Volume 41,Issue 1,2013 Table of Contents
2013, 41(1):1-7.
Abstract:
Accurate global radiation measured by pyranometer is very important for correcting radiation datasets observed by satellites, validating outputs of radiation transport model, climate change research, and quantitative evaluation of solar energy resources. Because most of pyranometers are made based the thermopile principle, the accuracy of global radiation measurement by pyranometers is impacted by all kinds of thermal noise inevitably. Namely there are thermal offsets in global radiation data observed by pyranometers. With the deepgoing of climate change researches in recent years, the accuracy requirement of ground measurements of the total solar radiation is higher. Many researchers at home and overseas have paid close attention to the researches on physical mechanisms and thermal offset correction methods of pyranometers. The following aspects are reviewed: (1) the discovery of thermal offsets of pyranometers; (2) progresses in characteristics and physical mechanisms of thermal offsets of pyranometers; (3) progresses in correction methods of thermal offsets. Appropriate comments about existing problems and research direction are given, and revelation about researches on physical mechanisms and thermal offset correction methods of homemade pyranometers are provided.
Accurate global radiation measured by pyranometer is very important for correcting radiation datasets observed by satellites, validating outputs of radiation transport model, climate change research, and quantitative evaluation of solar energy resources. Because most of pyranometers are made based the thermopile principle, the accuracy of global radiation measurement by pyranometers is impacted by all kinds of thermal noise inevitably. Namely there are thermal offsets in global radiation data observed by pyranometers. With the deepgoing of climate change researches in recent years, the accuracy requirement of ground measurements of the total solar radiation is higher. Many researchers at home and overseas have paid close attention to the researches on physical mechanisms and thermal offset correction methods of pyranometers. The following aspects are reviewed: (1) the discovery of thermal offsets of pyranometers; (2) progresses in characteristics and physical mechanisms of thermal offsets of pyranometers; (3) progresses in correction methods of thermal offsets. Appropriate comments about existing problems and research direction are given, and revelation about researches on physical mechanisms and thermal offset correction methods of homemade pyranometers are provided.
2013, 41(1):8-14.
Abstract:
Using the China surface climate data and the monthly mean data of ISCCP (International Satellite Cloud Climatology Project) D2, EAGSCDR (FY2 and GMS geostationary satellite climate data record over East Asia) are validated and evaluated. The distributions of annual mean total cloud amounts from the three kinds of data are analyzed and compared, and the results show that all the distributive patterns of cloud amounts agree well; however, total cloud amounts from ISCCP and geostationary satellite climate data sets are higher than station observations in the north of 40°N. Furthermore, it is indicated that about 8210% cloud detection product samples of EAGSCDR agree with surface observations, and the overall missing detected rate and false detected rate is 685% and 1105% respectively over South China and the Yangtze River basin; the accuracy of fall and winter is lower. The cloud amounts of EAGSCDR and ISCCP both are obtained from satellite data, and their major differences come from different algorithms. The analysis shows that the cloud product precision of EAGSCDR is higher than that of ISCCP, and the time resolution can reach 1 hour, and the spatial resolution is up to 5 km. The cloud products of EAGSCDR have advantages over ISCCP.
Using the China surface climate data and the monthly mean data of ISCCP (International Satellite Cloud Climatology Project) D2, EAGSCDR (FY2 and GMS geostationary satellite climate data record over East Asia) are validated and evaluated. The distributions of annual mean total cloud amounts from the three kinds of data are analyzed and compared, and the results show that all the distributive patterns of cloud amounts agree well; however, total cloud amounts from ISCCP and geostationary satellite climate data sets are higher than station observations in the north of 40°N. Furthermore, it is indicated that about 8210% cloud detection product samples of EAGSCDR agree with surface observations, and the overall missing detected rate and false detected rate is 685% and 1105% respectively over South China and the Yangtze River basin; the accuracy of fall and winter is lower. The cloud amounts of EAGSCDR and ISCCP both are obtained from satellite data, and their major differences come from different algorithms. The analysis shows that the cloud product precision of EAGSCDR is higher than that of ISCCP, and the time resolution can reach 1 hour, and the spatial resolution is up to 5 km. The cloud products of EAGSCDR have advantages over ISCCP.
2013, 41(1):15-19.
Abstract:
Due to the influence of the curve Earth, the fixed detection mode of the CINRAD/SA weather radar uses the minimum elevation angle of 0.5 °, so the blind area is relatively big, and the detection capability for low level precipitation echoes is limited. On the basis of experiments, the calculation formulas of the minimum height applicable when CINRAD/SA detects with positive and negative elevation angles are devised. Then the minimum detecting heights of CINRAD/SA at different distances with different elevation angles (0.5°, 0°, -0.3°,-0.5°) are calculated. Through analyzing characteristics of radar products detected under different elevation angles, some suggestions on CINRAD/SA about using negative elevation angles are presented.
Due to the influence of the curve Earth, the fixed detection mode of the CINRAD/SA weather radar uses the minimum elevation angle of 0.5 °, so the blind area is relatively big, and the detection capability for low level precipitation echoes is limited. On the basis of experiments, the calculation formulas of the minimum height applicable when CINRAD/SA detects with positive and negative elevation angles are devised. Then the minimum detecting heights of CINRAD/SA at different distances with different elevation angles (0.5°, 0°, -0.3°,-0.5°) are calculated. Through analyzing characteristics of radar products detected under different elevation angles, some suggestions on CINRAD/SA about using negative elevation angles are presented.
2013, 41(1):20-26.
Abstract:
At the Zhangjiakou Zhangbei National Fengguang Storage Test Site, by means of the Windcube laser radar system and a wind tower to observe the test data simultaneously and calculate a variety of statistic data, a comparative analysis is made of wind speed, wind direction, standard deviation, and turbulence intensity. The results show that: the data efficiency of Windcube reached 97% under 140 m, and the results are basically unaffected by rainfall; the correlation coefficients of wind speed and wind direction tested by Windcube and wind tower data are up to more than 99%. The average deviation of wind speed at 100 m is -0197 m/s; the relative deviation is -23%; the average deviation of wind direction is -62°; and the average deviation of turbulence intensity is 0009, which are consistent with results of other literature, meets the requirements of wind energy resource assessment.
At the Zhangjiakou Zhangbei National Fengguang Storage Test Site, by means of the Windcube laser radar system and a wind tower to observe the test data simultaneously and calculate a variety of statistic data, a comparative analysis is made of wind speed, wind direction, standard deviation, and turbulence intensity. The results show that: the data efficiency of Windcube reached 97% under 140 m, and the results are basically unaffected by rainfall; the correlation coefficients of wind speed and wind direction tested by Windcube and wind tower data are up to more than 99%. The average deviation of wind speed at 100 m is -0197 m/s; the relative deviation is -23%; the average deviation of wind direction is -62°; and the average deviation of turbulence intensity is 0009, which are consistent with results of other literature, meets the requirements of wind energy resource assessment.
2013, 41(1):27-31.
Abstract:
As the core component of the radar transmitter, the klystron performance has a direct influence on the radar performance. But technicians are not willing to doubt Klystron’s performance because of the structural stability of the cavity body and the high cost. As a result, the performance of Klystron is usually not well judged. Some measures and suggestions to the problems generated in the process of constructing and troubleshooting of Radar are presented. Through tracking the fault alarm information of the Wanzhou CINRAD/SB radar, the faults generated are reviewed. In combination with the radar working environment and conditions when faults happened, the radar data are tested. By analyzing the function module based on the working principles of the transmitter, several reasons for the monotonously declining power of the radar transmitter are identified, and some countermeasures are given.
As the core component of the radar transmitter, the klystron performance has a direct influence on the radar performance. But technicians are not willing to doubt Klystron’s performance because of the structural stability of the cavity body and the high cost. As a result, the performance of Klystron is usually not well judged. Some measures and suggestions to the problems generated in the process of constructing and troubleshooting of Radar are presented. Through tracking the fault alarm information of the Wanzhou CINRAD/SB radar, the faults generated are reviewed. In combination with the radar working environment and conditions when faults happened, the radar data are tested. By analyzing the function module based on the working principles of the transmitter, several reasons for the monotonously declining power of the radar transmitter are identified, and some countermeasures are given.
2013, 41(1):32-36.
Abstract:
The main signal flow of the frequency source for CINRAD/CC radar produced in the 7th batch is described. Through analyzing the main signal flow of the frequency source and using the waveform of the spectrum analyzer on key points, the fault phenomenon and the solution of the frequency source are discussed. The process is expounded, taking a typical fault phenonmenon for example. Requirements for the CC radar frequency source at the center frequency of key points and spectral amplitude are summed up. Some useful hints are given for radar users and the maintenance staff.
The main signal flow of the frequency source for CINRAD/CC radar produced in the 7th batch is described. Through analyzing the main signal flow of the frequency source and using the waveform of the spectrum analyzer on key points, the fault phenomenon and the solution of the frequency source are discussed. The process is expounded, taking a typical fault phenonmenon for example. Requirements for the CC radar frequency source at the center frequency of key points and spectral amplitude are summed up. Some useful hints are given for radar users and the maintenance staff.
2013, 41(1):37-41.
Abstract:
利用邢台国家基准气候站1992—2001年4—10月E 601B型与小型蒸发器10年蒸发量观测资料，分别进行了对比分析、离差分析和线性回归分析。结果表明：①两种蒸发器测定的平均蒸发量小型为2329 mm，E 601B型为1174 mm，差值为1155 mm，偏大率984%；②两种蒸发量4—10月的折算系数为0504，折算系数与相对湿度、日照时数和风速等气象条件有关；③统计了历年E 601B型4—10月蒸发量的气候估计值，可为刑台地区的气候评价、水量平衡分析和水资源调查等提供依据，并为邢台地区有效利用长序列小型蒸发资料提供了应用途径。
利用邢台国家基准气候站1992—2001年4—10月E 601B型与小型蒸发器10年蒸发量观测资料，分别进行了对比分析、离差分析和线性回归分析。结果表明：①两种蒸发器测定的平均蒸发量小型为2329 mm，E 601B型为1174 mm，差值为1155 mm，偏大率984%；②两种蒸发量4—10月的折算系数为0504，折算系数与相对湿度、日照时数和风速等气象条件有关；③统计了历年E 601B型4—10月蒸发量的气候估计值，可为刑台地区的气候评价、水量平衡分析和水资源调查等提供依据，并为邢台地区有效利用长序列小型蒸发资料提供了应用途径。
2013, 41(1):42-45.
Abstract:
The 28 soil relative humidity measurements from March to July 2011 from DZN3 automatic soil moisture observation stations and manual observation are compared and analyzed. The results indicate that measurements from the automatic station are generally smaller than those from manual observation; the difference in the 30 cm soil layer is the smaller，those of the 20, 40, 50 cm layers the next, and those of 10, 60, 80, 100 cm soil layers the greater; the variation tendency is close in 10, 20, 80, 100 cm soil layers, and their correlation is good; the sensor sensitivity of automatic observation is relatively low for soil moisture changes, and the fluctuation range of soil relative humidity is small in the same soil layer. The results can provide an objective basis for evaluating the monitoring capability and revising and applying the monitoring data from the DZN3 automatic soil moisture observation station.
The 28 soil relative humidity measurements from March to July 2011 from DZN3 automatic soil moisture observation stations and manual observation are compared and analyzed. The results indicate that measurements from the automatic station are generally smaller than those from manual observation; the difference in the 30 cm soil layer is the smaller，those of the 20, 40, 50 cm layers the next, and those of 10, 60, 80, 100 cm soil layers the greater; the variation tendency is close in 10, 20, 80, 100 cm soil layers, and their correlation is good; the sensor sensitivity of automatic observation is relatively low for soil moisture changes, and the fluctuation range of soil relative humidity is small in the same soil layer. The results can provide an objective basis for evaluating the monitoring capability and revising and applying the monitoring data from the DZN3 automatic soil moisture observation station.
2013, 41(1):46-50.
Abstract:
The total precipitable water in atmosphere is one of most important parameters in astronomical observation and meteorology．The measurement of total precipitable water in atmosphere by means of the Sky Brightness Monitor (SBM) is described. SBM is an exact tool used for precisely measuring various atmospheric parameters. The principles and method of measurement, the calibration method, and the performance of the water vapor measurement instrument are discussed, and the measurement results are given. The results indicate that the multi color photometric system of SBM can be used for the site survey in the western China for solar instruments.
The total precipitable water in atmosphere is one of most important parameters in astronomical observation and meteorology．The measurement of total precipitable water in atmosphere by means of the Sky Brightness Monitor (SBM) is described. SBM is an exact tool used for precisely measuring various atmospheric parameters. The principles and method of measurement, the calibration method, and the performance of the water vapor measurement instrument are discussed, and the measurement results are given. The results indicate that the multi color photometric system of SBM can be used for the site survey in the western China for solar instruments.
2013, 41(1):51-56.
Abstract:
The marine meteorological data acquisition system is designed based on the satellite communication network with the advantages of extensive range coverage, real time online, high quality communication, and low maintenance expense, according to the current situation of comprehensive marine meteorological monitoring equipment. The system architecture and functions of the system are demonstrated in detail, in the aspects of both hardware and software. The crucial techniques of the system hardware architecture include the structure of remote terminal unit and the usage of circuit chip. The system development methodology is elaborated on the basis of the Microsoft Visual Studio 60 integrated package environment. The practical application of the marine meteorological data acquisition system based on the Beidou satellite communication network is introduced.
The marine meteorological data acquisition system is designed based on the satellite communication network with the advantages of extensive range coverage, real time online, high quality communication, and low maintenance expense, according to the current situation of comprehensive marine meteorological monitoring equipment. The system architecture and functions of the system are demonstrated in detail, in the aspects of both hardware and software. The crucial techniques of the system hardware architecture include the structure of remote terminal unit and the usage of circuit chip. The system development methodology is elaborated on the basis of the Microsoft Visual Studio 60 integrated package environment. The practical application of the marine meteorological data acquisition system based on the Beidou satellite communication network is introduced.
2013, 41(1):57-61.
Abstract:
The visual meteorological observation station system is designed with the B/S structure system and the open source WebGIS layout, developed by using Flex, Jsp and Applet technology. The platform achieved the multi faceted and multi form display of station information, and can fully meet the current needs of the integrated, efficient and accurate management of the meteorology observation system. The application of the platform addresses the problems that the integrated meteorological observation management can not meet the needs of rapid development of meteorological service in recent years. It provides a decision support for equipment protection and station layout optimization, etc., can help improve the management of integrated meteorological observation comprehensively.
The visual meteorological observation station system is designed with the B/S structure system and the open source WebGIS layout, developed by using Flex, Jsp and Applet technology. The platform achieved the multi faceted and multi form display of station information, and can fully meet the current needs of the integrated, efficient and accurate management of the meteorology observation system. The application of the platform addresses the problems that the integrated meteorological observation management can not meet the needs of rapid development of meteorological service in recent years. It provides a decision support for equipment protection and station layout optimization, etc., can help improve the management of integrated meteorological observation comprehensively.
2013, 41(1):62-66.
Abstract:
The software for regional automatic center stations plays an important role in the detection of automatic stations. However, because the software provided by different equipment manufacturers is different, the unified version software is developed, which realizes that equipment from different manufacturers can be connected to the united data collection platform. The communication module is the core in the whole unified edition software. It is the bridge between equipment and general control module that can analyze the data from the equipment correctly and submit them to the master control module packaged in the united format and the order correctly from the master control module and then send to the corresponding equipment. The communication module is based on the concept of layering and modularization. The design uses the macro analytic and multi threading technology comprehensively. It realizes the united access with the equipment from many manufacturers in the communication layer.
The software for regional automatic center stations plays an important role in the detection of automatic stations. However, because the software provided by different equipment manufacturers is different, the unified version software is developed, which realizes that equipment from different manufacturers can be connected to the united data collection platform. The communication module is the core in the whole unified edition software. It is the bridge between equipment and general control module that can analyze the data from the equipment correctly and submit them to the master control module packaged in the united format and the order correctly from the master control module and then send to the corresponding equipment. The communication module is based on the concept of layering and modularization. The design uses the macro analytic and multi threading technology comprehensively. It realizes the united access with the equipment from many manufacturers in the communication layer.
2013, 41(1):67-71.
Abstract:
The remote desktop control software based on the RFB protocol is not available for overlay IP computers in WAN. A method based on RFB protocol is proposed to connect remote overlay IP computers. The communication handshaking and initialization protocol is newly developed and attached to standard RFB clients as well as the RFB server successfully. The application indicates that the modification method is feasible to be implemented and can play a critical role in monitoring and maintaining the distributed remote terminals which are in the overlap IP network with communication safety isolation technology.
The remote desktop control software based on the RFB protocol is not available for overlay IP computers in WAN. A method based on RFB protocol is proposed to connect remote overlay IP computers. The communication handshaking and initialization protocol is newly developed and attached to standard RFB clients as well as the RFB server successfully. The application indicates that the modification method is feasible to be implemented and can play a critical role in monitoring and maintaining the distributed remote terminals which are in the overlap IP network with communication safety isolation technology.
2013, 41(1):72-77.
Abstract:
Lightning information plays an important role in the theory analysis and practical application, such as in lightning disaster regionalization, lightning disaster evaluation, lightning warning, etc. The use of the relevant lightning information is yet in its beginning stage. According to actual service conditions, there is a marked gap from the operational needs. To take full advantages of the large amount of lightning related data for lightning protection technology services, Delphi 7.0 is used as the development tool, Firebird as the database, a lightning information processing, product making and distribution system is developed based on GIS and Google Map. The system uses charts, density plots, GIS thematic maps and other methods to achieve the visual analysis of lightning location, thunderstorm days , atmospheric electric field instrument, and lightning disaster data, as well as lightning detection units, and to realize the implementation of lightning information product production and release, based on results of lightning statistical analysis, which can provide reliable technical support for lightning operation and research.
Lightning information plays an important role in the theory analysis and practical application, such as in lightning disaster regionalization, lightning disaster evaluation, lightning warning, etc. The use of the relevant lightning information is yet in its beginning stage. According to actual service conditions, there is a marked gap from the operational needs. To take full advantages of the large amount of lightning related data for lightning protection technology services, Delphi 7.0 is used as the development tool, Firebird as the database, a lightning information processing, product making and distribution system is developed based on GIS and Google Map. The system uses charts, density plots, GIS thematic maps and other methods to achieve the visual analysis of lightning location, thunderstorm days , atmospheric electric field instrument, and lightning disaster data, as well as lightning detection units, and to realize the implementation of lightning information product production and release, based on results of lightning statistical analysis, which can provide reliable technical support for lightning operation and research.
2013, 41(1):78-82.
Abstract:
The visualization of meteorological service will directly influence the quality and effectiveness of the service. According to the characteristics and requirements of county level meteorological service，by means of VB.NET as the major programming languages on the .NET platform, a comprehensive service system for meteorological operation based on the three dimensional Geographic Information System (3D GIS) was built by using the techniques of the second development tool of the ArcGIS Explorer API and the standards of the Open Geospatial Consortium Keyhole Markup Language (OGC KML). The comprehensive service system has the capability to display, process and analyze variou kinds of meteorological elements in the 3D GIS background. The system can provide a vast amount of basic geographic information from the ERSI’s Digital Earth, which leads to the application of the 3D GIS information in the comprehensive service system for meteorological operation.
The visualization of meteorological service will directly influence the quality and effectiveness of the service. According to the characteristics and requirements of county level meteorological service，by means of VB.NET as the major programming languages on the .NET platform, a comprehensive service system for meteorological operation based on the three dimensional Geographic Information System (3D GIS) was built by using the techniques of the second development tool of the ArcGIS Explorer API and the standards of the Open Geospatial Consortium Keyhole Markup Language (OGC KML). The comprehensive service system has the capability to display, process and analyze variou kinds of meteorological elements in the 3D GIS background. The system can provide a vast amount of basic geographic information from the ERSI’s Digital Earth, which leads to the application of the 3D GIS information in the comprehensive service system for meteorological operation.
2013, 41(1):83-87.
Abstract:
The construction of the GPS water vapor auto processing system based on GAMIT, the system design concepts, and the specific implementation procedures are described. The accuracy check and error analysis of the GPS water vapor, the methods of the quality control 〖JP2〗and fault processing, and the application effectiveness in practical work are also discussed. The results show that the system can process the observation data from GPS stations to get atmospheric water vapor for weather analysis and forecasting. The system is highly automatic and easy to use, demonstrating great potential for operational use.
The construction of the GPS water vapor auto processing system based on GAMIT, the system design concepts, and the specific implementation procedures are described. The accuracy check and error analysis of the GPS water vapor, the methods of the quality control 〖JP2〗and fault processing, and the application effectiveness in practical work are also discussed. The results show that the system can process the observation data from GPS stations to get atmospheric water vapor for weather analysis and forecasting. The system is highly automatic and easy to use, demonstrating great potential for operational use.
2013, 41(1):88-92.
Abstract:
In order to understand of the influence of different calculation methods on the calculated daily mean temperature, an analysis is made of the difference in daily average temperature calculated from the observations between 24 and 4 times per day, as well as 4 and 3 times per day, by using the temperature obtained by manual observation data from 1961 to 2010 from 6 national base stations in Shaanxi. The homogeneity Penalized Maximal 〖WTBX〗F〖WTBZ〗 Test (PMFT) is carried out with the long temperature sequence, which consists of manual 4 and 24 times per day observation or 3 and 4 times per day times observation. The results indicate that the 24 times per day average temperature is higher than that from the 4 times per day calculation; the average difference is 013 ℃; and standard deviation is 039 ℃, with the biggest difference in autumn. The 4 times per day daily average temperature is 014 ℃ lower than that calculated by 3 times per day observation, and the standard deviation is 085 ℃, with the biggest difference value in summer. The monthly or annual mean temperature calculated from temperature observations with different number of observations varies, with the difference being about± 02 ℃. If the 24 times per day temperature is used, for a single station, the temperatures increasing rate may be 003 to 004 ℃/10a higher. Nevertheless, the calculation method (changing from 4 times to 24 times, or from 3 times to 4 times) will not change the inhomogeneity of a temperature sequence.
In order to understand of the influence of different calculation methods on the calculated daily mean temperature, an analysis is made of the difference in daily average temperature calculated from the observations between 24 and 4 times per day, as well as 4 and 3 times per day, by using the temperature obtained by manual observation data from 1961 to 2010 from 6 national base stations in Shaanxi. The homogeneity Penalized Maximal 〖WTBX〗F〖WTBZ〗 Test (PMFT) is carried out with the long temperature sequence, which consists of manual 4 and 24 times per day observation or 3 and 4 times per day times observation. The results indicate that the 24 times per day average temperature is higher than that from the 4 times per day calculation; the average difference is 013 ℃; and standard deviation is 039 ℃, with the biggest difference in autumn. The 4 times per day daily average temperature is 014 ℃ lower than that calculated by 3 times per day observation, and the standard deviation is 085 ℃, with the biggest difference value in summer. The monthly or annual mean temperature calculated from temperature observations with different number of observations varies, with the difference being about± 02 ℃. If the 24 times per day temperature is used, for a single station, the temperatures increasing rate may be 003 to 004 ℃/10a higher. Nevertheless, the calculation method (changing from 4 times to 24 times, or from 3 times to 4 times) will not change the inhomogeneity of a temperature sequence.
2013, 41(1):93-96.
Abstract:
The histories of early automatical weather stations in Guangxi are usually less than 7 years, and most of the stations are distributed on hills with different height. Because the data time series is too short, the climate threshold directly calculated with the observation data from this station cannot be representative of the station’s climate threshold range accurately. The altitude correction method is used to solve this problem: selecting the adjacent country stations as the benchmark stations and finding out the climate thresholds of reference stations; making altitude correction to the benchmark station climate thresholds according to the changes of temperature, pressure, and wind speed with the height correlation methods and getting the automatical weather station climate thresholds. The results show that the climate thresholds of the elements are more representative and more applicable after altitude revising. This method has been used in the real time data quality control system of automatic weather stations in Guangxi and achieved very good results.
The histories of early automatical weather stations in Guangxi are usually less than 7 years, and most of the stations are distributed on hills with different height. Because the data time series is too short, the climate threshold directly calculated with the observation data from this station cannot be representative of the station’s climate threshold range accurately. The altitude correction method is used to solve this problem: selecting the adjacent country stations as the benchmark stations and finding out the climate thresholds of reference stations; making altitude correction to the benchmark station climate thresholds according to the changes of temperature, pressure, and wind speed with the height correlation methods and getting the automatical weather station climate thresholds. The results show that the climate thresholds of the elements are more representative and more applicable after altitude revising. This method has been used in the real time data quality control system of automatic weather stations in Guangxi and achieved very good results.
2013, 41(1):97-102.
Abstract:
The main methods for identifying sea breeze days used in sea land breeze researches in the recent 20 years are summarized. These methods are classified as follows depending on the different types of datasets used: (1) conventional data, (2) atmospheric remote sensing data, and (3) the results of numerical simulation. For conventional data, the criteria of determining the establishment of sea breeze days are divided into 6 kinds depending on the main factors which trigger sea land breeze, and each kind is specifically discussed. For the other two categories, some typical methods are discussed in the aspects of their advantages and disadvantages.
The main methods for identifying sea breeze days used in sea land breeze researches in the recent 20 years are summarized. These methods are classified as follows depending on the different types of datasets used: (1) conventional data, (2) atmospheric remote sensing data, and (3) the results of numerical simulation. For conventional data, the criteria of determining the establishment of sea breeze days are divided into 6 kinds depending on the main factors which trigger sea land breeze, and each kind is specifically discussed. For the other two categories, some typical methods are discussed in the aspects of their advantages and disadvantages.
20 Characteristics of Low Altitude Temperature Inversion Layer in Freezing Weather in Southern China
2013, 41(1):103-107.
Abstract:
Based on the low altitude standard level and significant level data of 12 radiosonde stations from 7 provinces in the southern China in winter half year from 1960 to 1999, the frequency, intensity, and thickness of low altitude temperature inversion layers in winter in the southern China are analyzed statistically and its basic regularities and spatial distribution characteristics are revealed, compared with the historical temperature inversion characteristics of freezing rain and snow weather processes. The results indicate: (1) the low altitude temperature inversion occurred widely in the southern China during winter; (2) the inversion intensity index increased with the increasing bottom height of temperature inversion, and the biggest inversion intensity occurred between 700 and 600 hPa; (3) the average intensity of temperature inversion in the southwest region (southern Guizhou and Hunan) was generally higher than that in the northeast region (Anhui and Jiangsu); (4) the inversion intensity index had an annual increasing trend during freezing rain and snow weather processes from 1964 to 1995 while the average thickness of the inversion layer had a significant decreasing trend; (5) when inversion appeared,there was a warm temperature layer with the temperature greater than 0 ℃ around 700 hPa in the southwest region, but not in the northeast region; (6) during freezing rain and snow weather processes, the southwest region was dominated by freezing rains while the northeast region was dominated by snow.
Based on the low altitude standard level and significant level data of 12 radiosonde stations from 7 provinces in the southern China in winter half year from 1960 to 1999, the frequency, intensity, and thickness of low altitude temperature inversion layers in winter in the southern China are analyzed statistically and its basic regularities and spatial distribution characteristics are revealed, compared with the historical temperature inversion characteristics of freezing rain and snow weather processes. The results indicate: (1) the low altitude temperature inversion occurred widely in the southern China during winter; (2) the inversion intensity index increased with the increasing bottom height of temperature inversion, and the biggest inversion intensity occurred between 700 and 600 hPa; (3) the average intensity of temperature inversion in the southwest region (southern Guizhou and Hunan) was generally higher than that in the northeast region (Anhui and Jiangsu); (4) the inversion intensity index had an annual increasing trend during freezing rain and snow weather processes from 1964 to 1995 while the average thickness of the inversion layer had a significant decreasing trend; (5) when inversion appeared,there was a warm temperature layer with the temperature greater than 0 ℃ around 700 hPa in the southwest region, but not in the northeast region; (6) during freezing rain and snow weather processes, the southwest region was dominated by freezing rains while the northeast region was dominated by snow.
2013, 41(1):108-113.
Abstract:
Based on the observation data provided by the automatic meteorological stations for road weather information in Beijing, the characteristics of low visibility thick fogs and the method of nowcasting are studied. The main conclusions are as follows: (1) The thick fog with the visibility below 200 m happens mostly between 05:00 to 09:00, from September to December, and lest between 12:00 to 18:00, from June and July. (2) About 80 % of thick fog cases with visibility below 200 m appears in Daxing and Tongzhou districts in the southeastern Beijing, and seldom in downtown. (3) Before the formation of thick fogs, there was a thick thin thick fluctuating pattern in visibility variation. (4) The visibility changes with the wind, temperature, and relative humidity; the south and east wind is advantageous to the formation of thick fogs; the northwest wind is advantageous to their dissipation. During the development period of thick fogs, wind speed becomes slow; relative humidity rises; temperature reduces; and visibility becomes lower. During the maintain period, the wind speed, relative humidity, temperature, and visibility all change slightly. During its dissipation period of, the wind speed becomes big; relative humidity reduces; temperature rises; and visibility becomes bigger; but the reduction of relative humidity is later than the rise of visibility.
Based on the observation data provided by the automatic meteorological stations for road weather information in Beijing, the characteristics of low visibility thick fogs and the method of nowcasting are studied. The main conclusions are as follows: (1) The thick fog with the visibility below 200 m happens mostly between 05:00 to 09:00, from September to December, and lest between 12:00 to 18:00, from June and July. (2) About 80 % of thick fog cases with visibility below 200 m appears in Daxing and Tongzhou districts in the southeastern Beijing, and seldom in downtown. (3) Before the formation of thick fogs, there was a thick thin thick fluctuating pattern in visibility variation. (4) The visibility changes with the wind, temperature, and relative humidity; the south and east wind is advantageous to the formation of thick fogs; the northwest wind is advantageous to their dissipation. During the development period of thick fogs, wind speed becomes slow; relative humidity rises; temperature reduces; and visibility becomes lower. During the maintain period, the wind speed, relative humidity, temperature, and visibility all change slightly. During its dissipation period of, the wind speed becomes big; relative humidity reduces; temperature rises; and visibility becomes bigger; but the reduction of relative humidity is later than the rise of visibility.
2013, 41(1):114-120.
Abstract:
The conventional and intensive observing radiosonde data from the Beijing South Suburb station and NCEP data are used to analyze 30 cases of hails which happened form 2000 to 2009 in Beijing. The results show that the circulation patterns for hail weather can be classified into three weather types: Northeast cold vortex, Mongolia vortex, and trough; the three types of weather patterns occured 12, 10, and 8 times, respectively; hails often happened from 14:00 to 18:00 It can be seen from the characteristics of the large scale weather circulation that there was a dynamic convergence system at each level from 925 hPa to 500 hPa during hail weather. There were deeply dynamic systems passing through Beijing at upper levels. The stream fields of the Mongolia vortex and trough patterns have the typical characteristics that there is a big north west wind velocity area at 500 hPa between Beijing and Inner Mongolia with speed being 20 m/s or above, and a big south wind velocity area at 700 hPa and 850 hPa with the speed being about 12 m/s in the southeast of Beijing. The humidity condition is not very important to hails because the dew point deficit at each level was larger than 5 ℃. The stability parameters are as follow: the temperature difference between 500 hPa and 850 hPa being 28 to 35 ℃, large wind shear at lower levels, DCAPE greater than 800 J〖DK〗·kg-1, LI (Lifted Index) less than 0, DCI (Deep Convective Initiation) between 20 and 30, TT (Total Totals index) between 40 to 50 ℃, the 0 ℃ environmental temperature height between 3000 to 4000 meters, -20 ℃ environmental temperature height being between 6000 and 7500 meters.
The conventional and intensive observing radiosonde data from the Beijing South Suburb station and NCEP data are used to analyze 30 cases of hails which happened form 2000 to 2009 in Beijing. The results show that the circulation patterns for hail weather can be classified into three weather types: Northeast cold vortex, Mongolia vortex, and trough; the three types of weather patterns occured 12, 10, and 8 times, respectively; hails often happened from 14:00 to 18:00 It can be seen from the characteristics of the large scale weather circulation that there was a dynamic convergence system at each level from 925 hPa to 500 hPa during hail weather. There were deeply dynamic systems passing through Beijing at upper levels. The stream fields of the Mongolia vortex and trough patterns have the typical characteristics that there is a big north west wind velocity area at 500 hPa between Beijing and Inner Mongolia with speed being 20 m/s or above, and a big south wind velocity area at 700 hPa and 850 hPa with the speed being about 12 m/s in the southeast of Beijing. The humidity condition is not very important to hails because the dew point deficit at each level was larger than 5 ℃. The stability parameters are as follow: the temperature difference between 500 hPa and 850 hPa being 28 to 35 ℃, large wind shear at lower levels, DCAPE greater than 800 J〖DK〗·kg-1, LI (Lifted Index) less than 0, DCI (Deep Convective Initiation) between 20 and 30, TT (Total Totals index) between 40 to 50 ℃, the 0 ℃ environmental temperature height between 3000 to 4000 meters, -20 ℃ environmental temperature height being between 6000 and 7500 meters.
23 Main Factors Influencing Severe Precipitation over Southwestern Zhejiang Caused by Tropical Cyclones
2013, 41(1):121-125.
Abstract:
The main factors influencing tropical cyclone precipitation in Lishui from 1950 to 2010 are analyzed in the aspects of the moving path, duration and intensity of tropical cyclones，westerly trough, southwest monsoon, and topography. The results show that the tropical cyclones landed from the south from Yuhuan to Xiamen are the direct type which influenced Lishui. There is a positive correlation between duration and average maximum process rainfall, as well as maximum process rainfall. The relevance between typhoon intensity and precipitation is very high. The westerly trough not only influenced the moving path of tropical cyclones, but also provided adequate water vapor. At the same time the combination of cold air from the trough behind and tropical cyclones induced often another precipitation center. The southwest monsoon provided water vapor for tropical cyclones, which enhanced precipitation. The unique topography of Lishui also enhanced the precipitation of tropical cyclones landed from Xiamen to the south of Yuhuan against the mountain.
The main factors influencing tropical cyclone precipitation in Lishui from 1950 to 2010 are analyzed in the aspects of the moving path, duration and intensity of tropical cyclones，westerly trough, southwest monsoon, and topography. The results show that the tropical cyclones landed from the south from Yuhuan to Xiamen are the direct type which influenced Lishui. There is a positive correlation between duration and average maximum process rainfall, as well as maximum process rainfall. The relevance between typhoon intensity and precipitation is very high. The westerly trough not only influenced the moving path of tropical cyclones, but also provided adequate water vapor. At the same time the combination of cold air from the trough behind and tropical cyclones induced often another precipitation center. The southwest monsoon provided water vapor for tropical cyclones, which enhanced precipitation. The unique topography of Lishui also enhanced the precipitation of tropical cyclones landed from Xiamen to the south of Yuhuan against the mountain.
2013, 41(1):126-130.
Abstract:
Using the daily maximum, minimum, and mean temperature data sets from 1975 to 2008 of six representative climate stations in Yunnan Province, the trends of extreme temperature are analyzed and the possible causes are discussed. The results show that the temperature trends of all representative climate stations were generally rising, while there was no systematic difference among them. Especially, the warming trends of Shangrila (representing the Plateau Climate) were distinct. The main features include: the warming rate of minimum temperature was the biggest; that of mean temperature was the next, and that of maximum temperature was the smallest. Meanwhile DTR (Diurnal Temperature Range) showed significant decreasing trend, which resembled the features of the Northern, Middle and Southern Subtropical Zones. However, the temperature in the temperate zone and the Northern tropical zone displayed different characteristics. As for the temperate zone, the maximum temperature increased significantly, and the growth rate of minimum temperature was slightly less than that of mean temperature, while DTR had no significant variation. With regard to the Northern tropical zone, the growth rate of mean temperature was the greatest, then the minimum temperature, and the maximum temperature the least, and there was no significant change in DTR. In addition, the statistical analysis of warm days, cold days, warm nights, cold nights, and frost days show that cold events were decreasing and warm events were increasing.
Using the daily maximum, minimum, and mean temperature data sets from 1975 to 2008 of six representative climate stations in Yunnan Province, the trends of extreme temperature are analyzed and the possible causes are discussed. The results show that the temperature trends of all representative climate stations were generally rising, while there was no systematic difference among them. Especially, the warming trends of Shangrila (representing the Plateau Climate) were distinct. The main features include: the warming rate of minimum temperature was the biggest; that of mean temperature was the next, and that of maximum temperature was the smallest. Meanwhile DTR (Diurnal Temperature Range) showed significant decreasing trend, which resembled the features of the Northern, Middle and Southern Subtropical Zones. However, the temperature in the temperate zone and the Northern tropical zone displayed different characteristics. As for the temperate zone, the maximum temperature increased significantly, and the growth rate of minimum temperature was slightly less than that of mean temperature, while DTR had no significant variation. With regard to the Northern tropical zone, the growth rate of mean temperature was the greatest, then the minimum temperature, and the maximum temperature the least, and there was no significant change in DTR. In addition, the statistical analysis of warm days, cold days, warm nights, cold nights, and frost days show that cold events were decreasing and warm events were increasing.
2013, 41(1):131-137.
Abstract:
The continuous fog process from January 5 to 11 2008 in Shanghai is analyzed using remote sensing visibility and conventional observation, GFS and T213 model, and GPS PWV data. The results show when there are frequent synoptic scale troughs moving east and warm moist air flow in front of the troughs, it is easy to form radiation fog in sunny and breezing morning, in addition with warm moist air near the surface layer from warm water or sea surface. When warm moist air near the surface layer flows from the East China Sea or the Yellow Sea to cold water or land surface, it is also easy to form advection fog, in addition with the convergence of the low level southerly warm moist air from the south of the Yangtze. The range of advection fog from sea is closely related to the strength of easterly air flow. The stronger the easterly air flow is, the longer the advection fog would moves. The research also shows that the area with high average relative humidity within 0 to 300 m above the surface is consistent with the fog zone during the advection fog period. When absolute humidity is less than 3 g/kg, there would be no fog forming. While absolute humidity is between 9 and 15 g/kg and the GPS PWV is about 15 mm, the probability of thick fog would be high under appropriate weather condition.
The continuous fog process from January 5 to 11 2008 in Shanghai is analyzed using remote sensing visibility and conventional observation, GFS and T213 model, and GPS PWV data. The results show when there are frequent synoptic scale troughs moving east and warm moist air flow in front of the troughs, it is easy to form radiation fog in sunny and breezing morning, in addition with warm moist air near the surface layer from warm water or sea surface. When warm moist air near the surface layer flows from the East China Sea or the Yellow Sea to cold water or land surface, it is also easy to form advection fog, in addition with the convergence of the low level southerly warm moist air from the south of the Yangtze. The range of advection fog from sea is closely related to the strength of easterly air flow. The stronger the easterly air flow is, the longer the advection fog would moves. The research also shows that the area with high average relative humidity within 0 to 300 m above the surface is consistent with the fog zone during the advection fog period. When absolute humidity is less than 3 g/kg, there would be no fog forming. While absolute humidity is between 9 and 15 g/kg and the GPS PWV is about 15 mm, the probability of thick fog would be high under appropriate weather condition.
2013, 41(1):138-145.
Abstract:
By using the data of routine radiosonde, surface observation, 6 hour 1°×1° reanalysis and FY 2E satellite clouds, an analysis is made of a rainstorm influenced by a distant typhoon happened on 23 July 2010 over the central Shanxi Province. The results show that the role of the landed typhoon is important for this heavy rainfall in the following aspects: the landed typhoon provided a moisture channel, strong positive vorticity advection, convergence at lower levels, and a favorable circulation background for the rainstorm, directly or indirectly affecting the formation and extinction of mesoscale cloud cluster. The surface mesoscale system was the direct influencing system; the low jet is the power sources; and there is good correlation between the area of rainstorm and the area with TBB less than 233 K.
By using the data of routine radiosonde, surface observation, 6 hour 1°×1° reanalysis and FY 2E satellite clouds, an analysis is made of a rainstorm influenced by a distant typhoon happened on 23 July 2010 over the central Shanxi Province. The results show that the role of the landed typhoon is important for this heavy rainfall in the following aspects: the landed typhoon provided a moisture channel, strong positive vorticity advection, convergence at lower levels, and a favorable circulation background for the rainstorm, directly or indirectly affecting the formation and extinction of mesoscale cloud cluster. The surface mesoscale system was the direct influencing system; the low jet is the power sources; and there is good correlation between the area of rainstorm and the area with TBB less than 233 K.
2013, 41(1):146-152.
Abstract:
The daily precipitation data in Liaoning, daily NCEP/NCAR reanalysis data, and Subtropical High (SH) data are employed to investigate the relationships among the SH ridge, the northern and western boundaries of SH, upper and low level jets, stratification characteristics, and the starting/ending times, as well as the precipitation intensities and properties of six torrential rainfall processes occurred from June to August 2010 The results show that the SH ridge line was located averagely from 110°E to 130°E in July and August 2010, farther north than that in normal years for 81% probability, and the average position of the SH ridge line was 27° farther north than that in the same period of normal years. During the six torrential rainfall processes，the ridge line of SH was located between 27°N and 35°N, and the northern boundary of the 588 contour line near 130°E and the western boundary near 35°N were located between 38° and 45°N, 110° and 130°E, respectively. The heavy rain occurred when the jet core moved southwardly affecting Liaoning Province after the upper level jet reached its strongest phase in the background that the low level jet was well established and maintained. The forecast indexes are concisely summarized based on the characteristic analysis of facts, which provides reference for the like regional torrential rainfall forecasting in the future.
The daily precipitation data in Liaoning, daily NCEP/NCAR reanalysis data, and Subtropical High (SH) data are employed to investigate the relationships among the SH ridge, the northern and western boundaries of SH, upper and low level jets, stratification characteristics, and the starting/ending times, as well as the precipitation intensities and properties of six torrential rainfall processes occurred from June to August 2010 The results show that the SH ridge line was located averagely from 110°E to 130°E in July and August 2010, farther north than that in normal years for 81% probability, and the average position of the SH ridge line was 27° farther north than that in the same period of normal years. During the six torrential rainfall processes，the ridge line of SH was located between 27°N and 35°N, and the northern boundary of the 588 contour line near 130°E and the western boundary near 35°N were located between 38° and 45°N, 110° and 130°E, respectively. The heavy rain occurred when the jet core moved southwardly affecting Liaoning Province after the upper level jet reached its strongest phase in the background that the low level jet was well established and maintained. The forecast indexes are concisely summarized based on the characteristic analysis of facts, which provides reference for the like regional torrential rainfall forecasting in the future.
2013, 41(1):153-159.
Abstract:
The Hilbert spectral analysis based on the Empirical Mode Decomposition (EMD) method for analyzing nonlinear and non stationary data is introduced and applied to the analysis of the Atmospheric Boundary Layer (ABL) turbulent signals for the first time. The effectiveness of Hilbert the spectral analysis in the research on the ABL turbulence is explored. The energy distribution characteristics and the degree of statistic stationarity of the turbulent data above the urban and forest canopies are studied. The results show the Hilbert spectral analysis is powerful and effective in the study of ABL turbulence. The Hilbert marginal spectrum is effective to get the energy distribution characteristics of ABL turbulent signals, and the analysis of the statistic stationarity is also effective to quantitatively measure the stationarity of the ABL turbulent signals. This will help establish the appropriate data quality control methods and improve the calculation of diffusion parameters of air quality and dispersion models. The case analysis shows that the turbulent flow is well mixed above both canopies. Compared with the urban canopy, the turbulent energy above the forest canopy is more concentrated in the eddies on larger scales, and the high frequency part of wind disturbance is dominated by stronger intermittency. At a given height, turbulence eddies above the forest canopy are more unstable and contain less energy than those above the urban canopy.
The Hilbert spectral analysis based on the Empirical Mode Decomposition (EMD) method for analyzing nonlinear and non stationary data is introduced and applied to the analysis of the Atmospheric Boundary Layer (ABL) turbulent signals for the first time. The effectiveness of Hilbert the spectral analysis in the research on the ABL turbulence is explored. The energy distribution characteristics and the degree of statistic stationarity of the turbulent data above the urban and forest canopies are studied. The results show the Hilbert spectral analysis is powerful and effective in the study of ABL turbulence. The Hilbert marginal spectrum is effective to get the energy distribution characteristics of ABL turbulent signals, and the analysis of the statistic stationarity is also effective to quantitatively measure the stationarity of the ABL turbulent signals. This will help establish the appropriate data quality control methods and improve the calculation of diffusion parameters of air quality and dispersion models. The case analysis shows that the turbulent flow is well mixed above both canopies. Compared with the urban canopy, the turbulent energy above the forest canopy is more concentrated in the eddies on larger scales, and the high frequency part of wind disturbance is dominated by stronger intermittency. At a given height, turbulence eddies above the forest canopy are more unstable and contain less energy than those above the urban canopy.
2013, 41(1):160-164.
Abstract:
The changes of visibility in the different kinds of precipitation are studied. The raindrop size distribution data of two weather processes (continuous precipitation and thunderstorm) are analyzed. The results show that the thunderstorm precipitation with low visibility has a wide spectrum of drops, and the continuous precipitation has a narrow spectrum. The particle concentration and visibility are inversely related: the lower particle concentration leads to a rapid improvement in visibility. The concentration of small particles is significantly larger in low visibility, and the small concentration of particles less than 1 mm has the greatest impact on the visibility, followed by 1 to 2 mm particles, indicating that the high concentration of small particles corresponds to the low visibility. The characteristic quantities during precipitation and low visibility periods are relatively high, and after visibility improved, these quantities change suddenly and fluctuate. The calculated visibility is close to the observation at high particle concentration and low visibility.
The changes of visibility in the different kinds of precipitation are studied. The raindrop size distribution data of two weather processes (continuous precipitation and thunderstorm) are analyzed. The results show that the thunderstorm precipitation with low visibility has a wide spectrum of drops, and the continuous precipitation has a narrow spectrum. The particle concentration and visibility are inversely related: the lower particle concentration leads to a rapid improvement in visibility. The concentration of small particles is significantly larger in low visibility, and the small concentration of particles less than 1 mm has the greatest impact on the visibility, followed by 1 to 2 mm particles, indicating that the high concentration of small particles corresponds to the low visibility. The characteristic quantities during precipitation and low visibility periods are relatively high, and after visibility improved, these quantities change suddenly and fluctuate. The calculated visibility is close to the observation at high particle concentration and low visibility.
2013, 41(1):165-169.
Abstract:
The research and development of the information management software for weather modification rocket operations to process and display the radar data and operation information are important, which allows air traffic controllers out of drawing map，makes mobile airspace application more convenient，raises working efficiency，increases the success rate of airspace application，improves the timeliness of airspace approval，and enhances the accuracy and safety of aviation management. By means of mobile communication, LAN, and a leased line to get the airspace information flowing，it can meet the operational application needs and save expenses for network equipment. 〖JP2〗The trial use of the system shows that the approval rate of airspace application is 708%; the system is easy to use， and has a high value of promotion.〖JP〗
The research and development of the information management software for weather modification rocket operations to process and display the radar data and operation information are important, which allows air traffic controllers out of drawing map，makes mobile airspace application more convenient，raises working efficiency，increases the success rate of airspace application，improves the timeliness of airspace approval，and enhances the accuracy and safety of aviation management. By means of mobile communication, LAN, and a leased line to get the airspace information flowing，it can meet the operational application needs and save expenses for network equipment. 〖JP2〗The trial use of the system shows that the approval rate of airspace application is 708%; the system is easy to use， and has a high value of promotion.〖JP〗
2013, 41(1):170-176.
Abstract:
An analysis of the near surface atmospheric electric field data in the summer of 2009 is presented based on the empirical mode decomposition (EMD) method. The vari scaled components of the atmospheric electric field in thunderstorm and fair weather are decomposed and the atmospheric electric field oscillation characteristics of two types of weather conditions are extracted and compared. The results show that the EMD method is suitable for the analysis of atmospheric electric field data. The atmospheric electric field in thunderstorm weather is under the background of atmospheric electric field in fair weather, and so contains the steady periodic oscillation compositions of fair weather. The atmospheric electric field energy in fair weather is concentrated in the long period oscillation component, while that in thunderstorm weather is mainly concentrated in the short period oscillation component. Before cloud to ground lightning occurring, the central frequency of IMF1 (IMF: Intrinsic Mode Function) will jump or the corresponding amplitude of IMF1 will increased significantly. According to these characteristics, 38 thunderstorms selected randomly are tested with lightning location data and the results show that the detection probability of warning is 842%.
An analysis of the near surface atmospheric electric field data in the summer of 2009 is presented based on the empirical mode decomposition (EMD) method. The vari scaled components of the atmospheric electric field in thunderstorm and fair weather are decomposed and the atmospheric electric field oscillation characteristics of two types of weather conditions are extracted and compared. The results show that the EMD method is suitable for the analysis of atmospheric electric field data. The atmospheric electric field in thunderstorm weather is under the background of atmospheric electric field in fair weather, and so contains the steady periodic oscillation compositions of fair weather. The atmospheric electric field energy in fair weather is concentrated in the long period oscillation component, while that in thunderstorm weather is mainly concentrated in the short period oscillation component. Before cloud to ground lightning occurring, the central frequency of IMF1 (IMF: Intrinsic Mode Function) will jump or the corresponding amplitude of IMF1 will increased significantly. According to these characteristics, 38 thunderstorms selected randomly are tested with lightning location data and the results show that the detection probability of warning is 842%.
2013, 41(1):177-183.
Abstract:
In order to improve the validity of thunderstorm strength forecast, the data of lightning location are used to classify the thunderstorm strength from June to August, 2008 to 2010, and the radiosonde data are used to calculate 47 convective parameters to represent the characteristics of the Nanjing thunderstorm environment. The relationships of thunderstorm strength with 47 convective parameters are analyzed respectively. The convection parameters closely related to thunderstorm strength are selected as the forecasting predictors of thunderstorm strength. The Bayesian classification method and Logistic regression analysis are adopted to establish two thunderstorm forecasting models. By use of the testing samples, the forecasting models are tested and compared. The results indicate that the Hedike skill score of the Logistic regression analysis is 0396, can identify 30% of the severe thunderstorm, but that of the Bayesian classification’s is 037, can identify only 5% of the severe thunderstorms. It is obvious that Logistic regression has better indicative significance to thunderstorm potential strength forecast. The analysis of the nine convection parameters used to build the forecasting model, indicates that the stronger the thunderstorm activity, the warmer and moister the air at lower levels, the colder and drier the air at middle levels, the stronger the wind shear between lower and upper levels.
In order to improve the validity of thunderstorm strength forecast, the data of lightning location are used to classify the thunderstorm strength from June to August, 2008 to 2010, and the radiosonde data are used to calculate 47 convective parameters to represent the characteristics of the Nanjing thunderstorm environment. The relationships of thunderstorm strength with 47 convective parameters are analyzed respectively. The convection parameters closely related to thunderstorm strength are selected as the forecasting predictors of thunderstorm strength. The Bayesian classification method and Logistic regression analysis are adopted to establish two thunderstorm forecasting models. By use of the testing samples, the forecasting models are tested and compared. The results indicate that the Hedike skill score of the Logistic regression analysis is 0396, can identify 30% of the severe thunderstorm, but that of the Bayesian classification’s is 037, can identify only 5% of the severe thunderstorms. It is obvious that Logistic regression has better indicative significance to thunderstorm potential strength forecast. The analysis of the nine convection parameters used to build the forecasting model, indicates that the stronger the thunderstorm activity, the warmer and moister the air at lower levels, the colder and drier the air at middle levels, the stronger the wind shear between lower and upper levels.
2013, 41(1):184-190.
Abstract:
According to the lightning data of 2007 to 2008 and lightning disaster data in Yunnan Province, the distribution of lightning disasters in 16 prefecture level cities of Yunnan Province is analyzed, and the relationship between the distributions of lightning disasters and ground flashes is discussed. At the same time, six disaster degree indicators derived from lightning records and the hierarchical disaster assessment and disaster degree evaluation model equation are established. The disaster degree values of 522 lightning disasters are calculated, which can be divided into four degrees according to the cluster analysis in SAS. The distributions of lightning disaster levels for all regions are counted and analyzed. The results indicate that small and medium sized lightning disasters in Yunnan Province have a wide distribution and a large probability, and the occurrence probability of large and extra large lightning disasters is low, which concentrated mainly around Kunming and Dehong.
According to the lightning data of 2007 to 2008 and lightning disaster data in Yunnan Province, the distribution of lightning disasters in 16 prefecture level cities of Yunnan Province is analyzed, and the relationship between the distributions of lightning disasters and ground flashes is discussed. At the same time, six disaster degree indicators derived from lightning records and the hierarchical disaster assessment and disaster degree evaluation model equation are established. The disaster degree values of 522 lightning disasters are calculated, which can be divided into four degrees according to the cluster analysis in SAS. The distributions of lightning disaster levels for all regions are counted and analyzed. The results indicate that small and medium sized lightning disasters in Yunnan Province have a wide distribution and a large probability, and the occurrence probability of large and extra large lightning disasters is low, which concentrated mainly around Kunming and Dehong.
2013, 41(1):191-195.
Abstract:
The influence of the surrounding buildings on the equivalent area of the considered building is analyzed in combination with the related standards by the Rolling Sphere Method. The method for calculating the equivalent area is described in detail and the calculating formula is given under three cases: the surrounding buildings being the same, higher, and lower, compared with the studied building, in the condition of the surrounding building in parallel with the studied building and ignoring the building’s width. Whereupon, the limitation of the formula in the standards is discussed. The research results could meet the demands of the more elaborate lightning protection technology.
The influence of the surrounding buildings on the equivalent area of the considered building is analyzed in combination with the related standards by the Rolling Sphere Method. The method for calculating the equivalent area is described in detail and the calculating formula is given under three cases: the surrounding buildings being the same, higher, and lower, compared with the studied building, in the condition of the surrounding building in parallel with the studied building and ignoring the building’s width. Whereupon, the limitation of the formula in the standards is discussed. The research results could meet the demands of the more elaborate lightning protection technology.
2013, 41(1):196-201.
Abstract:
By using the soil moisture data of Heilongjiang Province from 1981 to 2010, selecting the Fujin county of the east, Longjiang county of the west, Shuangcheng county of the south, Heihe city of the north, and Hailun county of the middle in Heilongjiang province, the trends of soil moisture during winter and the drought wet change are analyzed, and the significance tests are conducted with three methods: linear trend, 5 year moving average, and Mann Kendall. The mutation test of soil moisture change is made with Mann Kendall and Yamamoto methods. The results show that the soil moisture at the depth of 0 to 30 cm underground showed various downtrend in the last 30 years: the decreasing of the soil moisture at the Longjiang county was the sharpest, Hailun county the second, and Heihe city and Shuangcheng county the next; moreover, the significance levels of soil moisture decreasing at 20 cm for all the stations were lest than 005, but the decreasing at Fujin county was slight. The results of the Mann Kendall test show that there appeared mutational zones in Longjiang and Hailun counties, and the downtrends of the other stations were close to, or exceeded the significant level in the recent years. The mutational time of soil moisture change was 1994 for the soil layer of 0 to 20 cm in Longjiang county. The decreasing of winter soil moisture in Heilongjiang Province is related to temperature and precipitation, as well as the deterioration of the soil physical properties.
By using the soil moisture data of Heilongjiang Province from 1981 to 2010, selecting the Fujin county of the east, Longjiang county of the west, Shuangcheng county of the south, Heihe city of the north, and Hailun county of the middle in Heilongjiang province, the trends of soil moisture during winter and the drought wet change are analyzed, and the significance tests are conducted with three methods: linear trend, 5 year moving average, and Mann Kendall. The mutation test of soil moisture change is made with Mann Kendall and Yamamoto methods. The results show that the soil moisture at the depth of 0 to 30 cm underground showed various downtrend in the last 30 years: the decreasing of the soil moisture at the Longjiang county was the sharpest, Hailun county the second, and Heihe city and Shuangcheng county the next; moreover, the significance levels of soil moisture decreasing at 20 cm for all the stations were lest than 005, but the decreasing at Fujin county was slight. The results of the Mann Kendall test show that there appeared mutational zones in Longjiang and Hailun counties, and the downtrends of the other stations were close to, or exceeded the significant level in the recent years. The mutational time of soil moisture change was 1994 for the soil layer of 0 to 20 cm in Longjiang county. The decreasing of winter soil moisture in Heilongjiang Province is related to temperature and precipitation, as well as the deterioration of the soil physical properties.
2013, 41(1):202-206.
Abstract:
Low temperature and freeze injury was one of three major disasters that have disastrous effect on the development of fruit trees in Xinjiang. The factors such as the happening time, type, and limit temperature are analyzed by making the investigation of historical disaster conditions, and the database of low temperature is built. The characteristics of meteorological factors are analyzed to study the relationship between freeze injury and meteorological factors, such as the mean temperature, minimum temperature, and the duration of minimum temperature. The results shows that the quantitative indexes of freeze injury can be devised according to such factors as mean temperature in winter, minimum temperature, and the duration of minimum temperature, etc. The results are beneficial for the prevention of the freeze injury and the meteorological service of fruit production effectively.
Low temperature and freeze injury was one of three major disasters that have disastrous effect on the development of fruit trees in Xinjiang. The factors such as the happening time, type, and limit temperature are analyzed by making the investigation of historical disaster conditions, and the database of low temperature is built. The characteristics of meteorological factors are analyzed to study the relationship between freeze injury and meteorological factors, such as the mean temperature, minimum temperature, and the duration of minimum temperature. The results shows that the quantitative indexes of freeze injury can be devised according to such factors as mean temperature in winter, minimum temperature, and the duration of minimum temperature, etc. The results are beneficial for the prevention of the freeze injury and the meteorological service of fruit production effectively.
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.