming stronger, but the contribution rates of average temperature and maximum temperature are declining.
2009, 37(6):665-669.
Abstract:
According to the relationship between conventional observational data, Lband radar data, and Air Pollution Index (API), an index of meteorological conditions for pollutant diffusion (Index 〖WTBX〗A〖WTBZ〗) for Chongqing is established, which consists of three meteorological elements and can be used to determine the pollution potential through grading by diagnosing the climatic probability in the corresponding periods. The correlation analysis indicates that there is close relationship between API and meteorological data at 08:00, not at 20:00; among the surface meteorological factors, the correlation coefficient between API and the 24hour pressure variation at 08:00 is the largest, and the effect of temperature on API is different in various seasons; the wind velocity at 150 meters and the temperature difference between the ground and 300 meter height exhibit good relationship with API in the Lband radar data. Index 〖WTBX〗A 〖WTBZ〗is therefore composed of the 24hour pressure variation at 08:00, the wind velocity at 150 meters, and the temperature difference between the ground and 300meter height. The application proved that Index A is reasonable and performs well in the operational service.
According to the relationship between conventional observational data, Lband radar data, and Air Pollution Index (API), an index of meteorological conditions for pollutant diffusion (Index 〖WTBX〗A〖WTBZ〗) for Chongqing is established, which consists of three meteorological elements and can be used to determine the pollution potential through grading by diagnosing the climatic probability in the corresponding periods. The correlation analysis indicates that there is close relationship between API and meteorological data at 08:00, not at 20:00; among the surface meteorological factors, the correlation coefficient between API and the 24hour pressure variation at 08:00 is the largest, and the effect of temperature on API is different in various seasons; the wind velocity at 150 meters and the temperature difference between the ground and 300 meter height exhibit good relationship with API in the Lband radar data. Index 〖WTBX〗A 〖WTBZ〗is therefore composed of the 24hour pressure variation at 08:00, the wind velocity at 150 meters, and the temperature difference between the ground and 300meter height. The application proved that Index A is reasonable and performs well in the operational service.
2009, 37(6):670-675.
Abstract:
Based on the routine observation synoptic charts and the synoptic charts at 500 hPa from 1988 to 2007, the temporal distribution, meteorological fields, and the stability factor of haze days during spring and summer are analyzed. The results indicate that the annual haze days increased, and the monthly distribution showed a single peak pattern with high values in December and January. There is a highest probability of haze at 14:00 in winter half year and at 08:00 in summer half year. The haze events in winter half year often occur under the weather condition of weakened cold air, decreased surface pressure, increased temperature, low wind velocity and high humidity. The correlative weather systems include the back of the denatured high, the warm sector ahead of fronts, and the ground inverse trough. Occasionally, haze events happened along with the inrush of cold air with the increasing pressure and decreasing temperature and low humidity, and the correlative weather system is the land cold high. The haze events in summer half year often happened in the morning with high temperature, low humidity and stable atmosphere. The influencing systems (500 hPa) include the subtropical high, the edge of the subtropical high, the weak ground inverse trough, and the dryhot descent flow controlled by a typhoon.
Based on the routine observation synoptic charts and the synoptic charts at 500 hPa from 1988 to 2007, the temporal distribution, meteorological fields, and the stability factor of haze days during spring and summer are analyzed. The results indicate that the annual haze days increased, and the monthly distribution showed a single peak pattern with high values in December and January. There is a highest probability of haze at 14:00 in winter half year and at 08:00 in summer half year. The haze events in winter half year often occur under the weather condition of weakened cold air, decreased surface pressure, increased temperature, low wind velocity and high humidity. The correlative weather systems include the back of the denatured high, the warm sector ahead of fronts, and the ground inverse trough. Occasionally, haze events happened along with the inrush of cold air with the increasing pressure and decreasing temperature and low humidity, and the correlative weather system is the land cold high. The haze events in summer half year often happened in the morning with high temperature, low humidity and stable atmosphere. The influencing systems (500 hPa) include the subtropical high, the edge of the subtropical high, the weak ground inverse trough, and the dryhot descent flow controlled by a typhoon.
2009, 37(6):676-681.
Abstract:
With the synoptic charts and meteorological data, the relationships between heavy air pollution processes and weather systems, as well as meteorological factors, are analyzed by statistical methods for 41 typical heavy air pollution processes from 2003 to 2007 in Fuzhou. On the basis of statistical analysis, the main circulation patterns that bring heavy air pollution are identified for winter, spring and summerautumn seasons, respectively, and a quasiquantitative analysis is made of the relation between surface meteorological elements and heavy pollution processes. The meteorological indexes and synoptic conceptive models for heavy air pollution weather processes in Fuzhou are established.
With the synoptic charts and meteorological data, the relationships between heavy air pollution processes and weather systems, as well as meteorological factors, are analyzed by statistical methods for 41 typical heavy air pollution processes from 2003 to 2007 in Fuzhou. On the basis of statistical analysis, the main circulation patterns that bring heavy air pollution are identified for winter, spring and summerautumn seasons, respectively, and a quasiquantitative analysis is made of the relation between surface meteorological elements and heavy pollution processes. The meteorological indexes and synoptic conceptive models for heavy air pollution weather processes in Fuzhou are established.
2009, 37(6):682-687.
Abstract:
Based on the data of fog, surface observations from 9 weather stations in Langfang, a city in the central seaside plain of North China, as well as the fog data for the eastern central Hebei Province，the historical radiosonde dada from 1980 to 2000, and MICAPS data from 2004 to 2007, the climatic characteristics and relationship between meteorological element distribution and the occurrence frequency of fogs and heavy fogs in Langfang are analyzed. The results show that fog is one of most disastrous weather with high occurrence frequency in Langfang and mainly appears in winter and autumn; favorable meteorological conditions include surface southerly/easterly wind speed being less than 3 m/s, relative humidity greater than 50%, |Δ〖WTBX〗p〖WTBZ〗6| less than 3 hPa, and there excising stable temperature inversion between 1000 hPa and 925 hPa, which can be used as indexes for forecasting the occurrence of fogs and heavy fogs. The forecasting and earlywarning techniques of fog are discussed.
Based on the data of fog, surface observations from 9 weather stations in Langfang, a city in the central seaside plain of North China, as well as the fog data for the eastern central Hebei Province，the historical radiosonde dada from 1980 to 2000, and MICAPS data from 2004 to 2007, the climatic characteristics and relationship between meteorological element distribution and the occurrence frequency of fogs and heavy fogs in Langfang are analyzed. The results show that fog is one of most disastrous weather with high occurrence frequency in Langfang and mainly appears in winter and autumn; favorable meteorological conditions include surface southerly/easterly wind speed being less than 3 m/s, relative humidity greater than 50%, |Δ〖WTBX〗p〖WTBZ〗6| less than 3 hPa, and there excising stable temperature inversion between 1000 hPa and 925 hPa, which can be used as indexes for forecasting the occurrence of fogs and heavy fogs. The forecasting and earlywarning techniques of fog are discussed.
2009, 37(6):688-692.
Abstract:
A comprehensive introduction is made to the design and features of the atmospheric composition information platform for Dalian. Based on the database system, by independent modules to accomplish data entry, quality control and analytical processing, etc, the modularized system can deal with a variety of atmospheric composition data received by the meteorological department and generate various operational application products. The system is highly automatic and easy to use, upgrade, and extend, having great potential in application. Several solutions to the analysis, processing, and application of atmospheric composition data are given, which are useful for the atmospheric composition service.
A comprehensive introduction is made to the design and features of the atmospheric composition information platform for Dalian. Based on the database system, by independent modules to accomplish data entry, quality control and analytical processing, etc, the modularized system can deal with a variety of atmospheric composition data received by the meteorological department and generate various operational application products. The system is highly automatic and easy to use, upgrade, and extend, having great potential in application. Several solutions to the analysis, processing, and application of atmospheric composition data are given, which are useful for the atmospheric composition service.
2009, 37(6):693-696.
Abstract:
The statistical relationship of cementsurface temperature and temperature observed simultaneously by the automatic temperature recorder in screen at Jiaxing Station in the summers of 2006 and 2007 (June to September) is analyzed. The results indicate that the average and extreme maximum summer cementsurface temperatures change simultaneously with the temperature in screen at the scales of day, month and quarter, but there is obvious difference between them, which is mainly manifested in the maximum temperature. Comparing with the temperature in screen, the cementsurface temperature has such features as earlier appearing of extreme maximum temperature, shorter high temperature episodes, greater difference, minimum temperature in morning close to temperature in screen or slightly higher. The cementsurface maximum temperature in summer is related closely to sunshine duration, precipitation, wind direction and wind speed, relative humidity, etc. By means of the second Kalman filter and Optimal subset regression, the quantitative prediction outputs of the cementsurface maximum temperature are given and revised artificially according to different weather situations (sunny, cloudy, precipitation). Those equations proved satisfactory in accuracy in forecasting operation and can help improve the specialized meteorological services.
The statistical relationship of cementsurface temperature and temperature observed simultaneously by the automatic temperature recorder in screen at Jiaxing Station in the summers of 2006 and 2007 (June to September) is analyzed. The results indicate that the average and extreme maximum summer cementsurface temperatures change simultaneously with the temperature in screen at the scales of day, month and quarter, but there is obvious difference between them, which is mainly manifested in the maximum temperature. Comparing with the temperature in screen, the cementsurface temperature has such features as earlier appearing of extreme maximum temperature, shorter high temperature episodes, greater difference, minimum temperature in morning close to temperature in screen or slightly higher. The cementsurface maximum temperature in summer is related closely to sunshine duration, precipitation, wind direction and wind speed, relative humidity, etc. By means of the second Kalman filter and Optimal subset regression, the quantitative prediction outputs of the cementsurface maximum temperature are given and revised artificially according to different weather situations (sunny, cloudy, precipitation). Those equations proved satisfactory in accuracy in forecasting operation and can help improve the specialized meteorological services.
2009, 37(6):697-704.
Abstract:
The system for numerical ultraviolet (UV) prediction (GRAPESUV) using Goddard shortwave radiative scheme with GRAPES (Global/Regional Assimilation PrEdiction System） is established. The Goddard shortwave radiative parameterization scheme and the executing of the GRAPESUV system are described, and case studies are conducted. It is shown that the effect of cloud microphysical processes in GRAPES on UV forecasts is important; the improvement of the cloud microphysical scheme make UV forecasts based on weather possibly; ultraviolet index （UVI） correlates to cloud distribution and weather situation; the strong contrast of UVI between clear sky and convective cloudy areas is an important feature of UVI. An application experiment of total ozone prediction was conducted using T213 to provide the meteorological background for the chemical transport model and using the satellite data assimilation technology to establish the initial fields. The UVI forecasts for Beijing and Shanghai in the summer of 2007 are verified statistically using the Critical Success Index (CSI) in common use internationally. The CSIs corresponding to the high and very high exposures of UV grades in 24 hours for Beijing and Shanghai are 0.625 and 0.780 respectively, approaching to the results of verification for United States with the same method. The GRAPESUV system has been running on the operational IBM computer system at the Center for Atmosphere Watch and Services (CAWAS), the Chinese Meteorological Administration (CMA), since March 2006, and has issued forecasts for UVI and UV exposure grades to remind the public of overexposure to UV radiation at the CMA/CAWAS website.
The system for numerical ultraviolet (UV) prediction (GRAPESUV) using Goddard shortwave radiative scheme with GRAPES (Global/Regional Assimilation PrEdiction System） is established. The Goddard shortwave radiative parameterization scheme and the executing of the GRAPESUV system are described, and case studies are conducted. It is shown that the effect of cloud microphysical processes in GRAPES on UV forecasts is important; the improvement of the cloud microphysical scheme make UV forecasts based on weather possibly; ultraviolet index （UVI） correlates to cloud distribution and weather situation; the strong contrast of UVI between clear sky and convective cloudy areas is an important feature of UVI. An application experiment of total ozone prediction was conducted using T213 to provide the meteorological background for the chemical transport model and using the satellite data assimilation technology to establish the initial fields. The UVI forecasts for Beijing and Shanghai in the summer of 2007 are verified statistically using the Critical Success Index (CSI) in common use internationally. The CSIs corresponding to the high and very high exposures of UV grades in 24 hours for Beijing and Shanghai are 0.625 and 0.780 respectively, approaching to the results of verification for United States with the same method. The GRAPESUV system has been running on the operational IBM computer system at the Center for Atmosphere Watch and Services (CAWAS), the Chinese Meteorological Administration (CMA), since March 2006, and has issued forecasts for UVI and UV exposure grades to remind the public of overexposure to UV radiation at the CMA/CAWAS website.
2009, 37(6):705-708.
Abstract:
According to the 3year daily statistical data about nonoccupational CO poisoned patients from 16 firstaid centers over the eight districts in the central Beijing, the relationship between the number of CO poisoned patients and ground meteorological elements is analyzed. The results show that the number of CO poisoned patients was greater in the winter half year (from October to April). The mean occurrence rate of CO poisoning in January was 8.1 per 107, being the largest in a whole year. The mean of monthly CO poisoned patients had positive correlation with monthly sea level pressure and negative correlation with monthly extreme low temperature. The correlation coefficient between the mean of extreme low temperature of the past 9 days and the number of CO poisoned patients of the future 9 days is －0.7661. It is important for meteorological service to provide CO poisoning warning based on weather forecast.
According to the 3year daily statistical data about nonoccupational CO poisoned patients from 16 firstaid centers over the eight districts in the central Beijing, the relationship between the number of CO poisoned patients and ground meteorological elements is analyzed. The results show that the number of CO poisoned patients was greater in the winter half year (from October to April). The mean occurrence rate of CO poisoning in January was 8.1 per 107, being the largest in a whole year. The mean of monthly CO poisoned patients had positive correlation with monthly sea level pressure and negative correlation with monthly extreme low temperature. The correlation coefficient between the mean of extreme low temperature of the past 9 days and the number of CO poisoned patients of the future 9 days is －0.7661. It is important for meteorological service to provide CO poisoning warning based on weather forecast.
2009, 37(6):709-712.
Abstract:
The relationship between influenza and meteorological factors in Shenzhen is analyzed by using the detailed data of influenza cases and meteorological data from 2003 to 2007 in Shenzhen. The results show that spring and summer is the influenza epidemic period in Shenzhen, and the epidemic period is tending to move toward summer gradually; the seasonal variation has a close relationship with the temperature and humidity; the influenza peak occurs frequently in the case of temperature being in the range of 25 ℃ to 30 ℃ and higher humidity. The regressive equation for forecasting the clinical rates of InfluenzaLike Illness (ILI) is established. The minimum air temperature, minimum relative humidity and sunshine duration are the typical meteorological forecasting factors.
The relationship between influenza and meteorological factors in Shenzhen is analyzed by using the detailed data of influenza cases and meteorological data from 2003 to 2007 in Shenzhen. The results show that spring and summer is the influenza epidemic period in Shenzhen, and the epidemic period is tending to move toward summer gradually; the seasonal variation has a close relationship with the temperature and humidity; the influenza peak occurs frequently in the case of temperature being in the range of 25 ℃ to 30 ℃ and higher humidity. The regressive equation for forecasting the clinical rates of InfluenzaLike Illness (ILI) is established. The minimum air temperature, minimum relative humidity and sunshine duration are the typical meteorological forecasting factors.
2009, 37(6):713-718.
Abstract:
In order to have a better understanding of the characteristics of lightning magnetic fields, an allphase magnetic field measurement system is developed, in which the electromagnetic induction method is used. The sensor consists of three 15 cm radius orthogonal magnetic loops. The data is recorded by an oscilloscope with high speed and high capacity. The pulse magnetic field waveform digital reconstruction method based on the full circuit equation is adopted in data restoration processing. The system is calibrated by a current generator with a maximum output of 6 kA in laboratory. The synchronized electric and magnetic observation data of two lightning flashes observed in the field experiment conducted in Conghua, Guangdong Province, is analyzed. It is found that the allphase magnetic field measurement system can reliably reflect lightning magnetic field change.
In order to have a better understanding of the characteristics of lightning magnetic fields, an allphase magnetic field measurement system is developed, in which the electromagnetic induction method is used. The sensor consists of three 15 cm radius orthogonal magnetic loops. The data is recorded by an oscilloscope with high speed and high capacity. The pulse magnetic field waveform digital reconstruction method based on the full circuit equation is adopted in data restoration processing. The system is calibrated by a current generator with a maximum output of 6 kA in laboratory. The synchronized electric and magnetic observation data of two lightning flashes observed in the field experiment conducted in Conghua, Guangdong Province, is analyzed. It is found that the allphase magnetic field measurement system can reliably reflect lightning magnetic field change.
2009, 37(6):719-723.
Abstract:
According to the characteristics of the action of the lightning electromagnetic field on overhead lines, the relation formula is devised between the position of any given strike point and the lightninginduced overvoltage along an overhead line by mathematics models. The influences on lightninginduced overvoltage are analyzed of such factors as the height of an overhead line, the distance between overhead line and strike point, the height of an object beside the overhead line, the length of a raising leader (return stroke), etc. The relationship between new formula and the formula from the standards DL/T6201997 (Overvoltage Protection and Insulation Coordination for AC Electrical Installations) is given, aiming to identify the causes of electronic and electrical equipment damages quantitatively to provide reference for lightning protection design.
According to the characteristics of the action of the lightning electromagnetic field on overhead lines, the relation formula is devised between the position of any given strike point and the lightninginduced overvoltage along an overhead line by mathematics models. The influences on lightninginduced overvoltage are analyzed of such factors as the height of an overhead line, the distance between overhead line and strike point, the height of an object beside the overhead line, the length of a raising leader (return stroke), etc. The relationship between new formula and the formula from the standards DL/T6201997 (Overvoltage Protection and Insulation Coordination for AC Electrical Installations) is given, aiming to identify the causes of electronic and electrical equipment damages quantitatively to provide reference for lightning protection design.
2009, 37(6):724-728.
Abstract:
Through the analysis of 12 typical thunderstorm processes around Shengxian County of Zhejiang Province recorded by the atmospheric electric field instrument from June to October 2007, in combination with the data recorded by lightning position finders, it is found that when thunderstorm clouds approach the station with an electric field instrument, there will occur the phenomenon of fastchanging dither before the occurrence of lightning within the protection range of the station (10 km around the station), which has the 01 relationship with lightning. That is, when the fastchanging dither in the electric field appears and the strength of the electric field reaches a certain threshold several times in a period of time, the electricfield strength will increase to achieve the intensity necessary for the appearance of lightning within the protection range, and there is little circumstances that the appearance of fastchanging dither is not accompanied by the appearance of lightning. The forecast equation and most appropriate electricfield parameters are given, and the method of thunderstorm warning is presented with the multivariate regression method. The results show that it is the best time to make warning when lightning strokes are concentrated within a range of 10 to 15 km around the atmospheric electric field instrument if the conditions of warning for the electric field instrument are satisfied, with the accuracy being up to about 73%.
Through the analysis of 12 typical thunderstorm processes around Shengxian County of Zhejiang Province recorded by the atmospheric electric field instrument from June to October 2007, in combination with the data recorded by lightning position finders, it is found that when thunderstorm clouds approach the station with an electric field instrument, there will occur the phenomenon of fastchanging dither before the occurrence of lightning within the protection range of the station (10 km around the station), which has the 01 relationship with lightning. That is, when the fastchanging dither in the electric field appears and the strength of the electric field reaches a certain threshold several times in a period of time, the electricfield strength will increase to achieve the intensity necessary for the appearance of lightning within the protection range, and there is little circumstances that the appearance of fastchanging dither is not accompanied by the appearance of lightning. The forecast equation and most appropriate electricfield parameters are given, and the method of thunderstorm warning is presented with the multivariate regression method. The results show that it is the best time to make warning when lightning strokes are concentrated within a range of 10 to 15 km around the atmospheric electric field instrument if the conditions of warning for the electric field instrument are satisfied, with the accuracy being up to about 73%.
2009, 37(6):729-733.
Abstract:
By means of the software programming and statistic methods, the data collected by three SAFIR3000 thunderstorm sensors are studied. Some useful conclusions about the distribution regularities of cloudtoground flushes in the Shanghai area are obtained: (1) because of the topography and high buildings in Shanghai, there occur more frequently lightning flushes in the north and south parts than in east and west parts, more frequently in the urban areas than in the rural areas; (2) although there are less flushes in the rural areas, the current is more powerful than that in the urban areas; (3) cloudtoground flushes happen mostly from 14:00 to 21:00. The number of lightning days is an important parameter that can be used to express the frequency of local lightning activity, but there are some problems in the use of this parameter in lightningprotection grade estimation and risk assessment. A suggestion to replace the number of lightning days with lightning density is presented and discussed.
By means of the software programming and statistic methods, the data collected by three SAFIR3000 thunderstorm sensors are studied. Some useful conclusions about the distribution regularities of cloudtoground flushes in the Shanghai area are obtained: (1) because of the topography and high buildings in Shanghai, there occur more frequently lightning flushes in the north and south parts than in east and west parts, more frequently in the urban areas than in the rural areas; (2) although there are less flushes in the rural areas, the current is more powerful than that in the urban areas; (3) cloudtoground flushes happen mostly from 14:00 to 21:00. The number of lightning days is an important parameter that can be used to express the frequency of local lightning activity, but there are some problems in the use of this parameter in lightningprotection grade estimation and risk assessment. A suggestion to replace the number of lightning days with lightning density is presented and discussed.
2009, 37(6):734-738.
Abstract:
The cloudtoground flash data of Chongqing from 2006 to 2008 from the lightning location system (ADTD) is used to analyze the regularity of lightning activities of the straddletype monorail system (No.2) by the linecorridor method. A vulnerability analysis is made, with the lightning parameters including the number of lightning strokes, the number of thunderstorm days per year, cloudtoground flash density, the distribution of lightning current magnitudes, and the distribution of lightning locations. The results indicate that the section from Linjiangmen to Fotuguan is the area that has higher occurrence probability of critical lightning current, relatively larger mean ground flash density, and shorter average distance from the stations, which is easy to be attacked by lightning strokes and is considered as the key area of lightning protection because it is located along the riverside and has steep topography.
The cloudtoground flash data of Chongqing from 2006 to 2008 from the lightning location system (ADTD) is used to analyze the regularity of lightning activities of the straddletype monorail system (No.2) by the linecorridor method. A vulnerability analysis is made, with the lightning parameters including the number of lightning strokes, the number of thunderstorm days per year, cloudtoground flash density, the distribution of lightning current magnitudes, and the distribution of lightning locations. The results indicate that the section from Linjiangmen to Fotuguan is the area that has higher occurrence probability of critical lightning current, relatively larger mean ground flash density, and shorter average distance from the stations, which is easy to be attacked by lightning strokes and is considered as the key area of lightning protection because it is located along the riverside and has steep topography.
2009, 37(6):739-743.
Abstract:
In order to make better use of the data from Lightning Location Systems (LLS) to calculate the number of lightning days and lightning parameters, by means of the conventionally observed lightning day data from 49 Stations over the central Yunnan Province from 1987 to 2006 and the lighting location data from 2005 to 2006, the grid method for calculating lightning days and lightning parameters automatically is presented on the basis of comparing the observed and LLS data. By means of the grid method, the area division is more detailed and reasonable with a satisfactory comparability between calculated and conventional lightning day data. The longrange lightning day data are needed as sources for determining the size of grids, and the calculated result with the 0.175°×0.175° grid is chosen for annual mean lightning days and 0.3°×0.3° for maximum lightning days in the central Yunnan Province. The results of lightning parameters with the grid method show that there are obvious local variations in lightning days and lightning density, and the density of ground lighting and the strength of lighting have an inverse proportional relationship, which provides theoretical foundations for the engineering design of lightning protection, as well as the assessment and causal analysis of Lightning Disasters.
In order to make better use of the data from Lightning Location Systems (LLS) to calculate the number of lightning days and lightning parameters, by means of the conventionally observed lightning day data from 49 Stations over the central Yunnan Province from 1987 to 2006 and the lighting location data from 2005 to 2006, the grid method for calculating lightning days and lightning parameters automatically is presented on the basis of comparing the observed and LLS data. By means of the grid method, the area division is more detailed and reasonable with a satisfactory comparability between calculated and conventional lightning day data. The longrange lightning day data are needed as sources for determining the size of grids, and the calculated result with the 0.175°×0.175° grid is chosen for annual mean lightning days and 0.3°×0.3° for maximum lightning days in the central Yunnan Province. The results of lightning parameters with the grid method show that there are obvious local variations in lightning days and lightning density, and the density of ground lighting and the strength of lighting have an inverse proportional relationship, which provides theoretical foundations for the engineering design of lightning protection, as well as the assessment and causal analysis of Lightning Disasters.
2009, 37(6):744-747.
Abstract:
According to the standards of meteorological disaster evaluating grades, as well as personnel casualties and property loss, thunder and lightning disasters are divided into 7 grades, and the corresponding standards are determined. Based on the characteristics of thunder and lightning occurrence in China, considering disasterinducing factors, disasterbreeding environments, and disasterbearing objects, the density of ground lightning （or the density of lightning strike）, the occurrence frequency of thunder and lightning disasters, the population density, and GDP per capita are chosen as indexes to evaluate the occurrence potential of thunder and lightning disasters, and examples are given.
According to the standards of meteorological disaster evaluating grades, as well as personnel casualties and property loss, thunder and lightning disasters are divided into 7 grades, and the corresponding standards are determined. Based on the characteristics of thunder and lightning occurrence in China, considering disasterinducing factors, disasterbreeding environments, and disasterbearing objects, the density of ground lightning （or the density of lightning strike）, the occurrence frequency of thunder and lightning disasters, the population density, and GDP per capita are chosen as indexes to evaluate the occurrence potential of thunder and lightning disasters, and examples are given.
2009, 37(6):748-752.
Abstract:
Using the lightning path taken by the high speed camera and the simulated lightning path, the electric field peak errors are analyzed by assuming the lightning path being vertical. The results show that at close distances, the field waveform is dependent strongly on azimuth; at distance of several hundreds, the ratio of the peak error values at two azimuths may be bigger than 2; at the distance of 1 km, the mean error is less than 10% with a maximum value of 50%.The calculated relative error decreases with the increasing of distance.
Using the lightning path taken by the high speed camera and the simulated lightning path, the electric field peak errors are analyzed by assuming the lightning path being vertical. The results show that at close distances, the field waveform is dependent strongly on azimuth; at distance of several hundreds, the ratio of the peak error values at two azimuths may be bigger than 2; at the distance of 1 km, the mean error is less than 10% with a maximum value of 50%.The calculated relative error decreases with the increasing of distance.
2009, 37(6):753-758.
Abstract:
According to the data of thunderstorm days of five weather stations in Suzhou from 1957 to 2008, the timespace distribution of thunderstorms and the relationship of thunderstorms to rainfall and temperature in Suzhou are analyzed. The results show that Suzhou is an area attacked frequently by Lightning, and more lightning activities happen in the south part than in the north, with maximum difference being 3.21 to 4.65 days. There is great interannual variability of thunderstorm weather in Suzhou, and the annual cumulative number of thunderstorm days is up to 37 days. There is a linear decreasing trend in thunderstorm days with the range being 1.61 to 2.89 days per 10 years. Thunderstorm days exhibit a singlepeak type seasonal distribution, occur mostly in summer and least in winter, and centralized in the period from April to September, with maximum in July and minimum in December. The daily distribution is also the singlepeak type, with the maximum frequency from 16:00 to 18:00. The longrange mean series of average thunderstorm days has significantly positive correlation with rainfall and temperature. In order to predict the trend of thunderstorms, taking Yongqiao as an example, the greyBP combined model is built, and the results show that the year of 2025 is the next year of thunderstorms occurring most frequently.
According to the data of thunderstorm days of five weather stations in Suzhou from 1957 to 2008, the timespace distribution of thunderstorms and the relationship of thunderstorms to rainfall and temperature in Suzhou are analyzed. The results show that Suzhou is an area attacked frequently by Lightning, and more lightning activities happen in the south part than in the north, with maximum difference being 3.21 to 4.65 days. There is great interannual variability of thunderstorm weather in Suzhou, and the annual cumulative number of thunderstorm days is up to 37 days. There is a linear decreasing trend in thunderstorm days with the range being 1.61 to 2.89 days per 10 years. Thunderstorm days exhibit a singlepeak type seasonal distribution, occur mostly in summer and least in winter, and centralized in the period from April to September, with maximum in July and minimum in December. The daily distribution is also the singlepeak type, with the maximum frequency from 16:00 to 18:00. The longrange mean series of average thunderstorm days has significantly positive correlation with rainfall and temperature. In order to predict the trend of thunderstorms, taking Yongqiao as an example, the greyBP combined model is built, and the results show that the year of 2025 is the next year of thunderstorms occurring most frequently.
2009, 37(6):759-762.
Abstract:
The lightning frequency, polarity, intensity and other parameters in each unit from 24 August, 2005 to 22 September 2008 are gained, with the range of 1 km2(1 km × 1 km) being the basic unit， for the whole area of the Huangshan Scenic Area (118.05°E to 118.13°E,30.06°N to 30.09°N). At the same time, the influences of geological features and the lightning environment and geographical environment of the Huangshan scenic area on lightning activities are analyzed. Research shows that in the mountainous areas, the lightning frequency also increases with increasing altitude, while the average lightning current intensity decreases.
The lightning frequency, polarity, intensity and other parameters in each unit from 24 August, 2005 to 22 September 2008 are gained, with the range of 1 km2(1 km × 1 km) being the basic unit， for the whole area of the Huangshan Scenic Area (118.05°E to 118.13°E,30.06°N to 30.09°N). At the same time, the influences of geological features and the lightning environment and geographical environment of the Huangshan scenic area on lightning activities are analyzed. Research shows that in the mountainous areas, the lightning frequency also increases with increasing altitude, while the average lightning current intensity decreases.
2009, 37(6):763-766.
Abstract:
A risk assessment of a photovoltaic standalone system is made according to the criteria IEC623052. Through calculating and analyzing the lightning stroke risk R2 and R4, the most effective protection measures (LPS and LPMS) for the object are selected according to the share of risk component R2 and the economical analysis of the measures (R4), so to reduce the risk to the tolerable level.
A risk assessment of a photovoltaic standalone system is made according to the criteria IEC623052. Through calculating and analyzing the lightning stroke risk R2 and R4, the most effective protection measures (LPS and LPMS) for the object are selected according to the share of risk component R2 and the economical analysis of the measures (R4), so to reduce the risk to the tolerable level.
2009, 37(6):767-770.
Abstract:
Based on theoretical calculations and engineering practice for the grounding resistance of the vertical grounding electrode using a steel pipe, an analysis is made of the relationship between the effect of the resistance reduction using the deep well method and soil resistivity, as well as the depth and diameter of the ground electrode. Its characteristics include: the deeper the depth, the worse the effect of reduced resistance; the bigger the soil resistivity, the better the effect of resistance reduction; the bigger the diameter, the worse the effect of reduced resistance. The characteristics of the effect of the resistance reduction using the deep well method are explained qualitatively from the influence of the grounding electrode current density and discharge end effect. Simultaneously, considering the earth skin effect of lightning current and the construction cost, it is concluded that the deep well method is not recommended in the areas with lower soil resistivity; after the grounding electrode diameter size reached a certain size, increasing the diameter of the grounding electrode will have little effect in the resistance reduction, so the diameter of the grounding electrode should not be too big.
Based on theoretical calculations and engineering practice for the grounding resistance of the vertical grounding electrode using a steel pipe, an analysis is made of the relationship between the effect of the resistance reduction using the deep well method and soil resistivity, as well as the depth and diameter of the ground electrode. Its characteristics include: the deeper the depth, the worse the effect of reduced resistance; the bigger the soil resistivity, the better the effect of resistance reduction; the bigger the diameter, the worse the effect of reduced resistance. The characteristics of the effect of the resistance reduction using the deep well method are explained qualitatively from the influence of the grounding electrode current density and discharge end effect. Simultaneously, considering the earth skin effect of lightning current and the construction cost, it is concluded that the deep well method is not recommended in the areas with lower soil resistivity; after the grounding electrode diameter size reached a certain size, increasing the diameter of the grounding electrode will have little effect in the resistance reduction, so the diameter of the grounding electrode should not be too big.
2009, 37(6):771-774.
Abstract:
Several methods for reducing resistance are discussed in detail theoretically. According to experiences from the practice in earthing projects, especially the experiences from unsuccessful resistance reducing events, a procedureoriented method for reducing resistance is proposed and has been used experimentally in the reconstruction of the earthing system for the 110kV Shimen substation, which can used as reference in earthing design and construction.
Several methods for reducing resistance are discussed in detail theoretically. According to experiences from the practice in earthing projects, especially the experiences from unsuccessful resistance reducing events, a procedureoriented method for reducing resistance is proposed and has been used experimentally in the reconstruction of the earthing system for the 110kV Shimen substation, which can used as reference in earthing design and construction.
2009, 37(6):775-778.
Abstract:
In view of the abnormal situation in the running process of the ADTD Lightning Location Monitoring System, an analysis is made of the causes of system failures caused by the abnormalities in the lightning location equipment, network communication module, central station receivers, and central station software. The relevant methods and measures used by the maintenance staff in troubleshooting are summarized. The abnormality analysis of the system is mainly based on the dataprocessing procedures and basic operating principles.
In view of the abnormal situation in the running process of the ADTD Lightning Location Monitoring System, an analysis is made of the causes of system failures caused by the abnormalities in the lightning location equipment, network communication module, central station receivers, and central station software. The relevant methods and measures used by the maintenance staff in troubleshooting are summarized. The abnormality analysis of the system is mainly based on the dataprocessing procedures and basic operating principles.
2009, 37(6):779-781.
Abstract:
A mediumwave broadcast relaying stations is usually built in the outskirts of a city. Because of the height of the antenna tower, these stations are attacked frequently by lightning strokes. Through analyzing technically the layout of the lightning protection system, it is found out that the main cause of the frequent lightning attacks is some leaks in the key techniques of the lightning protection system. According to the actual situation of mediumwave broadcast relaying stations, some solutions are presented: stepwise shunting in the grounding grid, shielding feeder along with the technology of shielding rings, coordination of various circuits and systems, etc., so to form a complete lightning protection system frame for mediumwave broadcast relays stations.
A mediumwave broadcast relaying stations is usually built in the outskirts of a city. Because of the height of the antenna tower, these stations are attacked frequently by lightning strokes. Through analyzing technically the layout of the lightning protection system, it is found out that the main cause of the frequent lightning attacks is some leaks in the key techniques of the lightning protection system. According to the actual situation of mediumwave broadcast relaying stations, some solutions are presented: stepwise shunting in the grounding grid, shielding feeder along with the technology of shielding rings, coordination of various circuits and systems, etc., so to form a complete lightning protection system frame for mediumwave broadcast relays stations.
2009, 37(6):782-784.
Abstract:
2009, 37(6):785-786.
Abstract:
External LinksChina Meteorological AdministrationCMA Meteorological Observation CentreChinese Academy of Meteorological SciencesBeijing Meteorological ServiceNational Satellite Meteorological Center
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Supported by:Beijing E-Tiller Technology Development Co., Ltd.
Supported by:Beijing E-Tiller Technology Development Co., Ltd.