Volume 40,Issue 5,2012 Table of Contents
2012, 40(5):689-697.
Abstract:
It is very important to obtain the base parameters of clouds sounding/detecting both qualitatively and quantitatively， so to understand the future weather variation trends. The researches on the methods for sounding clouds， such as the distribution structure of clouds in the recent years, are reviewed. The researches are described according to the characteristics of different observational tools， including space borne remote sensing, ground based remote sensing， and so on， and the analysis and comparison are conducted. The advantages and disadvantages of the methods are discussed， which is meaningful for various scientific researches in future. Some problems that further researches in this field may be confronted in and the probable directions of the future observation research are discussed.
It is very important to obtain the base parameters of clouds sounding/detecting both qualitatively and quantitatively， so to understand the future weather variation trends. The researches on the methods for sounding clouds， such as the distribution structure of clouds in the recent years, are reviewed. The researches are described according to the characteristics of different observational tools， including space borne remote sensing, ground based remote sensing， and so on， and the analysis and comparison are conducted. The advantages and disadvantages of the methods are discussed， which is meaningful for various scientific researches in future. Some problems that further researches in this field may be confronted in and the probable directions of the future observation research are discussed.
2012, 40(5):698-706.
Abstract:
Using the new channel simulation approach based on spectra matching, by means of the real data from the high spectral resolution atmospheric sounder, the brightness temperature in broadband imager IR channels of the observing target is simulated. The real data observed by IASI (Infrared Atmospheric Sounding Interferometer) are used to simulate the IR channels of the Imager (JAMI) of MTSAT 1R at 12：57UTC 14 February 2010, 00：57UTC 14 February, 2010, and 12：57UTC 2 May 2010. The results show that the absolute value of the average difference between simulating and observing brightness temperature is less than 1 K for JAMI IR1 IR4, and the correlation coefficient is lager than 0.93. The research shows that the method based on the high spectral resolution data is effective and can be used in the simulation of meteorological satellite IR channels. Moreover, the real data observed by IASI are used to simulate IR channels of the Imager (VISSR) of FY 2E, and the result shows that GSICS calibration improved greatly, compared with the operational calibration for IR2, IR3, and IR4 in November 2010.
Using the new channel simulation approach based on spectra matching, by means of the real data from the high spectral resolution atmospheric sounder, the brightness temperature in broadband imager IR channels of the observing target is simulated. The real data observed by IASI (Infrared Atmospheric Sounding Interferometer) are used to simulate the IR channels of the Imager (JAMI) of MTSAT 1R at 12：57UTC 14 February 2010, 00：57UTC 14 February, 2010, and 12：57UTC 2 May 2010. The results show that the absolute value of the average difference between simulating and observing brightness temperature is less than 1 K for JAMI IR1 IR4, and the correlation coefficient is lager than 0.93. The research shows that the method based on the high spectral resolution data is effective and can be used in the simulation of meteorological satellite IR channels. Moreover, the real data observed by IASI are used to simulate IR channels of the Imager (VISSR) of FY 2E, and the result shows that GSICS calibration improved greatly, compared with the operational calibration for IR2, IR3, and IR4 in November 2010.
2012, 40(5):707-712.
Abstract:
The China Meteorological Administration established meteorological industry measurement standards of photosynthetic effective radiation and ultraviolet radiation in 2010. The various performance indexes of calibrators must be verified by practical tests after the standards are put to use. By testing the wavelength precision, accuracy, stray light, repeatability, stability, and the cosine response of the optical input unit in the spectroradiometer, as well as evaluating the sources of errors and the uncertainty of the whole standard, it is verified that the ultraviolet radiation measurement standard, DTMC300 Multiple Grating Double Monochromator, satisfies the related technical specifications of WMO regulations.
The China Meteorological Administration established meteorological industry measurement standards of photosynthetic effective radiation and ultraviolet radiation in 2010. The various performance indexes of calibrators must be verified by practical tests after the standards are put to use. By testing the wavelength precision, accuracy, stray light, repeatability, stability, and the cosine response of the optical input unit in the spectroradiometer, as well as evaluating the sources of errors and the uncertainty of the whole standard, it is verified that the ultraviolet radiation measurement standard, DTMC300 Multiple Grating Double Monochromator, satisfies the related technical specifications of WMO regulations.
2012, 40(5):713-718.
Abstract:
The excitation source is the provider of the radio frequency excitation modulation pulse signals of the launch subsystem and the radio frequency test modulation pulse signals of the BITE subsystem for the fully coherent Doppler weather radar. If the power of the output RF modulation pulse signals output by the excitation source drops obviously, or the amplitude and width of the sequential control pulse change, or the frequency and power of the first LO (Local Oscillator) and the second LO signals entering the excitation source change, the transmitter power will drop greatly, so to induce the breakdowns such as unusual echo signals. The breakdown causes of the CINAD/CC weather radar excitation source are analyzed, as an example, by means of the breakdown case of the weather radar excitation source occurred on 27 October 2010 at the Aqsu radar station, Xinjiang. The key point waveforms under normal and abnormal conditions are analyzed and compared, and some suggestions for fault diagnosis and troubleshooting are given.
The excitation source is the provider of the radio frequency excitation modulation pulse signals of the launch subsystem and the radio frequency test modulation pulse signals of the BITE subsystem for the fully coherent Doppler weather radar. If the power of the output RF modulation pulse signals output by the excitation source drops obviously, or the amplitude and width of the sequential control pulse change, or the frequency and power of the first LO (Local Oscillator) and the second LO signals entering the excitation source change, the transmitter power will drop greatly, so to induce the breakdowns such as unusual echo signals. The breakdown causes of the CINAD/CC weather radar excitation source are analyzed, as an example, by means of the breakdown case of the weather radar excitation source occurred on 27 October 2010 at the Aqsu radar station, Xinjiang. The key point waveforms under normal and abnormal conditions are analyzed and compared, and some suggestions for fault diagnosis and troubleshooting are given.
2012, 40(5):719-722.
Abstract:
Along with the development of electronic technology and extensive application of all kinds of wireless transmitting devices, various unexpected electronic interferences are encountered in wireless receive devices, especially in high sensitive radar. Having experienced several electronic interference events, some typical cases are selected, such as the co frequency interference between weather radars, the co frequency interference between weather radar and military radar, as well as interferences from microwave relay stations and civil UHF transmitters. The electronic interference phenomenon and the detecting process are introduced, and the formation causes and practical solutions are discussed.
Along with the development of electronic technology and extensive application of all kinds of wireless transmitting devices, various unexpected electronic interferences are encountered in wireless receive devices, especially in high sensitive radar. Having experienced several electronic interference events, some typical cases are selected, such as the co frequency interference between weather radars, the co frequency interference between weather radar and military radar, as well as interferences from microwave relay stations and civil UHF transmitters. The electronic interference phenomenon and the detecting process are introduced, and the formation causes and practical solutions are discussed.
2012, 40(5):723-726.
Abstract:
To summarize the maintenance techniques of the CTL 713C weather radar receiver comprehensively, an analysis is made of the main component circuits and functions of the receiver, and the schematic signal flow chart is presented. The CTL 713C weather radar receiver faults are analyzed, and troubleshooting methods is discussed. The frame of reference for radar receiver maintenance is given: looking through the whole, starting with the easy, testing comprehensively, and being familiar with the working principles.
To summarize the maintenance techniques of the CTL 713C weather radar receiver comprehensively, an analysis is made of the main component circuits and functions of the receiver, and the schematic signal flow chart is presented. The CTL 713C weather radar receiver faults are analyzed, and troubleshooting methods is discussed. The frame of reference for radar receiver maintenance is given: looking through the whole, starting with the easy, testing comprehensively, and being familiar with the working principles.
2012, 40(5):727-730.
Abstract:
The failure in a transmitter of the new generation weather radar CINRAD/CD modulation system can affect the radar signals and even result in complete breakdown of the radar system. Two typical faults in the transmitter of the new generation weather radar CINRAD/CD modulation system are described, and the symptoms are analyzed in combination with the practical experiences, through step by step judging, checking, and testing the key circuit signals according to the composition and working principles of the modulation system, to identify the basic causes of failure and locate quickly the failure and then take the corresponding countermeasures.
The failure in a transmitter of the new generation weather radar CINRAD/CD modulation system can affect the radar signals and even result in complete breakdown of the radar system. Two typical faults in the transmitter of the new generation weather radar CINRAD/CD modulation system are described, and the symptoms are analyzed in combination with the practical experiences, through step by step judging, checking, and testing the key circuit signals according to the composition and working principles of the modulation system, to identify the basic causes of failure and locate quickly the failure and then take the corresponding countermeasures.
2012, 40(5):731-737.
Abstract:
The differences between the extreme ground temperature measured by two different types of temperatures sensors (automatic and manual observation) from 2004 to 2009 at the Mentougou weather station are analyzed. The monthly average differences between the maximum ground temperatures vary from －2.5 ℃ to 2.0 ℃ with obviously seasonal and annual variations, but the difference values have an average rate of 17.5% exceeding the mean value of 2 ℃ and the exceeding ratios decrease year by year. The monthly average differences between the minimum ground temperatures vary from －0.5 ℃ to 2.0 ℃ with obviously seasonal and annual variations, and the difference values have an average exceeding average rate of 3.8%. The influencing factors, such as the intrinsic errors of the platinum resistance thermometers and glass liquid thermometers, soil condition, rainfall, etc. are analyzed. The influences of the different soil environment, installation state, solar radiation intensity, weather conditions, and other external factors are more significant than the errors caused by the instrument itself. The suggestions on reducing human induced errors during ground temperature observation are given, which are helpful to the maintenance and quality improvement of ground temperature observation.
The differences between the extreme ground temperature measured by two different types of temperatures sensors (automatic and manual observation) from 2004 to 2009 at the Mentougou weather station are analyzed. The monthly average differences between the maximum ground temperatures vary from －2.5 ℃ to 2.0 ℃ with obviously seasonal and annual variations, but the difference values have an average rate of 17.5% exceeding the mean value of 2 ℃ and the exceeding ratios decrease year by year. The monthly average differences between the minimum ground temperatures vary from －0.5 ℃ to 2.0 ℃ with obviously seasonal and annual variations, and the difference values have an average exceeding average rate of 3.8%. The influencing factors, such as the intrinsic errors of the platinum resistance thermometers and glass liquid thermometers, soil condition, rainfall, etc. are analyzed. The influences of the different soil environment, installation state, solar radiation intensity, weather conditions, and other external factors are more significant than the errors caused by the instrument itself. The suggestions on reducing human induced errors during ground temperature observation are given, which are helpful to the maintenance and quality improvement of ground temperature observation.
2012, 40(5):738-744.
Abstract:
Based on many year practice of reactive gas observation and its sophisticated quality control and data processing methods, the comprehensive and rational functional design and orientation have been assigned to the data processing system, which is developed by using the Visual Studio development platform combined with MAP WinGIS and other display control by means of the modular functional design and development method. The system has realized easily the visualization of the 〖JP2〗observation data in space and time, the good capabilities of human computer interaction, certain data statistic and analysis, etc. The system is an efficient tool for managing and processing reactive gas observation data, and has become an important component of the operational reactive gas observation data quality control and processing system.
Based on many year practice of reactive gas observation and its sophisticated quality control and data processing methods, the comprehensive and rational functional design and orientation have been assigned to the data processing system, which is developed by using the Visual Studio development platform combined with MAP WinGIS and other display control by means of the modular functional design and development method. The system has realized easily the visualization of the 〖JP2〗observation data in space and time, the good capabilities of human computer interaction, certain data statistic and analysis, etc. The system is an efficient tool for managing and processing reactive gas observation data, and has become an important component of the operational reactive gas observation data quality control and processing system.
2012, 40(5):745-749.
Abstract:
The China Meteorological Administrator (CMA) offers varieties of meteorological data to the general office of the State Council regularly. Since the rules of meteorological data filenames changed and the way of monitoring became unsuitable to operators, a new system is designed and developed to address the related problems. The new data collection and distribution functionalities can solve such issues as the illegal file filtering and figuration flexibility; the upgrade monitoring system can meet the operational needs of data retrieval, problem alarm, and time efficiency calculation; and the expanded data download service is more convenient for the operators. The loose coupled structure of data dissemination and monitoring functions is designed to strengthen the reliability and scalability. After half a year running stably, it is shown that the system can meet the requirements and provides effective support in flooding season.
The China Meteorological Administrator (CMA) offers varieties of meteorological data to the general office of the State Council regularly. Since the rules of meteorological data filenames changed and the way of monitoring became unsuitable to operators, a new system is designed and developed to address the related problems. The new data collection and distribution functionalities can solve such issues as the illegal file filtering and figuration flexibility; the upgrade monitoring system can meet the operational needs of data retrieval, problem alarm, and time efficiency calculation; and the expanded data download service is more convenient for the operators. The loose coupled structure of data dissemination and monitoring functions is designed to strengthen the reliability and scalability. After half a year running stably, it is shown that the system can meet the requirements and provides effective support in flooding season.
2012, 40(5):750-754.
Abstract:
The characteristics of automatic weather stations (AWS) operation efficiency are discussed, by means of the data from 81 AWS stations over Anhui Province monitored by the Atmospheric Observing System Operations and Monitoring (ASOM), and the arrival rate and availability of AWS operation data in 2010 are statistically estimated. The statistical characteristics of operation efficiency of standard stations, basic stations, and general stations are studied month by month, and the influencing factors on operation availability are also analyzed, in allusion to the characteristics of the format error cases of data. The quantificational relation between data format errors and human computer interaction is studied emphatically, and it is determined that the quantificational threshold of data transmitting time is less that 45 seconds. In order to improve the performance and data quality of AWSs, some feasible measures are presented for eliminating format errors.
The characteristics of automatic weather stations (AWS) operation efficiency are discussed, by means of the data from 81 AWS stations over Anhui Province monitored by the Atmospheric Observing System Operations and Monitoring (ASOM), and the arrival rate and availability of AWS operation data in 2010 are statistically estimated. The statistical characteristics of operation efficiency of standard stations, basic stations, and general stations are studied month by month, and the influencing factors on operation availability are also analyzed, in allusion to the characteristics of the format error cases of data. The quantificational relation between data format errors and human computer interaction is studied emphatically, and it is determined that the quantificational threshold of data transmitting time is less that 45 seconds. In order to improve the performance and data quality of AWSs, some feasible measures are presented for eliminating format errors.
2012, 40(5):755-758.
Abstract:
In combination with the definition of the DT5*〖KG-*2〗* series acquisition program parameters, the connections of the data acquisition channels and sensors of the CAWS600 automatic weather stations are analyzed, and the deviation correction of the data acquired from the automatic weather stations are introduced, which includes the analysis of the quantitative relationship between parameters and observations and the adjustment methods of the parameters. The auxiliary correction parameters are added for each observation object, so to preserve the original nature of the calculation parameters. This correction method adjusts the calculation parameters of the acquisition program, and the adjusted program is uploaded to the data collector. Even if sensors are replaced or the collector is used in other automatic stations, the results of this channel deviation are still valid.
In combination with the definition of the DT5*〖KG-*2〗* series acquisition program parameters, the connections of the data acquisition channels and sensors of the CAWS600 automatic weather stations are analyzed, and the deviation correction of the data acquired from the automatic weather stations are introduced, which includes the analysis of the quantitative relationship between parameters and observations and the adjustment methods of the parameters. The auxiliary correction parameters are added for each observation object, so to preserve the original nature of the calculation parameters. This correction method adjusts the calculation parameters of the acquisition program, and the adjusted program is uploaded to the data collector. Even if sensors are replaced or the collector is used in other automatic stations, the results of this channel deviation are still valid.
2012, 40(5):759-762.
Abstract:
The scheme of the high precision temperature and humidity intelligent sensor system is determined through analyzing the functional requirements for the meteorological data acquisition system. The overall scheme and the realization of hardware and software systems are introduced. To realize the functions of high accuracy measurement, automatic collection, and real time processing, based on the CAN Bus, the main control chip LPC1768 is selected, in combination with the low power consumption architecture of ARM CORTEX M3, 16 bit serial A/D conversion chip AD7792 with low power consumption, and the high speed CAN transceiver SN65HVD230 with low power consumption. Compared with the existing meteorological data acquisition equipment, it has the characteristics of smaller size, lower power consumption, flexible networking, and higher measuring precision. The test results show that the high precision intelligent sensor is stable, reliable and has the functions of high precision,self checking, self calibration, and self adaption.
The scheme of the high precision temperature and humidity intelligent sensor system is determined through analyzing the functional requirements for the meteorological data acquisition system. The overall scheme and the realization of hardware and software systems are introduced. To realize the functions of high accuracy measurement, automatic collection, and real time processing, based on the CAN Bus, the main control chip LPC1768 is selected, in combination with the low power consumption architecture of ARM CORTEX M3, 16 bit serial A/D conversion chip AD7792 with low power consumption, and the high speed CAN transceiver SN65HVD230 with low power consumption. Compared with the existing meteorological data acquisition equipment, it has the characteristics of smaller size, lower power consumption, flexible networking, and higher measuring precision. The test results show that the high precision intelligent sensor is stable, reliable and has the functions of high precision,self checking, self calibration, and self adaption.
2012, 40(5):763-765.
Abstract:
In the practical work, the overcharge phenomenon of storage batteries is often found in regional automatic weather stations, which shortens the service life of the battery. To solve this problem, a self made solar charge/discharge controller can be used to stop charging when the battery terminal voltage reaches the upper limit value. As the protector uses only the electric energy of the solar battery rather than that of the storage battery, it will stop working when there is no sunlight. In this way the controller extends, to the greatest extent, the working hours of the collector. In addition, the controller can work anytime as it is plugged without altering any of its wiring, so to ensure the long term stable operation of the regional weather station.
In the practical work, the overcharge phenomenon of storage batteries is often found in regional automatic weather stations, which shortens the service life of the battery. To solve this problem, a self made solar charge/discharge controller can be used to stop charging when the battery terminal voltage reaches the upper limit value. As the protector uses only the electric energy of the solar battery rather than that of the storage battery, it will stop working when there is no sunlight. In this way the controller extends, to the greatest extent, the working hours of the collector. In addition, the controller can work anytime as it is plugged without altering any of its wiring, so to ensure the long term stable operation of the regional weather station.
2012, 40(5):766-771.
Abstract:
The advancements in the researches on LLJ (Low Level Jet) in China in recent 40 years are reviewed with emphases on the structure characteristics and possible mechanisms of LLJ and the relationship between LLJ and severe convective weather, which include the classification of LLJ in two different ways, the spatial distribution, and the formation causes. However, the observation time for collecting radiosonde data and the occurrence time for LLJ do not match. Moreover, the special observation of LLJ has not been widely applied because of its high cost. Therefore, due to the difficulty of LLJ observation and the lack of specialized researches in China, the further study will be needed, especially in the structure characteristics of LLJ itself.
The advancements in the researches on LLJ (Low Level Jet) in China in recent 40 years are reviewed with emphases on the structure characteristics and possible mechanisms of LLJ and the relationship between LLJ and severe convective weather, which include the classification of LLJ in two different ways, the spatial distribution, and the formation causes. However, the observation time for collecting radiosonde data and the occurrence time for LLJ do not match. Moreover, the special observation of LLJ has not been widely applied because of its high cost. Therefore, due to the difficulty of LLJ observation and the lack of specialized researches in China, the further study will be needed, especially in the structure characteristics of LLJ itself.
2012, 40(5):772-777.
Abstract:
The statistical models of SVM, Kalman and multi dimensional linear regression are established for extreme temperature with the ECMWF (European Centre for Medium Range Weather Forecasts) grid data and the observation data of Qingyan from 2003 to 2009. The methods of average, weighting, and regression are used in forecast integration. The integrated forecasts indicate that the accuracies of minimum temperature are 0.8% to 24.2% higher than those of maximum temperature by means of SVM, multiple regression and integrated methods at various time from June to December 2010. The weighting method is the best, then the integration, but the weight is different for maximum and minimum temperature: the accuracy of maximum temperature is better when the SVM weight is greater, and the accuracy of minimum temperature is better when the weight of multiple regression is greater. The forecasting accuracy decreases with increasing led time for both single and consensus forecast methods. The month to month verification indicates that the accuracy of the single SVM method is relatively high and stable; that of the Kalman is relatively low; and that of the regression is unstably. The integrated results of three methods show improving, and the absolute errors of both maximum and minimum temperature after weighting integration are small, better than those of the average and regression methods.
The statistical models of SVM, Kalman and multi dimensional linear regression are established for extreme temperature with the ECMWF (European Centre for Medium Range Weather Forecasts) grid data and the observation data of Qingyan from 2003 to 2009. The methods of average, weighting, and regression are used in forecast integration. The integrated forecasts indicate that the accuracies of minimum temperature are 0.8% to 24.2% higher than those of maximum temperature by means of SVM, multiple regression and integrated methods at various time from June to December 2010. The weighting method is the best, then the integration, but the weight is different for maximum and minimum temperature: the accuracy of maximum temperature is better when the SVM weight is greater, and the accuracy of minimum temperature is better when the weight of multiple regression is greater. The forecasting accuracy decreases with increasing led time for both single and consensus forecast methods. The month to month verification indicates that the accuracy of the single SVM method is relatively high and stable; that of the Kalman is relatively low; and that of the regression is unstably. The integrated results of three methods show improving, and the absolute errors of both maximum and minimum temperature after weighting integration are small, better than those of the average and regression methods.
2012, 40(5):778-782.
Abstract:
According the refined guidance temperature forecast data in 730 days from 2009 to 2010 in Shanxin, compared to the daily maximum and minimum temperature, using conventional statistical and EOF analysis methods, the temporal spatial distribution of the guidance forecast errors is studied. The results show: the temperature prediction accuracy in Shanxi is relatively stable, but there is obvious seasonal variation, the highest in summer, the second in autumn, and relatively low in winter and spring; both average positive and negative errors of daily maximum temperature are slightly higher than those of daily minimum temperature, the largest in spring, then in autumn and winter, the smallest in summer; the spatial distribution of errors is relative to the topography in Shanxi, and obvious consistency is found in the error distribution of daily maximum temperature and minimum temperature over the whole Shanxi.
According the refined guidance temperature forecast data in 730 days from 2009 to 2010 in Shanxin, compared to the daily maximum and minimum temperature, using conventional statistical and EOF analysis methods, the temporal spatial distribution of the guidance forecast errors is studied. The results show: the temperature prediction accuracy in Shanxi is relatively stable, but there is obvious seasonal variation, the highest in summer, the second in autumn, and relatively low in winter and spring; both average positive and negative errors of daily maximum temperature are slightly higher than those of daily minimum temperature, the largest in spring, then in autumn and winter, the smallest in summer; the spatial distribution of errors is relative to the topography in Shanxi, and obvious consistency is found in the error distribution of daily maximum temperature and minimum temperature over the whole Shanxi.
18 Application of Boundary Layer Wind Profiler Radar Data to Forecasting of Two Snowy Weather Events
2012, 40(5):783-788.
Abstract:
By analyzing the wind profiler data on two different snowy weather processes on 31 October and 9 November 2009 in Beijing. It is found: (1) The easterly flow established at lower levels 2 hours before the start of snowfall, and there occurred a phenomenon that the wind suddenly strengthened, which has reference value for forecasting the start of snowfall. (2) There existed cold advection at 700 hPa and above, or cold advection enhancement, which is also a sign of the snowfall start. (3) The profiles of temperature advection calculated from the wind profile data can reflect the atmospheric stability conditions and provide a reliable basis for determining whether the snow is convective. Therefore, it has great significance for critical weather nowcasting to strengthen the wind profile and temperature advection profile monitoring.
By analyzing the wind profiler data on two different snowy weather processes on 31 October and 9 November 2009 in Beijing. It is found: (1) The easterly flow established at lower levels 2 hours before the start of snowfall, and there occurred a phenomenon that the wind suddenly strengthened, which has reference value for forecasting the start of snowfall. (2) There existed cold advection at 700 hPa and above, or cold advection enhancement, which is also a sign of the snowfall start. (3) The profiles of temperature advection calculated from the wind profile data can reflect the atmospheric stability conditions and provide a reliable basis for determining whether the snow is convective. Therefore, it has great significance for critical weather nowcasting to strengthen the wind profile and temperature advection profile monitoring.
2012, 40(5):789-793.
Abstract:
In order to analyze the variation of the temperature inversion layer in the lower atmosphere over Chongqing, the daily L band radar data set in the period of 2005 to 2009 in Shapingba Weather Station is used. The frequency, intensity, thickness, and distribution of temperature inversion are analyzed in detail. The results reveal that there existed temperature inversion in the lower atmosphere over Chongqing in most days of a year, up to 93%, most frequent in summer and rarely in winter; the overall intensity of is modest, with the average intensity of touchdown inversion at 07:00 and 19:00 being 0.53 ℃/hm and 06 ℃/hm, respectively, which are two times as much as those of suspension inversion at the same time. In respect of the characteristics in the vertical distribution, the lower level temperature inversion layers are relatively thin and divided into many layers, sometimes up to 6 layers.
In order to analyze the variation of the temperature inversion layer in the lower atmosphere over Chongqing, the daily L band radar data set in the period of 2005 to 2009 in Shapingba Weather Station is used. The frequency, intensity, thickness, and distribution of temperature inversion are analyzed in detail. The results reveal that there existed temperature inversion in the lower atmosphere over Chongqing in most days of a year, up to 93%, most frequent in summer and rarely in winter; the overall intensity of is modest, with the average intensity of touchdown inversion at 07:00 and 19:00 being 0.53 ℃/hm and 06 ℃/hm, respectively, which are two times as much as those of suspension inversion at the same time. In respect of the characteristics in the vertical distribution, the lower level temperature inversion layers are relatively thin and divided into many layers, sometimes up to 6 layers.
2012, 40(5):794-798.
Abstract:
The R style factor analysis is carried out for the summer rainfall fields of 16 observation station over Anhui Province from 1957 to 2000, by means of the factor load scatter diagram to carry out the division of observation stations to find the representative stations within the region, the summer rainfall statistical characteristics of the region, the long term trend of summer precipitation, the characteristics of regional droughts,and the inter decadal variation. The analysis indicates that the rainfall fields can be divided into 3 sub regions, in which Dangshan, 〖JP2〗Chuzhou and Ningguo can be used as their standard stations respectively. The results indicate that there is great difference in the characteristics of summer rainfall among the three regions for more than four decades. The summer rainfall in Zone 1 was the least, and that in Zone 3 was the greatest; there is most obvious difference between three zones in June; the long term trends of summer precipitation in Zone 1 and Zone 2 were not significant, but that in Zone 3 was very obvious. There were frequent droughts in Zone 1 from 1957 to 1970 and 1991 to 2000. The overall trends of the drought/flood occurrence frequencies in Zone 2 and Zone 3 varied over time, changing from droughts to floods.
The R style factor analysis is carried out for the summer rainfall fields of 16 observation station over Anhui Province from 1957 to 2000, by means of the factor load scatter diagram to carry out the division of observation stations to find the representative stations within the region, the summer rainfall statistical characteristics of the region, the long term trend of summer precipitation, the characteristics of regional droughts,and the inter decadal variation. The analysis indicates that the rainfall fields can be divided into 3 sub regions, in which Dangshan, 〖JP2〗Chuzhou and Ningguo can be used as their standard stations respectively. The results indicate that there is great difference in the characteristics of summer rainfall among the three regions for more than four decades. The summer rainfall in Zone 1 was the least, and that in Zone 3 was the greatest; there is most obvious difference between three zones in June; the long term trends of summer precipitation in Zone 1 and Zone 2 were not significant, but that in Zone 3 was very obvious. There were frequent droughts in Zone 1 from 1957 to 1970 and 1991 to 2000. The overall trends of the drought/flood occurrence frequencies in Zone 2 and Zone 3 varied over time, changing from droughts to floods.
2012, 40(5):799-806.
Abstract:
By investigation of the visibility data at 08:00 over Guizhou Province and surface 08:00 weather charts from 1971 to 2008, a total of 382 regional radiation fog processes are selected to analyze the spatial and temporal distribution characteristics of regional radiation fogs in Guizhou. Using the surface and upper air weather charts at 08:00 of 93 radiation fog processes during the 10 years, the corresponding weather circulation conditions are researched. Using the surface and radiosonde meteorological data, the meteorological elements of influencing the formation of radiation fogs are studied. The results show that regional radiation fogs in Guizhou mainly happened in mid autumn and winter, more frequently in the east than in the west of Guizhou, and there was an evenly distributed pressure field while regional radiation fogs occurred. There are four upper air circulation conditions of regional radiation fog: northwest flow type, southwest flow type, subtropical high type and straightly west flow type. There are four meteorological conditions beneficial to the formation of regional radiation fog: low surface wind speed, high surface humidity, significant radiation cooling at night and temperature inversion at surface layer, and the vertical air with upper layer dry and lower layer wet.
By investigation of the visibility data at 08:00 over Guizhou Province and surface 08:00 weather charts from 1971 to 2008, a total of 382 regional radiation fog processes are selected to analyze the spatial and temporal distribution characteristics of regional radiation fogs in Guizhou. Using the surface and upper air weather charts at 08:00 of 93 radiation fog processes during the 10 years, the corresponding weather circulation conditions are researched. Using the surface and radiosonde meteorological data, the meteorological elements of influencing the formation of radiation fogs are studied. The results show that regional radiation fogs in Guizhou mainly happened in mid autumn and winter, more frequently in the east than in the west of Guizhou, and there was an evenly distributed pressure field while regional radiation fogs occurred. There are four upper air circulation conditions of regional radiation fog: northwest flow type, southwest flow type, subtropical high type and straightly west flow type. There are four meteorological conditions beneficial to the formation of regional radiation fog: low surface wind speed, high surface humidity, significant radiation cooling at night and temperature inversion at surface layer, and the vertical air with upper layer dry and lower layer wet.
2012, 40(5):807-813.
Abstract:
Using the conventional, automatic, satellite, and radar data, a comprehensive analysis is conducted of the heavy rain occurred on 19 September 2010 in the middle Shanxi. The results show:(1) The subtropical high at 500 hPa, which changed from block pattern to zonal pattern, was strong, and the horizontal anticyclone at 200 hPa maintained stably, which were important background factors for the formation and maintenance of the horizontal shear line at lower levels. The vortex and horizontal shear line were mainly influencing systems. (2) There were typical β meso scale characteristics in precipitation. A convective cloud mass first occurred in the west side of the vortex; with the strengthening of SW flow before the vortex, the convective cloud mass promptly developed and moved to east; and the heavy rain was caused by the β meso scale convective cloud mass triggered the shear line. 〖JP2〗Opposite correlation was found between TBB and rainfall in future 6 hours. (3) There was a line shaped echo band in radar, and the heavy rain was located at the area of over 45 dBz. (4) There existed cold advection in the northwest of vortex, which enhanced the vortex, and there existed positive vortex advection at 500 hPa, which were the dynamical factors for the maintenance and development of the horizontal shear line that induced the heavy rain.
Using the conventional, automatic, satellite, and radar data, a comprehensive analysis is conducted of the heavy rain occurred on 19 September 2010 in the middle Shanxi. The results show:(1) The subtropical high at 500 hPa, which changed from block pattern to zonal pattern, was strong, and the horizontal anticyclone at 200 hPa maintained stably, which were important background factors for the formation and maintenance of the horizontal shear line at lower levels. The vortex and horizontal shear line were mainly influencing systems. (2) There were typical β meso scale characteristics in precipitation. A convective cloud mass first occurred in the west side of the vortex; with the strengthening of SW flow before the vortex, the convective cloud mass promptly developed and moved to east; and the heavy rain was caused by the β meso scale convective cloud mass triggered the shear line. 〖JP2〗Opposite correlation was found between TBB and rainfall in future 6 hours. (3) There was a line shaped echo band in radar, and the heavy rain was located at the area of over 45 dBz. (4) There existed cold advection in the northwest of vortex, which enhanced the vortex, and there existed positive vortex advection at 500 hPa, which were the dynamical factors for the maintenance and development of the horizontal shear line that induced the heavy rain.
23 Convective Vorticity Vector Analysis of a Heavy Rainstorm under Long Distance Influence of Typhoon
2012, 40(5):814-819.
Abstract:
An analysis is made of a heavy rainstorm under the long distance influence of the Typhoon from 16 to 19 July 2010 from convective vorticity vector (CVV) on the basis of conventional observation data, NCEP reanalysis data, automatic station data, and satellite cloud data. The results show that the high 〖WTBX〗θ〖WTBZ〗e value area located in the warm wet airflow on the south side of southwest vortex; the 〖WTBX〗θ〖WTBZ〗e contours over the heavy rainstorm center were nearly vertical, which presented a funnel shaped structure,and there was a deep moist column of 90% relative humidity from low levels to the tropopause； the northeast southwest upper jet strengthened the high level divergence on the right side of the jet entrance region, which caused deep and strong vertical ascending motion over the heavy rainstorm area；there existed southeast winds at low levels, southwest winds at middle levels and northwest winds at high levels; there was great convective instability over the heavy rainstorm and obvious latitudinal wind shear at middle levels and meridional wind shear at mid upper levels over the heavy rainstorm centers. The heavy rainstorm appeared in the coincidence area of the large CVV and atmospheric column cloud water.
An analysis is made of a heavy rainstorm under the long distance influence of the Typhoon from 16 to 19 July 2010 from convective vorticity vector (CVV) on the basis of conventional observation data, NCEP reanalysis data, automatic station data, and satellite cloud data. The results show that the high 〖WTBX〗θ〖WTBZ〗e value area located in the warm wet airflow on the south side of southwest vortex; the 〖WTBX〗θ〖WTBZ〗e contours over the heavy rainstorm center were nearly vertical, which presented a funnel shaped structure,and there was a deep moist column of 90% relative humidity from low levels to the tropopause； the northeast southwest upper jet strengthened the high level divergence on the right side of the jet entrance region, which caused deep and strong vertical ascending motion over the heavy rainstorm area；there existed southeast winds at low levels, southwest winds at middle levels and northwest winds at high levels; there was great convective instability over the heavy rainstorm and obvious latitudinal wind shear at middle levels and meridional wind shear at mid upper levels over the heavy rainstorm centers. The heavy rainstorm appeared in the coincidence area of the large CVV and atmospheric column cloud water.
2012, 40(5):820-826.
Abstract:
The mesoscale meteorological model (MM5V3.7) is used to simulate a strong sand and dust storm (SDS) process in North China from 18 to 22 March 2002. With the high resolution data from MM5V3.7, the PV theory (potential vorticity) is applied to reveal the mechanism of downward momentum transport. The results show that: (1) the Mongolia cyclone was the main weather system during this strong SDS process, and gales and dryness were the preconditions of the wind erosion; (2) the downward transportation of potential vorticity along the iso entropy surface was the most important process during the SDS, which clearly reveals the mechanism of downward momentum transport.
The mesoscale meteorological model (MM5V3.7) is used to simulate a strong sand and dust storm (SDS) process in North China from 18 to 22 March 2002. With the high resolution data from MM5V3.7, the PV theory (potential vorticity) is applied to reveal the mechanism of downward momentum transport. The results show that: (1) the Mongolia cyclone was the main weather system during this strong SDS process, and gales and dryness were the preconditions of the wind erosion; (2) the downward transportation of potential vorticity along the iso entropy surface was the most important process during the SDS, which clearly reveals the mechanism of downward momentum transport.
2012, 40(5):827-833.
Abstract:
An analysis is made of the effect of tall buildings on the thunderstorm electric fields by using the finite difference method. The results show that: (1)The atmospheric electric fields are greatly affected by surrounding buildings; for example, the field intensities at the top of a 40m〖WTBX〗×〖WTBZ〗40m building (at the center point of its flat roof) with the heights of 10, 20, 50, and 100 m are about 1.4, 1.7, 2.8 or 4.5 times greater than that on the ground surface without any building, respectively. (2) The field intensity at the ground level in the immediate vicinity of the building is reduced relative to the case without buildings, with this shielding effect becoming negligible at horizontal distances from the building exceeding about 3.5 times of the height of the building. Therefore, the errors caused by the tall buildings should be considered in the measurement of thunderstorm electric fields.
An analysis is made of the effect of tall buildings on the thunderstorm electric fields by using the finite difference method. The results show that: (1)The atmospheric electric fields are greatly affected by surrounding buildings; for example, the field intensities at the top of a 40m〖WTBX〗×〖WTBZ〗40m building (at the center point of its flat roof) with the heights of 10, 20, 50, and 100 m are about 1.4, 1.7, 2.8 or 4.5 times greater than that on the ground surface without any building, respectively. (2) The field intensity at the ground level in the immediate vicinity of the building is reduced relative to the case without buildings, with this shielding effect becoming negligible at horizontal distances from the building exceeding about 3.5 times of the height of the building. Therefore, the errors caused by the tall buildings should be considered in the measurement of thunderstorm electric fields.
2012, 40(5):834-838.
Abstract:
The analysis of metallographic structure is one of the important methods for lightning disaster investigation. The metallographic structure analysis is made of different metal materials that had been impacted by simulate lightning currents, with emphasis on the influence of lightning current impulses on the metal materials through changing microstructure. The results show that the metallographic structure of the metal materials changed obviously after impacted by simulated lightning currents. The metallographic structure changes for different metal material are different obviously. For the same metal material impacted by lightning currents, the amplitude of metallographic structure change is in inverse proportion to the sectional area.
The analysis of metallographic structure is one of the important methods for lightning disaster investigation. The metallographic structure analysis is made of different metal materials that had been impacted by simulate lightning currents, with emphasis on the influence of lightning current impulses on the metal materials through changing microstructure. The results show that the metallographic structure of the metal materials changed obviously after impacted by simulated lightning currents. The metallographic structure changes for different metal material are different obviously. For the same metal material impacted by lightning currents, the amplitude of metallographic structure change is in inverse proportion to the sectional area.
2012, 40(5):839-842.
Abstract:
In the statistical process of ground flash density, the grids need to be divided in kilometer, and then the data of lightning flushes falling in the grids need be counted. The concept of dimension reduction is used to compute the ground flash density for the first time. During the contour drawing, all the data are involved without missing data. The manual statistical method is described, and the statistical method of dimension reduction is achieved by using the Java language at the same time, which provides a friendly interactive interface. The application proved that the statistical method has a very good practicability.
In the statistical process of ground flash density, the grids need to be divided in kilometer, and then the data of lightning flushes falling in the grids need be counted. The concept of dimension reduction is used to compute the ground flash density for the first time. During the contour drawing, all the data are involved without missing data. The manual statistical method is described, and the statistical method of dimension reduction is achieved by using the Java language at the same time, which provides a friendly interactive interface. The application proved that the statistical method has a very good practicability.
2012, 40(5):843-848.
Abstract:
A diffusion simulating system of point source catalysts in convective clouds is established based on the theory of catalyst diffusion in convective clouds，and the system design and its application are described. The relationship of catalyst diffusion to the time, wind speed, turbulence coefficient, and vertical speed is discussed. The results indicate that in convective clouds the catalysts diffuse relatively quickly and the diffusion speed can reach a steady extension after several minutes; the larger the wind speed and turbulence coefficient, the wider the diffused area can be; the catalyst diffusion is mainly concentrated around the explosive height. The conclusion could be useful for artificial precipitation enhancement in convective clouds and the evaluation of precipitation enhancement effectiveness.
A diffusion simulating system of point source catalysts in convective clouds is established based on the theory of catalyst diffusion in convective clouds，and the system design and its application are described. The relationship of catalyst diffusion to the time, wind speed, turbulence coefficient, and vertical speed is discussed. The results indicate that in convective clouds the catalysts diffuse relatively quickly and the diffusion speed can reach a steady extension after several minutes; the larger the wind speed and turbulence coefficient, the wider the diffused area can be; the catalyst diffusion is mainly concentrated around the explosive height. The conclusion could be useful for artificial precipitation enhancement in convective clouds and the evaluation of precipitation enhancement effectiveness.
29 Application of Multiparty Communication Platform in Rocket Operations for Precipitation Elimination
2012, 40(5):849-853.
Abstract:
The choice of operation time is essential to the effects of artificial precipitation mitigation, and the command for rocket operations needs rapid and efficient, unity and accurate responding. A method for realizing regional command is introduced. The specialized users are determined on the existing network communication platform, and a one party to multiparty communication platform is built. A corresponding contact list is set up according to the specific deployment scheme, and the corresponding conference groups are established according to the operational region division. Except instant meetings, there are also such functions as reserved meetings, inbound type meetings and text message reminders on this platform, which can play an important role in the process of regional command in rocket operations for artificial precipitation mitigation. The method has great application potential in cross regional and large scale operations of weather modification.
The choice of operation time is essential to the effects of artificial precipitation mitigation, and the command for rocket operations needs rapid and efficient, unity and accurate responding. A method for realizing regional command is introduced. The specialized users are determined on the existing network communication platform, and a one party to multiparty communication platform is built. A corresponding contact list is set up according to the specific deployment scheme, and the corresponding conference groups are established according to the operational region division. Except instant meetings, there are also such functions as reserved meetings, inbound type meetings and text message reminders on this platform, which can play an important role in the process of regional command in rocket operations for artificial precipitation mitigation. The method has great application potential in cross regional and large scale operations of weather modification.
2012, 40(5):854-857.
Abstract:
The downward trend of sunshine duration in growing season adversely affects agricultural production in Inner Mongolia. Through analyzing the sunshine duration data of 20 stations over Inner Mongolia from 1961 to 2010, using the methods of least square, cumulative anomaly, and moving 〖WTBX〗t〖WTBZ〗 test, the variation characteristics of sunshine duration in Inner Mongolia in the growing season in the 50 years are analyzed. The results show that: (1) The annual sunshine duration in growing season generally exhibited a decreasing tendency, and the decreasing rate in the central part was the most fast (－29.1 h/10a), the next in the west (－19.10 h/10a), and the least in the east (－14.7h/10a). (2) There was a sudden change in 1978 and the decreasing tendency speeded up after 1978, but there were two slight increase periods in the process of reduction. (3) The monthly variation tendency of sunshine duration was different, which was the biggest in June，and the least in April.
The downward trend of sunshine duration in growing season adversely affects agricultural production in Inner Mongolia. Through analyzing the sunshine duration data of 20 stations over Inner Mongolia from 1961 to 2010, using the methods of least square, cumulative anomaly, and moving 〖WTBX〗t〖WTBZ〗 test, the variation characteristics of sunshine duration in Inner Mongolia in the growing season in the 50 years are analyzed. The results show that: (1) The annual sunshine duration in growing season generally exhibited a decreasing tendency, and the decreasing rate in the central part was the most fast (－29.1 h/10a), the next in the west (－19.10 h/10a), and the least in the east (－14.7h/10a). (2) There was a sudden change in 1978 and the decreasing tendency speeded up after 1978, but there were two slight increase periods in the process of reduction. (3) The monthly variation tendency of sunshine duration was different, which was the biggest in June，and the least in April.
2012, 40(5):858-864.
Abstract:
With plenty of data on sand dust storm disaster losses, the data of economic and agricultural losses caused by spring sand dust storms in the northwestern China are processed respectively. Based on the information diffusion theory, the information diffusion method is used to analyze the risk of economic loss and agricultural loss respectively. The results show: (1) Both the economic loss and agricultural loss show an increasing trend on the climatic background of decreasing spring sand dust storm events. (2) The risk of economic loss is higher in Alashan, Xilingole, Tarim, Altai, Tacheng, Turpan, and Turpan Basin, and the risk of agricultural loss is higher in Turpan, Aksu, Hetian, Guazhou, and Alashan.
With plenty of data on sand dust storm disaster losses, the data of economic and agricultural losses caused by spring sand dust storms in the northwestern China are processed respectively. Based on the information diffusion theory, the information diffusion method is used to analyze the risk of economic loss and agricultural loss respectively. The results show: (1) Both the economic loss and agricultural loss show an increasing trend on the climatic background of decreasing spring sand dust storm events. (2) The risk of economic loss is higher in Alashan, Xilingole, Tarim, Altai, Tacheng, Turpan, and Turpan Basin, and the risk of agricultural loss is higher in Turpan, Aksu, Hetian, Guazhou, and Alashan.
2012, 40(5):865-868.
Abstract:
Different meteorological conditions lead to different road surface conditions. In order to increase the safety level of driving on the different road conditions on high way, from the view of meteorological conditions, the influences of different road conditions, such as dry, wet, snow and ice on road traffic safety are analyzed. Using the method of the mathematical method, under the condition that the sum of running distance and braking distance is less than the visible distance, the calculation formulas of the maximum speed limits on the different road conditions on the high way are derived based on the safe distance. The dual exponential model is used to evaluate the longitudinal road friction coefficient，and the values of the corresponding safely limited speeds are computed according to different visible distance and road fiction coefficients.
Different meteorological conditions lead to different road surface conditions. In order to increase the safety level of driving on the different road conditions on high way, from the view of meteorological conditions, the influences of different road conditions, such as dry, wet, snow and ice on road traffic safety are analyzed. Using the method of the mathematical method, under the condition that the sum of running distance and braking distance is less than the visible distance, the calculation formulas of the maximum speed limits on the different road conditions on the high way are derived based on the safe distance. The dual exponential model is used to evaluate the longitudinal road friction coefficient，and the values of the corresponding safely limited speeds are computed according to different visible distance and road fiction coefficients.
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.