Volume 41,Issue 3,2013 Table of Contents
2013, 41(3):425-429.
Abstract:
There are presently about 150 radar sets in operation in the CINRAD network, but radar detection data are still displayed mostly on conventional 2D images in operational application. The volumetric cloud data are reconstructed based on the single radar base data and the 3D Geographic Information System (3D GIS). The geographical spatial processing technology of radar base data and 3D cloud volume visualization technology such as volume rendering for isosurface based on 3D grid data are discussed. It provides a new perspective to understand the cloud volume structure for radar base data analysis.
There are presently about 150 radar sets in operation in the CINRAD network, but radar detection data are still displayed mostly on conventional 2D images in operational application. The volumetric cloud data are reconstructed based on the single radar base data and the 3D Geographic Information System (3D GIS). The geographical spatial processing technology of radar base data and 3D cloud volume visualization technology such as volume rendering for isosurface based on 3D grid data are discussed. It provides a new perspective to understand the cloud volume structure for radar base data analysis.
2013, 41(3):430-435.
Abstract:
Using the data of Doppler radar from May to September, 2004 to 2008 and automatic station data in Dalian, by means of the echo typing, optimal Z I relation, system error elimination techniques, the overall localized Z I relation is obtained, which is applicable to operational observation. Taking five heavy rain events in Dalian in 2008 as examples, application experiments are conducted. The results indicate that there is a substantial increase(more than 40%) in the accuracy of precipitation estimate of RPG precipitation estimate products, compared with the default estimate value from WSR 88D. The application from 2009 to 2011 shows that the accuracy of the estimate values is up to more than 75% steadily.
Using the data of Doppler radar from May to September, 2004 to 2008 and automatic station data in Dalian, by means of the echo typing, optimal Z I relation, system error elimination techniques, the overall localized Z I relation is obtained, which is applicable to operational observation. Taking five heavy rain events in Dalian in 2008 as examples, application experiments are conducted. The results indicate that there is a substantial increase(more than 40%) in the accuracy of precipitation estimate of RPG precipitation estimate products, compared with the default estimate value from WSR 88D. The application from 2009 to 2011 shows that the accuracy of the estimate values is up to more than 75% steadily.
3 Rainfall Observation Consistency Verification of Weather Radar and Automatic Weather Station Data
Li Yan
,
Zhang Lejian
,
Liang Haihe
,
Li Feng
,
Zhou Wei
,
Xia Yuancai
,
Zhou Qing
,
Cao Tingting
,
Guo Haiping
2013, 41(3):436-442.
Abstract:
The ground precipitation is divided into 3 intervals (10 to 25, 25 to 50, and 50 to 100 mm/h), and with the hourly precipitation measurements from weather radar and national surface observation automatic weather stations from ASOM from May to October in 2010, using three time standard deviation method, the threshold parameters of precipitation observation differences for two kind of equipment are determined month by month, and a real time rainfall calibration technique between weather radar and automatic weather stations is devised. Using this method, the accuracy of rainfall between May and October 2011 is tested. The results show that the correct rate of the rainfall is greater than 85% after using this new method, which means that this method is effectible in testing the surface precipitation measurements from automatic weather stations in real time.
The ground precipitation is divided into 3 intervals (10 to 25, 25 to 50, and 50 to 100 mm/h), and with the hourly precipitation measurements from weather radar and national surface observation automatic weather stations from ASOM from May to October in 2010, using three time standard deviation method, the threshold parameters of precipitation observation differences for two kind of equipment are determined month by month, and a real time rainfall calibration technique between weather radar and automatic weather stations is devised. Using this method, the accuracy of rainfall between May and October 2011 is tested. The results show that the correct rate of the rainfall is greater than 85% after using this new method, which means that this method is effectible in testing the surface precipitation measurements from automatic weather stations in real time.
2013, 41(3):443-447.
Abstract:
Statistical analysis of radar failure based on three CINRAD/CC radar sets in Gansu Province in the past four years indicates that as a major failure component of the radar system, the data transmission system has a significantly increasing trend in failure with the increasing lifetime of radar. The main factors and causes of the failure are analyzed, and the improvement scheme is presented. It is suggested that the data transmission based on the standard network should abandon the optical fiber data transmission system and discard the optical terminals and the multiplex communication mode, use the terminal software developed by Anhui Sun Create Electronics Co., Ltd (Version 20), which newly integrates the network functionality, user permission feature, automatic generation of data and image products, data file indexing capabilities, voice alarm, and other functions. The operation of the improved radar data transmission system indicate that the failure rate of radar data transmission in the network optical fiber communication systems reduced; the radar system reliability and stability were enhanced; and the radar data transfer rate and efficiency improved, which help ensure the operation of new generation weather radar.
Statistical analysis of radar failure based on three CINRAD/CC radar sets in Gansu Province in the past four years indicates that as a major failure component of the radar system, the data transmission system has a significantly increasing trend in failure with the increasing lifetime of radar. The main factors and causes of the failure are analyzed, and the improvement scheme is presented. It is suggested that the data transmission based on the standard network should abandon the optical fiber data transmission system and discard the optical terminals and the multiplex communication mode, use the terminal software developed by Anhui Sun Create Electronics Co., Ltd (Version 20), which newly integrates the network functionality, user permission feature, automatic generation of data and image products, data file indexing capabilities, voice alarm, and other functions. The operation of the improved radar data transmission system indicate that the failure rate of radar data transmission in the network optical fiber communication systems reduced; the radar system reliability and stability were enhanced; and the radar data transfer rate and efficiency improved, which help ensure the operation of new generation weather radar.
2013, 41(3):448-452.
Abstract:
The essential factor for determining the operational capability of automatic weather stations is its reliability; the purpose of operational capability assessment of automatic weather stations is to guide the establishment and improvement of the support and maintenance system for automatic weather stations. Based on a measurement model of atmospheric transparency, the reliability of automatic weather stations is discussed and the physical meaning of the exponential distribution of product reliability is explained. According to the model, the operation capacity (MTBF: Mean Time Between Failures) of the automatic weather stations is defermined by its relibility after adjusting the collection of data, and calculating the relevant evaluation parameters. The MTBF and the minimum time to fail (with the confidence level being 095) of the experimental products were obtained by experiments. The MTBF and the average maintenance cycle of the double or three station system that will be implemenfed are discussed, which can provide technical support for scientific decision making.
The essential factor for determining the operational capability of automatic weather stations is its reliability; the purpose of operational capability assessment of automatic weather stations is to guide the establishment and improvement of the support and maintenance system for automatic weather stations. Based on a measurement model of atmospheric transparency, the reliability of automatic weather stations is discussed and the physical meaning of the exponential distribution of product reliability is explained. According to the model, the operation capacity (MTBF: Mean Time Between Failures) of the automatic weather stations is defermined by its relibility after adjusting the collection of data, and calculating the relevant evaluation parameters. The MTBF and the minimum time to fail (with the confidence level being 095) of the experimental products were obtained by experiments. The MTBF and the average maintenance cycle of the double or three station system that will be implemenfed are discussed, which can provide technical support for scientific decision making.
2013, 41(3):453-458.
Abstract:
The assessment of domestic scholars and WMO suggests that the GTS1 2 radiosonde needs technological improvement to meet the needs of operational upper air observation, which was conducted on the basis of original technical structure in 2012 and the improved radiosonde was temporarily named GTS1 2A. In August 2012, its test was carried out in the Yangjiang radiosonde station. The results show that it performed well in temperature measurement at night with system error less than-03 ℃ and overall standard deviation within 02 ℃; but in the daytime, except at upper levels and when in/out of clouds, overall its system error is-03 ℃ and its standard deviation is less than 04 ℃. As for pressure measurements, in the near surface layer, the system error is about-15 hPa, and its accuracy and stability are better than GTS1 2 Especially its standard deviation is less than 07 hPa within full range. Its humidity has good consistency with RS92 with sensitivity better than GTS1 2 and overall system error and standard deviation within 10%RH.
The assessment of domestic scholars and WMO suggests that the GTS1 2 radiosonde needs technological improvement to meet the needs of operational upper air observation, which was conducted on the basis of original technical structure in 2012 and the improved radiosonde was temporarily named GTS1 2A. In August 2012, its test was carried out in the Yangjiang radiosonde station. The results show that it performed well in temperature measurement at night with system error less than-03 ℃ and overall standard deviation within 02 ℃; but in the daytime, except at upper levels and when in/out of clouds, overall its system error is-03 ℃ and its standard deviation is less than 04 ℃. As for pressure measurements, in the near surface layer, the system error is about-15 hPa, and its accuracy and stability are better than GTS1 2 Especially its standard deviation is less than 07 hPa within full range. Its humidity has good consistency with RS92 with sensitivity better than GTS1 2 and overall system error and standard deviation within 10%RH.
2013, 41(3):459-463.
Abstract:
In order to design ARGO floats based on China’s own satellite navigation system, a new design of ARGO floats based on the Beidou Navigation Satellite System is presented. The basic principles of ARGO floats, application profiles, and the basic application of the existing Beidou satellite navigation and positioning system are described; the design scheme of ARGO floats based on the Beidou system is introduced; and the feasibility of the ARGO floats is analyzed in the aspects of communication, positioning systems, weight, etc. The communication system of ARGO floats based on the Beidou system, as well as two communication modes, is studied. The results show that the design scheme of ARGO floats based the Beidou system is feasible.
In order to design ARGO floats based on China’s own satellite navigation system, a new design of ARGO floats based on the Beidou Navigation Satellite System is presented. The basic principles of ARGO floats, application profiles, and the basic application of the existing Beidou satellite navigation and positioning system are described; the design scheme of ARGO floats based on the Beidou system is introduced; and the feasibility of the ARGO floats is analyzed in the aspects of communication, positioning systems, weight, etc. The communication system of ARGO floats based on the Beidou system, as well as two communication modes, is studied. The results show that the design scheme of ARGO floats based the Beidou system is feasible.
2013, 41(3):464-469.
Abstract:
In order to improve the support capability and service level of weather forecast service, the weather forecast television discussion system based on the preset scene and double stream real time back up is established. It realizes the preset operation mode according to the conference content by the central control system. The operation procedures, such as audio video matrix switch and camera adjustment, are simplified. The downlink/uplink audio and video signals are backed up in real time. If the main equipment in run abruptly breaks off, the back up equipment will be put into use at once. The digital processor is used to deal with audio signals to improve the sound effect and reduce the noises induced from improper manual adjustment. This system is suitable for both standard and high definition systems after adjusting some correlation parameters. The structure and principles of the system are introduced, which supplies references for the maintenance, operation, and construction of the like weather forecast television discussion systems.
In order to improve the support capability and service level of weather forecast service, the weather forecast television discussion system based on the preset scene and double stream real time back up is established. It realizes the preset operation mode according to the conference content by the central control system. The operation procedures, such as audio video matrix switch and camera adjustment, are simplified. The downlink/uplink audio and video signals are backed up in real time. If the main equipment in run abruptly breaks off, the back up equipment will be put into use at once. The digital processor is used to deal with audio signals to improve the sound effect and reduce the noises induced from improper manual adjustment. This system is suitable for both standard and high definition systems after adjusting some correlation parameters. The structure and principles of the system are introduced, which supplies references for the maintenance, operation, and construction of the like weather forecast television discussion systems.
2013, 41(3):470-475.
Abstract:
Image processing technology is applied to recognize target clouds, and a real time calculation software for artificial precipitation instructions is designed and developed. Radar products are analyzed and processed such as the image pixel set expressed in polar coordinates. According to radar echo statistical analysis results in Sichuan Basin, the image processing methods of region segmentation and region labeling are used to recognize target clouds. In combination with the locations of operating points and operating tool performance, the relevant parameters in operating instruction are computed, which can greatly improve the automation of operation commanding.
Image processing technology is applied to recognize target clouds, and a real time calculation software for artificial precipitation instructions is designed and developed. Radar products are analyzed and processed such as the image pixel set expressed in polar coordinates. According to radar echo statistical analysis results in Sichuan Basin, the image processing methods of region segmentation and region labeling are used to recognize target clouds. In combination with the locations of operating points and operating tool performance, the relevant parameters in operating instruction are computed, which can greatly improve the automation of operation commanding.
2013, 41(3):476-479.
Abstract:
As WebGIS has many shortcomings in publishing mass meteorological data, GIS technology is applied to meteorological data processing. Considering the characteristics of meteorological data, GIS is a good tool to publish mass spatial meteorological data efficiently. To publish grid meteorological data, a flexible and efficient constructing algorithm using the image pyramid model is adopted, combined with the method of generating tiles dynamically on the server, which aims at reducing I/O operations and resampling calculation. Besides the publishing of vector meteorological data, the multi level display of data from various stations and the publishing and sharing on the Internet of mass meteorological information are realized satisfactorily. The application proved that by this way, map data can be processed and published very fast, which can provide references for the follow up development of the meteorological GIS platform.
As WebGIS has many shortcomings in publishing mass meteorological data, GIS technology is applied to meteorological data processing. Considering the characteristics of meteorological data, GIS is a good tool to publish mass spatial meteorological data efficiently. To publish grid meteorological data, a flexible and efficient constructing algorithm using the image pyramid model is adopted, combined with the method of generating tiles dynamically on the server, which aims at reducing I/O operations and resampling calculation. Besides the publishing of vector meteorological data, the multi level display of data from various stations and the publishing and sharing on the Internet of mass meteorological information are realized satisfactorily. The application proved that by this way, map data can be processed and published very fast, which can provide references for the follow up development of the meteorological GIS platform.
2013, 41(3):480-483.
Abstract:
By studying the problems of the ASOM system encountered in monitoring at automatic weather stations, such as not in time, weather radar without sound and light alarm, etc, as well as grasping the operational state in time, collecting and sorting the relevant observation and supporting information, a secondary ASOM monitoring platform is established, and the efficient guaranteeing of the monitoring of the meteorological observing equipment is realized. The monitoring practice shows that this secondary monitoring system solved the problems existing in ASOM and made the ASOM system more convenient, timely, dependable, and accurate.
By studying the problems of the ASOM system encountered in monitoring at automatic weather stations, such as not in time, weather radar without sound and light alarm, etc, as well as grasping the operational state in time, collecting and sorting the relevant observation and supporting information, a secondary ASOM monitoring platform is established, and the efficient guaranteeing of the monitoring of the meteorological observing equipment is realized. The monitoring practice shows that this secondary monitoring system solved the problems existing in ASOM and made the ASOM system more convenient, timely, dependable, and accurate.
2013, 41(3):484-489.
Abstract:
After the recent adjustment of message transmission mode of the surfer observational data, it is necessary for observers to pay attention to the data acquisition on the hour of automatic weather stations and the accuracy checking up of the data processed by the OSSMO software. Taking some representative examples of the abnormal data, the analysis and processing of the abnormal data are conducted to help observers identify skeptical surface observation records quickly in daily data maintenance and to complete the quality control of automatic weather station data, so to ensure the integrity, timeliness and quality of surface metrological observation data.
After the recent adjustment of message transmission mode of the surfer observational data, it is necessary for observers to pay attention to the data acquisition on the hour of automatic weather stations and the accuracy checking up of the data processed by the OSSMO software. Taking some representative examples of the abnormal data, the analysis and processing of the abnormal data are conducted to help observers identify skeptical surface observation records quickly in daily data maintenance and to complete the quality control of automatic weather station data, so to ensure the integrity, timeliness and quality of surface metrological observation data.
2013, 41(3):490-495.
Abstract:
By comparing and analyzing the temperature data and soil temperature data at various levels, the vertical variation of temperature under the surface is revealed, and the relationship between rules base in the parameter setting of ground meteorological software and data quality control of meteorological stations are studied. The methods for determining the abnormal data are introduced. The results can help observers to understand the variation characteristics and regularities of soil temperature, thus analyzing, identifying, and discovering abnormal data.
By comparing and analyzing the temperature data and soil temperature data at various levels, the vertical variation of temperature under the surface is revealed, and the relationship between rules base in the parameter setting of ground meteorological software and data quality control of meteorological stations are studied. The methods for determining the abnormal data are introduced. The results can help observers to understand the variation characteristics and regularities of soil temperature, thus analyzing, identifying, and discovering abnormal data.
2013, 41(3):496-500.
Abstract:
The modern management technology of meteorological equipment warehouse is discussed according to the present management situation of meteorological equipment warehouses, combined with RFID tag technology. Based on the composition and working principles of RFID electronic tags, a meteorological equipment management system was designed, and the system components and information flow are introduced, emphatically the system design and working principles of the meteorological equipment information input subsystem. A summary of improvements in meteorological equipment management relied on tag technology is given. The future application and benefits of tag technology in meteorological equipment warehouse management is explored.
The modern management technology of meteorological equipment warehouse is discussed according to the present management situation of meteorological equipment warehouses, combined with RFID tag technology. Based on the composition and working principles of RFID electronic tags, a meteorological equipment management system was designed, and the system components and information flow are introduced, emphatically the system design and working principles of the meteorological equipment information input subsystem. A summary of improvements in meteorological equipment management relied on tag technology is given. The future application and benefits of tag technology in meteorological equipment warehouse management is explored.
2013, 41(3):501-505.
Abstract:
The management system for the surface meteorological observation test database is developed by using VB 6, Access 2003, and Word 2003, with its test database including surface meteorological observation rules and the basic knowledge in surface meteorological observation and meteorology. The functions of the system, such as user management, database management, test database management, automatic question generation, and test paper editing and printing, are realized. The design ideas, working procedures, and performance in application of the system are introduced.
The management system for the surface meteorological observation test database is developed by using VB 6, Access 2003, and Word 2003, with its test database including surface meteorological observation rules and the basic knowledge in surface meteorological observation and meteorology. The functions of the system, such as user management, database management, test database management, automatic question generation, and test paper editing and printing, are realized. The design ideas, working procedures, and performance in application of the system are introduced.
2013, 41(3):506-515.
Abstract:
By using ADAS (ARPS Data Analysis System) and NCEP GFS data as the background field, an assimilation experiment is conducted on CB\\CC Doppler radar reflectivity in Northwest China, and by means of WRF (Weather Research and Forecasting Model), a weather process occurred around the Hetao region of Yellow River and Hebei Province is simulated. The contrast between the experiment results using different simulation schemes and the forecasting verification show that: (1) the introducing of the C Band radar reflectivity data is complementary in space with the S Band radar data, and the rainfall field and vertical structure information given by the complex cloud analysis scheme with satellite and surface observation data are closer to reality. (2) The scheme with C Band radar reflectivity assimilated is superior to the unassimilated for the simulation of the reflectivity echoes, but the simulated system is gradually ebbed because of the inadequate water supply, which is different from reality. (3) The contrast between different assimilation schemes with the real precipitation indicates that the assimilated reflectivities improved the short time precipitation forecast.
By using ADAS (ARPS Data Analysis System) and NCEP GFS data as the background field, an assimilation experiment is conducted on CB\\CC Doppler radar reflectivity in Northwest China, and by means of WRF (Weather Research and Forecasting Model), a weather process occurred around the Hetao region of Yellow River and Hebei Province is simulated. The contrast between the experiment results using different simulation schemes and the forecasting verification show that: (1) the introducing of the C Band radar reflectivity data is complementary in space with the S Band radar data, and the rainfall field and vertical structure information given by the complex cloud analysis scheme with satellite and surface observation data are closer to reality. (2) The scheme with C Band radar reflectivity assimilated is superior to the unassimilated for the simulation of the reflectivity echoes, but the simulated system is gradually ebbed because of the inadequate water supply, which is different from reality. (3) The contrast between different assimilation schemes with the real precipitation indicates that the assimilated reflectivities improved the short time precipitation forecast.
2013, 41(3):516-521.
Abstract:
Based on TREC (Tracking Reflectivity Echo by Correlation) method, selecting single radar CAPPI data, introducing three kinds of artificial neural networks, such as the radial basis function network, generalized regression neural network, and back propagation neural network with wavelet, as well as support vector machine (SVM), one hour forecast experiments of radar reflectivity are made, and the forecast results are compared with those of TREC. Six indexes of hit rate (HR), false alarm rate (FAR), no alarm probability (NAP), critical success index (CSI), correlation coefficient, and root mean square error are applied to evaluate the forecast effectiveness. The results show that when using HR, FAR, NAP, and CSI, the given thresholds play a key role on the evaluation and the smaller thresholds show better results. There is difference between various networks, as well as SVM and TREC. SVM performs better in one hour nowcasting on the whole, compared with TREC on forecasting strong convective development and changes of storms.
Based on TREC (Tracking Reflectivity Echo by Correlation) method, selecting single radar CAPPI data, introducing three kinds of artificial neural networks, such as the radial basis function network, generalized regression neural network, and back propagation neural network with wavelet, as well as support vector machine (SVM), one hour forecast experiments of radar reflectivity are made, and the forecast results are compared with those of TREC. Six indexes of hit rate (HR), false alarm rate (FAR), no alarm probability (NAP), critical success index (CSI), correlation coefficient, and root mean square error are applied to evaluate the forecast effectiveness. The results show that when using HR, FAR, NAP, and CSI, the given thresholds play a key role on the evaluation and the smaller thresholds show better results. There is difference between various networks, as well as SVM and TREC. SVM performs better in one hour nowcasting on the whole, compared with TREC on forecasting strong convective development and changes of storms.
2013, 41(3):522-528.
Abstract:
To describe the characteristics quantitatively of the spatial heterogeneities of regional persistent heavy precipitation, a new approach is promoted, which can generate quantitatively the spatial heterogeneities of regional persistent heavy precipitation based on the dynamic operation and computational geometry of the Voronoi\\Delaunay model. The daily precipitation dataset in China from 1959 to 2002 is used to build the time series of regional 5 day (10 day) persistent extreme precipitation events to test the application effectiveness, and this method is applied to analyze the spatial heterogeneities, variations, and climatic trends of annual extreme regional 5 day and (10 day) persistent precipitation. The results indicate that comparing with the traditional quantitative statistic method and Kriging interpolation method, this method can easily handle the spatial heterogeneities of regional persistent heavy precipitation and is applicable in the climate change, climate features, and impact researches, and there is a notable advance trend for the occurring date of annual extreme regional 5 day persistent precipitation from 1959 to 2002.
To describe the characteristics quantitatively of the spatial heterogeneities of regional persistent heavy precipitation, a new approach is promoted, which can generate quantitatively the spatial heterogeneities of regional persistent heavy precipitation based on the dynamic operation and computational geometry of the Voronoi\\Delaunay model. The daily precipitation dataset in China from 1959 to 2002 is used to build the time series of regional 5 day (10 day) persistent extreme precipitation events to test the application effectiveness, and this method is applied to analyze the spatial heterogeneities, variations, and climatic trends of annual extreme regional 5 day and (10 day) persistent precipitation. The results indicate that comparing with the traditional quantitative statistic method and Kriging interpolation method, this method can easily handle the spatial heterogeneities of regional persistent heavy precipitation and is applicable in the climate change, climate features, and impact researches, and there is a notable advance trend for the occurring date of annual extreme regional 5 day persistent precipitation from 1959 to 2002.
2013, 41(3):529-536.
Abstract:
The weather products of FY 2 geostationary meteorological satellite are used to gain the hourly precipitation estimation data and surface incident solar radiation data. The high spatial and temporal resolution atmospheric forcing fields of surface temperature, humidity, pressure and wind speed from NCEP/NCAR reanalysis data are established to drive the CLM30 model and simulate the 10 km daily soil moisture dataset from July 2005 to June 2010 of China. Through the comparison to agro meteorological soil moisture observation data, it is found that at the depths of 0 to 10 cm and 0 to 20 cm, the CLM30 model simulation results are consistent with observations in the spatial distribution and time change rate, and at 70 to 100 cm depths, the spatial distributions are in good agreement, but the time change rate is smaller. According to the climate characteristics, China can be divided into eight regions. The analysis of the temporal variations of the regional average soil moisture indicates that the northwest and southwest regions are in good agreement, followed by the northeast and north regions.
The weather products of FY 2 geostationary meteorological satellite are used to gain the hourly precipitation estimation data and surface incident solar radiation data. The high spatial and temporal resolution atmospheric forcing fields of surface temperature, humidity, pressure and wind speed from NCEP/NCAR reanalysis data are established to drive the CLM30 model and simulate the 10 km daily soil moisture dataset from July 2005 to June 2010 of China. Through the comparison to agro meteorological soil moisture observation data, it is found that at the depths of 0 to 10 cm and 0 to 20 cm, the CLM30 model simulation results are consistent with observations in the spatial distribution and time change rate, and at 70 to 100 cm depths, the spatial distributions are in good agreement, but the time change rate is smaller. According to the climate characteristics, China can be divided into eight regions. The analysis of the temporal variations of the regional average soil moisture indicates that the northwest and southwest regions are in good agreement, followed by the northeast and north regions.
20 Characteristics of Surface Layer Bulk Transfer Coefficients over Semi Arid Region of Inner Mongolia
2013, 41(3):537-543.
Abstract:
Based on the data of turbulence flux observed from January 2009 to December 2010 at the Xilinhot National Climate Observatory, the bulk transfer coefficients for momentum and heat are estimated by using the eddy correlation method. The results show that bulk transfer coefficients for momentum (〖WTBX〗C〖WTBZ〗d) and heat(〖WTBX〗C〖WTBZ〗h) exhibit obvious same seasonal variation and different diurnal variation. The seasonal variation was the strongest in summer and the weakest in winter. The diurnal cycle of 〖WTBX〗C〖WTBZ〗d showed a single peak, while 〖WTBX〗C〖WTBZ〗h showed double peaks. With the increase of height the 〖WTBX〗C〖WTBZ〗d decreased, but the 〖WTBX〗C〖WTBZ〗h decreased with the increase of height only in summer. In the unstable atmosphere, both 〖WTBX〗C〖WTBZ〗d and 〖WTBX〗C〖WTBZ〗h decreased with the increasing wind speed. While in the stable atmospheric condition, 〖WTBX〗C〖WTBZ〗d decreased with the wind speed if under 6 m/s, then increased with the wind speed if over 6 m/s. But 〖WTBX〗C〖WTBZ〗h had no obvious trend with the wind speed. As the surface was colder than the air, 〖WTBX〗C〖WTBZ〗d and 〖WTBX〗C〖WTBZ〗h increased with the decrease of temperature difference between surface and air. On the contrary, the larger the temperature difference the stronger the 〖WTBX〗C〖WTBZ〗d, and the 〖WTBX〗C〖WTBZ〗h was inversely proportional to the variation of temperature difference.
Based on the data of turbulence flux observed from January 2009 to December 2010 at the Xilinhot National Climate Observatory, the bulk transfer coefficients for momentum and heat are estimated by using the eddy correlation method. The results show that bulk transfer coefficients for momentum (〖WTBX〗C〖WTBZ〗d) and heat(〖WTBX〗C〖WTBZ〗h) exhibit obvious same seasonal variation and different diurnal variation. The seasonal variation was the strongest in summer and the weakest in winter. The diurnal cycle of 〖WTBX〗C〖WTBZ〗d showed a single peak, while 〖WTBX〗C〖WTBZ〗h showed double peaks. With the increase of height the 〖WTBX〗C〖WTBZ〗d decreased, but the 〖WTBX〗C〖WTBZ〗h decreased with the increase of height only in summer. In the unstable atmosphere, both 〖WTBX〗C〖WTBZ〗d and 〖WTBX〗C〖WTBZ〗h decreased with the increasing wind speed. While in the stable atmospheric condition, 〖WTBX〗C〖WTBZ〗d decreased with the wind speed if under 6 m/s, then increased with the wind speed if over 6 m/s. But 〖WTBX〗C〖WTBZ〗h had no obvious trend with the wind speed. As the surface was colder than the air, 〖WTBX〗C〖WTBZ〗d and 〖WTBX〗C〖WTBZ〗h increased with the decrease of temperature difference between surface and air. On the contrary, the larger the temperature difference the stronger the 〖WTBX〗C〖WTBZ〗d, and the 〖WTBX〗C〖WTBZ〗h was inversely proportional to the variation of temperature difference.
2013, 41(3):544-551.
Abstract:
The invasion of cold air caused a regional strong cooling weather in Chongqing from 13 to 15 March 2011 The significant cooling occurred in the mid west Chongqing, and the heavy precipitation in the mid east Chongqing. Analysis indicates that the temperature and precipitation distribution characteristics are mainly caused by the path of cold air and the occluded front generated in the eastern Sichuan. The turning of the high altitude transverse trough (becoming vertical) guided the north cold air to move southwards. The cold air invaded the Sichuan basin by two paths, the northwest path and the northeast path, when it arrived at the Hetao Region. The cold air invaded the Sichuan Basin by the northwest path, which was the main path of the cold air, caused significant cooling in the mid west Chongqing; the occluded front appeared when the cold air of the two paths met, and its appearance time and location basically consisted with the heavy precipitation. The diagnostic analysis shows that the occluded front region corresponded to the high value region of strong ascending motion and moisture convergence, so it is the main reason for the heavy precipitation in the mid east Chongqing.
The invasion of cold air caused a regional strong cooling weather in Chongqing from 13 to 15 March 2011 The significant cooling occurred in the mid west Chongqing, and the heavy precipitation in the mid east Chongqing. Analysis indicates that the temperature and precipitation distribution characteristics are mainly caused by the path of cold air and the occluded front generated in the eastern Sichuan. The turning of the high altitude transverse trough (becoming vertical) guided the north cold air to move southwards. The cold air invaded the Sichuan basin by two paths, the northwest path and the northeast path, when it arrived at the Hetao Region. The cold air invaded the Sichuan Basin by the northwest path, which was the main path of the cold air, caused significant cooling in the mid west Chongqing; the occluded front appeared when the cold air of the two paths met, and its appearance time and location basically consisted with the heavy precipitation. The diagnostic analysis shows that the occluded front region corresponded to the high value region of strong ascending motion and moisture convergence, so it is the main reason for the heavy precipitation in the mid east Chongqing.
2013, 41(3):552-557.
Abstract:
Based on the observational data obtained from the 200 m meteorological tower in the urban area of Nanjing, together with the L band radar and conventional observational data, a comparative analysis of the boundary layer structures of two fog events in the autumn of 2010 is conducted. The results are:(1) The fog occurred on 17 November was a typical radiation fog, but that on 21 November a typical advection fog. (2) There existed a thick temperature inversion layer for both radiation fog and advection fog at lower levels; during the radiation fog, there was multilayer and subsidence inversion, but during the advection fog, there was single layer inversion due to warm airflow in the boundary layer. The intensity of temperature version during the radiation fog was stronger than that during advection fog, and there was an upper temperature inversion during the development of both.(3) The development of both fog had a close relation to the evolution of the surface temperature: after the sudden drop of surface temperature and the quick stronger intensity of temperature inversion, the relative humidity of the boundary layer increased more significantly, and the fog got thicker. The height of fog top during radiation fog was much higher than that of advection fog.(4) The wind velocity in the boundary layer displayed a peak valley variation. There was a certain relationship between wind velocity fluctuation and fog development:when the wind velocity decreased obviously, the fog got thicker; with the strengthening of turbulence, the fog tended to clear away.
Based on the observational data obtained from the 200 m meteorological tower in the urban area of Nanjing, together with the L band radar and conventional observational data, a comparative analysis of the boundary layer structures of two fog events in the autumn of 2010 is conducted. The results are:(1) The fog occurred on 17 November was a typical radiation fog, but that on 21 November a typical advection fog. (2) There existed a thick temperature inversion layer for both radiation fog and advection fog at lower levels; during the radiation fog, there was multilayer and subsidence inversion, but during the advection fog, there was single layer inversion due to warm airflow in the boundary layer. The intensity of temperature version during the radiation fog was stronger than that during advection fog, and there was an upper temperature inversion during the development of both.(3) The development of both fog had a close relation to the evolution of the surface temperature: after the sudden drop of surface temperature and the quick stronger intensity of temperature inversion, the relative humidity of the boundary layer increased more significantly, and the fog got thicker. The height of fog top during radiation fog was much higher than that of advection fog.(4) The wind velocity in the boundary layer displayed a peak valley variation. There was a certain relationship between wind velocity fluctuation and fog development:when the wind velocity decreased obviously, the fog got thicker; with the strengthening of turbulence, the fog tended to clear away.
2013, 41(3):558-562.
Abstract:
Based on the daily ground temperature, air temperature, wind speed, solar duration, and total cloud cover observation data of 5 stations in Shijiazhuang from 1961 to 2010， the characteristics of the maximum and minimum ground temperature，as well as the relationship of air temperature， precipitation，wind speed，solar duration，and total cloud cover to ground temperature, are analyzed. The results show that the diurnal amplitudes of the maximums were bigger, obviously in winter; those of the minimums were smaller, obviously in summer. The maximums had a clear cooling trend in summer and autumn， the minimums had a clear warming trend in various seasons. There was a positive correlation between maximum ground temperature and maximum air temperature，solar duration，and wind speed，while a negative correlation between maximum ground temperature and total cloud cover. There was a positive correlation between minimum ground temperature and minimum air temperature， total cloud cover， while a negative correlation between minimum ground temperature and wind speed， solar duration. The maximum air temperature had a maximal positive effect on the maximum ground temperature， while wind speed had a minimal positive effect. The total cloud cover had a negative effect on the maximum ground temperature and was stronger in summer and winter. The minimum air temperature had the strongest positive effect on the minimum ground temperature， while total cloud cover had the weakest positive effect. The wind speed had a negative effect on the minimum ground temperature and was stronger in spring and autumn， while solar duration was stronger in autumn and winter.
Based on the daily ground temperature, air temperature, wind speed, solar duration, and total cloud cover observation data of 5 stations in Shijiazhuang from 1961 to 2010， the characteristics of the maximum and minimum ground temperature，as well as the relationship of air temperature， precipitation，wind speed，solar duration，and total cloud cover to ground temperature, are analyzed. The results show that the diurnal amplitudes of the maximums were bigger, obviously in winter; those of the minimums were smaller, obviously in summer. The maximums had a clear cooling trend in summer and autumn， the minimums had a clear warming trend in various seasons. There was a positive correlation between maximum ground temperature and maximum air temperature，solar duration，and wind speed，while a negative correlation between maximum ground temperature and total cloud cover. There was a positive correlation between minimum ground temperature and minimum air temperature， total cloud cover， while a negative correlation between minimum ground temperature and wind speed， solar duration. The maximum air temperature had a maximal positive effect on the maximum ground temperature， while wind speed had a minimal positive effect. The total cloud cover had a negative effect on the maximum ground temperature and was stronger in summer and winter. The minimum air temperature had the strongest positive effect on the minimum ground temperature， while total cloud cover had the weakest positive effect. The wind speed had a negative effect on the minimum ground temperature and was stronger in spring and autumn， while solar duration was stronger in autumn and winter.
2013, 41(3):563-568.
Abstract:
A new computer based single station VHF system for lightning warning based on broadband interferometer technology is developed. The vertical antenna array was set to get the phase difference of lightning radiation signals, and then the elevation of the arrival signal was obtained. Both the distances of the cloud to ground and cloud flashes can be estimated from the elevations. According to the lightning distance and lighting activity, the different levels of lightning alarm can be given. The error analysis of lightning distance finding indicates that the overall uncertainty of the new method is less than 25% in the range of 50 km, less than 30% in the range of 100 km. The system has been used to detect the lightning during a thunderstorm in Chongqing on 26 July 2011 Thousands of lightning have been detected in the thunderstorm by this system, whose frequency distribution corresponded with the multi station lightning location frequency well. The distance finding results were matched with the multi station lightning location results by using time stamp. The comparison shows that the distance finding errors of most lightning are less than 20%, which proved that the new system can detect lightning in the range of 100 km and play the role of lightning early warning.
A new computer based single station VHF system for lightning warning based on broadband interferometer technology is developed. The vertical antenna array was set to get the phase difference of lightning radiation signals, and then the elevation of the arrival signal was obtained. Both the distances of the cloud to ground and cloud flashes can be estimated from the elevations. According to the lightning distance and lighting activity, the different levels of lightning alarm can be given. The error analysis of lightning distance finding indicates that the overall uncertainty of the new method is less than 25% in the range of 50 km, less than 30% in the range of 100 km. The system has been used to detect the lightning during a thunderstorm in Chongqing on 26 July 2011 Thousands of lightning have been detected in the thunderstorm by this system, whose frequency distribution corresponded with the multi station lightning location frequency well. The distance finding results were matched with the multi station lightning location results by using time stamp. The comparison shows that the distance finding errors of most lightning are less than 20%, which proved that the new system can detect lightning in the range of 100 km and play the role of lightning early warning.
2013, 41(3):569-571.
Abstract:
Parameter 〖WTBX〗P〖WTBZ〗c refers to the reference value of electrical and electronic system failure probability in buildings resulted from lightning strokes in the evaluation of lightning disaster risk, and the selection methods of the factor directly influence the accuracy of assessment results. Based on the concept of 〖WTBX〗P〖WTBZ〗c, an analysis is made of 〖WTBX〗P〖WTBZ〗c, and the quantitative calculating methods are discussed. It is concluded that while choosing the parameter, the rationality of SPD design and the limitations of SPD protection should be considered according the relevant national stands, and also the statistical analysis should be conducted of the historical data of local lightning locations to determine the probability distribution of the lightning current peak. The selection of 〖WTBX〗P〖WTBZ〗c should be carried out to ensure the design of SPD is scientific and effective. The protection probability is determined through the analysis of the probability of lightning current peaks, to determine quantitatively the values of 〖WTBX〗P〖WTBZ〗c.
Parameter 〖WTBX〗P〖WTBZ〗c refers to the reference value of electrical and electronic system failure probability in buildings resulted from lightning strokes in the evaluation of lightning disaster risk, and the selection methods of the factor directly influence the accuracy of assessment results. Based on the concept of 〖WTBX〗P〖WTBZ〗c, an analysis is made of 〖WTBX〗P〖WTBZ〗c, and the quantitative calculating methods are discussed. It is concluded that while choosing the parameter, the rationality of SPD design and the limitations of SPD protection should be considered according the relevant national stands, and also the statistical analysis should be conducted of the historical data of local lightning locations to determine the probability distribution of the lightning current peak. The selection of 〖WTBX〗P〖WTBZ〗c should be carried out to ensure the design of SPD is scientific and effective. The protection probability is determined through the analysis of the probability of lightning current peaks, to determine quantitatively the values of 〖WTBX〗P〖WTBZ〗c.
2013, 41(3):572-576.
Abstract:
Based on the circulation patterns in the upper air and at surface, C band Doppler radar products such as reflectivity factor and radar velocity, and automatic station data in Datong, the large area precipitation process on 29 July 2011 is analyzed. The operational conditions for weather modification operation are investigated based on automatic station data. The effect of the weather modification operation is examined scientifically through radar tracking and observing, radar echo animation demonstration, echo strength comparison before and after the operation, and comparison between operation spot and non operation spot, combined with automatic weather station data.The results show that there is certain correlation between the large area continuous precipitation and artificial precipitation enhancement operation.
Based on the circulation patterns in the upper air and at surface, C band Doppler radar products such as reflectivity factor and radar velocity, and automatic station data in Datong, the large area precipitation process on 29 July 2011 is analyzed. The operational conditions for weather modification operation are investigated based on automatic station data. The effect of the weather modification operation is examined scientifically through radar tracking and observing, radar echo animation demonstration, echo strength comparison before and after the operation, and comparison between operation spot and non operation spot, combined with automatic weather station data.The results show that there is certain correlation between the large area continuous precipitation and artificial precipitation enhancement operation.
2013, 41(3):577-582.
Abstract:
Using the hourly electrical load data from 2002 to 2005 and the year to year data of electrical load in the recent 30 years in Tianjin, the characteristics of electrical load and its relationship with meteorological factors are analyzed. The results show that the long term interannual trend of electrical load in recent 30 years was dominantly influenced by the local GDP, whereas meteorological factors such as temperature showed no significant effect. At the seasonal and daily scales, the electrical load was obviously related with air temperature. Especially in July and August, if temperature increased 1 ℃, electrical load rose by about 120 MW. Besides the influence of temperature, relative humidity had remarkable effect on electrical load in summer and early autumn. Moreover, the effect of winds on electrical load should be considered in April, June, July, and December. Generally, extreme electrical load might appear when the maximum temperature was up to 30 ℃, and average humidity was more than 65% in summer.
Using the hourly electrical load data from 2002 to 2005 and the year to year data of electrical load in the recent 30 years in Tianjin, the characteristics of electrical load and its relationship with meteorological factors are analyzed. The results show that the long term interannual trend of electrical load in recent 30 years was dominantly influenced by the local GDP, whereas meteorological factors such as temperature showed no significant effect. At the seasonal and daily scales, the electrical load was obviously related with air temperature. Especially in July and August, if temperature increased 1 ℃, electrical load rose by about 120 MW. Besides the influence of temperature, relative humidity had remarkable effect on electrical load in summer and early autumn. Moreover, the effect of winds on electrical load should be considered in April, June, July, and December. Generally, extreme electrical load might appear when the maximum temperature was up to 30 ℃, and average humidity was more than 65% in summer.
2013, 41(3):583-586.
Abstract:
The method for calculating time sequences through ordinal analysis, unlike correlation coefficient calculation, is presented, in which the idea comes from the closeness of the geometry between the variable sequences. For the sequences with the geometry closer to each other, the index that measures the closeness is bigger and vice versa. Putting the closeness in numerical order, the ranking of degree of contact between the variable sequences can be obtained. Four sequence calculation methods for different nature of the data from the practical point of view are proposed. Choosing the scheme of calculating the weighted squared distance, the related calculation is conducted with air pollution and its related meteorological elements data. By calculating the closeness degree of sequences and comparing with the coefficient method, it is concluded that by the method it is more reliable to use a meteorological element in forecasting. The relationship between the ordinal analysis and the correlation degree of absolute values, as well as the Euclidean distance mathematically, is proved, and the mathematical foundation of ordinal analysis is thus demonstrated. Mathematical derivation and numerical calculations both confirm the availability of ordinal analysis; especially it is useful in the case of measurements for small samples.
The method for calculating time sequences through ordinal analysis, unlike correlation coefficient calculation, is presented, in which the idea comes from the closeness of the geometry between the variable sequences. For the sequences with the geometry closer to each other, the index that measures the closeness is bigger and vice versa. Putting the closeness in numerical order, the ranking of degree of contact between the variable sequences can be obtained. Four sequence calculation methods for different nature of the data from the practical point of view are proposed. Choosing the scheme of calculating the weighted squared distance, the related calculation is conducted with air pollution and its related meteorological elements data. By calculating the closeness degree of sequences and comparing with the coefficient method, it is concluded that by the method it is more reliable to use a meteorological element in forecasting. The relationship between the ordinal analysis and the correlation degree of absolute values, as well as the Euclidean distance mathematically, is proved, and the mathematical foundation of ordinal analysis is thus demonstrated. Mathematical derivation and numerical calculations both confirm the availability of ordinal analysis; especially it is useful in the case of measurements for small samples.
2013, 41(3):587-590.
Abstract:
The filament supply is an AC stabilized voltage supply, powering the klystron filament through a filament intermediate transformer, the pulse transformer located in the fuel tank, and the filament transformer. On 18 July 2011, at the Tongliao weather radar station, Inner Mongolia, the CINRAD/CB radar transmitter recurred filament power supply failure: there was no high voltage, leading to radar shutdown. By careful troubleshooting, the radar failure was removed successfully. The failure reasons are analyzed in detail, and the results are suggestive for the maintenance staff at radar stations
The filament supply is an AC stabilized voltage supply, powering the klystron filament through a filament intermediate transformer, the pulse transformer located in the fuel tank, and the filament transformer. On 18 July 2011, at the Tongliao weather radar station, Inner Mongolia, the CINRAD/CB radar transmitter recurred filament power supply failure: there was no high voltage, leading to radar shutdown. By careful troubleshooting, the radar failure was removed successfully. The failure reasons are analyzed in detail, and the results are suggestive for the maintenance staff at radar stations
2013, 41(3):591-593.
Abstract:
The maximum allowable error of rainfall sensors for automatic weather stations is 10 ±04 mm and the common error is the over tolerance rainfall records, namely the abnormal rainfall records from rainfall collectors or generated by computers. Through the years use and maintenance practice, some experiences are accumulated; for example, by adjusting the base, namely changing sensor measurement tipping bucket deflection angle, the error usually can be controlled within the allowable range. Two cases of the SL3 1 rainfall sensor faults are described, in which regular/irregular multi count over tolerance records are processed properly.
The maximum allowable error of rainfall sensors for automatic weather stations is 10 ±04 mm and the common error is the over tolerance rainfall records, namely the abnormal rainfall records from rainfall collectors or generated by computers. Through the years use and maintenance practice, some experiences are accumulated; for example, by adjusting the base, namely changing sensor measurement tipping bucket deflection angle, the error usually can be controlled within the allowable range. Two cases of the SL3 1 rainfall sensor faults are described, in which regular/irregular multi count over tolerance records are processed properly.
2013, 41(3):594-596.
Abstract:
In order to improve the level of operational strong convective nowcasting, the quantitative assessment software is established. The methods for assessing thunderstorms, local torrential rainfall, and gale, and the software development, are introduced. The assessments of severe rainfall and gale are conducted in a graded mode with intensive observation data, and that of lightning is based on the data of ground lightning strokes from the ADTD system. The assessment results in 2011 show that the method is reasonable and feasible in operation. There are also some problems because it is simple, preliminary, and experimental.
In order to improve the level of operational strong convective nowcasting, the quantitative assessment software is established. The methods for assessing thunderstorms, local torrential rainfall, and gale, and the software development, are introduced. The assessments of severe rainfall and gale are conducted in a graded mode with intensive observation data, and that of lightning is based on the data of ground lightning strokes from the ADTD system. The assessment results in 2011 show that the method is reasonable and feasible in operation. There are also some problems because it is simple, preliminary, and experimental.
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.