Volume 40,Issue 3,2012 Table of Contents
2012, 40(3):321-331.
Abstract:
With the development of radar technology across the world, the domestic radar has developed from conventional radar to single polarization Doppler, then double polarization Doppler, with the target information obtained being more abundant. The principles and product information of conventional radar, single polarization Doppler, and double polarization Doppler radar are introduced in detail. The performances of the next generation S , C , and X band radar are compared, which has a certain reference value for the selection of the radar wavelength. The millimeter wave Doppler radar is also introduced, which can obtain cloud structure information. The performance and trends of the next generation radar network are evaluated. The double polarization Doppler radar will be the main trend; the electronic scanning small mobile radar will also become important for its flexibility, to make up the blind spots of next generation weather radar sounding.
With the development of radar technology across the world, the domestic radar has developed from conventional radar to single polarization Doppler, then double polarization Doppler, with the target information obtained being more abundant. The principles and product information of conventional radar, single polarization Doppler, and double polarization Doppler radar are introduced in detail. The performances of the next generation S , C , and X band radar are compared, which has a certain reference value for the selection of the radar wavelength. The millimeter wave Doppler radar is also introduced, which can obtain cloud structure information. The performance and trends of the next generation radar network are evaluated. The double polarization Doppler radar will be the main trend; the electronic scanning small mobile radar will also become important for its flexibility, to make up the blind spots of next generation weather radar sounding.
2012, 40(3):332-339.
Abstract:
By means of the radiosonde data and retrieved data during some important activities in Beijing, evaluation and analysis are conducted from the aspects of the errors of the total average, the differences at different times, and weather conditions with or without rainfall. The results show that (1) Total average: the error variation range of temperature was great in rainy days, and small in no rain days. The retrieved temperature from microwave radiometers was closer to the radiosonde temperature in rainy days than in no rain days. The error variation trend of relative humidity was similar to that of temperature, but for the relative error, the values in rainy days were smaller than those in no rain days. (2) Different times: the statistic parameters of temperature varied with height, and the regularity was obvious in no rain days, but not in rainy days. In no rain days, the error was the smallest at 20:00, closer to the radiosonde measurements and the greatest at 14:00. In rainy days, the errors at various times were bigger than those in no rain days, and the retrieved temperature from the microwave radiometer data at 20:00 was close to the radiosonde measurements. For relative humidity, the regularities were obvious and the variation trend was the same as in no rain days, but not in rainy days. Generally, the influence of rainfall on the retrieved data from microwave radiometers is greater. The error of the retrieved data was the smallest at 20:00. The statistic value varied most obviously at 5000 m, relative to clouds.
By means of the radiosonde data and retrieved data during some important activities in Beijing, evaluation and analysis are conducted from the aspects of the errors of the total average, the differences at different times, and weather conditions with or without rainfall. The results show that (1) Total average: the error variation range of temperature was great in rainy days, and small in no rain days. The retrieved temperature from microwave radiometers was closer to the radiosonde temperature in rainy days than in no rain days. The error variation trend of relative humidity was similar to that of temperature, but for the relative error, the values in rainy days were smaller than those in no rain days. (2) Different times: the statistic parameters of temperature varied with height, and the regularity was obvious in no rain days, but not in rainy days. In no rain days, the error was the smallest at 20:00, closer to the radiosonde measurements and the greatest at 14:00. In rainy days, the errors at various times were bigger than those in no rain days, and the retrieved temperature from the microwave radiometer data at 20:00 was close to the radiosonde measurements. For relative humidity, the regularities were obvious and the variation trend was the same as in no rain days, but not in rainy days. Generally, the influence of rainfall on the retrieved data from microwave radiometers is greater. The error of the retrieved data was the smallest at 20:00. The statistic value varied most obviously at 5000 m, relative to clouds.
2012, 40(3):340-344.
Abstract:
Taking the application of the Beidou satellite SMS to the unmanned automatic weather station network of the Xinjiang Meteorological Service as an example, an introduction is made to the application of the Beidou satellite SMS to the data transmission of the unmanned automatic weather station network, with the emphases on the specific requirements of data transmission, the framework of the telecommunication transmission network, information processing, control modes, etc. The advantages and disadvantages of the proposed method are analyzed, in combination with the practical application in the Xinjiang Meteorological Service. The application of the Beidou satellite SMS has great potentials in the data transmission of the unmanned automatic weather station network.
Taking the application of the Beidou satellite SMS to the unmanned automatic weather station network of the Xinjiang Meteorological Service as an example, an introduction is made to the application of the Beidou satellite SMS to the data transmission of the unmanned automatic weather station network, with the emphases on the specific requirements of data transmission, the framework of the telecommunication transmission network, information processing, control modes, etc. The advantages and disadvantages of the proposed method are analyzed, in combination with the practical application in the Xinjiang Meteorological Service. The application of the Beidou satellite SMS has great potentials in the data transmission of the unmanned automatic weather station network.
2012, 40(3):345-348.
Abstract:
Most of tipping bucket rain sensor faults have the feature of concealment. An optimized method of rainfall acquisition is introduced. Based on the operational principles of reed switches, the analysis of the abnormity in rainfall acquisition and the summarization of shortcomings of the current rainfall acquisition are conducted, and effective solutions are proposed to solve such problems as the failure of reed switches, the shifting resulted from the pulling in of two reed switches, and the sudden abnormal fragmentary rainfall and heavy rainfall, etc. The solutions include the diagnosis of the pulse width in the reed switch pulling in, the periodic diagnosis of the pulses of rainfall, measures to screen electromagnetic interference, and a new technique for diagnosing the long opening state of reed switches based on the trend analysis. Practice shows that these solutions are feasible and efficient to improve the credibility and accuracy of rainfall acquisition data.
Most of tipping bucket rain sensor faults have the feature of concealment. An optimized method of rainfall acquisition is introduced. Based on the operational principles of reed switches, the analysis of the abnormity in rainfall acquisition and the summarization of shortcomings of the current rainfall acquisition are conducted, and effective solutions are proposed to solve such problems as the failure of reed switches, the shifting resulted from the pulling in of two reed switches, and the sudden abnormal fragmentary rainfall and heavy rainfall, etc. The solutions include the diagnosis of the pulse width in the reed switch pulling in, the periodic diagnosis of the pulses of rainfall, measures to screen electromagnetic interference, and a new technique for diagnosing the long opening state of reed switches based on the trend analysis. Practice shows that these solutions are feasible and efficient to improve the credibility and accuracy of rainfall acquisition data.
2012, 40(3):349-353.
Abstract:
Equipment troubleshooting and maintenance support capability for automatic weather stations (AWS) is extremely critical to the operation efficiency of AWS. Based on more than 2400 sets of national automatic weather stations monitored by the Atmospheric Observing System Operation Monitoring (ASOM), the investigation of spare parts from various types of AWS manufacturers, and the AWS failure information and maintenance data of 22 provinces (regions) national from 2007 to 2008, a comprehensive evaluation is conducted on the maintenance support capability of AWS by calculating the Mean Time To Repair (MTTR) and average failure duration. A statistical classification and analysis of fault locations and fault causes of AWS across China is carried out, thus to lay a solid foundation for achieving a unified fault management, improving logistic support capability, and promoting the automation and standardization of the evaluation of AWS Troubleshooting.
Equipment troubleshooting and maintenance support capability for automatic weather stations (AWS) is extremely critical to the operation efficiency of AWS. Based on more than 2400 sets of national automatic weather stations monitored by the Atmospheric Observing System Operation Monitoring (ASOM), the investigation of spare parts from various types of AWS manufacturers, and the AWS failure information and maintenance data of 22 provinces (regions) national from 2007 to 2008, a comprehensive evaluation is conducted on the maintenance support capability of AWS by calculating the Mean Time To Repair (MTTR) and average failure duration. A statistical classification and analysis of fault locations and fault causes of AWS across China is carried out, thus to lay a solid foundation for achieving a unified fault management, improving logistic support capability, and promoting the automation and standardization of the evaluation of AWS Troubleshooting.
2012, 40(3):354-357.
Abstract:
The trigger of the new generation CINRAD/CB weather radar provides discharged signals for the modulator. In case of trigger failure, the transmitter cannot work properly. The reasons for failure and the solution are expatiated, based on the analysis of a radar trigger failure event. The main reason of R33 overheating is that the turn on time of the trigger control panel V1 (IRF450, MOSFET) was too long; meanwhile, the excessive power consumption of R33 led to the overload and burnout of the adjustment amplification tube V4, V5(MJ12005) of the trigger power board. Based on the analysis of signal processing circuit diagram and trigger circuitry, the troubleshooting methods and some suggestions to prevent the faults of the like are given, aiming to help technical support staff understand the test and maintenance methods of the trigger.
The trigger of the new generation CINRAD/CB weather radar provides discharged signals for the modulator. In case of trigger failure, the transmitter cannot work properly. The reasons for failure and the solution are expatiated, based on the analysis of a radar trigger failure event. The main reason of R33 overheating is that the turn on time of the trigger control panel V1 (IRF450, MOSFET) was too long; meanwhile, the excessive power consumption of R33 led to the overload and burnout of the adjustment amplification tube V4, V5(MJ12005) of the trigger power board. Based on the analysis of signal processing circuit diagram and trigger circuitry, the troubleshooting methods and some suggestions to prevent the faults of the like are given, aiming to help technical support staff understand the test and maintenance methods of the trigger.
2012, 40(3):358-362.
Abstract:
The transmitter is a key part of CINRAD/SA weather radar, which has complex circuits and works continuously in an environment of high voltage and strong electricity, so it is a component that has relatively high failure rate in the CINRAD/SA radar. Based on Guangzhou radar, in combination with the experiences of other stations, the typical failures of CINRAD/SA transmitter occurred in operation and the troubleshooting procedures are analyzed. The formation causes of the faults are summarized, and some solutions are proposed, which can be used as references for maintenance technicians.
The transmitter is a key part of CINRAD/SA weather radar, which has complex circuits and works continuously in an environment of high voltage and strong electricity, so it is a component that has relatively high failure rate in the CINRAD/SA radar. Based on Guangzhou radar, in combination with the experiences of other stations, the typical failures of CINRAD/SA transmitter occurred in operation and the troubleshooting procedures are analyzed. The formation causes of the faults are summarized, and some solutions are proposed, which can be used as references for maintenance technicians.
2012, 40(3):363-367.
Abstract:
The GYR1 electronic pilot balloon theodolite is a new type of upper level wind sounding instruments, has put to operational use since 2010, so it is necessary to understand its structure and working principles. A brief introduction is made to the structure and principles of the GYR1 Electronic pilot balloon theodolite in combination with the practical operating experiences, and a comparison is made between the GYR1 Electronic pilot balloon theodolite and the original 70 I type theodolite. Two different data processing approaches (online output and manual input) are described. The methods and skills for routine maintenance and some issues needing to pay attention are discussed, to provide some references for the technical staff of meteorological stations.
The GYR1 electronic pilot balloon theodolite is a new type of upper level wind sounding instruments, has put to operational use since 2010, so it is necessary to understand its structure and working principles. A brief introduction is made to the structure and principles of the GYR1 Electronic pilot balloon theodolite in combination with the practical operating experiences, and a comparison is made between the GYR1 Electronic pilot balloon theodolite and the original 70 I type theodolite. Two different data processing approaches (online output and manual input) are described. The methods and skills for routine maintenance and some issues needing to pay attention are discussed, to provide some references for the technical staff of meteorological stations.
2012, 40(3):368-372.
Abstract:
The communication of the Keithley 2000 Digital Multimeter and PC, and the automatic batch acquisition of the 10 channel 4 wire soil temperature sensors are realized, based on the serial communication subroutine of VB, by means of the model multiplexing scanner card of the Keithley 2000 It solved the existing problems of channel errors and low precision in the calibration of platinum resistance temperature sensors using automatic weather station data loggers in laboratory. The practical application shows that this system can provide high accuracy test results in calibrating soil temperature sensors, fast real time data refreshing, and improved working efficiency.
The communication of the Keithley 2000 Digital Multimeter and PC, and the automatic batch acquisition of the 10 channel 4 wire soil temperature sensors are realized, based on the serial communication subroutine of VB, by means of the model multiplexing scanner card of the Keithley 2000 It solved the existing problems of channel errors and low precision in the calibration of platinum resistance temperature sensors using automatic weather station data loggers in laboratory. The practical application shows that this system can provide high accuracy test results in calibrating soil temperature sensors, fast real time data refreshing, and improved working efficiency.
2012, 40(3):373-377.
Abstract:
Video conference systems are widely applied in meteorological service. With the increasing of demands for multiple sub venues (conference rooms) and equipment complexity, the previous independent management mode for video conference systems has resulted in greater pressure of the staff in recent years. Taking for an example, the construction of the digital video conference system in Hubei Provincial Meteorological Service is described. According to the needs analysis and the network conditions, a solution is proposed based on the digital centralized controlling mechanism. With fewer technical staff, it realizes more video conference modes at more conference rooms, by using centralized major equipments, devices for remote acquisition and distribution of integrated signals, and a digital controlling system on the network. The operational application shows that this solution can not only ensure the quality and the scale of conference, but also improve management efficiency. This system can provide references for the construction of similar systems.
Video conference systems are widely applied in meteorological service. With the increasing of demands for multiple sub venues (conference rooms) and equipment complexity, the previous independent management mode for video conference systems has resulted in greater pressure of the staff in recent years. Taking for an example, the construction of the digital video conference system in Hubei Provincial Meteorological Service is described. According to the needs analysis and the network conditions, a solution is proposed based on the digital centralized controlling mechanism. With fewer technical staff, it realizes more video conference modes at more conference rooms, by using centralized major equipments, devices for remote acquisition and distribution of integrated signals, and a digital controlling system on the network. The operational application shows that this solution can not only ensure the quality and the scale of conference, but also improve management efficiency. This system can provide references for the construction of similar systems.
2012, 40(3):378-383.
Abstract:
The meteorological information displaying on a spherical screen has a strong three dimensional sense, and it has great application prospects in multiple industries. Based on the meteorological data of the China Meteorological Administration, the Global Earth Observation display system software is developed for the first time, and the system has put into operation and performs stably. The core technology of the system and the system design and implementation of image processing are described. Image processing includes two steps: image enhancement and image distortion. Image enhancement processing enhances the image display that contains a large amount of meteorological information. Through the geometric image distortion correction, the metrological data are projected onto a spherical screen. In this system, after image processing, global observational data can be displayed properly on the spherical screen in the manner of seamless and no distortion. The system can help people experience the planet and living environment from the perspective of the space.
The meteorological information displaying on a spherical screen has a strong three dimensional sense, and it has great application prospects in multiple industries. Based on the meteorological data of the China Meteorological Administration, the Global Earth Observation display system software is developed for the first time, and the system has put into operation and performs stably. The core technology of the system and the system design and implementation of image processing are described. Image processing includes two steps: image enhancement and image distortion. Image enhancement processing enhances the image display that contains a large amount of meteorological information. Through the geometric image distortion correction, the metrological data are projected onto a spherical screen. In this system, after image processing, global observational data can be displayed properly on the spherical screen in the manner of seamless and no distortion. The system can help people experience the planet and living environment from the perspective of the space.
2012, 40(3):384-387.
Abstract:
Focused on the efficiency and timeliness of the meteorological warning SMS (Short Message Service), a warning text message sending system is developed, which integrates with the meteorological operational platform seamlessly, combining various data resources from different kinds of automatic meteorological stations. It can monitor meteorological elements in real time and create warning text messages to meet the given needs. By a phone number database to control the scope of warning message sending, this system implements the automatization and standardization of meteorological warning SMS sending. Based on the Web Service technology to enter directly the gateway of China Telecom, instead of using the previous GPRS model, GSM Modem model, or the sending platform which providers offer, this system does not need to edit messages manually. It has achieved the high efficient distribution of warning messages, so to improve the overall quality of meteorological service.
Focused on the efficiency and timeliness of the meteorological warning SMS (Short Message Service), a warning text message sending system is developed, which integrates with the meteorological operational platform seamlessly, combining various data resources from different kinds of automatic meteorological stations. It can monitor meteorological elements in real time and create warning text messages to meet the given needs. By a phone number database to control the scope of warning message sending, this system implements the automatization and standardization of meteorological warning SMS sending. Based on the Web Service technology to enter directly the gateway of China Telecom, instead of using the previous GPRS model, GSM Modem model, or the sending platform which providers offer, this system does not need to edit messages manually. It has achieved the high efficient distribution of warning messages, so to improve the overall quality of meteorological service.
2012, 40(3):388-393.
Abstract:
A general propose electronic examination platform is established for testing meteorological skills and knowledge, which is based on the Excel spreadsheet system, considering the inadequacy of the traditional paper based tests and conventional paperless examination systems for Meteorological Service. It has most of the features and functions of a standard paperless examination system, and the embedded VBA programming language is used in the design of the modularized programs. The application shows that it has obvious advantages: low cost, easy maintenance, good applicability, etc. Detailed description is made of the design of the conceptual model and the realization of main function modules. The problems encountered in the module development process and some issues needing pay attention about the system, and the assumption of further expansion are analyzed.
A general propose electronic examination platform is established for testing meteorological skills and knowledge, which is based on the Excel spreadsheet system, considering the inadequacy of the traditional paper based tests and conventional paperless examination systems for Meteorological Service. It has most of the features and functions of a standard paperless examination system, and the embedded VBA programming language is used in the design of the modularized programs. The application shows that it has obvious advantages: low cost, easy maintenance, good applicability, etc. Detailed description is made of the design of the conceptual model and the realization of main function modules. The problems encountered in the module development process and some issues needing pay attention about the system, and the assumption of further expansion are analyzed.
2012, 40(3):394-400.
Abstract:
Based on the ice characteristics of the Bohai Sea, the advances in the researches on sea ice numerical models are reviewed from the two aspects: thermodynamic and dynamic. The new generation sea ice thermodynamic models for the Bohai sea are discussed from the thermodynamic parameter schemes and climate characteristics. The SPH (Smoothed Particle Hydrodynamics) method is introduced for ice short term prediction of the Bohai sea, and the main characteristics and practical application of three common numerical methods in dynamic sea ice model development are described. Whereby, combined with the development of marine meteorology, the key technology of short term ice forecasts is discussed. It is pointed that an operational sea ice forecast system with numerical and statistical techniques would be the future direction of sea ice model development.
Based on the ice characteristics of the Bohai Sea, the advances in the researches on sea ice numerical models are reviewed from the two aspects: thermodynamic and dynamic. The new generation sea ice thermodynamic models for the Bohai sea are discussed from the thermodynamic parameter schemes and climate characteristics. The SPH (Smoothed Particle Hydrodynamics) method is introduced for ice short term prediction of the Bohai sea, and the main characteristics and practical application of three common numerical methods in dynamic sea ice model development are described. Whereby, combined with the development of marine meteorology, the key technology of short term ice forecasts is discussed. It is pointed that an operational sea ice forecast system with numerical and statistical techniques would be the future direction of sea ice model development.
2012, 40(3):401-405.
Abstract:
By virtue of the similarity between the dynamic processes from the T213 products on the MICAPS platform corresponding to the three dimensional physical element fields relative to the formation, development, and extinction of heavy rainfall, the yes/no prediction of regional heavy rainfall is made according to the comprehensive examination and analysis of the number of similar fields. Forecast factors include vorticity, divergence, vertical velocity, and moisture flux convergence at 850 hPa, 700 hPa, and 500 hPa, at the time scales of 12 , 24 and 36 hour forecast fields, respectively. The programming, automation, and objectivity are realized. The two types of models constructed by means of weather processes are based on the field mean distance. The verification indicates that the prediction results of heavy rainfall are satisfactory, with the mean TS of 2004 to 2010 (May to October) being over 33%.
By virtue of the similarity between the dynamic processes from the T213 products on the MICAPS platform corresponding to the three dimensional physical element fields relative to the formation, development, and extinction of heavy rainfall, the yes/no prediction of regional heavy rainfall is made according to the comprehensive examination and analysis of the number of similar fields. Forecast factors include vorticity, divergence, vertical velocity, and moisture flux convergence at 850 hPa, 700 hPa, and 500 hPa, at the time scales of 12 , 24 and 36 hour forecast fields, respectively. The programming, automation, and objectivity are realized. The two types of models constructed by means of weather processes are based on the field mean distance. The verification indicates that the prediction results of heavy rainfall are satisfactory, with the mean TS of 2004 to 2010 (May to October) being over 33%.
2012, 40(3):406-410.
Abstract:
Based on the relevance between the number of the stations where had a hail weather in the northern Fujian and the physical element fields from 2003 to 2005, the physical factors closely related to hail weather in different seasons (March to April in spring, and May to June in flood season) in the northern Fujian are identified. In combination with the numerical physical element forecast products of T213 and the actual physical element products summarized from the practical forecast experiences of several years in Fujian, the objective forecasting system of hail weather for different seasons in the northern Fujian is established by using the index superposition method. This system achieved good result in operation from 2008 to 2010, in which there was no missing alarm and very low false alarm rate after using the unique elimination conditions in the model.
Based on the relevance between the number of the stations where had a hail weather in the northern Fujian and the physical element fields from 2003 to 2005, the physical factors closely related to hail weather in different seasons (March to April in spring, and May to June in flood season) in the northern Fujian are identified. In combination with the numerical physical element forecast products of T213 and the actual physical element products summarized from the practical forecast experiences of several years in Fujian, the objective forecasting system of hail weather for different seasons in the northern Fujian is established by using the index superposition method. This system achieved good result in operation from 2008 to 2010, in which there was no missing alarm and very low false alarm rate after using the unique elimination conditions in the model.
2012, 40(3):411-416.
Abstract:
A method for verifying precipitation predication of transition weather is developed. It focuses on the evaluation of the performance of numerical prediction models from the prediction capability for transition weather. The precipitation predictions from several global medium range numerical prediction models (including China, Japan and German) are selected and verified by using this method during the period from September 2006 to August 2008. The verification results show that the method is an effective complement to the currently used precipitation prediction verification methods. The forecast skills for transition weather tend to decrease with the growth of leadtime. The short range forecast skill analysis indicates that T213 and JMA global models perform better in spring and the German model is the best in summer. But for 48 hour prediction, results are different, depending on the forecast areas. For example, T213 and the JMA model perform better in the middle lower reaches of the Yangtze River and in some parts of North and Northeast China. The German model performs best in Sichuan Basin and South China.
A method for verifying precipitation predication of transition weather is developed. It focuses on the evaluation of the performance of numerical prediction models from the prediction capability for transition weather. The precipitation predictions from several global medium range numerical prediction models (including China, Japan and German) are selected and verified by using this method during the period from September 2006 to August 2008. The verification results show that the method is an effective complement to the currently used precipitation prediction verification methods. The forecast skills for transition weather tend to decrease with the growth of leadtime. The short range forecast skill analysis indicates that T213 and JMA global models perform better in spring and the German model is the best in summer. But for 48 hour prediction, results are different, depending on the forecast areas. For example, T213 and the JMA model perform better in the middle lower reaches of the Yangtze River and in some parts of North and Northeast China. The German model performs best in Sichuan Basin and South China.
2012, 40(3):417-422.
Abstract:
Two kinds of unconventional detection data from GPS and automatic weather stations and the role in weather forecast are analyzed. The result shows that the unconventional data can compensate the defects for conventional detection data in temporal and spatial scales. There is good corresponding relation between the time evolution characteristics of GPS/MET data and rainfall, and the distribution characteristics of precipitation are different for different weather systems, different types of precipitation and in different seasons, which can be used as important references for precipitation process analysis and short time forecasting and warning. Automatic weather station data are useful and important in analyzing the strength, scope, the maintain time, and evolution characteristics of meso and micro scale weather systems in local rainfall forecasting and warning.
Two kinds of unconventional detection data from GPS and automatic weather stations and the role in weather forecast are analyzed. The result shows that the unconventional data can compensate the defects for conventional detection data in temporal and spatial scales. There is good corresponding relation between the time evolution characteristics of GPS/MET data and rainfall, and the distribution characteristics of precipitation are different for different weather systems, different types of precipitation and in different seasons, which can be used as important references for precipitation process analysis and short time forecasting and warning. Automatic weather station data are useful and important in analyzing the strength, scope, the maintain time, and evolution characteristics of meso and micro scale weather systems in local rainfall forecasting and warning.
2012, 40(3):423-427.
Abstract:
The persistent heavy rainfall is a kind of extreme precipitation events that have a long duration， extensive coverage, and relatively stable heavy precipitation areas. Based on the daily averaged data derived from the NCEP/NCAR reanalysis dataset, the preceding signals in atmospheric circulation of persistent heavy rainfall events happened in the Yangtze and Huaihe River Basin in June are revealed by using the moving average analysis and composite methods. The results suggest that Australia high and the Mascarene high has a relation of “seesaw”; the subtropical high is obviously stronger than usual; the average position of the ridge line is farther south, and the average position of the west ridge point is farther west; the South Asia high，belonging to the west type high，is weaker, and the eastward stretch ridge point is farther east; the eastward stretch ridge point of the South Asia high and the westward stretch ridge point obviously come toward each other and goes away from each other; the ridge line of the subtropical high is 4 to 6 latitude distances farther south that that of the South Asia high, and they have concerted north south movement, but the movement of the ridge line of the South Asia high is about one day later than that of the ridge line of the subtropical high.
The persistent heavy rainfall is a kind of extreme precipitation events that have a long duration， extensive coverage, and relatively stable heavy precipitation areas. Based on the daily averaged data derived from the NCEP/NCAR reanalysis dataset, the preceding signals in atmospheric circulation of persistent heavy rainfall events happened in the Yangtze and Huaihe River Basin in June are revealed by using the moving average analysis and composite methods. The results suggest that Australia high and the Mascarene high has a relation of “seesaw”; the subtropical high is obviously stronger than usual; the average position of the ridge line is farther south, and the average position of the west ridge point is farther west; the South Asia high，belonging to the west type high，is weaker, and the eastward stretch ridge point is farther east; the eastward stretch ridge point of the South Asia high and the westward stretch ridge point obviously come toward each other and goes away from each other; the ridge line of the subtropical high is 4 to 6 latitude distances farther south that that of the South Asia high, and they have concerted north south movement, but the movement of the ridge line of the South Asia high is about one day later than that of the ridge line of the subtropical high.
2012, 40(3):428-435.
Abstract:
The Meiyu torrential rain rainstorm took place on 29 June 2009 in Hubei Province is analyzed by applying intensive meteorological radiosonde data, reanalysis data from NCEP, and precipitation data of automatic meteorological stations in Hubei Province. The results show that during the heavy rain, there existed a long quasi zonal Jianghuai shear at 700 hPa; the north frontier of the low level jet stream at 850 hPa moved to the northern Jiangnan. The 〖WTBX〗θ〖WTBZ〗se front at the northwestern Hubei Province moved southward and enhanced slowly, and the rainstorm region was to the south of the〖WTBX〗 θ〖WTBZ〗se front, where the local change of〖WTBX〗 θ〖WTBZ〗se was always positive though the change amount was little. The convergence of vertically integrated moisture flux occurred before the heavy rain, and the convergence area was in accord with the location of the rainstorm. In both Enshi and Wuhan radiosonde stations, besides the large scale low level shear line, the occurrence of heavy rainfall was influenced by the local meteorological elements, especially plenty of water vapor at low levels, which was a necessary condition for heavy rainfall. The rainfall became severer after the high level trough passing Enshi and the vertical shear of horizontal wind between middle and high levels appearing. The descending dry air at high or middle levels was a good condition for heavy rainfall at Wuhan for unstable stratification was intensified accordingly. The abrupt increase of rainfall coincided with the southward passing of the horizontal wind shear at low levels.
The Meiyu torrential rain rainstorm took place on 29 June 2009 in Hubei Province is analyzed by applying intensive meteorological radiosonde data, reanalysis data from NCEP, and precipitation data of automatic meteorological stations in Hubei Province. The results show that during the heavy rain, there existed a long quasi zonal Jianghuai shear at 700 hPa; the north frontier of the low level jet stream at 850 hPa moved to the northern Jiangnan. The 〖WTBX〗θ〖WTBZ〗se front at the northwestern Hubei Province moved southward and enhanced slowly, and the rainstorm region was to the south of the〖WTBX〗 θ〖WTBZ〗se front, where the local change of〖WTBX〗 θ〖WTBZ〗se was always positive though the change amount was little. The convergence of vertically integrated moisture flux occurred before the heavy rain, and the convergence area was in accord with the location of the rainstorm. In both Enshi and Wuhan radiosonde stations, besides the large scale low level shear line, the occurrence of heavy rainfall was influenced by the local meteorological elements, especially plenty of water vapor at low levels, which was a necessary condition for heavy rainfall. The rainfall became severer after the high level trough passing Enshi and the vertical shear of horizontal wind between middle and high levels appearing. The descending dry air at high or middle levels was a good condition for heavy rainfall at Wuhan for unstable stratification was intensified accordingly. The abrupt increase of rainfall coincided with the southward passing of the horizontal wind shear at low levels.
2012, 40(3):436-444.
Abstract:
Using the conventional observation data, NCEP (1°×1° lat/lon, 6 hours) reanalysis data and surface intensive automatic meteorological observation data, a severe hail event occurred on 15 May 2010 in Shaya County, Xingjiang is analyzed. The results show that the major influencing systems of the hail event include the low trough over Lake Balkhash and the mesoscale shear line upstream of the hail region, whose vapor came from the west and middle regions of the Tarim basin, gathered and dispersed at the lower levels of the atmosphere. The convergent ascending motion over the hail region provided the vapor and dynamic conditions for the hail. The severe hail event appeared near the high energy region at surface. There existed unstable energies both at the lower levels and in the whole atmosphere before the hail. During the course of the severe hail, there was a mesoscale low pressure, a mesoscale convergence line, and a mesoscale vortex at surface. The severe hail was produced by a γ mesoscale convective cell. The mesoscale convergence line and mesoscale vortex lasted for 5 hours and 3 hours, respectively, and the lifetime of the γ mesoscale convective cell was about 30 minutes.
Using the conventional observation data, NCEP (1°×1° lat/lon, 6 hours) reanalysis data and surface intensive automatic meteorological observation data, a severe hail event occurred on 15 May 2010 in Shaya County, Xingjiang is analyzed. The results show that the major influencing systems of the hail event include the low trough over Lake Balkhash and the mesoscale shear line upstream of the hail region, whose vapor came from the west and middle regions of the Tarim basin, gathered and dispersed at the lower levels of the atmosphere. The convergent ascending motion over the hail region provided the vapor and dynamic conditions for the hail. The severe hail event appeared near the high energy region at surface. There existed unstable energies both at the lower levels and in the whole atmosphere before the hail. During the course of the severe hail, there was a mesoscale low pressure, a mesoscale convergence line, and a mesoscale vortex at surface. The severe hail was produced by a γ mesoscale convective cell. The mesoscale convergence line and mesoscale vortex lasted for 5 hours and 3 hours, respectively, and the lifetime of the γ mesoscale convective cell was about 30 minutes.
2012, 40(3):445-449.
Abstract:
The structure characteristics during the landing of Typhoon Hagupit occurred in 2008 are analyzed based on the composite reflectivity (CR) and echo top (ET) data from the products of three dimensional mosaic system (CINRAD Mosaic). The characteristics of CR and ET are discussed, and the possible causes of differences between the two network products are pointed out. The results show that the convective activities in the core area of Typhoon Hagupit declined rapidly after short enhancing when its eye areas became filled from convection during the landing period. The curves of CR and ET along with the distance away from the center of Typhoon Hagupit exhibits a single peak distribution, but the former is closer to the typhoon center, with an average peak distance of 64 km and 76 km, respectively.
The structure characteristics during the landing of Typhoon Hagupit occurred in 2008 are analyzed based on the composite reflectivity (CR) and echo top (ET) data from the products of three dimensional mosaic system (CINRAD Mosaic). The characteristics of CR and ET are discussed, and the possible causes of differences between the two network products are pointed out. The results show that the convective activities in the core area of Typhoon Hagupit declined rapidly after short enhancing when its eye areas became filled from convection during the landing period. The curves of CR and ET along with the distance away from the center of Typhoon Hagupit exhibits a single peak distribution, but the former is closer to the typhoon center, with an average peak distance of 64 km and 76 km, respectively.
2012, 40(3):450-455.
Abstract:
The main causes of the high temperature weather occurred in Zhangjiakou in late July 2010 are analyzed by using the data from weather maps, NCEP reanalysis data and ground observations, based on the heat flow equation. The results show: (1) High temperature appeared in the background of the steady control of the mainland high. (2) Under the control of the mainland high, the non adiabatic condition was the key factor leading to high temperature, while the thermal advection had less effect. (3) Higher surface temperature and the longer duration may also make some contributions to the new record breaking high temperature on July 29 2010. (4) The maximum temperatures were compared with the corresponding 850 hPa temperatures at 14:00 of the hot days, and a difference of 9 ℃ between them can be used as a suitable reference in maximum temperature forecasting.
The main causes of the high temperature weather occurred in Zhangjiakou in late July 2010 are analyzed by using the data from weather maps, NCEP reanalysis data and ground observations, based on the heat flow equation. The results show: (1) High temperature appeared in the background of the steady control of the mainland high. (2) Under the control of the mainland high, the non adiabatic condition was the key factor leading to high temperature, while the thermal advection had less effect. (3) Higher surface temperature and the longer duration may also make some contributions to the new record breaking high temperature on July 29 2010. (4) The maximum temperatures were compared with the corresponding 850 hPa temperatures at 14:00 of the hot days, and a difference of 9 ℃ between them can be used as a suitable reference in maximum temperature forecasting.
2012, 40(3):456-465.
Abstract:
Stratospheric sulfate aerosols play an important role in the radiation and chemical equilibrium of the global atmosphere, and have significant impact on global climate changes. The numerical simulation of stratospheric aerosols is one of major methods in studying the concentration, particle size distribution, and chemical composition of stratospheric sulfate aerosols. A brief review of the development and application of stratospheric aerosol models are given, and comparison between five stratospheric aerosol models that have been widely used in recent years is conducted. Special attention is paid on the differences between simulation results and satellite observations on the distribution of OCS (Carbonyl Sulfide) and SO2, and it is found that all five models can represent most of the characters of stratospheric aerosols and their precursors, but each has its own limitations. The prospects for future stratospheric aerosol model development and issues need to be improved are also discussed.
Stratospheric sulfate aerosols play an important role in the radiation and chemical equilibrium of the global atmosphere, and have significant impact on global climate changes. The numerical simulation of stratospheric aerosols is one of major methods in studying the concentration, particle size distribution, and chemical composition of stratospheric sulfate aerosols. A brief review of the development and application of stratospheric aerosol models are given, and comparison between five stratospheric aerosol models that have been widely used in recent years is conducted. Special attention is paid on the differences between simulation results and satellite observations on the distribution of OCS (Carbonyl Sulfide) and SO2, and it is found that all five models can represent most of the characters of stratospheric aerosols and their precursors, but each has its own limitations. The prospects for future stratospheric aerosol model development and issues need to be improved are also discussed.
Wang Tingting
,
Sun Junying
,
Shen Xiaojing
,
Deng Zhaoze
,
Zhang Yangmei
,
An Linchang
,
Zhang Xiaochun
,
Yan Peng
,
Liang Wende
,
Chen Lili
2012, 40(3):466-473.
Abstract:
Based on the cloud condensation nuclei (CCN) concentration and aerosol size distribution measured at the Wuqing Meteorological Service of Tianjin from November to December of 2009, the variation characteristics of CCN concentrations and activation rates at different degrees of supersaturation (01% to 10%) are analyzed. The results show that the CCN concentration varies in the range of 4000 to 32000 cm-3 in the supersaturation of 1% and is affected by the wind speed significantly at Wuqing in winter. Under the wind speed of 15 to 33 m/s, the CCN concentration is very high, can reach 16000 cm-3 at 1% supersaturation, but is just one forth of that under the wind speed of 35 to 55 m/s. The CCN concentration varies greatly in the range of 01% to 04% supersaturation. The increase of CCN concentration for every 01% supersaturation in the range of 01 to 04% is about 5 times of those in the range of 04% to 10% supersaturation. The activation rate is affected significantly by the wind speed at the low supersaturation (01%, 02%), and the value under the wind speed smaller than 15 m·s-1is about three times of that under the wind speed larger than 55 m/s, but at the supersaturation of 1%, the activation rate difference with wind speed is little. The diurnal variation of CCN concentration shows two peaks at 08:00 and 18:00, as there are two valleys in the diurnal variation of the activation rate, which suggests the effects from the local emissions. The power law fitting for the relationship of CCN concentration and supersaturation under different wind speeds shows that the supersaturation spectrum of CCN at Wuqing belongs to the continental style.
Based on the cloud condensation nuclei (CCN) concentration and aerosol size distribution measured at the Wuqing Meteorological Service of Tianjin from November to December of 2009, the variation characteristics of CCN concentrations and activation rates at different degrees of supersaturation (01% to 10%) are analyzed. The results show that the CCN concentration varies in the range of 4000 to 32000 cm-3 in the supersaturation of 1% and is affected by the wind speed significantly at Wuqing in winter. Under the wind speed of 15 to 33 m/s, the CCN concentration is very high, can reach 16000 cm-3 at 1% supersaturation, but is just one forth of that under the wind speed of 35 to 55 m/s. The CCN concentration varies greatly in the range of 01% to 04% supersaturation. The increase of CCN concentration for every 01% supersaturation in the range of 01 to 04% is about 5 times of those in the range of 04% to 10% supersaturation. The activation rate is affected significantly by the wind speed at the low supersaturation (01%, 02%), and the value under the wind speed smaller than 15 m·s-1is about three times of that under the wind speed larger than 55 m/s, but at the supersaturation of 1%, the activation rate difference with wind speed is little. The diurnal variation of CCN concentration shows two peaks at 08:00 and 18:00, as there are two valleys in the diurnal variation of the activation rate, which suggests the effects from the local emissions. The power law fitting for the relationship of CCN concentration and supersaturation under different wind speeds shows that the supersaturation spectrum of CCN at Wuqing belongs to the continental style.
2012, 40(3):474-480.
Abstract:
The evaluation of sensible heat flux is crucial in the boundary layer study. Based on the boundary layer observation data at Wenjiang Station in the eastern edge of the Sichuan Basin, the method for calculating sensible heat flux with ANN (artificial neural network) is preliminarily studied and compared with the empirical method. The corresponding correlation analysis and error analysis are conducted with the true values. Two cases on April and May in 2009 are studied, and the results show that the correlation coefficient and variation trend of the ANN method are better than those of the empirical method; the root mean square error (RMSE) of ANN is slightly larger than that of the empirical method in April 2009 but obviously smaller in May 2009.
The evaluation of sensible heat flux is crucial in the boundary layer study. Based on the boundary layer observation data at Wenjiang Station in the eastern edge of the Sichuan Basin, the method for calculating sensible heat flux with ANN (artificial neural network) is preliminarily studied and compared with the empirical method. The corresponding correlation analysis and error analysis are conducted with the true values. Two cases on April and May in 2009 are studied, and the results show that the correlation coefficient and variation trend of the ANN method are better than those of the empirical method; the root mean square error (RMSE) of ANN is slightly larger than that of the empirical method in April 2009 but obviously smaller in May 2009.
2012, 40(3):481-484.
Abstract:
In order to provide technical bases for blue green alga treatment, according to the data on the degree of blue algal occurrence in Dianshan Lake and the observation data from 1998 to 2009, an analysis is made of meteorological conditions for the occurrence of blue green algae by adopting the statistical method, and the prediction model is devised. The meteorological indexes of blue green alga bloom are: the mean temperature in July and August greater than 29℃; the number of hot days with daily maximum temperature above 35℃ is great than 16 days from June to September; the number of monthly sunlight hours is greater than 420 hours in July and August; the monthly rainfall is less than 420 mm from June to August. Based on the inspection of historical data, the result shows that the accuracy of Model Ⅰ (prediction starts in early June) and Model Ⅱ (prediction starts in early August) are 91.7% and 100%, respectively. The trial running in 2010 shows that the prediction result of Model Ⅰis correct and that of Model Ⅱ is 1 grade lower than the real, which can be applied in operational meteorological service.
In order to provide technical bases for blue green alga treatment, according to the data on the degree of blue algal occurrence in Dianshan Lake and the observation data from 1998 to 2009, an analysis is made of meteorological conditions for the occurrence of blue green algae by adopting the statistical method, and the prediction model is devised. The meteorological indexes of blue green alga bloom are: the mean temperature in July and August greater than 29℃; the number of hot days with daily maximum temperature above 35℃ is great than 16 days from June to September; the number of monthly sunlight hours is greater than 420 hours in July and August; the monthly rainfall is less than 420 mm from June to August. Based on the inspection of historical data, the result shows that the accuracy of Model Ⅰ (prediction starts in early June) and Model Ⅱ (prediction starts in early August) are 91.7% and 100%, respectively. The trial running in 2010 shows that the prediction result of Model Ⅰis correct and that of Model Ⅱ is 1 grade lower than the real, which can be applied in operational meteorological service.
2012, 40(3):485-488.
Abstract:
The relationships between the dates of initial blooming of pear trees and meteorological factors are analyzed based on the temperature, sunshine, and precipitation data of Fengxian from 1984 to 2009. The results indicate: (1) the influence of the meteorological factors in the late period is greater compared to that in the previous period; (2) the influence of temperature and sunshine is obvious, and that of precipitation is small. The greater the temperature and the more the sunshine, the earlier the pear trees flower; on the contrary, the later the pear trees flowering. From December to next January (except the late December), the higher the maximum temperatures, the lower the chilling requirement to be accumulated, the later the flowering; the lower the maximum temperature (the accumulation of chilling requirement is conducive to dormancy release), the earlier the flowering. By means of the method of stepwise regression using the SPSS software, a model is established to predict the beginning of the flowering period, the accuracy of which can meet the requirements of operational meteorological service to the government and farmers.
The relationships between the dates of initial blooming of pear trees and meteorological factors are analyzed based on the temperature, sunshine, and precipitation data of Fengxian from 1984 to 2009. The results indicate: (1) the influence of the meteorological factors in the late period is greater compared to that in the previous period; (2) the influence of temperature and sunshine is obvious, and that of precipitation is small. The greater the temperature and the more the sunshine, the earlier the pear trees flower; on the contrary, the later the pear trees flowering. From December to next January (except the late December), the higher the maximum temperatures, the lower the chilling requirement to be accumulated, the later the flowering; the lower the maximum temperature (the accumulation of chilling requirement is conducive to dormancy release), the earlier the flowering. By means of the method of stepwise regression using the SPSS software, a model is established to predict the beginning of the flowering period, the accuracy of which can meet the requirements of operational meteorological service to the government and farmers.
2012, 40(3):489-496.
Abstract:
The TREC algorithm，based on maximum correlation coefficients, is used in the successive tracking of selected radar echoes, and its effectiveness is evaluated by using the CAPPI grid data from Yangjing, Shenzhen, Guangzhou, Meizhou, and Shaoguan radar stations. The results show that, for ordinary mixed clouds, this particular TREC method is effective within a certain time limit, but its stability becomes weak with time beyond the limit, which leads to less satisfying tracking results. Also included is an application case of the TREC algorithm for weather modification operation in Beijing. Tracking is made with the CAPPI grid data to locate different cloud systems in different operational periods. The area of pixels exceeding the threshold and the total VIL of the tracking areas are calculated simultaneously, which can be used as the evaluation reference for weather modification operations.
The TREC algorithm，based on maximum correlation coefficients, is used in the successive tracking of selected radar echoes, and its effectiveness is evaluated by using the CAPPI grid data from Yangjing, Shenzhen, Guangzhou, Meizhou, and Shaoguan radar stations. The results show that, for ordinary mixed clouds, this particular TREC method is effective within a certain time limit, but its stability becomes weak with time beyond the limit, which leads to less satisfying tracking results. Also included is an application case of the TREC algorithm for weather modification operation in Beijing. Tracking is made with the CAPPI grid data to locate different cloud systems in different operational periods. The area of pixels exceeding the threshold and the total VIL of the tracking areas are calculated simultaneously, which can be used as the evaluation reference for weather modification operations.
2012, 40(3):497-501.
Abstract:
Since 2004, there occurred lightning accidents many times to airport facilities at Mianyang Airport，such as the Doppler VHF Omnidirectional Radio/Distance Measurement Equipment, Instrument Landing System, No Directional Beacon, Transportable Earth Stations, Aviation Automated Weather Observing Systems, Very High Frequency radio and so on, which caused equipment failure and work interruptions in different degrees. Through analyzing the lightning cases, some countermeasures are introduced, such as multi level SPD protection, eliminating lightning residual voltage step by step, integrated grounding and equipotential bonding for all the equipments within the same building, standardizing the generic cabling and establishing the regular maintenance and detection system, checking potential safety hazard timely, etc. Some experiences and effective means to clear up faults in communication and navigation facilities induced by lightning accidents are summarized.
Since 2004, there occurred lightning accidents many times to airport facilities at Mianyang Airport，such as the Doppler VHF Omnidirectional Radio/Distance Measurement Equipment, Instrument Landing System, No Directional Beacon, Transportable Earth Stations, Aviation Automated Weather Observing Systems, Very High Frequency radio and so on, which caused equipment failure and work interruptions in different degrees. Through analyzing the lightning cases, some countermeasures are introduced, such as multi level SPD protection, eliminating lightning residual voltage step by step, integrated grounding and equipotential bonding for all the equipments within the same building, standardizing the generic cabling and establishing the regular maintenance and detection system, checking potential safety hazard timely, etc. Some experiences and effective means to clear up faults in communication and navigation facilities induced by lightning accidents are summarized.
2012, 40(3):502-506.
Abstract:
The attention for the lightning protection of temporary buildings is always held throughout the emergency rescue by people. The limitation of GB50057 is simply analyzed by explaining the characteristics of temporary buildings, and the techniques of lightning protection devices installation for temporary buildings are judged and analyzed by the IEC62305 recommended method. The results indicate that the technological indexes of GB50057-1994 for buildings are inapplicable for temporary buildings, but the IEC62305 recommended method is applicable. The installation of lightning protection devices for temporary buildings is depended on their dimension and the parameters of lightning days. Based on these, the relationship between the lightning disaster risk of temporary buildings and their areas, perimeters, and the number of lightning days is given, which can be used as the theoretical basis of lightning protection device installation.
The attention for the lightning protection of temporary buildings is always held throughout the emergency rescue by people. The limitation of GB50057 is simply analyzed by explaining the characteristics of temporary buildings, and the techniques of lightning protection devices installation for temporary buildings are judged and analyzed by the IEC62305 recommended method. The results indicate that the technological indexes of GB50057-1994 for buildings are inapplicable for temporary buildings, but the IEC62305 recommended method is applicable. The installation of lightning protection devices for temporary buildings is depended on their dimension and the parameters of lightning days. Based on these, the relationship between the lightning disaster risk of temporary buildings and their areas, perimeters, and the number of lightning days is given, which can be used as the theoretical basis of lightning protection device installation.
2012, 40(3):507-512.
Abstract:
The lightning disaster vulnerability over Hebei is evaluated, based on the conception of lightning disaster vulnerability analysis, choosing the lightning disaster density, lightning disaster frequency, economy vulnerable modulus, and life vulnerable modulus as vulnerability evaluation indexes and using the post disaster evaluation method, by means of the data from 11 meteorological stations from 1971 to 2000 and lightning disaster data from 2003 to 2009 from the statistical data of the Hebei Lightning Protection Center. The results show that Tangshan, Baoding, and Qinhuangdao belong to the maximal damageable area; Xingtai, Hengshui, Langfang, Zhangjiakou, and Shijiazhang belong to the high damageable area; Chengde belongs to the medium damageable area; Cangzhou and Handan belong to the low damageable area. The vulnerability degree of each district is calculated and vulnerability regionalization over Hebei is made by means of GIS data, which can give some references to lightning protection and disaster reduction service.
The lightning disaster vulnerability over Hebei is evaluated, based on the conception of lightning disaster vulnerability analysis, choosing the lightning disaster density, lightning disaster frequency, economy vulnerable modulus, and life vulnerable modulus as vulnerability evaluation indexes and using the post disaster evaluation method, by means of the data from 11 meteorological stations from 1971 to 2000 and lightning disaster data from 2003 to 2009 from the statistical data of the Hebei Lightning Protection Center. The results show that Tangshan, Baoding, and Qinhuangdao belong to the maximal damageable area; Xingtai, Hengshui, Langfang, Zhangjiakou, and Shijiazhang belong to the high damageable area; Chengde belongs to the medium damageable area; Cangzhou and Handan belong to the low damageable area. The vulnerability degree of each district is calculated and vulnerability regionalization over Hebei is made by means of GIS data, which can give some references to lightning protection and disaster reduction service.
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.