Volume 45,Issue 2,2017 Table of Contents
2017, 45(2):209-216.
Abstract:
By analyzing and evaluating the uncertainty of the provincial working standard pyranometer tracing to World Radiometric Reference,the main uncertainty sources are given such as the measurement repeatability, voltage output, the change of incident angle, thermal offset and the standard instrument. The expand uncertainty of calibration results for the provincial working standard pyranometer is 06%. The provincial working standard pyranometer is calibrated using the component summation method in China. The proportion of uncertainty component caused by standard instruments is over 90%. So the key to reduce the uncertainty of traceability is to reduce the measurement uncertainty of the direct radiation standard (03%) and diffuse radiation standard (10%). The accuracy for solar radiation measurement is also greatly impacted by weather conditions. Choosing the stable weather with good atmospheric transparency and solar altitude angle over 30° and increasing the number of measurements can decrease the data dispersibility and reduce the uncertainty component caused by the measurement repeatability; the thermal offset can be reduced by ventilating the calibrated pyranometer. The proper installation of instruments such as ensuring the level of sensors and suntracking accurately with a shading system can further reduce the uncertainty of traceability and improve the accuracy of shortwave radiation measurement.
By analyzing and evaluating the uncertainty of the provincial working standard pyranometer tracing to World Radiometric Reference,the main uncertainty sources are given such as the measurement repeatability, voltage output, the change of incident angle, thermal offset and the standard instrument. The expand uncertainty of calibration results for the provincial working standard pyranometer is 06%. The provincial working standard pyranometer is calibrated using the component summation method in China. The proportion of uncertainty component caused by standard instruments is over 90%. So the key to reduce the uncertainty of traceability is to reduce the measurement uncertainty of the direct radiation standard (03%) and diffuse radiation standard (10%). The accuracy for solar radiation measurement is also greatly impacted by weather conditions. Choosing the stable weather with good atmospheric transparency and solar altitude angle over 30° and increasing the number of measurements can decrease the data dispersibility and reduce the uncertainty component caused by the measurement repeatability; the thermal offset can be reduced by ventilating the calibrated pyranometer. The proper installation of instruments such as ensuring the level of sensors and suntracking accurately with a shading system can further reduce the uncertainty of traceability and improve the accuracy of shortwave radiation measurement.
2017, 45(2):217-222.
Abstract:
It is significant to measure visibility accurately in real time for guiding the traffic early warning and air quality assessment. The principles of forward scattering visibility meters are depicted,and the detection techniques and methods in the laboratory are introduced briefly. Based on the visibility environment simulation cabin developed by the Anhui Atmospheric Observation and Technical Support Center, multiple forward scattering visibility meters produced by three domestic manufacturers are tested. The consistency of various visibility values is examined,and the reasons for deviation are analyzed. In present, there is no standard verification scheme for visibility meters, so a method by using system constant calibration is proposed to reduce the measurement errors. The results show that visibility values are in good consistency with forward scattering visibility meters produced by the same manufacturer. The maximum of standard deviation is 1313 m when visibility is less than 15 km, and 4574 m in 15 to 10 km visibility condition. But there are obvious deviations for the meters produced by different manufacturers with the maximum of relative error up to -409% in 15 to 10 km visibility condition. After the calibration of the system constant,the accuracy of forward scattering visibility meters is improved obviously.
It is significant to measure visibility accurately in real time for guiding the traffic early warning and air quality assessment. The principles of forward scattering visibility meters are depicted,and the detection techniques and methods in the laboratory are introduced briefly. Based on the visibility environment simulation cabin developed by the Anhui Atmospheric Observation and Technical Support Center, multiple forward scattering visibility meters produced by three domestic manufacturers are tested. The consistency of various visibility values is examined,and the reasons for deviation are analyzed. In present, there is no standard verification scheme for visibility meters, so a method by using system constant calibration is proposed to reduce the measurement errors. The results show that visibility values are in good consistency with forward scattering visibility meters produced by the same manufacturer. The maximum of standard deviation is 1313 m when visibility is less than 15 km, and 4574 m in 15 to 10 km visibility condition. But there are obvious deviations for the meters produced by different manufacturers with the maximum of relative error up to -409% in 15 to 10 km visibility condition. After the calibration of the system constant,the accuracy of forward scattering visibility meters is improved obviously.
2017, 45(2):223-227.
Abstract:
This temperature sensor detector adopts semiconductor refrigeration technology to produce the temperature generator, intelligent PID temperature control technology to design the temperature control device, and a single chip to realize the intelligent control of data collection and detection processes. Through tests, it proved that various indices all satisfy the technical requirements for field detection and by comparing this detector with the regular laboratory detection and field calibration devices used in national automatic meteorological stations, the results of three devices are basically consistent. The temperature increase and decrease of this detector is fast, and it is portable and easy to operate. The detecting accuracy can satisfy the quality evaluation requirements of temperature detecting data in regional stations,which provide effective and feasible technical guarantee for the field testing of temperature sensor detectors in regional automatic weather stations.
This temperature sensor detector adopts semiconductor refrigeration technology to produce the temperature generator, intelligent PID temperature control technology to design the temperature control device, and a single chip to realize the intelligent control of data collection and detection processes. Through tests, it proved that various indices all satisfy the technical requirements for field detection and by comparing this detector with the regular laboratory detection and field calibration devices used in national automatic meteorological stations, the results of three devices are basically consistent. The temperature increase and decrease of this detector is fast, and it is portable and easy to operate. The detecting accuracy can satisfy the quality evaluation requirements of temperature detecting data in regional stations,which provide effective and feasible technical guarantee for the field testing of temperature sensor detectors in regional automatic weather stations.
2017, 45(2):228-233.
Abstract:
In order to study the influence of observation methods on precipitation measurements,several gauges and installation modes were used for experimental contrast in the atmospheric sounding testbed of CMAMOC. In this paper, we analyzed the different rain gauges and their influences of observation methods on rainfall measurements by using the experiment data,and gave the precipitation measurements of rain gauges. Result shows that the measuremens are highly relevant to gauge installation modes: the pit gauge recorded the maximum precipitation, followed by the records from the doublefence gauge,Tretyakov gauge, and normalinstallation gauge (the receiver is 70 cm above the ground). Result also shows that the current operational records by the normalinstallation gauge are slightly under the truth. Compared with rainfall measurements, snowfall measuremens are more susceptible to winds.
In order to study the influence of observation methods on precipitation measurements,several gauges and installation modes were used for experimental contrast in the atmospheric sounding testbed of CMAMOC. In this paper, we analyzed the different rain gauges and their influences of observation methods on rainfall measurements by using the experiment data,and gave the precipitation measurements of rain gauges. Result shows that the measuremens are highly relevant to gauge installation modes: the pit gauge recorded the maximum precipitation, followed by the records from the doublefence gauge,Tretyakov gauge, and normalinstallation gauge (the receiver is 70 cm above the ground). Result also shows that the current operational records by the normalinstallation gauge are slightly under the truth. Compared with rainfall measurements, snowfall measuremens are more susceptible to winds.
5 A Flexible Website Architecture of Weather China Based on Comprehensive Monitors and Load Control
2017, 45(2):234-239.
Abstract:
Weather China is the key Internet portal, from which CMA provides meteorological information to the public. In order to meet the requirements of growing load traffic, availability, and user experience, we established a comprehensive monitoring system which monitors various aspects including user experience, availability, website visits, and traffic, network, information security, operating systems, and applications. For many complex business scenarios,we present a set of load control methods aiming at those aspects, especially user experience, availability, cost and security. Based on the monitoring system and control methods, we build a flexible website architecture with CDN and multiple source data centers, which strengthens the capabilities in access experience, availability, bandwidth capacity, security, cost, and operational characteristics.
Weather China is the key Internet portal, from which CMA provides meteorological information to the public. In order to meet the requirements of growing load traffic, availability, and user experience, we established a comprehensive monitoring system which monitors various aspects including user experience, availability, website visits, and traffic, network, information security, operating systems, and applications. For many complex business scenarios,we present a set of load control methods aiming at those aspects, especially user experience, availability, cost and security. Based on the monitoring system and control methods, we build a flexible website architecture with CDN and multiple source data centers, which strengthens the capabilities in access experience, availability, bandwidth capacity, security, cost, and operational characteristics.
2017, 45(2):240-246.
Abstract:
Aiming at the defects and disadvantages of the traditional model data services,we study the classification and characteristics of model data in accordance with the Internet plus thinking. On this basis,we analyze in detail the resolution of the type, level, time, hour, data center, parameters, number, step, area, and grid in each model data and design the conversion algorithm from data configuration to MARS (Meteorological Archival and Retrival System) command scripts. The processes,databases,functions, and pages are designed from the viewpoint of usability, and a refined data service system is implemented based on B/S architecture. It greatly reduces the work intensity of the data service personnel and improves the working efficiency of operational and research users.
Aiming at the defects and disadvantages of the traditional model data services,we study the classification and characteristics of model data in accordance with the Internet plus thinking. On this basis,we analyze in detail the resolution of the type, level, time, hour, data center, parameters, number, step, area, and grid in each model data and design the conversion algorithm from data configuration to MARS (Meteorological Archival and Retrival System) command scripts. The processes,databases,functions, and pages are designed from the viewpoint of usability, and a refined data service system is implemented based on B/S architecture. It greatly reduces the work intensity of the data service personnel and improves the working efficiency of operational and research users.
2017, 45(2):247-253.
Abstract:
In order to improve the quality and efficiency of weather services in civil aviation,a warning system for aviation weather is proposed, in which through a series of warning levels for airport weather,users can retrieve the meteorological database periodically to get Aviation Weather Reports, calculate the weather alert levels for airports in China, and translate Aviation Weather Reports into plain language. Technologies, such as JSON (JavaScript Object Notation) and AJAX (Asynchronous Javascript And XML), are applied to send the analytical results to the browsers, which load map and display the weather alert levels of each airport through the BaiduMap API. This system achieved the function of allowing user through the PC and mobile devices to obtain the realtime display of the airport weather of the whole country, weather warnings and related data. The application indicates that the system has good reference value for the enhancement in application of API for maps in the aviation weather field, enriches and improves the way and efficiency of civil aviation meteorological services, being of broad prospects.
In order to improve the quality and efficiency of weather services in civil aviation,a warning system for aviation weather is proposed, in which through a series of warning levels for airport weather,users can retrieve the meteorological database periodically to get Aviation Weather Reports, calculate the weather alert levels for airports in China, and translate Aviation Weather Reports into plain language. Technologies, such as JSON (JavaScript Object Notation) and AJAX (Asynchronous Javascript And XML), are applied to send the analytical results to the browsers, which load map and display the weather alert levels of each airport through the BaiduMap API. This system achieved the function of allowing user through the PC and mobile devices to obtain the realtime display of the airport weather of the whole country, weather warnings and related data. The application indicates that the system has good reference value for the enhancement in application of API for maps in the aviation weather field, enriches and improves the way and efficiency of civil aviation meteorological services, being of broad prospects.
2017, 45(2):254-260.
Abstract:
With the popularity of mobile information technology development and smart phones and the increasing public demands for mobile Internet weather information service, such as WeChat, the public, especially coastal users, have increasingly high requirements for typhoon information in convenience, timeliness, and comprehensiveness. This article is to introduce the rapid iterative development of the Zhejiang typhoon information release system by using mobile Internet technology, which is suitable for WeChat propagation, and also can be downloaded from the mobile app market and able to meet the needs of the public.
With the popularity of mobile information technology development and smart phones and the increasing public demands for mobile Internet weather information service, such as WeChat, the public, especially coastal users, have increasingly high requirements for typhoon information in convenience, timeliness, and comprehensiveness. This article is to introduce the rapid iterative development of the Zhejiang typhoon information release system by using mobile Internet technology, which is suitable for WeChat propagation, and also can be downloaded from the mobile app market and able to meet the needs of the public.
2017, 45(2):261-268.
Abstract:
Finemesh grid element forecast is important service in the China Meteorological Administration,and also the future development direction of weather forecast. How to effectively provide forecast products to users is the final step of finemesh grid point forecast. This article introduces a finemesh grid point forecast and display system in Shaanxi based on the BaiduMap application programming interface. This system uses the dynamical bias correction method to improve precipitation forecast,based on the hourly fusion precipitation data of CMORPH (NOAA Climate Prediction Center Morphing Method) satellites and gauged rainfall from about 30 000 automatic weather stations. At the same time, the moving linear regression method is used to improve temperature prediction. It can get geographic information of any position and display 240hour meteorological element forecast in realtime for the corresponding grids. Through calculating the forecast values with the finemesh grid value for 98 station spots in Shaanxi for 3 hours, the errors between the precipitation forecast, temperature forecast and the observed values are analyzed in the last 24 hours in realtime for users to anticipate possible errors in future to provide the daily element forecast of 98 stations in the next 168 hours. Different from the previous database background support, the system reads the 35 GB gridpoint forecast data directly into memory at one time, and intercepts, so to solve the low efficiency problem of database searches and calls.
Finemesh grid element forecast is important service in the China Meteorological Administration,and also the future development direction of weather forecast. How to effectively provide forecast products to users is the final step of finemesh grid point forecast. This article introduces a finemesh grid point forecast and display system in Shaanxi based on the BaiduMap application programming interface. This system uses the dynamical bias correction method to improve precipitation forecast,based on the hourly fusion precipitation data of CMORPH (NOAA Climate Prediction Center Morphing Method) satellites and gauged rainfall from about 30 000 automatic weather stations. At the same time, the moving linear regression method is used to improve temperature prediction. It can get geographic information of any position and display 240hour meteorological element forecast in realtime for the corresponding grids. Through calculating the forecast values with the finemesh grid value for 98 station spots in Shaanxi for 3 hours, the errors between the precipitation forecast, temperature forecast and the observed values are analyzed in the last 24 hours in realtime for users to anticipate possible errors in future to provide the daily element forecast of 98 stations in the next 168 hours. Different from the previous database background support, the system reads the 35 GB gridpoint forecast data directly into memory at one time, and intercepts, so to solve the low efficiency problem of database searches and calls.
2017, 45(2):269-275.
Abstract:
In order to meet the needs of meteorological modernization and save resources, the design and application of meteorological resource pool are studied,which contains the construction of the server, storage resource pool,desktop and application resource pool,as well as the operational integration of the provincial, city, and county levels,and the innovation of “cloud+end” and mobility is conducted. Key technology, such as the composition of cloud computing, core technology, virtualization storing, application virtualization technology, network virtualization technology,and the mainstream methods are introduced. The overall architecture of the Anhui provincial meteorological service cloud platform,the server and storage resource pool, the virtual application and desktop resource pool and the methods of cloud platform management are presented. The performance comparison of traditional PC and desktop cloud systems and the comparison of fault handling reliability tests are conducted. The resource utilization and maintenance efficiency are improved after adopting cloud computing, and the 24hours power consumption and the preparation cycle of the server are reduced. The influencing and maintenance time of software failure is reduced. The result shows that the construction of the private cloud has practical application value.
In order to meet the needs of meteorological modernization and save resources, the design and application of meteorological resource pool are studied,which contains the construction of the server, storage resource pool,desktop and application resource pool,as well as the operational integration of the provincial, city, and county levels,and the innovation of “cloud+end” and mobility is conducted. Key technology, such as the composition of cloud computing, core technology, virtualization storing, application virtualization technology, network virtualization technology,and the mainstream methods are introduced. The overall architecture of the Anhui provincial meteorological service cloud platform,the server and storage resource pool, the virtual application and desktop resource pool and the methods of cloud platform management are presented. The performance comparison of traditional PC and desktop cloud systems and the comparison of fault handling reliability tests are conducted. The resource utilization and maintenance efficiency are improved after adopting cloud computing, and the 24hours power consumption and the preparation cycle of the server are reduced. The influencing and maintenance time of software failure is reduced. The result shows that the construction of the private cloud has practical application value.
2017, 45(2):276-280.
Abstract:
Aiming at the troubleshooting of AWS temperature signal interference in the north suburbs of Taiyuan, a detailed analysis is made of the signal transmission mode and structure of the DYYZII automatic weather station,the distribution,working principles of the equipment grounding grid,and earthing resistance measurements, as well as the influence of metal oxides on actual grounding effectiveness in the grounding wire and the origin of the temperature sensor signal interference. The earthing resistance correspondence between requirements and actual grounding effect is discussed,and it is point out that meeting the requirements of grounding resistance values is not necessarily equal to meeting the requirements of the actual grounding effect. The troubleshooting and verification process indicates that there is direct impact of metal oxides on the conductivity of the grounding wire,which provides an analytical solution for future AWS temperature signal interference researches.
Aiming at the troubleshooting of AWS temperature signal interference in the north suburbs of Taiyuan, a detailed analysis is made of the signal transmission mode and structure of the DYYZII automatic weather station,the distribution,working principles of the equipment grounding grid,and earthing resistance measurements, as well as the influence of metal oxides on actual grounding effectiveness in the grounding wire and the origin of the temperature sensor signal interference. The earthing resistance correspondence between requirements and actual grounding effect is discussed,and it is point out that meeting the requirements of grounding resistance values is not necessarily equal to meeting the requirements of the actual grounding effect. The troubleshooting and verification process indicates that there is direct impact of metal oxides on the conductivity of the grounding wire,which provides an analytical solution for future AWS temperature signal interference researches.
2017, 45(2):281-284.
Abstract:
In the countylevel network topology of the Shaanxi meteorological communication system,a single router connects two ISPlinks simultaneously. This architecture may lead to high risk of singlepoint failure and competition for bandwidth among different services as well. To tackle these two problems,this article proposes a dualrouter architecture,each connecting an ISP line respectively. Configuring Virtual Router Redundancy Protocol (VRRP),with load balance mode enabled,the data flow sharing between two ISP lines can be realized. Both router hot standby and link redundancy are achieved under this schema. Furthermore, the Bidirectional Forwarding Detection (BFD) is employed to improve the switch speed between Master and Backup router of VRRP. After the application of about one year, the result indicates that the design target is achieved. The system offers a reference for other municipal or county level meteorological network system designing and implementation.
In the countylevel network topology of the Shaanxi meteorological communication system,a single router connects two ISPlinks simultaneously. This architecture may lead to high risk of singlepoint failure and competition for bandwidth among different services as well. To tackle these two problems,this article proposes a dualrouter architecture,each connecting an ISP line respectively. Configuring Virtual Router Redundancy Protocol (VRRP),with load balance mode enabled,the data flow sharing between two ISP lines can be realized. Both router hot standby and link redundancy are achieved under this schema. Furthermore, the Bidirectional Forwarding Detection (BFD) is employed to improve the switch speed between Master and Backup router of VRRP. After the application of about one year, the result indicates that the design target is achieved. The system offers a reference for other municipal or county level meteorological network system designing and implementation.
2017, 45(2):285-297.
Abstract:
Wind profiler radar (WPR) is the vertical wind profile detection equipment, which has been attached great importance to the development in China and plays an important role in weather forecast and nowcasting. This paper reviews the application of wind profiler radar data in different types of severe weather monitoring and forecasting. The main problems in the application and its prospects are discussed. WPR products can monitor not only the structures and evolution of different scale weather systems,but also the phase of the precipitation and estimate the size and height distributions of precipitation particles. Wind profiler data has positive impact on the Rapid Update Cycle (RUC) model and mesoscale models, and help provide improved skill in shortrange weather forecasts. The operational application of severe weather monitoring and forecasting by single stations and the network of WPR is illustrated to provide some references for NWS forecasters.
Wind profiler radar (WPR) is the vertical wind profile detection equipment, which has been attached great importance to the development in China and plays an important role in weather forecast and nowcasting. This paper reviews the application of wind profiler radar data in different types of severe weather monitoring and forecasting. The main problems in the application and its prospects are discussed. WPR products can monitor not only the structures and evolution of different scale weather systems,but also the phase of the precipitation and estimate the size and height distributions of precipitation particles. Wind profiler data has positive impact on the Rapid Update Cycle (RUC) model and mesoscale models, and help provide improved skill in shortrange weather forecasts. The operational application of severe weather monitoring and forecasting by single stations and the network of WPR is illustrated to provide some references for NWS forecasters.
2017, 45(2):298-306.
Abstract:
Using CMIP5 multimode collection data, we analyze the climate change under different scenarios(RCP26,RCP45,RCP85) in Northeast China over the next 100 years from time and space distributions. The results show that under three emission scenarios, the temperature and precipitation during the 21st Century in Northeast China show a significant growth trend; at the medium and late stages, there is obvious increase with the increase higher in winter than in other seasons; under the RCP85 scenario, the warming is most significant,RCP45 follows,RCP26 the least; over years, the annual ranges of temperature and precipitation anomalies decreased and their spatial distributions show that the temperature increase distributions in various periods are basically consistent, gradually increasing from south to north; the warming is the smallest in the southern Liaoning and the most notable in the Daxinganling area; the distributions of temperature change rates under different scenarios are slightly different, with significant warming trends; the precipitation anomaly percentage has an increasing trend, with a meridional distribution of gradual increase from east to west; the rates of precipitation change are similar, presenting the characteristics of greater in South and smaller in north; the growth is most obvious in Liaoning,and relatively small in the western Heilongjiang.
Using CMIP5 multimode collection data, we analyze the climate change under different scenarios(RCP26,RCP45,RCP85) in Northeast China over the next 100 years from time and space distributions. The results show that under three emission scenarios, the temperature and precipitation during the 21st Century in Northeast China show a significant growth trend; at the medium and late stages, there is obvious increase with the increase higher in winter than in other seasons; under the RCP85 scenario, the warming is most significant,RCP45 follows,RCP26 the least; over years, the annual ranges of temperature and precipitation anomalies decreased and their spatial distributions show that the temperature increase distributions in various periods are basically consistent, gradually increasing from south to north; the warming is the smallest in the southern Liaoning and the most notable in the Daxinganling area; the distributions of temperature change rates under different scenarios are slightly different, with significant warming trends; the precipitation anomaly percentage has an increasing trend, with a meridional distribution of gradual increase from east to west; the rates of precipitation change are similar, presenting the characteristics of greater in South and smaller in north; the growth is most obvious in Liaoning,and relatively small in the western Heilongjiang.
15 Simplification of Barometric Height Formula in Geopotential Height Calculation and Resulted Errors
2017, 45(2):307-312.
Abstract:
The geopotential height is usually calculated with the measured temperature,pressure and humidity, and the calculation formula is called barometric height formula. In this paper,we analyze the derivation of the formula and point out that the origin of the simplified formula. The errors caused by the simplification are calculated quantitatively. The analysis shows that the gravitational acceleration in the barometric height formula should be the local actual variable value instead of the current constant value,and the replacement can reduce errors of the potential height calculation.
The geopotential height is usually calculated with the measured temperature,pressure and humidity, and the calculation formula is called barometric height formula. In this paper,we analyze the derivation of the formula and point out that the origin of the simplified formula. The errors caused by the simplification are calculated quantitatively. The analysis shows that the gravitational acceleration in the barometric height formula should be the local actual variable value instead of the current constant value,and the replacement can reduce errors of the potential height calculation.
2017, 45(2):313-323.
Abstract:
Based on the Data Sets of CMASTI Tropical Cyclones Optimal Tracks from 1949 to 2015, the NCEP 25°×25° reanalysis data, and conventional data, the characteristics of northward moving Tropical Cyclones (TC,Tropical Cyclones) are studied. The results show that there were 91 TCs moving northward into the defined area from 1949 to 2015,accounting for 41% of total TCs over the Northwest Pacific(including the South China Sea), and the annual average was 14 The TCs entered the definition areas the earliest in May,the latest in September,most frequently in August,and moving northward most likely in July. Based on the morphological characteristics of TCs, the tracks of northward moving TCs are divided into turning northward and moving northward directly. The tracks of TCs after turning northward are in close relationship with turning points. It is important to forecast the tracks of northward moving TCs. The sources of northward moving TCs are ranging from 8° to 25°N，122° to 155°E. There are differences in latitude and longitude distributions for the different sources. For the northerly source TCs,there is a great possibility of more northerly turning points and directly northward moving. The life history of northward moving TCs reaches the maximum intensity around 20°N out of the definition areas. When entering the definition areas, TCs are mostly downgraded to tropical storms and the stronger the intensity, the faster TCs weaken, and after entering the influence areas, the neutral TCs increase.The tracks of northward moving TCs are relevant with the position, shape, and intensity of the West Pacific subtropical high. The steering currents in the high ridge of the west edge of the subtropical high decide the future TC track turning or northward moving. The position of the west ridge points decides the position of future TC turning points. There are differences in torrential rain and high wind regions for different northward moving TC tracks. The mainly tracks of bringing strong rainfall and winds include midlatitude turning,highlatitude turning, and direct northward.
Based on the Data Sets of CMASTI Tropical Cyclones Optimal Tracks from 1949 to 2015, the NCEP 25°×25° reanalysis data, and conventional data, the characteristics of northward moving Tropical Cyclones (TC,Tropical Cyclones) are studied. The results show that there were 91 TCs moving northward into the defined area from 1949 to 2015,accounting for 41% of total TCs over the Northwest Pacific(including the South China Sea), and the annual average was 14 The TCs entered the definition areas the earliest in May,the latest in September,most frequently in August,and moving northward most likely in July. Based on the morphological characteristics of TCs, the tracks of northward moving TCs are divided into turning northward and moving northward directly. The tracks of TCs after turning northward are in close relationship with turning points. It is important to forecast the tracks of northward moving TCs. The sources of northward moving TCs are ranging from 8° to 25°N，122° to 155°E. There are differences in latitude and longitude distributions for the different sources. For the northerly source TCs,there is a great possibility of more northerly turning points and directly northward moving. The life history of northward moving TCs reaches the maximum intensity around 20°N out of the definition areas. When entering the definition areas, TCs are mostly downgraded to tropical storms and the stronger the intensity, the faster TCs weaken, and after entering the influence areas, the neutral TCs increase.The tracks of northward moving TCs are relevant with the position, shape, and intensity of the West Pacific subtropical high. The steering currents in the high ridge of the west edge of the subtropical high decide the future TC track turning or northward moving. The position of the west ridge points decides the position of future TC turning points. There are differences in torrential rain and high wind regions for different northward moving TC tracks. The mainly tracks of bringing strong rainfall and winds include midlatitude turning,highlatitude turning, and direct northward.
2017, 45(2):324-330.
Abstract:
By use of the data of 33 coastal weather stations in Zhejiang from 1958 to 2012, the occurrence and dissipation characteristics of coastal fogs and the relationship between coastal fog and surface wind are analyzed. The results show that the annual mean number of fog days is over 10 days at 28 stations and the distribution in the whole coastal area is relatively uniform. The annual mean number of coastal fog days in Zhejiang is 517 days from 1971 to 2012, which presents obvious interannual characteristics. The coastal fog also has seasonal and monthly variation. The number of fog days is the greatest in spring and early summer. Coastal fogs have obvious diurnal variation: mainly form from 23:00 to 06:00 and dissipate from 06:00 to 10:00 Coastal fogs occur mostly under the southern wind condition with the wind speed being less 120 m/s. The weather situations corresponding the coastal fogs from 2005 to 2011 are analyzed. The main circulation patterns for fog occurrence include the western extratropical coldcore high, the surface inverted trough, the forepart of the stationary front or cold front, the bottom of weak high pressure, saddle field, and the southwest Japan Sea high.
By use of the data of 33 coastal weather stations in Zhejiang from 1958 to 2012, the occurrence and dissipation characteristics of coastal fogs and the relationship between coastal fog and surface wind are analyzed. The results show that the annual mean number of fog days is over 10 days at 28 stations and the distribution in the whole coastal area is relatively uniform. The annual mean number of coastal fog days in Zhejiang is 517 days from 1971 to 2012, which presents obvious interannual characteristics. The coastal fog also has seasonal and monthly variation. The number of fog days is the greatest in spring and early summer. Coastal fogs have obvious diurnal variation: mainly form from 23:00 to 06:00 and dissipate from 06:00 to 10:00 Coastal fogs occur mostly under the southern wind condition with the wind speed being less 120 m/s. The weather situations corresponding the coastal fogs from 2005 to 2011 are analyzed. The main circulation patterns for fog occurrence include the western extratropical coldcore high, the surface inverted trough, the forepart of the stationary front or cold front, the bottom of weak high pressure, saddle field, and the southwest Japan Sea high.
2017, 45(2):331-341.
Abstract:
Based on the daily precipitation datasets of 158 stations in Sichuan from 1961 to 2014,the definition and characteristics of persistent heavy rainfall in the last 54 years in Sichuan, for the single station persistent heavy rainfall and the regional persistent heavy rainfall,are discussed,respectively. According to the first definition, the results show that the single station persistent heavy rainfall occurred in September frequently, and mostly in northwest，southwest, and northeast of Sichuan in the last 54 years. The single station persistent heavy rainfall usually lasts 3 days, and can bring 150 to 200 mm of rainfall to the local place. The frequency of the single station persistent heavy rainfall was 1 to 3 in the Panxi area. The single station persistent heavy rainfall had the largest range in June, and lasted 4 days at most. According to the second definition, the results show that the regional persistent heavy rainfall occurred in July frequently, and the characteristics of geographical distribution of regional persistent heavy rainfall were consistent with those the single station persistent heavy rainfall: the high incidence areas of the regional persistent heavy rainfall were in the western area of the basin and the northeastern hillside area of the basin. The regional persistent heavy rainfall occurred frequently after 2001, specifically the heavy rainfall events of lasting 3 days, but their strength reduced slightly.
Based on the daily precipitation datasets of 158 stations in Sichuan from 1961 to 2014,the definition and characteristics of persistent heavy rainfall in the last 54 years in Sichuan, for the single station persistent heavy rainfall and the regional persistent heavy rainfall,are discussed,respectively. According to the first definition, the results show that the single station persistent heavy rainfall occurred in September frequently, and mostly in northwest，southwest, and northeast of Sichuan in the last 54 years. The single station persistent heavy rainfall usually lasts 3 days, and can bring 150 to 200 mm of rainfall to the local place. The frequency of the single station persistent heavy rainfall was 1 to 3 in the Panxi area. The single station persistent heavy rainfall had the largest range in June, and lasted 4 days at most. According to the second definition, the results show that the regional persistent heavy rainfall occurred in July frequently, and the characteristics of geographical distribution of regional persistent heavy rainfall were consistent with those the single station persistent heavy rainfall: the high incidence areas of the regional persistent heavy rainfall were in the western area of the basin and the northeastern hillside area of the basin. The regional persistent heavy rainfall occurred frequently after 2001, specifically the heavy rainfall events of lasting 3 days, but their strength reduced slightly.
2017, 45(2):342-348.
Abstract:
The cloudtoground flash data (2004-2015) monitored by the Jiangxi lightning location system is analyzed,through the methods of statistics and linear regression to reveal the impact of different altitudes on lightning characteristics. The results show: (1) In Jiangxi Province,835% of lightning and 910% of positive lightning occurred in the plain and hill areas （with the total area being 74000 km2） and mountain area (the total area being 61000 km2） at the altitudes of 0 to 500 m above sea level. (2) The lightning density gradually decreases with the increase of altitude and the rate of change is different at the different altitudes; the current intensity of positive and negative lightning increases with the increase of altitude, and the rate of change is different at the different altitudes; the change of positive lightning is significant, and the variation of negative lightning is less than that of the positive lightning. (3)The proportion of heavy lightning area is the largest and the heavy lightning areas are basically in the southern Jiangxi; the heavy lightning and strong lightning areas are in the plain, hill and mountain areas with the altitudes ranging from 0 to 500 m; the weak lightning area is mainly in the mountain area with the altitudes ranging from 500 to 2200 m.
The cloudtoground flash data (2004-2015) monitored by the Jiangxi lightning location system is analyzed,through the methods of statistics and linear regression to reveal the impact of different altitudes on lightning characteristics. The results show: (1) In Jiangxi Province,835% of lightning and 910% of positive lightning occurred in the plain and hill areas （with the total area being 74000 km2） and mountain area (the total area being 61000 km2） at the altitudes of 0 to 500 m above sea level. (2) The lightning density gradually decreases with the increase of altitude and the rate of change is different at the different altitudes; the current intensity of positive and negative lightning increases with the increase of altitude, and the rate of change is different at the different altitudes; the change of positive lightning is significant, and the variation of negative lightning is less than that of the positive lightning. (3)The proportion of heavy lightning area is the largest and the heavy lightning areas are basically in the southern Jiangxi; the heavy lightning and strong lightning areas are in the plain, hill and mountain areas with the altitudes ranging from 0 to 500 m; the weak lightning area is mainly in the mountain area with the altitudes ranging from 500 to 2200 m.
2017, 45(2):349-354.
Abstract:
The decision tree analysis method is applied to Doppler radar data to identify hail weather. Based on the radar data of 25 cases of hails in the Tianjin area from April to September, 2005 to 2014, we select 6 parameters: probability of hail (POH), probability of severe hail (POSH), vertically integrated liquid water (VIL), maximum reflectivity (DBZM), the height of storms centroid (HT), and the top of storm (TOP). By the decision tree analysis method, we found that there will be hail weather when DBZM is greater that 545 dBz and POSH is greater than 35 Using the decision tree analysis method,we have better results: the percent of doom (POD) is 902% and critical success index (CSI) is 784%, which are higher than the results by the discriminant analysis method.
The decision tree analysis method is applied to Doppler radar data to identify hail weather. Based on the radar data of 25 cases of hails in the Tianjin area from April to September, 2005 to 2014, we select 6 parameters: probability of hail (POH), probability of severe hail (POSH), vertically integrated liquid water (VIL), maximum reflectivity (DBZM), the height of storms centroid (HT), and the top of storm (TOP). By the decision tree analysis method, we found that there will be hail weather when DBZM is greater that 545 dBz and POSH is greater than 35 Using the decision tree analysis method,we have better results: the percent of doom (POD) is 902% and critical success index (CSI) is 784%, which are higher than the results by the discriminant analysis method.
2017, 45(2):355-363.
Abstract:
Based on the data from the Doppler radar, two wind profilers in Baodi and Xiqing, the tower in Tianjin, as well as NCEP/NCAR 1°×1° reanalysis data, radiosonde data,intensified automatic surface observation data and automatic station minute data, a thunderstorm case in Tianjin on 8 June 2014 is analyzed. The results show: (1) It is a thunderstorm gale case of the northwestern current type, in which the wind vertical shear with a large temperature lapse rate was favorable for the occurrence of disastrous gale. (2) This case experienced three stages: bow echo complex, gust front, and cell bow echo. The intensity of the thunderstorm wind was related to the falling time and the height of the echo core: the higher extension of height, the shorter the falling time, the stronger of the thunderstorm. (3) The rapid movement of a strong cold pool was direct cause of the bow echo complex. The wind profiler data indicate that the intrusion of dry cold air was at 23 km in the bow echo complex, with a 10 minute lead time for wind gust in the surface. The surface mesoscale convergence line matching with surface highly unstable region triggered the thunderstorm at the stage of the cell bow echo. (4) When the gust front approaching, the rising flow was in coexistence with the sinking flow; the sink flow began at the boundary layer below 15 km with the maximum up to 09 m〖DK〗·s-1 at 630 to 750 m. The downward propagation of the sinking velocity peak indicated the emergence of the gust about 20 minute in advance, while the upward was above 2 km in the middle and lower troposphere.
Based on the data from the Doppler radar, two wind profilers in Baodi and Xiqing, the tower in Tianjin, as well as NCEP/NCAR 1°×1° reanalysis data, radiosonde data,intensified automatic surface observation data and automatic station minute data, a thunderstorm case in Tianjin on 8 June 2014 is analyzed. The results show: (1) It is a thunderstorm gale case of the northwestern current type, in which the wind vertical shear with a large temperature lapse rate was favorable for the occurrence of disastrous gale. (2) This case experienced three stages: bow echo complex, gust front, and cell bow echo. The intensity of the thunderstorm wind was related to the falling time and the height of the echo core: the higher extension of height, the shorter the falling time, the stronger of the thunderstorm. (3) The rapid movement of a strong cold pool was direct cause of the bow echo complex. The wind profiler data indicate that the intrusion of dry cold air was at 23 km in the bow echo complex, with a 10 minute lead time for wind gust in the surface. The surface mesoscale convergence line matching with surface highly unstable region triggered the thunderstorm at the stage of the cell bow echo. (4) When the gust front approaching, the rising flow was in coexistence with the sinking flow; the sink flow began at the boundary layer below 15 km with the maximum up to 09 m〖DK〗·s-1 at 630 to 750 m. The downward propagation of the sinking velocity peak indicated the emergence of the gust about 20 minute in advance, while the upward was above 2 km in the middle and lower troposphere.
2017, 45(2):364-374.
Abstract:
The primary goal is to evaluate and discuss the validation of gridded precipitation and temperature data by means of three products (ANUSPLIN,SHERPAD,and Optimal Interpolation Method)at 05°×05° spatial resolution, using the daily data of precipitation and temperature from the network of 2419 national ground meteorological stations and 839 basic/reference meteorological stations from the National Meteorological Information Center (NMIC) of China in 2013 Results show that the accuracy of gridded precipitation and temperature data is higher, when the number of stations is greater. The correlation coefficient increases and the root mean square error (RMSE) decrease with increasing station density, which are different and change with seasons and months. The correlation coefficient and RMSE calculated from gridded precipitation in summer are better than those of the whole year,and the correlation coefficient calculated from gridded temperature in summer is worse than that of the whole year. The time series of evaluation indexes has greater uncertainty and larger fluctuation range for gridded precipitation than for gridded temperature. The comprehensive evaluation of the gridded precipitation data based on the climatic background filed by the Optimal Interpolation Method of NMIC and the elevation of the gridded temperature data by ANUSPLIN of NMIC are better than others.
The primary goal is to evaluate and discuss the validation of gridded precipitation and temperature data by means of three products (ANUSPLIN,SHERPAD,and Optimal Interpolation Method)at 05°×05° spatial resolution, using the daily data of precipitation and temperature from the network of 2419 national ground meteorological stations and 839 basic/reference meteorological stations from the National Meteorological Information Center (NMIC) of China in 2013 Results show that the accuracy of gridded precipitation and temperature data is higher, when the number of stations is greater. The correlation coefficient increases and the root mean square error (RMSE) decrease with increasing station density, which are different and change with seasons and months. The correlation coefficient and RMSE calculated from gridded precipitation in summer are better than those of the whole year,and the correlation coefficient calculated from gridded temperature in summer is worse than that of the whole year. The time series of evaluation indexes has greater uncertainty and larger fluctuation range for gridded precipitation than for gridded temperature. The comprehensive evaluation of the gridded precipitation data based on the climatic background filed by the Optimal Interpolation Method of NMIC and the elevation of the gridded temperature data by ANUSPLIN of NMIC are better than others.
2017, 45(2):375-382.
Abstract:
Based on the daily precipitation, temperature and sunshine data from 80 meteorological stations in Hunan, NCEP/NCAR reanalysis data and sea temperature data from 1961 to 2013, the distribution types, the circulation patterns of the same period, and the previous winter SST field characteristics of cold rainy weather during spring sowing and seedlingraising periods in the past 53 years are studied. The results show: (1) There are mainly two anomalous distribution types: above normal (below normal)in whole province; above normal (below normal)in the northern and below normal (above normal) in the southern.(2) When East Asia major trough controls over the Eurasia, coupled with the convergence of lowlevel cold and worm air and the better humidity conditions, the above normal in whole province types is prone to appear. On the contrary, when the Eurasia is controlled by high pressure, coupled with the lowlevel abnormal north winds in the mideastern China and negative relative humidity, the below normal in whole province type is easy to appear. When the northern Hunan is affected by a trough and relative humidity is relatively high, the above normal in the northern province and below normal in the southern province types are easy to appear. When the southern Hunan is affected by a trough and topography and the Nanling stationary front, at the same time, the relative humidity in its south part is relatively high, the below normal in the northern province and above normal in the southern province types are easy to appear.(3) The above normal (below normal) in whole province type is easy to appear if the previous winter SST in the area of the equatorial central and eastern Pacific and Alaska is obviously higher (lower) than normal and that in the area of the Northwest Pacific Ocean and North Atlantic Ocean in the east of North America is obviously lower (higher) than normal. The above normal (below normal) in the northern province and below normal (above normal) in the southern province type is easy to appear if the previous winter SST is obviously higher (lower) than normal in both the area of the equatorial central and eastern Pacific and Alaska and the area of the Northwest Pacific Ocean, and that in the North Atlantic Ocean in the east of North America.
Based on the daily precipitation, temperature and sunshine data from 80 meteorological stations in Hunan, NCEP/NCAR reanalysis data and sea temperature data from 1961 to 2013, the distribution types, the circulation patterns of the same period, and the previous winter SST field characteristics of cold rainy weather during spring sowing and seedlingraising periods in the past 53 years are studied. The results show: (1) There are mainly two anomalous distribution types: above normal (below normal)in whole province; above normal (below normal)in the northern and below normal (above normal) in the southern.(2) When East Asia major trough controls over the Eurasia, coupled with the convergence of lowlevel cold and worm air and the better humidity conditions, the above normal in whole province types is prone to appear. On the contrary, when the Eurasia is controlled by high pressure, coupled with the lowlevel abnormal north winds in the mideastern China and negative relative humidity, the below normal in whole province type is easy to appear. When the northern Hunan is affected by a trough and relative humidity is relatively high, the above normal in the northern province and below normal in the southern province types are easy to appear. When the southern Hunan is affected by a trough and topography and the Nanling stationary front, at the same time, the relative humidity in its south part is relatively high, the below normal in the northern province and above normal in the southern province types are easy to appear.(3) The above normal (below normal) in whole province type is easy to appear if the previous winter SST in the area of the equatorial central and eastern Pacific and Alaska is obviously higher (lower) than normal and that in the area of the Northwest Pacific Ocean and North Atlantic Ocean in the east of North America is obviously lower (higher) than normal. The above normal (below normal) in the northern province and below normal (above normal) in the southern province type is easy to appear if the previous winter SST is obviously higher (lower) than normal in both the area of the equatorial central and eastern Pacific and Alaska and the area of the Northwest Pacific Ocean, and that in the North Atlantic Ocean in the east of North America.
2017, 45(2):383-389.
Abstract:
Using the regional boundary layer model developed by the Nanjing University (RBLM), the radiosonde and ground observation data of the Yinchuan national reference climatological station,the characteristics of the temperature fields before and after the implementation of the current urban planning are simulated under three typical wind speed conditions in four seasons. Results show that in the present situation, the high temperature area is greater in small wind and high wind conditions than in general wind condition in summer; the high temperature area is the largest in small wind and the least in high wind in winter; the high temperature area is the largest in general wind in the spring and autumn. The urban heat island effect is very significant in all seasons in Yinchuan, and temperature is greater around the waters than in the urban area in the night time, and vice versa in the day time, especially around 14:00 At 14:00 air temperature in the urban construction is obviously higher, and the denser the construction sites, the higher temperature is; only in the winter small wind and the spring strong wind conditions, the difference is small. After the implementation of the urban planning, the temperature field distributions under three kinds of typical wind conditions are consistent with the present situation in general,but the high temperature area is smaller and the low temperature area is larger. Under the three typical wind conditions, the heat island area is less, and the urban heat island effect weakens, compared to that before the implementation of the urban planning.
Using the regional boundary layer model developed by the Nanjing University (RBLM), the radiosonde and ground observation data of the Yinchuan national reference climatological station,the characteristics of the temperature fields before and after the implementation of the current urban planning are simulated under three typical wind speed conditions in four seasons. Results show that in the present situation, the high temperature area is greater in small wind and high wind conditions than in general wind condition in summer; the high temperature area is the largest in small wind and the least in high wind in winter; the high temperature area is the largest in general wind in the spring and autumn. The urban heat island effect is very significant in all seasons in Yinchuan, and temperature is greater around the waters than in the urban area in the night time, and vice versa in the day time, especially around 14:00 At 14:00 air temperature in the urban construction is obviously higher, and the denser the construction sites, the higher temperature is; only in the winter small wind and the spring strong wind conditions, the difference is small. After the implementation of the urban planning, the temperature field distributions under three kinds of typical wind conditions are consistent with the present situation in general,but the high temperature area is smaller and the low temperature area is larger. Under the three typical wind conditions, the heat island area is less, and the urban heat island effect weakens, compared to that before the implementation of the urban planning.
Chen Jing
,
Xie Yiyang
,
Zhang Rongyan
,
Li Peiyang
,
Yan Pingyong
,
Duan Liyao
,
Qiu Xiaobin
,
Wang Xuelian
2017, 45(2):390-397.
Abstract:
According to the topography, geomorphology, and drainage system of the Putian coastal area, the Putian Coastal StormSurge TorrentialRain Waterlogging Simulation Model is established, aiming at the influence of both storm surge and typhooninduced torrential rainfall. Using the area rainfall calculated with the quantitative estimation of precipitation using radar and AWS’s, and the boundary conditions of the model based on the dynamic water level set at the coastal border and the estuary, the operational experiment for the risk assessment of storm surge disaster in Putian area was carried out during Typhoon Nanmadol. The model is used in experimental research for the storm surge caused by Typhoon Nanmadol on 1 September 2011. These simulation results are directly used in contrasting and assessing the actual disaster caused by Typhoon Nanmadol. The simulation results are close to the actual disaster, which will lay a foundation for risk assessment and division on the typhoon and torrential rain scenarios.
According to the topography, geomorphology, and drainage system of the Putian coastal area, the Putian Coastal StormSurge TorrentialRain Waterlogging Simulation Model is established, aiming at the influence of both storm surge and typhooninduced torrential rainfall. Using the area rainfall calculated with the quantitative estimation of precipitation using radar and AWS’s, and the boundary conditions of the model based on the dynamic water level set at the coastal border and the estuary, the operational experiment for the risk assessment of storm surge disaster in Putian area was carried out during Typhoon Nanmadol. The model is used in experimental research for the storm surge caused by Typhoon Nanmadol on 1 September 2011. These simulation results are directly used in contrasting and assessing the actual disaster caused by Typhoon Nanmadol. The simulation results are close to the actual disaster, which will lay a foundation for risk assessment and division on the typhoon and torrential rain scenarios.
2017, 45(2):398-404.
Abstract:
A laboratory experiment was performed in order to dissipate the warm fog by using 6 kinds of hygroscopic catalysts of powdered rareearth salt materials in a 43 m3 warm cloud chamber. The microphysical characteristic data of warm fog, such as number concentration, diameters of fog droplets, and fog droplet spectrum,were continuously detected by a fog monitor (FM100). The fog transmissivity,temperature, and humidity of the cloud chamber were also continuously measured during every experiment process. Eight experiments, including two blank experiments (BE) of fog disperse spontaneously and six seeding experiments (SE) of fog seeding by using rareearth salts catalysts, were executed. The characteristic differences of warm fog in eight experiments are analyzed,and the effect and physical mechanisms of fog dispersal effect of 6 catalysts are studied through comparing measuring data between 2 BE and 6 SE. The experimental results show that 5 kinds of catalysts, including CeCl3, La(NO3)3, La2(CO3)3, LaCl3 and Ce2(CO3)3, can dispel warm fogs in the experiments,but Ce(NO3)3 can not achieve the effect of fog dispersal. There are differences in the effects on fog dispersal among five effective catalysts. The effects of CeCl3, La(NO3)3 and La2(CO3)3 are preferable,and those of LaCl3 and Ce2(CO3)3take second place. The analysis shows that the microphysical characteristics of warm fogs were obviously changed through seeding hygroscopic catalytic agents. The fog dissipation processes were accelerated or postponed because of seeding in 6 SEs.
A laboratory experiment was performed in order to dissipate the warm fog by using 6 kinds of hygroscopic catalysts of powdered rareearth salt materials in a 43 m3 warm cloud chamber. The microphysical characteristic data of warm fog, such as number concentration, diameters of fog droplets, and fog droplet spectrum,were continuously detected by a fog monitor (FM100). The fog transmissivity,temperature, and humidity of the cloud chamber were also continuously measured during every experiment process. Eight experiments, including two blank experiments (BE) of fog disperse spontaneously and six seeding experiments (SE) of fog seeding by using rareearth salts catalysts, were executed. The characteristic differences of warm fog in eight experiments are analyzed,and the effect and physical mechanisms of fog dispersal effect of 6 catalysts are studied through comparing measuring data between 2 BE and 6 SE. The experimental results show that 5 kinds of catalysts, including CeCl3, La(NO3)3, La2(CO3)3, LaCl3 and Ce2(CO3)3, can dispel warm fogs in the experiments,but Ce(NO3)3 can not achieve the effect of fog dispersal. There are differences in the effects on fog dispersal among five effective catalysts. The effects of CeCl3, La(NO3)3 and La2(CO3)3 are preferable,and those of LaCl3 and Ce2(CO3)3take second place. The analysis shows that the microphysical characteristics of warm fogs were obviously changed through seeding hygroscopic catalytic agents. The fog dissipation processes were accelerated or postponed because of seeding in 6 SEs.
2017, 45(2):405-408.
Abstract:
In order to study the equivalent relation between the maximum discharge currents (〖WTBX〗I〖WTBZ〗max)of two types of SPDs (ClassⅡ test and ClassⅠ test), the paper uses the method of taking 〖WTBX〗I〖WTBZ〗max 〖KG*5〗(8/20 μs) and 〖WTBX〗I〖WTBZ〗imp〖KG*5〗(10/35 μs) current waves as oblique waves, and calculates the 〖WTBX〗I〖WTBZ〗max〖KG*5〗(8/20 μs) current wave energy exerted on the ClassⅡ test SPD and 〖WTBX〗I〖WTBZ〗imp〖KG*5〗(10/350 μs) current wave energy exerted on the ClassⅠtest SPD, equals the energy of the two, then calculates the ratio of 〖WTBX〗I〖WTBZ〗max〖KG*5〗(8/20 μs)and 〖WTBX〗I〖WTBZ〗imp〖KG*5〗(10/350 μs), both of which should be satisfied. It is concluded through the calculation that when the voltage protection level of ClassⅡ test SPD is equal to that of ClassⅠtest SPD and the ClassⅡ test SPD maximum discharge current is 2156 times as much as that of ClassⅠtest SPD, the both bear the same energy.
In order to study the equivalent relation between the maximum discharge currents (〖WTBX〗I〖WTBZ〗max)of two types of SPDs (ClassⅡ test and ClassⅠ test), the paper uses the method of taking 〖WTBX〗I〖WTBZ〗max 〖KG*5〗(8/20 μs) and 〖WTBX〗I〖WTBZ〗imp〖KG*5〗(10/35 μs) current waves as oblique waves, and calculates the 〖WTBX〗I〖WTBZ〗max〖KG*5〗(8/20 μs) current wave energy exerted on the ClassⅡ test SPD and 〖WTBX〗I〖WTBZ〗imp〖KG*5〗(10/350 μs) current wave energy exerted on the ClassⅠtest SPD, equals the energy of the two, then calculates the ratio of 〖WTBX〗I〖WTBZ〗max〖KG*5〗(8/20 μs)and 〖WTBX〗I〖WTBZ〗imp〖KG*5〗(10/350 μs), both of which should be satisfied. It is concluded through the calculation that when the voltage protection level of ClassⅡ test SPD is equal to that of ClassⅠtest SPD and the ClassⅡ test SPD maximum discharge current is 2156 times as much as that of ClassⅠtest SPD, the both bear the same energy.
External LinksChina Meteorological AdministrationCMA Meteorological Observation CentreChinese Academy of Meteorological SciencesBeijing Meteorological ServiceNational Satellite Meteorological Center
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