Volume 42,Issue 5,2014 Table of Contents
2014, 42(5):731-736.
Abstract:
Comparison is conducted between automatic soil moisture monitoring data and manual measured relative soil moisture data from the Meteorological Data Storage System (MDSS) of the National Meteorological Information Center (NMIC), and it is found that there is about 15% of difference between different observing times in daytime. According to the structural characteristics of the two sets of measurements and the operational requirements of the Chinese Meteorological Administration (CMA), the reasons for the differences are analyzed from several aspects, such as measurement and calculation, repeatable errors, differences in monitoring soil depth and monitoring time, calculation of soil moisture constant, and soil structure change, etc. It is concluded that when the various differences are overlaid together, the maximum difference of about 20% can be found; other factors are also known to impact the difference, so a difference of about 15% is reasonable in practice. The differences of the measured data between observing sites are analyzed by selecting a long sequence observation data. According to commonly used operational indicators of moisture level, the data disturbance and data loss influencing objective judgment induced by the data differences between the two methods are analyzed. It is suggested that the volumetric water content should be used directly in operational application analysis; new application methods of automatic soil moisture monitoring data should be developed, and the corresponding indicator systems or models should be established; the advantages of automatic soil moisture monitoring should be fully taken.
Comparison is conducted between automatic soil moisture monitoring data and manual measured relative soil moisture data from the Meteorological Data Storage System (MDSS) of the National Meteorological Information Center (NMIC), and it is found that there is about 15% of difference between different observing times in daytime. According to the structural characteristics of the two sets of measurements and the operational requirements of the Chinese Meteorological Administration (CMA), the reasons for the differences are analyzed from several aspects, such as measurement and calculation, repeatable errors, differences in monitoring soil depth and monitoring time, calculation of soil moisture constant, and soil structure change, etc. It is concluded that when the various differences are overlaid together, the maximum difference of about 20% can be found; other factors are also known to impact the difference, so a difference of about 15% is reasonable in practice. The differences of the measured data between observing sites are analyzed by selecting a long sequence observation data. According to commonly used operational indicators of moisture level, the data disturbance and data loss influencing objective judgment induced by the data differences between the two methods are analyzed. It is suggested that the volumetric water content should be used directly in operational application analysis; new application methods of automatic soil moisture monitoring data should be developed, and the corresponding indicator systems or models should be established; the advantages of automatic soil moisture monitoring should be fully taken.
2014, 42(5):737-741.
Abstract:
The diurnal variation characteristics of microwave radiometer measurement deviation and the time series are analyzed by using the high temporal spatial resolution radiosonde data (3 h, 30 m in vertical) and the corresponding MP 3000A microwave radiometer data of Wuhan. The results show that the measurements of atmospheric elements have higher accuracy, but there are still some deviations. The large values of temperature deviation are found in afternoon, and those of relative humidity and water vapor density are in the early morning. The detection deviations of temperature and relative humidity time series exhibit noticeable variations, and water vapor density is relatively stable. The precipitation, especially heavy rain, has significant impact on the accuracy of microwave radiometer detection.
The diurnal variation characteristics of microwave radiometer measurement deviation and the time series are analyzed by using the high temporal spatial resolution radiosonde data (3 h, 30 m in vertical) and the corresponding MP 3000A microwave radiometer data of Wuhan. The results show that the measurements of atmospheric elements have higher accuracy, but there are still some deviations. The large values of temperature deviation are found in afternoon, and those of relative humidity and water vapor density are in the early morning. The detection deviations of temperature and relative humidity time series exhibit noticeable variations, and water vapor density is relatively stable. The precipitation, especially heavy rain, has significant impact on the accuracy of microwave radiometer detection.
2014, 42(5):742-747.
Abstract:
A statistical analysis is carried out on the simultaneous observation data of the temperature inside and outside the thermometer shelter in Changsha during summer in 2011 and 2012 The results show that the temperature outside the thermometer shelter is higher (lower) than that inside the thermometer shelter in the daytime (nighttime). However, there exists a similar variation trend for average temperature and extreme maximum temperature inside and outside the thermometer shelter. The average temperature and extreme maximum temperature outside the thermometer shelter is higher than that inside the thermometer shelter. Furthermore, there exists difference between temperature inside and outside the thermometer shelter during different weather conditions，with an average difference of 12 ℃ in rainy days, 28 ℃ in sunny days, and 31 ℃cloudy days. The difference of extreme maximum temperature inside and outside the thermometer shelters is up to 64 ℃. Especially, the number of days with the extreme maximum temperature inside the thermometer shelter higher than 35 ℃ is 61 days in two year, and that inside the thermometer shelter up to 125 days. The extreme maximum temperature inside and outside the thermometer shelter is 389 ℃ and 420 ℃ respectively. Therefore, the difference between temperature inside and outside the thermometer shelter should be taken into account in high temperature forecast and public meteorological service.
A statistical analysis is carried out on the simultaneous observation data of the temperature inside and outside the thermometer shelter in Changsha during summer in 2011 and 2012 The results show that the temperature outside the thermometer shelter is higher (lower) than that inside the thermometer shelter in the daytime (nighttime). However, there exists a similar variation trend for average temperature and extreme maximum temperature inside and outside the thermometer shelter. The average temperature and extreme maximum temperature outside the thermometer shelter is higher than that inside the thermometer shelter. Furthermore, there exists difference between temperature inside and outside the thermometer shelter during different weather conditions，with an average difference of 12 ℃ in rainy days, 28 ℃ in sunny days, and 31 ℃cloudy days. The difference of extreme maximum temperature inside and outside the thermometer shelters is up to 64 ℃. Especially, the number of days with the extreme maximum temperature inside the thermometer shelter higher than 35 ℃ is 61 days in two year, and that inside the thermometer shelter up to 125 days. The extreme maximum temperature inside and outside the thermometer shelter is 389 ℃ and 420 ℃ respectively. Therefore, the difference between temperature inside and outside the thermometer shelter should be taken into account in high temperature forecast and public meteorological service.
2014, 42(5):748-752.
Abstract:
FY3A/VIRR SST (Sea Surface Temperature) is cooler than other reference SST, mainly because the radiation emitted from ocean has to go through a longer atmospheric path before reaching the VIRR instrument at higher zenith angles. Only when the satellite zenith angles less than 50°, is SST evaluated. The disadvantage of limiting zenith angle leads to the loss in geographic coverage. The brightness temperatures for channels 108 μm and 12 μm are examined for all pixels within a 3×3 pixel box centered on the pixel being spatial uniformity tested, and the cloud contaminated pixels are identified. The climate threshold test is also introduced to further eliminate the outliers. After the improvement of FY3A/VIRR SST algorithm, the global coverage of daily SST is decreased, but the consistency of SST is increased, and cloud contamination phenomena are suppressed, especially for monthly SST. Comparison with the global grid daily OISST within 70°N to 70°S of latitude, the global accuracy of FY3A/VIRR SST is -023 ℃±174 ℃. The negative bias shows that the effect of clouds and aerosols still exists. RMS of the improved FY3A/VIRR SST is 174 ℃, which quite agrees with the calibration accuracy (16 K) of the FY3A VIRR 11 μm channel.
FY3A/VIRR SST (Sea Surface Temperature) is cooler than other reference SST, mainly because the radiation emitted from ocean has to go through a longer atmospheric path before reaching the VIRR instrument at higher zenith angles. Only when the satellite zenith angles less than 50°, is SST evaluated. The disadvantage of limiting zenith angle leads to the loss in geographic coverage. The brightness temperatures for channels 108 μm and 12 μm are examined for all pixels within a 3×3 pixel box centered on the pixel being spatial uniformity tested, and the cloud contaminated pixels are identified. The climate threshold test is also introduced to further eliminate the outliers. After the improvement of FY3A/VIRR SST algorithm, the global coverage of daily SST is decreased, but the consistency of SST is increased, and cloud contamination phenomena are suppressed, especially for monthly SST. Comparison with the global grid daily OISST within 70°N to 70°S of latitude, the global accuracy of FY3A/VIRR SST is -023 ℃±174 ℃. The negative bias shows that the effect of clouds and aerosols still exists. RMS of the improved FY3A/VIRR SST is 174 ℃, which quite agrees with the calibration accuracy (16 K) of the FY3A VIRR 11 μm channel.
2014, 42(5):753-758.
Abstract:
The wind measurement algorithm of the L Band Upper Air Meteorological Sounding System is discussed and the existing problems are analyzed. An improvement scheme for calculating upper air winds, which uses the average wind vector algorithm, is presented. Using the contrast observation data set from a ball launching simultaneously RS92 GPS radiosonde and the L band radar-GTS1 radiosonde at Xilinhaote and Yangjiang stations, comparison and analysis are conducted of the regular wind layer calculation results with a variety of average wind vector calculation schemes in the time window of 2 s to 200 s. Based on this analysis, it is suggested that in the time window of 30 s to 45 s, the average wind vector should be used for the future improvement of upper air winds measured by the operational L band radar and radiosonde sounding system, which can set a measurement wind layer every 150 to 350 m elevation, to further improve the consistency with the results of GPS measuring winds.
The wind measurement algorithm of the L Band Upper Air Meteorological Sounding System is discussed and the existing problems are analyzed. An improvement scheme for calculating upper air winds, which uses the average wind vector algorithm, is presented. Using the contrast observation data set from a ball launching simultaneously RS92 GPS radiosonde and the L band radar-GTS1 radiosonde at Xilinhaote and Yangjiang stations, comparison and analysis are conducted of the regular wind layer calculation results with a variety of average wind vector calculation schemes in the time window of 2 s to 200 s. Based on this analysis, it is suggested that in the time window of 30 s to 45 s, the average wind vector should be used for the future improvement of upper air winds measured by the operational L band radar and radiosonde sounding system, which can set a measurement wind layer every 150 to 350 m elevation, to further improve the consistency with the results of GPS measuring winds.
2014, 42(5):759-763.
Abstract:
The background and urgency of giving meteorological equipment a unique code are discussed, and the principles of coding system design are presented. The classification of meteorological equipment and the details of the coding scheme are proposed. Examples are given for how to generate the codes for certain equipment and how to verify the correctness and effectiveness of the approach. The coding design has the feature of unique identification and can embody the characteristics of meteorological service. The coding methods such as implication coding, concatenation coding, level coding, and ascending coding have been appropriately putting into use in the coding design. More importantly, the static coding and dynamic coding are distinguished; the static coding normalizes the meteorological equipment coding regulation, and the dynamic coding achieves the informationized management of meteorological equipment. The practice in several provinces has proved that it can improve the efficiency of meteorological equipment management.
The background and urgency of giving meteorological equipment a unique code are discussed, and the principles of coding system design are presented. The classification of meteorological equipment and the details of the coding scheme are proposed. Examples are given for how to generate the codes for certain equipment and how to verify the correctness and effectiveness of the approach. The coding design has the feature of unique identification and can embody the characteristics of meteorological service. The coding methods such as implication coding, concatenation coding, level coding, and ascending coding have been appropriately putting into use in the coding design. More importantly, the static coding and dynamic coding are distinguished; the static coding normalizes the meteorological equipment coding regulation, and the dynamic coding achieves the informationized management of meteorological equipment. The practice in several provinces has proved that it can improve the efficiency of meteorological equipment management.
2014, 42(5):764-768.
Abstract:
This design adopts the CC2530 chip (one type of ZigBee chips) produced by TI Company as both master chip and communication chip, and the Platinum Resistance PT100 is used as the temperature sensor. The programing of collection, transmission, and management software is based on the Z Stack of TI company, to realize the temperature acquisition and wireless transmission. Meanwhile, the hardware circuits and software programs take full account of the low power and high reliability design. The entire temperature sensor is powered by a lithium battery, which can be charged by a solar panel, and can be used independently in a outdoor environment for a long time.
This design adopts the CC2530 chip (one type of ZigBee chips) produced by TI Company as both master chip and communication chip, and the Platinum Resistance PT100 is used as the temperature sensor. The programing of collection, transmission, and management software is based on the Z Stack of TI company, to realize the temperature acquisition and wireless transmission. Meanwhile, the hardware circuits and software programs take full account of the low power and high reliability design. The entire temperature sensor is powered by a lithium battery, which can be charged by a solar panel, and can be used independently in a outdoor environment for a long time.
2014, 42(5):769-772.
Abstract:
In order to solve the field calibration problem of rain sensors, a new portable automatic calibrator of rain sensors is developed. In the calibrator, the second class standard glass container is used as standard device, and the digitally controlled constant flow pumps are used to control flowing speed. It has high accuracy of rainfall and rain intensity simulation. The system structure and working principles of the automatic calibrator are described in detail. The technical parameters and main functions are clarified. The multiple parameters of the automatic calibrator were tested by the national center for meteorological metrology and the results show that it satisfies the technical requirements of the field test. The calibration results of the automatic calibrator are compared with the 765 type flow meter. The calibration results of both calibrators indicate that the quality of the automatic calibrator is credible.
In order to solve the field calibration problem of rain sensors, a new portable automatic calibrator of rain sensors is developed. In the calibrator, the second class standard glass container is used as standard device, and the digitally controlled constant flow pumps are used to control flowing speed. It has high accuracy of rainfall and rain intensity simulation. The system structure and working principles of the automatic calibrator are described in detail. The technical parameters and main functions are clarified. The multiple parameters of the automatic calibrator were tested by the national center for meteorological metrology and the results show that it satisfies the technical requirements of the field test. The calibration results of the automatic calibrator are compared with the 765 type flow meter. The calibration results of both calibrators indicate that the quality of the automatic calibrator is credible.
2014, 42(5):773-776.
Abstract:
According to the verification regulations for rainfall sensors of automatic meteorological stations and the procedures and methods of measurement uncertainty evaluation, the sources of measurement errors and the resulted measurement uncertainty are analyzed. Using different types of evaluation approaches and different mathematical calculation methods, the standard uncertainty for each component is evaluated, and ultimately the expanded uncertainty of the indoor verification measurement results of the SL3 1 double tipping bucket raingauge is given. For two types of precipitation intensity, the measurement uncertainty 〖WTBX〗U〖WTBZ〗95=014 mm, and the coverage factor 〖WTBX〗k〖WTBZ〗95=206 The verification by the comparative transmission method indicates that the measurement uncertainty meets the requirements of the related rules for the examinations of both measurement standards and legal metrological verification service. This evaluation method can improve the work flow and the quality of indoor rainfall sensor verification.
According to the verification regulations for rainfall sensors of automatic meteorological stations and the procedures and methods of measurement uncertainty evaluation, the sources of measurement errors and the resulted measurement uncertainty are analyzed. Using different types of evaluation approaches and different mathematical calculation methods, the standard uncertainty for each component is evaluated, and ultimately the expanded uncertainty of the indoor verification measurement results of the SL3 1 double tipping bucket raingauge is given. For two types of precipitation intensity, the measurement uncertainty 〖WTBX〗U〖WTBZ〗95=014 mm, and the coverage factor 〖WTBX〗k〖WTBZ〗95=206 The verification by the comparative transmission method indicates that the measurement uncertainty meets the requirements of the related rules for the examinations of both measurement standards and legal metrological verification service. This evaluation method can improve the work flow and the quality of indoor rainfall sensor verification.
2014, 42(5):777-781.
Abstract:
There exists antenna oscillation in PPI scan in Yangjiang CINRAD/SA radar, which may cause data loss in the azimuth sector, leading to limited functions. In order to find the cause of the malfunction, the signal flow of the servo system of the Yangjiang CINRAD/SA radar is analyzed. Combining with the analysis software of base data, the running track of the antenna is examined. Through measuring and comparing the key parameters in the signal flow, it is discovered that the faults are mainly resulted from the azimuth encoder. The analysis methods and experiences in handling are summarized, which is of reference significance for the station level technological support of radar.
There exists antenna oscillation in PPI scan in Yangjiang CINRAD/SA radar, which may cause data loss in the azimuth sector, leading to limited functions. In order to find the cause of the malfunction, the signal flow of the servo system of the Yangjiang CINRAD/SA radar is analyzed. Combining with the analysis software of base data, the running track of the antenna is examined. Through measuring and comparing the key parameters in the signal flow, it is discovered that the faults are mainly resulted from the azimuth encoder. The analysis methods and experiences in handling are summarized, which is of reference significance for the station level technological support of radar.
2014, 42(5):782-784.
Abstract:
The data gaps in CINRAD/SA radar image products are one of typical faults. Through the detail analysis of signal flow and movement locus of antenna with BDAVC5, it is found that the rotary transformer works abnormally because of low excitation voltage, which makes the radar directly skip to the next elevation scan without completing the current elevation scan. Such faults always occur along with the problems of the transmitter system or servo system, and induce the absence of radar data. Based on the findings, a serial of suggestions for different faults are proposed, and the software of BDAVC5 is useful for the fault location in servo system.
The data gaps in CINRAD/SA radar image products are one of typical faults. Through the detail analysis of signal flow and movement locus of antenna with BDAVC5, it is found that the rotary transformer works abnormally because of low excitation voltage, which makes the radar directly skip to the next elevation scan without completing the current elevation scan. Such faults always occur along with the problems of the transmitter system or servo system, and induce the absence of radar data. Based on the findings, a serial of suggestions for different faults are proposed, and the software of BDAVC5 is useful for the fault location in servo system.
2014, 42(5):785-789.
Abstract:
Intensive management of meteorological terminals is an inexorable trend along with the development of meteorological operational systems and meteorological service. From the current status and needs of meteorological terminal management, technology embodied in virtualized cloud platforms and applications deployment, the application characteristics, and actual effectiveness of the meteorological terminal intensive management based on the virtualized cloud platform are discussed. It provides the strategy management and strategy service, such as the virtual protection, desktop management, and behavior control and so on, enhances the capacity of meteorological support and satisfys the needs of meteorological users, and opens a new approach for the terminal management of meteorological platform construction, information sharing, application service, and provides various solutions of application, integration, maintenance, security, and cost control.
Intensive management of meteorological terminals is an inexorable trend along with the development of meteorological operational systems and meteorological service. From the current status and needs of meteorological terminal management, technology embodied in virtualized cloud platforms and applications deployment, the application characteristics, and actual effectiveness of the meteorological terminal intensive management based on the virtualized cloud platform are discussed. It provides the strategy management and strategy service, such as the virtual protection, desktop management, and behavior control and so on, enhances the capacity of meteorological support and satisfys the needs of meteorological users, and opens a new approach for the terminal management of meteorological platform construction, information sharing, application service, and provides various solutions of application, integration, maintenance, security, and cost control.
2014, 42(5):790-794.
Abstract:
In view of the scattered information resources, highly professional knowledge, and the unreliability and uncertainty in gaining network meteorological information accurately, a meteorological information retrieval system is designed based on semantics, which provides a human computer interaction platform for users. The system mainly uses the semantic retrieval and semantic extension capabilities based on ontology. Through building the meteorological knowledge ontology, an ontology base of meteorological information is set, and by using the inference rules, the explaining properties of the retrieved entry, such as description, keywords, etc., can be queried, as well as the extended queries about its brother, father, and subclass entries. By constantly adjust search terms in the process of interaction, the accurate obtaining of meteorological knowledge is realized. The experimental results show that the system can effectively improve the utilization rate of meteorological hydrological information and improve the accuracy of access to information for users.
In view of the scattered information resources, highly professional knowledge, and the unreliability and uncertainty in gaining network meteorological information accurately, a meteorological information retrieval system is designed based on semantics, which provides a human computer interaction platform for users. The system mainly uses the semantic retrieval and semantic extension capabilities based on ontology. Through building the meteorological knowledge ontology, an ontology base of meteorological information is set, and by using the inference rules, the explaining properties of the retrieved entry, such as description, keywords, etc., can be queried, as well as the extended queries about its brother, father, and subclass entries. By constantly adjust search terms in the process of interaction, the accurate obtaining of meteorological knowledge is realized. The experimental results show that the system can effectively improve the utilization rate of meteorological hydrological information and improve the accuracy of access to information for users.
2014, 42(5):795-798.
Abstract:
Disseminating meteorological information through TV has become an important way in meteorological service. A introduction is made to the automatic processing technology in meteorological TV media service, which aims to realize the TV automatic play of the local real time meteorological service information and meet the needs of the public in timely and visually understanding of the local meteorological information services and the needs of the relevant government departments and other users to participate in information releasing. The main findings are as follows: (1) the automatic generating and processing technology of meteorological information, including automatic collection, internet releasing of information to users, and automatic conversion processing technology of information into video, images, or text; (2) the real time automatic transmission technology of weather information to particular terminals.
Disseminating meteorological information through TV has become an important way in meteorological service. A introduction is made to the automatic processing technology in meteorological TV media service, which aims to realize the TV automatic play of the local real time meteorological service information and meet the needs of the public in timely and visually understanding of the local meteorological information services and the needs of the relevant government departments and other users to participate in information releasing. The main findings are as follows: (1) the automatic generating and processing technology of meteorological information, including automatic collection, internet releasing of information to users, and automatic conversion processing technology of information into video, images, or text; (2) the real time automatic transmission technology of weather information to particular terminals.
2014, 42(5):799-803.
Abstract:
The Beidou satellite is the first generation satellite navigation system with independent intellectual property right in China, having the functions of timing, positioning, and short message transmission. The needs analysis, system functions, and structure of the Beidou Satellite Early Warning Release System are described. The system is an effective solution to the bottleneck problem of early warning release in remote rural and mountainous areas, and it expands the coverage of warning service; in the densely populated urban area, the problems of delay and information blocking of releasing warning information are solved, which greatly improves the timeliness of warning release. The system achieves the real time uploading of disaster release information, and becomes a warning dissemination system that combines information releasing, receiving, and feedback together. Some suggestions are given for the application of the Beidou satellite in the emergency response system of China.
The Beidou satellite is the first generation satellite navigation system with independent intellectual property right in China, having the functions of timing, positioning, and short message transmission. The needs analysis, system functions, and structure of the Beidou Satellite Early Warning Release System are described. The system is an effective solution to the bottleneck problem of early warning release in remote rural and mountainous areas, and it expands the coverage of warning service; in the densely populated urban area, the problems of delay and information blocking of releasing warning information are solved, which greatly improves the timeliness of warning release. The system achieves the real time uploading of disaster release information, and becomes a warning dissemination system that combines information releasing, receiving, and feedback together. Some suggestions are given for the application of the Beidou satellite in the emergency response system of China.
2014, 42(5):804-810.
Abstract:
In order to deal with such key issues as the severe weather monitoring, identification and alarming, joint disastrous weather defense, operational guidance and feedback, products sharing, intensive operation management, etc., in base level meteorological offices, a severe weather monitoring and warning platform is designed and discussed based on the B/S architecture, using Web, GIS, and database technology, combined with the existing MICAPS. The platform is used broadly in Shandong in meteorological services for weather processes and major events, such as meteorological emergencies. The platform is fit for not only the modern weather forecasting service development of at the provincial, municipal, and county levels, but also for the intensive operational processes.
In order to deal with such key issues as the severe weather monitoring, identification and alarming, joint disastrous weather defense, operational guidance and feedback, products sharing, intensive operation management, etc., in base level meteorological offices, a severe weather monitoring and warning platform is designed and discussed based on the B/S architecture, using Web, GIS, and database technology, combined with the existing MICAPS. The platform is used broadly in Shandong in meteorological services for weather processes and major events, such as meteorological emergencies. The platform is fit for not only the modern weather forecasting service development of at the provincial, municipal, and county levels, but also for the intensive operational processes.
2014, 42(5):811-817.
Abstract:
The overall design of the system and the implementation of key technologies are introduced. Using the new generation meteorological communication system and storage technology, the system realized the collection, monitoring, quality control, storage, and sharing of real time meteorological data, which covers 703 national automatic meteorological stations, more than 12000 regional automatic stations, etc., of meteorological service in 12 provinces (cities) over the Yangtze River Catchment. Meanwhile the system fills the requirements of high efficiency and high quality on the data monitoring and analysis. Taking advantage of the historical and real time meteorological data in the Yangtze River basin, the rainfall monitoring on fixed time scales such as day, month, season, year and so on or any period time is achieved, and using the method of statistical physics, the spatial distribution of precipitation in different seasons over the Yangtze River basin is extracted. Using the WebGIS framework based on Flex technology, the real time analysis of human computer interaction is achieved to meet the quick response of high density automatic stations under a multi user concurrent condition. The system provides an integrated operational application system combining the collection, collation, processing, analysis, product displaying and so on of meteorological information together for the Three Gorges Cascade Dispatching Center, and provides technical support for hydro meteorological service in the integrated scheduling and developing of upstream water resources.
The overall design of the system and the implementation of key technologies are introduced. Using the new generation meteorological communication system and storage technology, the system realized the collection, monitoring, quality control, storage, and sharing of real time meteorological data, which covers 703 national automatic meteorological stations, more than 12000 regional automatic stations, etc., of meteorological service in 12 provinces (cities) over the Yangtze River Catchment. Meanwhile the system fills the requirements of high efficiency and high quality on the data monitoring and analysis. Taking advantage of the historical and real time meteorological data in the Yangtze River basin, the rainfall monitoring on fixed time scales such as day, month, season, year and so on or any period time is achieved, and using the method of statistical physics, the spatial distribution of precipitation in different seasons over the Yangtze River basin is extracted. Using the WebGIS framework based on Flex technology, the real time analysis of human computer interaction is achieved to meet the quick response of high density automatic stations under a multi user concurrent condition. The system provides an integrated operational application system combining the collection, collation, processing, analysis, product displaying and so on of meteorological information together for the Three Gorges Cascade Dispatching Center, and provides technical support for hydro meteorological service in the integrated scheduling and developing of upstream water resources.
2014, 42(5):818-822.
Abstract:
Based on the snowstorm data in Huangshi from January 1980 to December 2010 and NCEP reanalysis data, the artificial neural network forecast model of snowstorm is established by using neural network method. On the basis of the forecast model and the MICAPS 30 system, by means of the VB language and VFP database, the snowstorm forecast system of Huangshi is devised under Windows operating system, achieving the objective forecasting of snowstorm weather in Huangshi. The establishment of this system has a practical significance to the improvement of snowstorm forecast accuracy. The system operates on the forecast platform of the Huangshi Meteorological Office; since putting into operation, it has performed satisfactorily.
Based on the snowstorm data in Huangshi from January 1980 to December 2010 and NCEP reanalysis data, the artificial neural network forecast model of snowstorm is established by using neural network method. On the basis of the forecast model and the MICAPS 30 system, by means of the VB language and VFP database, the snowstorm forecast system of Huangshi is devised under Windows operating system, achieving the objective forecasting of snowstorm weather in Huangshi. The establishment of this system has a practical significance to the improvement of snowstorm forecast accuracy. The system operates on the forecast platform of the Huangshi Meteorological Office; since putting into operation, it has performed satisfactorily.
2014, 42(5):823-831.
Abstract:
In order to improve the weather forecast quality over the low latitude plateau regions, the wind data retrieved with VAD (Velocity Azimuth Display) method are assimilated to the WRF (Weather Research and Forecasting) model by WRF 3DVar (3 Dimensional Variational Data Assimilation System). With different assimilation schemes, a torrential rain event occurred in Yunnan Province from 00:00UTC 30 June 2009 to 00:00UTC 1 July 2009 is numerically simulated and comparatively analyzed. The results indicate that the initial wind fields of the WRF model are markedly improved by assimilating the retrieved wind data. The WRF 3DVar can availably introduce the information of the retrieved wind to the initial conditions of the regional numerical model. The assimilation of the retrieved wind data helps enhance the wind convergence and vapor transportation over the rainy area. Furthermore, the assimilation help improve quantitative precipitation forecasts. The quantitative test of the 18 hour rainfall forecast shows that forecasts are more accurate, less pretermissions, and more rational pertinence for over 250 mm precipitation in the assimilation experimentations. The higher the assimilation frequency and the longer the assimilation time is, the more obvious the influence of data assimilation on the initial fields and forecast fields of the regional model is. But long assimilation time may increase the speed of synoptic systems and the overestimate rainfall, and so the suitable selection of frequency and time is crucial in numerical experimentations.
In order to improve the weather forecast quality over the low latitude plateau regions, the wind data retrieved with VAD (Velocity Azimuth Display) method are assimilated to the WRF (Weather Research and Forecasting) model by WRF 3DVar (3 Dimensional Variational Data Assimilation System). With different assimilation schemes, a torrential rain event occurred in Yunnan Province from 00:00UTC 30 June 2009 to 00:00UTC 1 July 2009 is numerically simulated and comparatively analyzed. The results indicate that the initial wind fields of the WRF model are markedly improved by assimilating the retrieved wind data. The WRF 3DVar can availably introduce the information of the retrieved wind to the initial conditions of the regional numerical model. The assimilation of the retrieved wind data helps enhance the wind convergence and vapor transportation over the rainy area. Furthermore, the assimilation help improve quantitative precipitation forecasts. The quantitative test of the 18 hour rainfall forecast shows that forecasts are more accurate, less pretermissions, and more rational pertinence for over 250 mm precipitation in the assimilation experimentations. The higher the assimilation frequency and the longer the assimilation time is, the more obvious the influence of data assimilation on the initial fields and forecast fields of the regional model is. But long assimilation time may increase the speed of synoptic systems and the overestimate rainfall, and so the suitable selection of frequency and time is crucial in numerical experimentations.
Xun Xueyi
,
Meng Xuefeng
,
Wang Xueqiang
,
Hu Yinghua
,
Jin Yingchun
,
Zhao Fei
,
Tuo Yanjun
,
Zhang Xu
2014, 42(5):832-838.
Abstract:
Based on T639 and EC model data and ECMWF reanalysis data over 500 hPa in 2012, the forecast products are validated by the synoptic verification method in terms of the starting time, moving velocity, trough line position, and central intensity of the weather systems. The results show that the forecasting of synoptic systems in Inner Mongolia is relatively accurate based on T639 and EC models, especially for 36 hour forecasting. The accuracy of EC model forecast products is better than that of the T639 model, but the stability of EC model products is poorer in the eastern region of Inner Mongolia. The accuracy of T639 model products is greater than 80% in the starting time, moving velocity, trough line position, and central intensity of the systems for 36 hour forecasting. The accuracy of EC model products is higher than that of T639 model products, with the accuracy being greater than 80% in four test indexes for 48 hour forecasting. The prediction capabilities of both T639 and EC model products decrease with the increasing of lead time. There is a significantly correlation between forecast and observation for both models, corresponding well with the distribution of correlation coefficients, and the high value centers of standard deviation are in agreement with the low value centers of correlation coefficient.
Based on T639 and EC model data and ECMWF reanalysis data over 500 hPa in 2012, the forecast products are validated by the synoptic verification method in terms of the starting time, moving velocity, trough line position, and central intensity of the weather systems. The results show that the forecasting of synoptic systems in Inner Mongolia is relatively accurate based on T639 and EC models, especially for 36 hour forecasting. The accuracy of EC model forecast products is better than that of the T639 model, but the stability of EC model products is poorer in the eastern region of Inner Mongolia. The accuracy of T639 model products is greater than 80% in the starting time, moving velocity, trough line position, and central intensity of the systems for 36 hour forecasting. The accuracy of EC model products is higher than that of T639 model products, with the accuracy being greater than 80% in four test indexes for 48 hour forecasting. The prediction capabilities of both T639 and EC model products decrease with the increasing of lead time. There is a significantly correlation between forecast and observation for both models, corresponding well with the distribution of correlation coefficients, and the high value centers of standard deviation are in agreement with the low value centers of correlation coefficient.
2014, 42(5):839-846.
Abstract:
According the comparison between observation temperature from stations and SCMOC refined guidance temperature forecast starting at 00:00GMT and 12:00GMT for 366 days in 2012 for 99 stations over Shaanxi, the characteristics of prediction errors of three hourly predicted temperature, daily maximum, and minimum temperature are annalyzed. The result shows: the accuracy of the predicted temperature starting at 00:00GMT is better than that starting at 12:00GMT, and there is obvious seasonal variation, higher in summer and autumn, lower in winter and spring. The accuracy of daily maximum and minimum temperature prediction has negative correlation with lead time, and the topographic height influences the accuracy of temperature prediction remarkably. The three hourly predicted temperature starting at 00:00GMT for 48 hours has greater negative errors, but that starting at 12:00GMT has greater positive errors. The predicted daily maximum and minimum temperatures are often smaller than observations, except the predicted minimum temperature starting at 00:00GMT. The accuracy of temperature prediction is lower in obvious temperature drop weather, comparing with other weather, according to the quality test of temperature prediction in different weather conditions.
According the comparison between observation temperature from stations and SCMOC refined guidance temperature forecast starting at 00:00GMT and 12:00GMT for 366 days in 2012 for 99 stations over Shaanxi, the characteristics of prediction errors of three hourly predicted temperature, daily maximum, and minimum temperature are annalyzed. The result shows: the accuracy of the predicted temperature starting at 00:00GMT is better than that starting at 12:00GMT, and there is obvious seasonal variation, higher in summer and autumn, lower in winter and spring. The accuracy of daily maximum and minimum temperature prediction has negative correlation with lead time, and the topographic height influences the accuracy of temperature prediction remarkably. The three hourly predicted temperature starting at 00:00GMT for 48 hours has greater negative errors, but that starting at 12:00GMT has greater positive errors. The predicted daily maximum and minimum temperatures are often smaller than observations, except the predicted minimum temperature starting at 00:00GMT. The accuracy of temperature prediction is lower in obvious temperature drop weather, comparing with other weather, according to the quality test of temperature prediction in different weather conditions.
2014, 42(5):847-851.
Abstract:
Using the wind data of two stations in the Bohai Bay from 1988 to 2010, the characteristics of over 17 m/s strong wind are analyzed. The analysis concludes that in winter, the prevailing wind direction for strong wind is northwest, and in spring, summer, and autumn, the prevailing wind direction is northeast, occasionally south wind; over the Bohai Sea, strong wind of grade 10 plus mainly appears in October, November, and December; the annual distribution of strong wind exhibits a two peak and two valley pattern, most frequently in November and least in August. According to the principles of synoptic meteorology and statistic screening, it is found that the extreme wind speed of strong wind has good correlation with the maximum wind speed of the day. The regression prediction equations of the extreme wind speed and the maximum wind speed of the day on the different underlying surface (sea, land surface) are established. The forecast equations passed the test of α=001, with a fitting rate of 75% to 94%. The method is used to revise the WRF numerical forecast wind, substituted into the regression equation to calculate strong wind quickly.
Using the wind data of two stations in the Bohai Bay from 1988 to 2010, the characteristics of over 17 m/s strong wind are analyzed. The analysis concludes that in winter, the prevailing wind direction for strong wind is northwest, and in spring, summer, and autumn, the prevailing wind direction is northeast, occasionally south wind; over the Bohai Sea, strong wind of grade 10 plus mainly appears in October, November, and December; the annual distribution of strong wind exhibits a two peak and two valley pattern, most frequently in November and least in August. According to the principles of synoptic meteorology and statistic screening, it is found that the extreme wind speed of strong wind has good correlation with the maximum wind speed of the day. The regression prediction equations of the extreme wind speed and the maximum wind speed of the day on the different underlying surface (sea, land surface) are established. The forecast equations passed the test of α=001, with a fitting rate of 75% to 94%. The method is used to revise the WRF numerical forecast wind, substituted into the regression equation to calculate strong wind quickly.
2014, 42(5):852-855.
Abstract:
The annual average, maximum, and minimum temperature data from Chaoyang, Haidian, and Fengtai (Beijing urban area) from 1975 to 2012 are studied. The results show: (1) Temperature in Beijing in recent 40 years increased significantly, and the warming rates of annual mean, maximum and minimum air temperature are 0445, 033, and 05 ℃ per 10 years, respectively; the warming in Beijing was most significant in the 1990’s and 2000’s. (2) The M K method is used to test temperature jumps in Beijing, and the results indicate that there were jumps in average, maximum, and minimum temperature with time in 1992, 1992, and 1991, respectively. (3) After the mutation, the average minimum temperature rose most noticeably with the rising amplitude up to 11 ℃, then the average temperature and maximun temperature, with the rising amplitudes being 10 ℃ and 08 ℃. (4) After the mutation, the number of high temperature days increased, while the number of cold days reduced, but precipitation decreased; precipitation and temperature change with anti phase distribution.
The annual average, maximum, and minimum temperature data from Chaoyang, Haidian, and Fengtai (Beijing urban area) from 1975 to 2012 are studied. The results show: (1) Temperature in Beijing in recent 40 years increased significantly, and the warming rates of annual mean, maximum and minimum air temperature are 0445, 033, and 05 ℃ per 10 years, respectively; the warming in Beijing was most significant in the 1990’s and 2000’s. (2) The M K method is used to test temperature jumps in Beijing, and the results indicate that there were jumps in average, maximum, and minimum temperature with time in 1992, 1992, and 1991, respectively. (3) After the mutation, the average minimum temperature rose most noticeably with the rising amplitude up to 11 ℃, then the average temperature and maximun temperature, with the rising amplitudes being 10 ℃ and 08 ℃. (4) After the mutation, the number of high temperature days increased, while the number of cold days reduced, but precipitation decreased; precipitation and temperature change with anti phase distribution.
2014, 42(5):856-864.
Abstract:
Based on the high density precipitation data of automatic weather stations (AWS), the spatial temporal characteristics of extremely intensive precipitation on 21and 22 July 2012 over the Beijing area are analyzed. The results show that during the rainstorm, there were 211 stations recorded greater than 100 mm cumulative rainfall except for Yanqing Station, 96 stations recorded greater than 200 mm cumulative precipitation, and 12 stations greater than 300 mm. In most regions, the durations of precipitation were above 16 hours, with the largest in the southwestern Beijing, and the secondary in the northeast of Beijing. The average precipitation intensity exceeded 16 mm/h in Fangshan, and 14 mm/h in northeastern parts of the urban zone, in spite of the fact that precipitation intensities were less than 6 mm/h in the mountains of the north and northwest. The maximum hourly precipitation intensity was found in the northeast of Beijing and the second in the southwest. The larger average precipitation intensities occurred during 18:00〖KG-*3〗〖CD*2/3〗〖KG-*9〗21:00 of 21 July, with the maximum of 22 mm/h recorded at 19:00 Abnormally strong precipitation intensities of more than 70 mm/h appeared during 19:00〖KG-*3〗〖CD*2/3〗〖KG-*9〗22:00 over the whole city and 13:00〖KG-*3〗〖CD*2/3〗〖KG-*9〗14:00 at Longquan Station. The analysis also shows that the 24 h maximum precipitation of Fangshan on 21 July 2012 ranks the second for the time period of 1961 to 2012 The average 24 h maximum precipitation of 15 stations broke the record of Beijing since 1961, much larger than the second (9 August 1963).
Based on the high density precipitation data of automatic weather stations (AWS), the spatial temporal characteristics of extremely intensive precipitation on 21and 22 July 2012 over the Beijing area are analyzed. The results show that during the rainstorm, there were 211 stations recorded greater than 100 mm cumulative rainfall except for Yanqing Station, 96 stations recorded greater than 200 mm cumulative precipitation, and 12 stations greater than 300 mm. In most regions, the durations of precipitation were above 16 hours, with the largest in the southwestern Beijing, and the secondary in the northeast of Beijing. The average precipitation intensity exceeded 16 mm/h in Fangshan, and 14 mm/h in northeastern parts of the urban zone, in spite of the fact that precipitation intensities were less than 6 mm/h in the mountains of the north and northwest. The maximum hourly precipitation intensity was found in the northeast of Beijing and the second in the southwest. The larger average precipitation intensities occurred during 18:00〖KG-*3〗〖CD*2/3〗〖KG-*9〗21:00 of 21 July, with the maximum of 22 mm/h recorded at 19:00 Abnormally strong precipitation intensities of more than 70 mm/h appeared during 19:00〖KG-*3〗〖CD*2/3〗〖KG-*9〗22:00 over the whole city and 13:00〖KG-*3〗〖CD*2/3〗〖KG-*9〗14:00 at Longquan Station. The analysis also shows that the 24 h maximum precipitation of Fangshan on 21 July 2012 ranks the second for the time period of 1961 to 2012 The average 24 h maximum precipitation of 15 stations broke the record of Beijing since 1961, much larger than the second (9 August 1963).
25 Characteristics of Precipitation Structure and Lightning Activities during a Thunderstorm Process
2014, 42(5):865-873.
Abstract:
To better understood the characteristics of precipitation and lightning activities during a thunderstorms in Sichuan, by using the statistical and contrast methods, the features of the lightning activity and precipitation structure during a thunderstorm occurred in the southeastern Sichuan are analyzed. The results show that the heavy rainfall occurred in the flow field with low level convergence and upper level divergence, and the height of the local maximum precipitation zone located between 2 km and 5 km. After one hour of precipitation, the frequency of lightning flashes began to achieve the maximum, and the ground flashes were mainly negative CG (cloud to ground) flashes, and there were few positive CG flashes. According to the relationship between lightning activity and brightness temperature distribution, it is known that lightning activity occurs mainly in precipitation clouds with temperature being less than 220 K, and the areas of lightning activity are in agreement with precipitation areas. From the distribution of the total flashes and CG flashes, it can be known that negative CG flashes are distributed outside of the total flash area, and IC (intracloud) and CG flashes together impacted on the occurrence of lightning activities in the cloud system.The findings are useful to thunderstorm forecasting.
To better understood the characteristics of precipitation and lightning activities during a thunderstorms in Sichuan, by using the statistical and contrast methods, the features of the lightning activity and precipitation structure during a thunderstorm occurred in the southeastern Sichuan are analyzed. The results show that the heavy rainfall occurred in the flow field with low level convergence and upper level divergence, and the height of the local maximum precipitation zone located between 2 km and 5 km. After one hour of precipitation, the frequency of lightning flashes began to achieve the maximum, and the ground flashes were mainly negative CG (cloud to ground) flashes, and there were few positive CG flashes. According to the relationship between lightning activity and brightness temperature distribution, it is known that lightning activity occurs mainly in precipitation clouds with temperature being less than 220 K, and the areas of lightning activity are in agreement with precipitation areas. From the distribution of the total flashes and CG flashes, it can be known that negative CG flashes are distributed outside of the total flash area, and IC (intracloud) and CG flashes together impacted on the occurrence of lightning activities in the cloud system.The findings are useful to thunderstorm forecasting.
2014, 42(5):874-880.
Abstract:
Based on the conventional observational data, automatic observational data of 123 stations in Shandong Province, and NCEP reanalysis data, the causes of a late spring extreme snowstorm on 19 and 20 April 2013 in Shandong Province are analyzed comprehensively, focusing on the temperature condition. The results show that the previous low temperature is the climate background, and the return flow synoptic pattern, the low level southwesterly jet, and the shear line in the north of Shandong are direct causes. The holding and convergence of water vapor were both happened in the layer between 700 and 500 hPa. The coupled reaction between high and low level jets and the positive vorticity column corresponding to the zonal shear line in the troposphere provided dynamic conditions for the snowstorm. The snowstorm of return flow weather occurred in the atmosphere with convective stability, and there was energy frontogenesis of θse over the snowstorm area in the mid low layer of the troposphere. Before the occurring of the snowstorm, the cold air pool accumulated by the return flow northeasterly wind blocked by the eastern foot of Taihang Mountain was the background of sharply falling surface temperature. The weak descending motion of the cold air mass between 700 and 500 hPa leaded to a funnel shaped 0 ℃ isotherm extending downward, resulted in the sharp falling of surface temperature and the conversion of precipitation phase from rain to snow in the snowstorm zone. So the zone with funnel shaped 0 ℃ isotherm extending downward can be regarded as the indicator of the conversion of precipitation phase from rain to snow and the occurrence of snowstorm in the future.
Based on the conventional observational data, automatic observational data of 123 stations in Shandong Province, and NCEP reanalysis data, the causes of a late spring extreme snowstorm on 19 and 20 April 2013 in Shandong Province are analyzed comprehensively, focusing on the temperature condition. The results show that the previous low temperature is the climate background, and the return flow synoptic pattern, the low level southwesterly jet, and the shear line in the north of Shandong are direct causes. The holding and convergence of water vapor were both happened in the layer between 700 and 500 hPa. The coupled reaction between high and low level jets and the positive vorticity column corresponding to the zonal shear line in the troposphere provided dynamic conditions for the snowstorm. The snowstorm of return flow weather occurred in the atmosphere with convective stability, and there was energy frontogenesis of θse over the snowstorm area in the mid low layer of the troposphere. Before the occurring of the snowstorm, the cold air pool accumulated by the return flow northeasterly wind blocked by the eastern foot of Taihang Mountain was the background of sharply falling surface temperature. The weak descending motion of the cold air mass between 700 and 500 hPa leaded to a funnel shaped 0 ℃ isotherm extending downward, resulted in the sharp falling of surface temperature and the conversion of precipitation phase from rain to snow in the snowstorm zone. So the zone with funnel shaped 0 ℃ isotherm extending downward can be regarded as the indicator of the conversion of precipitation phase from rain to snow and the occurrence of snowstorm in the future.
2014, 42(5):881-887.
Abstract:
With the fast urbanization of China, the existence of obstacles around the meteorological sites makes observational data lose representativeness, accuracy and comparability. In order to study how obstacles affect wind fields quantitatively, an observational experiment of a building is carried out in Guyuan, Hebei Province. The influence of obstacles on wind speed and wind direction is analyzed by comparing the wind data before and after the completion of the building. The analysis of the experiment results shows: (1) Obstacles can weaken wind speed, which is related to the background wind speed, the greater the wind speed the more obvious the attenuation. (2) While the wind velocity is between 2 m/s and 6 m/s, the wind speed attenuation of the lee sites decreases with the increasing of distance behind the obstacle, with the attenuation rate of wind speed being 15 percent or so at the distance of 10 times as long as the height of the obstacle; when the background wind velocity is more than 6 m/s, the wind speed attenuation of the lee sides weakens firstly and then strengthens, with the maximum attenuation at the distance of 5 times as long as the height of the obstacle, and the velocity attenuation by about 20 to 30 percent at the distance of 10 times as long as the height of the obstacle. (3) The frequency of prevailing wind direction decreases because of the obstacle, and the influence distance is 6 times as long as the height of the obstacle.
With the fast urbanization of China, the existence of obstacles around the meteorological sites makes observational data lose representativeness, accuracy and comparability. In order to study how obstacles affect wind fields quantitatively, an observational experiment of a building is carried out in Guyuan, Hebei Province. The influence of obstacles on wind speed and wind direction is analyzed by comparing the wind data before and after the completion of the building. The analysis of the experiment results shows: (1) Obstacles can weaken wind speed, which is related to the background wind speed, the greater the wind speed the more obvious the attenuation. (2) While the wind velocity is between 2 m/s and 6 m/s, the wind speed attenuation of the lee sites decreases with the increasing of distance behind the obstacle, with the attenuation rate of wind speed being 15 percent or so at the distance of 10 times as long as the height of the obstacle; when the background wind velocity is more than 6 m/s, the wind speed attenuation of the lee sides weakens firstly and then strengthens, with the maximum attenuation at the distance of 5 times as long as the height of the obstacle, and the velocity attenuation by about 20 to 30 percent at the distance of 10 times as long as the height of the obstacle. (3) The frequency of prevailing wind direction decreases because of the obstacle, and the influence distance is 6 times as long as the height of the obstacle.
2014, 42(5):888-892.
Abstract:
With the method of artificial soil columns, several kinds of soil, such as loam, clay, and sandy soil, were used in the FDR (Frequency Domain Reflectometry) moisture sensor calibration experiment to analyze the relationship between sensor frequency and soil moisture. The effects of soil textures on calibration parameters are studied through calibration experiments on different kinds of soil. The results show that the frequency of the FDR soil moisture sensor is monotonously decreasing with the increase of soil volumetric water content; the correlation is obvious, and different kinds of soil affect moisture sensor parameters remarkably. The normalized frequency of the sensor for clay testing ranges between 064 and 094, loam between 04 and 086, soil between 03 and 094 A better result is obtained in classification calibration than in concentration calibration. The experimental results have significance for the fine calibration of automatic soil water detectors in the areas with complex soil.
With the method of artificial soil columns, several kinds of soil, such as loam, clay, and sandy soil, were used in the FDR (Frequency Domain Reflectometry) moisture sensor calibration experiment to analyze the relationship between sensor frequency and soil moisture. The effects of soil textures on calibration parameters are studied through calibration experiments on different kinds of soil. The results show that the frequency of the FDR soil moisture sensor is monotonously decreasing with the increase of soil volumetric water content; the correlation is obvious, and different kinds of soil affect moisture sensor parameters remarkably. The normalized frequency of the sensor for clay testing ranges between 064 and 094, loam between 04 and 086, soil between 03 and 094 A better result is obtained in classification calibration than in concentration calibration. The experimental results have significance for the fine calibration of automatic soil water detectors in the areas with complex soil.
2014, 42(5):893-896.
Abstract:
Artificial precipitation enhancement is an experimental science, in which detection and field operations are its key tasks. According to the needs of artificial enhancement precipitation operations and aircraft detection analysis and researches, the detection purposes and the corresponding designs of five cloud microphysical detection operations are discussed: the typical vertical profile of frontal cloud system structure, the vertical structure of precipitating stratus detection, the effectiveness of artificial enhancement precipitation seeding, supercooled water in clouds, and the diffusion of catalysts in clouds and their physical responses. The aircraft detection operation on 25 March 2013 is taken an example, to explore the effectiveness of artificial enhancement precipitation seeding.
Artificial precipitation enhancement is an experimental science, in which detection and field operations are its key tasks. According to the needs of artificial enhancement precipitation operations and aircraft detection analysis and researches, the detection purposes and the corresponding designs of five cloud microphysical detection operations are discussed: the typical vertical profile of frontal cloud system structure, the vertical structure of precipitating stratus detection, the effectiveness of artificial enhancement precipitation seeding, supercooled water in clouds, and the diffusion of catalysts in clouds and their physical responses. The aircraft detection operation on 25 March 2013 is taken an example, to explore the effectiveness of artificial enhancement precipitation seeding.
2014, 42(5):897-905.
Abstract:
Using Doppler radar data, the retrieved cloud parameters from FY 2E geostationary satellite, the retrieved products of MODIS polar orbiting satellites, and conventional precipitation data, the precipitation structure and catalytic effect of the stratus cumulus mixed clouds in a precipitation enhancement operation in Hunan on 17 August 2013 are analyzed. The results show: the clouds in the operation were mainly stratus cumulus mixed clouds with low cloud top temperature; above the -10 ℃ level, there was a deep ice phase growth zone and there were mainly ice phase particles at the cloud tops; beneath the -10 ℃ level, both cloud condensation coalescence and ice phase process were significant. Optical thickness and surface rainfall were correlated positively, reflecting well the area of precipitation. The vertical profiles of echoes show that the cold catalyzed layer had thicker thickness; there was abundant liquid water around the 0 ℃ layer; precipitation was produced by ice phase processes. For the configuration of the deep ice layer and the mixed layer was favorable to the occurrence of precipitation, catalysis operation was conducted in the area where precipitation formed in the cold cloud process, which is more scientific and reasonable. Physical statistical analysis indicates that the echo intensity at upper levels enhanced first after catalysis, and there was a lag at the lower levels, which means that catalysis induced raindrop growth first, and then the falling of the raindrop grown raindrops resulted in the enhancement of echoes at lower levels. Relative to the contrast region, catalysis can increase echo intensity,e.g., precipitation; relative to the prolonged life span of the target cloud area, the catalytic effect was more apparent.
Using Doppler radar data, the retrieved cloud parameters from FY 2E geostationary satellite, the retrieved products of MODIS polar orbiting satellites, and conventional precipitation data, the precipitation structure and catalytic effect of the stratus cumulus mixed clouds in a precipitation enhancement operation in Hunan on 17 August 2013 are analyzed. The results show: the clouds in the operation were mainly stratus cumulus mixed clouds with low cloud top temperature; above the -10 ℃ level, there was a deep ice phase growth zone and there were mainly ice phase particles at the cloud tops; beneath the -10 ℃ level, both cloud condensation coalescence and ice phase process were significant. Optical thickness and surface rainfall were correlated positively, reflecting well the area of precipitation. The vertical profiles of echoes show that the cold catalyzed layer had thicker thickness; there was abundant liquid water around the 0 ℃ layer; precipitation was produced by ice phase processes. For the configuration of the deep ice layer and the mixed layer was favorable to the occurrence of precipitation, catalysis operation was conducted in the area where precipitation formed in the cold cloud process, which is more scientific and reasonable. Physical statistical analysis indicates that the echo intensity at upper levels enhanced first after catalysis, and there was a lag at the lower levels, which means that catalysis induced raindrop growth first, and then the falling of the raindrop grown raindrops resulted in the enhancement of echoes at lower levels. Relative to the contrast region, catalysis can increase echo intensity,e.g., precipitation; relative to the prolonged life span of the target cloud area, the catalytic effect was more apparent.
2014, 42(5):906-911.
Abstract:
Independent lightning rods on building roofs or nearby areas will produce transient high potential, which may damage electric and electronic equipment through electromagnetic induction and couple, and step voltage may harm pedestrians. Based on electromagnetic theory, by means of the building down lead current splitting technique, the calculation formula and security thresholds of step voltage are given. In order to relieve the adverse effects of independent lightning rods, the current splitting technique, in which the multi channel several anti fire copper lines are used in the hollow steel pipes of the lightning rods, is proposed, and it has been applied in the lightning protection of cultural relics.
Independent lightning rods on building roofs or nearby areas will produce transient high potential, which may damage electric and electronic equipment through electromagnetic induction and couple, and step voltage may harm pedestrians. Based on electromagnetic theory, by means of the building down lead current splitting technique, the calculation formula and security thresholds of step voltage are given. In order to relieve the adverse effects of independent lightning rods, the current splitting technique, in which the multi channel several anti fire copper lines are used in the hollow steel pipes of the lightning rods, is proposed, and it has been applied in the lightning protection of cultural relics.
2014, 42(5):912-917.
Abstract:
In order to identify the difference of the lightning protection device design of radar station under high soil resistivity condition, the lightning protection devices for new generation weather radar stations in Sanming of Fujian Province are discussed, based on the location analysis in combination with the characteristic of high soil resistivity. The common grounding system is used, and the design value of grounding resistance is less than 4 Ω. In order to fill the design requirements, the project took such methods as the loose ground net, steel grounding, deep well grounding device, external ring grounding device, etc. for grounding device construction. The deep well method and cage type discharge pit grounding can be applied in the high soil resistivity area. The zero potential drift method can be used in the grounding resistance test of complex soil environments. The practice shows that the lightning protection devices of this station have been running more than a year without damaged by thunders and lightning, and have reached the requirements of lightning protection and grounding protection. This study can be used as a reference in other designs and construction of high soil resistivity grounding devices.
In order to identify the difference of the lightning protection device design of radar station under high soil resistivity condition, the lightning protection devices for new generation weather radar stations in Sanming of Fujian Province are discussed, based on the location analysis in combination with the characteristic of high soil resistivity. The common grounding system is used, and the design value of grounding resistance is less than 4 Ω. In order to fill the design requirements, the project took such methods as the loose ground net, steel grounding, deep well grounding device, external ring grounding device, etc. for grounding device construction. The deep well method and cage type discharge pit grounding can be applied in the high soil resistivity area. The zero potential drift method can be used in the grounding resistance test of complex soil environments. The practice shows that the lightning protection devices of this station have been running more than a year without damaged by thunders and lightning, and have reached the requirements of lightning protection and grounding protection. This study can be used as a reference in other designs and construction of high soil resistivity grounding devices.
2014, 42(5):918-921.
Abstract:
In recent years, lightning induced elevator accidents often occur. The damage to the elevator is caused mainly through the approaches of surge intrusion, ground potential counterattack, and electromagnetic impulses. Through the on site identification of the professional personnel, it is found that the accidents are mostly caused by the damaged control board resulted from the lightning induced electromagnetic effect. The magnetic field intensities, for example, are calculated for the area of 218 m around the stroked building and the LPZ1, LPZ2 in the studied area in the case of lightning directly stroked on the buildings. The analysis is made of the damage mechanisms of lightning electromagnetic pulses to control equipment in the LPZ2 area of the elevator machine room, and it is concluded that to make the distance of 〖WTBX〗d〖WTBZ〗w as big as possible can reduce the magnetic field intensity values; if the shielding meshes for the LPZ1 area of the elevator machine room has a width of 015 m or less, when the lightning arrester on the top of the elevator machine room suffered a direct lightning of 150 kA or less, the control device in the computer room will not usually interfered by lightning electromagnetic pulses.
In recent years, lightning induced elevator accidents often occur. The damage to the elevator is caused mainly through the approaches of surge intrusion, ground potential counterattack, and electromagnetic impulses. Through the on site identification of the professional personnel, it is found that the accidents are mostly caused by the damaged control board resulted from the lightning induced electromagnetic effect. The magnetic field intensities, for example, are calculated for the area of 218 m around the stroked building and the LPZ1, LPZ2 in the studied area in the case of lightning directly stroked on the buildings. The analysis is made of the damage mechanisms of lightning electromagnetic pulses to control equipment in the LPZ2 area of the elevator machine room, and it is concluded that to make the distance of 〖WTBX〗d〖WTBZ〗w as big as possible can reduce the magnetic field intensity values; if the shielding meshes for the LPZ1 area of the elevator machine room has a width of 015 m or less, when the lightning arrester on the top of the elevator machine room suffered a direct lightning of 150 kA or less, the control device in the computer room will not usually interfered by lightning electromagnetic pulses.
2014, 42(5):922-927.
Abstract:
The long term trends of precipitation acidity at Guangzhou are analyzed, based on the monitoring data from 1992 to 2012. The results indicate that there was obvious inter annual variation in precipitation pH from 1992 to 2012, the lowest in 1998 with the annual mean pH being 3.43, the highest in 2012 with the annual mean pH being 4.65. The variation of annual precipitation pH values can be divided into two stages: before 1998, precipitation pH decreased fluctuatingly, with an annual mean rate of about -0.14 a-1; after 1999, precipitation pH increased gradually, especially after 2009 increasing steadily, with an annual mean rate about 0.03 a-1. The seasonal distribution of acid rains was uneven, lower in winter and spring and higher in summer and autumn. The annual variation of acid rains was also obvious, the heaviest in February with the average pH being 3.95, the lightest in December with the average 〖JP2〗pH being 4.36. When the sources of air pollution were stable, the greater the wind speed was, the higher the pH value and the lower the〖WTBX〗 K 〖WTBZ〗(precipitation conductivity) was, consequently the smaller the occurrence frequency of acid rains. Wind direction also affects precipitation pH values. The average pH was generally lower when west winds blow in Guangzhou. When precipitation increased, the higher the pH value was, the lower the 〖WTBX〗K〖WTBZ〗.
The long term trends of precipitation acidity at Guangzhou are analyzed, based on the monitoring data from 1992 to 2012. The results indicate that there was obvious inter annual variation in precipitation pH from 1992 to 2012, the lowest in 1998 with the annual mean pH being 3.43, the highest in 2012 with the annual mean pH being 4.65. The variation of annual precipitation pH values can be divided into two stages: before 1998, precipitation pH decreased fluctuatingly, with an annual mean rate of about -0.14 a-1; after 1999, precipitation pH increased gradually, especially after 2009 increasing steadily, with an annual mean rate about 0.03 a-1. The seasonal distribution of acid rains was uneven, lower in winter and spring and higher in summer and autumn. The annual variation of acid rains was also obvious, the heaviest in February with the average pH being 3.95, the lightest in December with the average 〖JP2〗pH being 4.36. When the sources of air pollution were stable, the greater the wind speed was, the higher the pH value and the lower the〖WTBX〗 K 〖WTBZ〗(precipitation conductivity) was, consequently the smaller the occurrence frequency of acid rains. Wind direction also affects precipitation pH values. The average pH was generally lower when west winds blow in Guangzhou. When precipitation increased, the higher the pH value was, the lower the 〖WTBX〗K〖WTBZ〗.
2014, 42(5):928-933.
Abstract:
The content and format of the sharing products are defined by means of the transportation meteorological information datasets. The Java Servlet technique is used to build a map service based on the GeoServer and the Tomcat platform specifically, which allows consumers to combine the map resources provided by the system freely to satisfy their needs for map service polymerization application. The GIS based system is finally accomplished through such functional modules as the jigsaw algorithm of traffic weather products, core GIS processing, XML parsing, etc., which can satisfy the requirements for transportation meteorological service and provide technical supports for the monitoring, analysis, and the sharing of forecasting products.
The content and format of the sharing products are defined by means of the transportation meteorological information datasets. The Java Servlet technique is used to build a map service based on the GeoServer and the Tomcat platform specifically, which allows consumers to combine the map resources provided by the system freely to satisfy their needs for map service polymerization application. The GIS based system is finally accomplished through such functional modules as the jigsaw algorithm of traffic weather products, core GIS processing, XML parsing, etc., which can satisfy the requirements for transportation meteorological service and provide technical supports for the monitoring, analysis, and the sharing of forecasting products.
2014, 42(5):934-937.
Abstract:
Based on the data of daily meteorological elements and traffic accidents during from 2010 to 2012, a comprehensive analysis is made. Results show: in Zhangjiagang, there exists relationship between traffic accidents and meteorological phenomena, such as meteorological elements as seasons (solar terms), strong wind, rainfall, snow cover, visibility, and temperature. The weather impacts road traffic safety not only through objective road traffic conditions，but also driver’s psychology indirectly. If weather forecast can be paid enough attention, the probability of traffic accidents can be significantly reduced.
Based on the data of daily meteorological elements and traffic accidents during from 2010 to 2012, a comprehensive analysis is made. Results show: in Zhangjiagang, there exists relationship between traffic accidents and meteorological phenomena, such as meteorological elements as seasons (solar terms), strong wind, rainfall, snow cover, visibility, and temperature. The weather impacts road traffic safety not only through objective road traffic conditions，but also driver’s psychology indirectly. If weather forecast can be paid enough attention, the probability of traffic accidents can be significantly reduced.
2014, 42(5):938-944.
Abstract:
Based on the snow data of seven weather stations of Chengde and the meteorological data of Weichang Weather Station from 1951 to 2011, the climate suitability, sustainability, and climate risk for the construction of a ski resort in Weichang are analyzed and evaluated through studying of the inter annual variation characteristics of meteorological factors such as snow, temperature, wind, precipitation, and weather disasters (including fog, dust, thunderstorms, and hail). The results show that Weichang is the best place to build the ski field in Chengde, where there exists snow cover mostly from November to the following March (the best time for skiing is November and December), and there are more than 20 comfortable days from June to August, which is suitable to carry out other tourism projects in the ski resort. The possibility of avalanche is very low in Weichang, but severe weather occurs frequently in off season of skiing, so the early warning and defense measures of 〖JP2〗weather disasters should be taken during this time. In order to ensure the sustainable development of the ski resort, it is recommended that the construction scale of the ski resort cannot be too large and the numbers of ski activities should be limited strictly.
Based on the snow data of seven weather stations of Chengde and the meteorological data of Weichang Weather Station from 1951 to 2011, the climate suitability, sustainability, and climate risk for the construction of a ski resort in Weichang are analyzed and evaluated through studying of the inter annual variation characteristics of meteorological factors such as snow, temperature, wind, precipitation, and weather disasters (including fog, dust, thunderstorms, and hail). The results show that Weichang is the best place to build the ski field in Chengde, where there exists snow cover mostly from November to the following March (the best time for skiing is November and December), and there are more than 20 comfortable days from June to August, which is suitable to carry out other tourism projects in the ski resort. The possibility of avalanche is very low in Weichang, but severe weather occurs frequently in off season of skiing, so the early warning and defense measures of 〖JP2〗weather disasters should be taken during this time. In order to ensure the sustainable development of the ski resort, it is recommended that the construction scale of the ski resort cannot be too large and the numbers of ski activities should be limited strictly.
2014, 42(5):945-950.
Abstract:
The climatological quality indices are designed to support the quality certification of spring Longjing Tea. Considering the close connection between tea quality and climate conditions, the relationship between climate conditions during the growth period of the buds and leaves of tea plants, and the quality, color, taste of the tea is established using agrometeorological technology. Climatological quality certification indices are designed for spring Longjing Tea by using Wuniuzao, Longjing 43, and Jiukeng tea plants. Climatological quality during the growth period of the buds and leaves is classified into four types: superfine, fine, good, and ordinary, as a basis for the certification of climatological quality of Longjing Tea. As a third party independent of the tea producers, dealers, and consumers, the Meteorological Department is acceptable by the three relevant parties to conduct the certification of climatological quality.
The climatological quality indices are designed to support the quality certification of spring Longjing Tea. Considering the close connection between tea quality and climate conditions, the relationship between climate conditions during the growth period of the buds and leaves of tea plants, and the quality, color, taste of the tea is established using agrometeorological technology. Climatological quality certification indices are designed for spring Longjing Tea by using Wuniuzao, Longjing 43, and Jiukeng tea plants. Climatological quality during the growth period of the buds and leaves is classified into four types: superfine, fine, good, and ordinary, as a basis for the certification of climatological quality of Longjing Tea. As a third party independent of the tea producers, dealers, and consumers, the Meteorological Department is acceptable by the three relevant parties to conduct the certification of climatological quality.
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.