Volume 40,Issue 2,2012 Table of Contents
2012, 40(2):145-152.
Abstract:
The threedimensional structure and change of a typhoon in the landing period have close relationship with the its path and intensity. Using the CINRAD 3D mosaic typhoon products to analyze in realtime the threedimensional structure of the typhoon is important to typhoon nowcasting and warning. According to the actual situation of typhoon monitoring and warning, a CINRAD 3D mosaic product display system for typhoon is developed, on the basis of the CINRAD 3D mosaic product production system for typhoon. Taking into account the demand of realtime processing and postanalysis, the realtime monitoring, the animated display of the typhoon and CINRAD 3D mosaic products, the superposition of wind and other functions are realized. Using the section interpolation algorithm and the identification algorithm of nonsymmetric direction of typhoons, the automatic positioning and display section of the largest symmetry axis, nonsymmetric axis and the average RHI section at different distances of the typhoon are achieved. The display method, the related algorithms, and the main functional modules of the system are described. By using Typhoon HAGUPIT as an example, analyzed are the asymmetry and movement of the typhoon path and the correspondence between the strong echo areas and spiral rainbands with the images of Typhoon HAGUPIT. The application indicates that the product display system achieved satisfactory results.
The threedimensional structure and change of a typhoon in the landing period have close relationship with the its path and intensity. Using the CINRAD 3D mosaic typhoon products to analyze in realtime the threedimensional structure of the typhoon is important to typhoon nowcasting and warning. According to the actual situation of typhoon monitoring and warning, a CINRAD 3D mosaic product display system for typhoon is developed, on the basis of the CINRAD 3D mosaic product production system for typhoon. Taking into account the demand of realtime processing and postanalysis, the realtime monitoring, the animated display of the typhoon and CINRAD 3D mosaic products, the superposition of wind and other functions are realized. Using the section interpolation algorithm and the identification algorithm of nonsymmetric direction of typhoons, the automatic positioning and display section of the largest symmetry axis, nonsymmetric axis and the average RHI section at different distances of the typhoon are achieved. The display method, the related algorithms, and the main functional modules of the system are described. By using Typhoon HAGUPIT as an example, analyzed are the asymmetry and movement of the typhoon path and the correspondence between the strong echo areas and spiral rainbands with the images of Typhoon HAGUPIT. The application indicates that the product display system achieved satisfactory results.
2012, 40(2):153-159.
Abstract:
The research and development of an operational objective analysis (OA) system are conducted based on the Cressman linear interpolation method. Several methods for solving the problems encountered in the operation of the OA system are presented: (1) the stations of low creditability are automatically detected, so that their negative effect on the computation of analytic field is minimized; (2) a postprocessing step is conducted on the isopleths so that they agree with observation data, without added or subtracted high/low value centers; (3) an adaptive smooth method is applied to the analytic field so that the smallarea centers can be preserved and meanwhile isopleths are still smooth. The feasibility and validity of the proposed methods are verified by the experimental results, which show that the analytic results of the OA system agree well with observation data, and the smoothness of the analytic isopleths is comparable to that drawn manually by forecasters.
The research and development of an operational objective analysis (OA) system are conducted based on the Cressman linear interpolation method. Several methods for solving the problems encountered in the operation of the OA system are presented: (1) the stations of low creditability are automatically detected, so that their negative effect on the computation of analytic field is minimized; (2) a postprocessing step is conducted on the isopleths so that they agree with observation data, without added or subtracted high/low value centers; (3) an adaptive smooth method is applied to the analytic field so that the smallarea centers can be preserved and meanwhile isopleths are still smooth. The feasibility and validity of the proposed methods are verified by the experimental results, which show that the analytic results of the OA system agree well with observation data, and the smoothness of the analytic isopleths is comparable to that drawn manually by forecasters.
2012, 40(2):160-164.
Abstract:
The new generation weather Doppler radar is a complex construction system. The radar breaks down because of its continuous running and strict environment requirements. The various failures of the radar system are summarized and classified. Based on the failure cause classification, the failures are sorted into 5 categories: (1) hardware malfunction; (2) software collapse; (3) the failures induced by natural disaster; (4) false alarm; and (5) false radar image. A radar failure analysis and standardization platform is developed, aiming at the rapid repairing of the radar failures. The operation capacity of the new generation weather Doppler radar from June 2007 to May 2010 is calculated. Two kinds of radar failures are discussed and the distribution of the radar subsystem failures is given.
The new generation weather Doppler radar is a complex construction system. The radar breaks down because of its continuous running and strict environment requirements. The various failures of the radar system are summarized and classified. Based on the failure cause classification, the failures are sorted into 5 categories: (1) hardware malfunction; (2) software collapse; (3) the failures induced by natural disaster; (4) false alarm; and (5) false radar image. A radar failure analysis and standardization platform is developed, aiming at the rapid repairing of the radar failures. The operation capacity of the new generation weather Doppler radar from June 2007 to May 2010 is calculated. Two kinds of radar failures are discussed and the distribution of the radar subsystem failures is given.
2012, 40(2):165-169.
Abstract:
As the failure rate of the CINRAD radar is much greater than that of WSR88D radar, the faults occurred in the earlymade CINRAD/SB at Zhoushan are summarized and analyzed, and the causes of those faults are discussed. Those faults are statistically classified according to the causes, location, and time; and the repairing procedures for some type faults are simply described. The results show that so long as the technological level and design of the CINRAD radar in the process of production, installation, and adjusting are improved continuously， the fault rate of CINRAD can decrease efficiently.
As the failure rate of the CINRAD radar is much greater than that of WSR88D radar, the faults occurred in the earlymade CINRAD/SB at Zhoushan are summarized and analyzed, and the causes of those faults are discussed. Those faults are statistically classified according to the causes, location, and time; and the repairing procedures for some type faults are simply described. The results show that so long as the technological level and design of the CINRAD radar in the process of production, installation, and adjusting are improved continuously， the fault rate of CINRAD can decrease efficiently.
2012, 40(2):170-174.
Abstract:
Chinese BeidouI was completed in 2000 and has been opened for public use since 2003 The application of BeidouI data in the meteorological field is widely concerned. The feasibility of upper wind sounding with BeidouI is analyzed, experimented and validated. The threedimensional location of the radiosonde is determined in passive positioning way by injecting the realtime height, which is determined by using the realtime highprecision sounding data from radiosondes, into the Beidou positioning unit by twinflight test with the GPS and Beidou radiosondes, so the calculated winds at the sounding level are derived. The deviation between the two systems is about 05 m/s, which proved that the Beidou sounding system preliminarily meets operation requirements.
Chinese BeidouI was completed in 2000 and has been opened for public use since 2003 The application of BeidouI data in the meteorological field is widely concerned. The feasibility of upper wind sounding with BeidouI is analyzed, experimented and validated. The threedimensional location of the radiosonde is determined in passive positioning way by injecting the realtime height, which is determined by using the realtime highprecision sounding data from radiosondes, into the Beidou positioning unit by twinflight test with the GPS and Beidou radiosondes, so the calculated winds at the sounding level are derived. The deviation between the two systems is about 05 m/s, which proved that the Beidou sounding system preliminarily meets operation requirements.
2012, 40(2):175-179.
Abstract:
In order to calibrate the winddirection sensors automatically, an automatic calibration system is developed independently, based on the AVR singlechip computer and the photoelectric detecting technology. The core of the system is the microprocessor ATMEGA16 of ATMEL, which realize the automatic calibration of winddirection sensors through detecting the electric pulses. The system can display the information of winddirection sensors and print the results of the sensor detecting, has the advantages of lowcost, high stability, and low power consumption, and has realized the automation of wind direction sensor calibration.
In order to calibrate the winddirection sensors automatically, an automatic calibration system is developed independently, based on the AVR singlechip computer and the photoelectric detecting technology. The core of the system is the microprocessor ATMEGA16 of ATMEL, which realize the automatic calibration of winddirection sensors through detecting the electric pulses. The system can display the information of winddirection sensors and print the results of the sensor detecting, has the advantages of lowcost, high stability, and low power consumption, and has realized the automation of wind direction sensor calibration.
2012, 40(2):180-184.
Abstract:
The detecting principles of the ADTD lightning detection system are introduced, and the effects of faults in substations on the stability of the whole detection system, as well as the qualities of collected data, are analyzed. By analyzing the structure and basic equipment status of the ADTD lightning detection system, a set of ideas and methods for troubleshooting of the ADTD lightning detection system are presented. Through examining of the major faults of the ADTD lightning detection system occurred in operation from 2006 to 2010, the typical faults and their symptoms are summarized, and the possible causes and troubleshooting methods are discussed. A series of measures to improve the system are provided, and the main factors influencing the stability of the system are studied. Practice shows that the fault analysis method is highly maneuverable, can locate the faulty components with ideal accuracy and effectiveness.
The detecting principles of the ADTD lightning detection system are introduced, and the effects of faults in substations on the stability of the whole detection system, as well as the qualities of collected data, are analyzed. By analyzing the structure and basic equipment status of the ADTD lightning detection system, a set of ideas and methods for troubleshooting of the ADTD lightning detection system are presented. Through examining of the major faults of the ADTD lightning detection system occurred in operation from 2006 to 2010, the typical faults and their symptoms are summarized, and the possible causes and troubleshooting methods are discussed. A series of measures to improve the system are provided, and the main factors influencing the stability of the system are studied. Practice shows that the fault analysis method is highly maneuverable, can locate the faulty components with ideal accuracy and effectiveness.
2012, 40(2):185-188.
Abstract:
It is an important function to provide data discovery, access and retrieval service in the WMO Information System (WIS). In recent years, the OAIPMH protocol is widely used in data sharing and the metadata synchronization field because of its simplicity, openness and operability. After a brief introduction of the OAIPMH protocol, the design of the metadata synchronization function of WIS is presented. The design is composed of metadata repository, metadata provider service, and metadata harvester service. Then the work flow of metadata provider and harvester service is discussed in detail. The metadata synchronization function is developed using Java language. The provider service has passed the testing of the open source software OAI (Open Archive Initiative) and JOAI (Javabased OAI) official website, and the harvester service has successfully harvested the metadata of DLESE （Digital Library for Earth System Education） and the Climate Data Center of Deutscher Wetterdienst.
It is an important function to provide data discovery, access and retrieval service in the WMO Information System (WIS). In recent years, the OAIPMH protocol is widely used in data sharing and the metadata synchronization field because of its simplicity, openness and operability. After a brief introduction of the OAIPMH protocol, the design of the metadata synchronization function of WIS is presented. The design is composed of metadata repository, metadata provider service, and metadata harvester service. Then the work flow of metadata provider and harvester service is discussed in detail. The metadata synchronization function is developed using Java language. The provider service has passed the testing of the open source software OAI (Open Archive Initiative) and JOAI (Javabased OAI) official website, and the harvester service has successfully harvested the metadata of DLESE （Digital Library for Earth System Education） and the Climate Data Center of Deutscher Wetterdienst.
2012, 40(2):189-193.
Abstract:
Considering the actual situation of Xiamen, from the view of meteorological information transmission, the wireless communication solution is suitable for processing the data acquired by automatic weather stations (AWS). Based on the GPRS network, a multihost to oneclient data communication system for AWSs is presented. The meteorological element information acquisition is achieved by the data acquisition devices of various AWSs. The central server of the mobile company with static IP communicates with each GPRS DTU of AWSs through DDN in the GPRS network. The realtime communication is implemented between the central server of the mobile company and the network information center of the Xiamen Meteorological Observatory by TCP/IP technology. Data storage and processing are accomplished by the terminal meteorological observation software. By September 2010, the system has run over 8 months in good stability. The system is not limited by transmission distance with low costs, suited for the data acquisition and control of various kinds of AWSs, and can improve the efficiency of meteorological information releasing.
Considering the actual situation of Xiamen, from the view of meteorological information transmission, the wireless communication solution is suitable for processing the data acquired by automatic weather stations (AWS). Based on the GPRS network, a multihost to oneclient data communication system for AWSs is presented. The meteorological element information acquisition is achieved by the data acquisition devices of various AWSs. The central server of the mobile company with static IP communicates with each GPRS DTU of AWSs through DDN in the GPRS network. The realtime communication is implemented between the central server of the mobile company and the network information center of the Xiamen Meteorological Observatory by TCP/IP technology. Data storage and processing are accomplished by the terminal meteorological observation software. By September 2010, the system has run over 8 months in good stability. The system is not limited by transmission distance with low costs, suited for the data acquisition and control of various kinds of AWSs, and can improve the efficiency of meteorological information releasing.
2012, 40(2):194-197.
Abstract:
With the further expansion of weather service, the monitoring of special elements, such as ultraviolet radiation and underlying surface temperature, has been added to the daily meteorological observation in Jiaxing Meteorological Service since 2006, and the surface meteorological autoobservation system has been accomplished based on the CAN bus in cooperation with by the Wireless Scientific Research Institute of Jiangsu Province. The system is composed of the central station computer, integrated observing service software, and various subcollectors. Characterized with the cordwoodlike expansion style and equipped with Microsoft VB60 as a development tool, the professional version of MS SQL Server 2000 based on the backstage database, and C/S as architecture, the system works satisfactorily for the multipoint and multielemental monitoring, can be widely applied in data query, statistical calculation, alarm monitoring, etc. Having excellent stability, minor signal attenuation, perfect capabilities, and friendly interface, and being easy to be expanded, the system can meet the increasing needs of meteorological service and be widely employed throughout the nation.
With the further expansion of weather service, the monitoring of special elements, such as ultraviolet radiation and underlying surface temperature, has been added to the daily meteorological observation in Jiaxing Meteorological Service since 2006, and the surface meteorological autoobservation system has been accomplished based on the CAN bus in cooperation with by the Wireless Scientific Research Institute of Jiangsu Province. The system is composed of the central station computer, integrated observing service software, and various subcollectors. Characterized with the cordwoodlike expansion style and equipped with Microsoft VB60 as a development tool, the professional version of MS SQL Server 2000 based on the backstage database, and C/S as architecture, the system works satisfactorily for the multipoint and multielemental monitoring, can be widely applied in data query, statistical calculation, alarm monitoring, etc. Having excellent stability, minor signal attenuation, perfect capabilities, and friendly interface, and being easy to be expanded, the system can meet the increasing needs of meteorological service and be widely employed throughout the nation.
2012, 40(2):198-202.
Abstract:
An introduction is made to the principles and measuring method of the ultrasonic snow depth sensor. Based on the snow depth data observed by the two methods, ultrasonic sensor and manual observation in the Jiamusi national reference climatological station，comparison and analysis are made in different weather conditions (high wind velocity, low wind velocity, low temperature). The results show that the differences are mainly influenced by wind velocity and temperature. At high wind velocity, the ultrasonic pulses are greatly affected by wind speed, leading to the departure of the ultrasonic pulses from the bottom of the ultrasonic sensor; meanwhile, the speed of ultrasound pulses is also affected, and thus, the measurement results are affected. The travel time of ultrasonic pulses is affected by the temperature, so when the temperature was extremely low, the performance of ultrasonic sensors is obviously affected.
An introduction is made to the principles and measuring method of the ultrasonic snow depth sensor. Based on the snow depth data observed by the two methods, ultrasonic sensor and manual observation in the Jiamusi national reference climatological station，comparison and analysis are made in different weather conditions (high wind velocity, low wind velocity, low temperature). The results show that the differences are mainly influenced by wind velocity and temperature. At high wind velocity, the ultrasonic pulses are greatly affected by wind speed, leading to the departure of the ultrasonic pulses from the bottom of the ultrasonic sensor; meanwhile, the speed of ultrasound pulses is also affected, and thus, the measurement results are affected. The travel time of ultrasonic pulses is affected by the temperature, so when the temperature was extremely low, the performance of ultrasonic sensors is obviously affected.
2012, 40(2):203-206.
Abstract:
In connection with the quality problems of the roadstate monitoring data of automatic weather stations from August 2009 to July 2010, the methods for controlling the quality of meteorological monitoring data on expressway surface state are discussed. Results show that the techniques for checking allowable values, state consistency, spatial consistency, and integrity, as well as manual identification, can be used for data quality controlling of expressway surface state. These methods, to some extent, suffice the needs of traffic weather services and scientific research.
In connection with the quality problems of the roadstate monitoring data of automatic weather stations from August 2009 to July 2010, the methods for controlling the quality of meteorological monitoring data on expressway surface state are discussed. Results show that the techniques for checking allowable values, state consistency, spatial consistency, and integrity, as well as manual identification, can be used for data quality controlling of expressway surface state. These methods, to some extent, suffice the needs of traffic weather services and scientific research.
2012, 40(2):207-212.
Abstract:
The inhomogeneous characteristics of the underlying surface have huge influence on severe convective weather, which achieves mainly through changing the thermal and dynamical processes within the boundary layer and changing the heat transfer and water circulation between air and land, thereby changing the temperature and humidity distribution of the atmosphere, as well as atmospheric vertical motion. The advancements in the researches on the characteristics of the underlying surface with the landsurface process models are described and the achievements in the impacts of different types, including the natural formation of surface features, vegetation and urbanization, of the underlying surface on severe convective weather, are studied, with emphasis in China. The simulation methods of landsurface process models and the problems arising from land surface changing are also discussed.
The inhomogeneous characteristics of the underlying surface have huge influence on severe convective weather, which achieves mainly through changing the thermal and dynamical processes within the boundary layer and changing the heat transfer and water circulation between air and land, thereby changing the temperature and humidity distribution of the atmosphere, as well as atmospheric vertical motion. The advancements in the researches on the characteristics of the underlying surface with the landsurface process models are described and the achievements in the impacts of different types, including the natural formation of surface features, vegetation and urbanization, of the underlying surface on severe convective weather, are studied, with emphasis in China. The simulation methods of landsurface process models and the problems arising from land surface changing are also discussed.
2012, 40(2):213-218.
Abstract:
Two methods for retrieving the average divergence and radial divergence are introduced by means of the Doppler radar radial velocity data. Their application in rainstorm tracking and heavy rainfall forecasting is discussed, as an example, by a rainstorm process on 11 and 12 July 2004. The results indicate: (1) The average divergence field can be used as the background of rainstorm tracking and heavy rainfall forecasting. Before precipitation, there exists convergence at low levels averagely. If the convergence strengthens or maintains, precipitation will increase in the whole region. While if the height of the convergence lifts at middle levels and maintains, precipitation will be the strongest. If the convergence weakens or begins to become divergent at low levels, regional precipitation will gradually end. (2) According to the distribution of radial divergence, the area of heavy rainfall can be forecasted two hours ahead: the area of heavy rainfall will be within the rear weak convergence zone of the largest radial convergence area; the stronger the intensity weak convergence zone is, the greater the rain intensity is. Therefore, by means of the comprehensive analysis of average and radial divergence changes along with time, the development and evolution of precipitation can be tracked and forecasted, especially, the area of heavy rainfall can be located roughly.
Two methods for retrieving the average divergence and radial divergence are introduced by means of the Doppler radar radial velocity data. Their application in rainstorm tracking and heavy rainfall forecasting is discussed, as an example, by a rainstorm process on 11 and 12 July 2004. The results indicate: (1) The average divergence field can be used as the background of rainstorm tracking and heavy rainfall forecasting. Before precipitation, there exists convergence at low levels averagely. If the convergence strengthens or maintains, precipitation will increase in the whole region. While if the height of the convergence lifts at middle levels and maintains, precipitation will be the strongest. If the convergence weakens or begins to become divergent at low levels, regional precipitation will gradually end. (2) According to the distribution of radial divergence, the area of heavy rainfall can be forecasted two hours ahead: the area of heavy rainfall will be within the rear weak convergence zone of the largest radial convergence area; the stronger the intensity weak convergence zone is, the greater the rain intensity is. Therefore, by means of the comprehensive analysis of average and radial divergence changes along with time, the development and evolution of precipitation can be tracked and forecasted, especially, the area of heavy rainfall can be located roughly.
2012, 40(2):219-225.
Abstract:
According to the principles of analog forecast, the stepbystep filter and the smallest degree of analogue deviation are applied to make 4to10day wind forecast for the area around Bohai Sea based on the T213 numerical forecast products, NCEP reanalyzed daily data, and the wind speed data of 72 stations around Bohai Sea. Various forecast schemes for 4 to 10 days are established. Forecast results were tested to choose the optimal scheme, which is used to forecast wind speeds four times per day and the daily maximum wind speeds for 72 stations around Bohai sea from 2007 to 2008. The results show that the TS score for windscale 0 to 2 forecast is better in forecasting wind speeds four times per day, and the 4to10day mean TS score is 67%; the 4to10day mean TS score for wind scale 3 to 4 of maximum daily wind speed forecast is 54.1%; above wind scale 5, the 4to10day mean TS score is 17.1%. The results also indicate that the analog method is of good capability in 4to10day wind speed forecasting.
According to the principles of analog forecast, the stepbystep filter and the smallest degree of analogue deviation are applied to make 4to10day wind forecast for the area around Bohai Sea based on the T213 numerical forecast products, NCEP reanalyzed daily data, and the wind speed data of 72 stations around Bohai Sea. Various forecast schemes for 4 to 10 days are established. Forecast results were tested to choose the optimal scheme, which is used to forecast wind speeds four times per day and the daily maximum wind speeds for 72 stations around Bohai sea from 2007 to 2008. The results show that the TS score for windscale 0 to 2 forecast is better in forecasting wind speeds four times per day, and the 4to10day mean TS score is 67%; the 4to10day mean TS score for wind scale 3 to 4 of maximum daily wind speed forecast is 54.1%; above wind scale 5, the 4to10day mean TS score is 17.1%. The results also indicate that the analog method is of good capability in 4to10day wind speed forecasting.
2012, 40(2):226-231.
Abstract:
The prediction precision of the precipitation trend over the Haihe River basin in summer (JJA) 2010 and the prediction techniques and major forecast bases are reviewed. The causes of the summer drought in 2010 are analyzed from the aspects of the climatic background, SST，general circulation patterns, etc. It reveals that the Haihe River basin is presently still in a lessrain climate background. The differences in the general circulation patterns were the major causes of the summer drought in 2010, including the preceding SST anomalies, a weaker East Asian Summer Monsoon,and a stronger and more westward subtropical high over the western Pacific. The merits and demerits of forecasting are summarized as well, so to improve the forecasting accuracy of precipitation trends in flood season and provide better climate prediction service.
The prediction precision of the precipitation trend over the Haihe River basin in summer (JJA) 2010 and the prediction techniques and major forecast bases are reviewed. The causes of the summer drought in 2010 are analyzed from the aspects of the climatic background, SST，general circulation patterns, etc. It reveals that the Haihe River basin is presently still in a lessrain climate background. The differences in the general circulation patterns were the major causes of the summer drought in 2010, including the preceding SST anomalies, a weaker East Asian Summer Monsoon,and a stronger and more westward subtropical high over the western Pacific. The merits and demerits of forecasting are summarized as well, so to improve the forecasting accuracy of precipitation trends in flood season and provide better climate prediction service.
2012, 40(2):232-240.
Abstract:
The contribution of sophisticated terrain is a key factor of the generation of strong convective weather, which is hard to forecast. In order to improve the model simulation of rainfall in South China, the impact of terrain must be taken into account. A rainstorm occurred in the warm section in the southeast of Yunwushan is used as an example to investigate the simulation capability of Gravity Wave Drag by Orography (GWDO) parameterization, which is newly added into WRFV3.1, and its mechanisms. The simulation is conducted for 36 hours using the reanalysis data of NCEP (1°×1°) from 5 to 6 June 2008. Through the analysis and comparison of two experiments, it is concluded: (1) The sensitivity experiment achieved a success in the simulation of the center and strength of the rainstorm, and it revealed the largeand mesoscale circulation pattern and evolution of the heavy rain event and successfully duplicated the mesoscale lowvortex, whose temporal evolution characteristics were in accord with the movement of the precipitation center, while the control experiment without using the parameterization scheme failed. (2) The using of GWDO parameterization effectively reduced the zonal wind deviation in the middle troposphere, and the impact of terrain on the dynamic uplift of airflow was simulated reasonably. (3) According to experiments, the energy divergence in the middle caused by the orographyinduced gravity wave was the main cause of the rainstorm, which enhanced the vertical movement and made the precipitation strengthened and relatively concentrated.
The contribution of sophisticated terrain is a key factor of the generation of strong convective weather, which is hard to forecast. In order to improve the model simulation of rainfall in South China, the impact of terrain must be taken into account. A rainstorm occurred in the warm section in the southeast of Yunwushan is used as an example to investigate the simulation capability of Gravity Wave Drag by Orography (GWDO) parameterization, which is newly added into WRFV3.1, and its mechanisms. The simulation is conducted for 36 hours using the reanalysis data of NCEP (1°×1°) from 5 to 6 June 2008. Through the analysis and comparison of two experiments, it is concluded: (1) The sensitivity experiment achieved a success in the simulation of the center and strength of the rainstorm, and it revealed the largeand mesoscale circulation pattern and evolution of the heavy rain event and successfully duplicated the mesoscale lowvortex, whose temporal evolution characteristics were in accord with the movement of the precipitation center, while the control experiment without using the parameterization scheme failed. (2) The using of GWDO parameterization effectively reduced the zonal wind deviation in the middle troposphere, and the impact of terrain on the dynamic uplift of airflow was simulated reasonably. (3) According to experiments, the energy divergence in the middle caused by the orographyinduced gravity wave was the main cause of the rainstorm, which enhanced the vertical movement and made the precipitation strengthened and relatively concentrated.
2012, 40(2):241-248.
Abstract:
A 72hour numerical simulation of Typhoon Damrey is performed by using WRF (V311). The possible mechanism resulted in the rapid intensification is explored. The results show that: (1) Interaction between easterly waves and typhoon’s circulation at upperlevels during the slowly intensify stage induced a broad range of northeastsouthwest direction outflow channel, which increased divergence at upperlevels and was favorable to the intensification; the vertical wind shear reduced in the first 12 hours, and the rapid intensification lagged behind the vertical wind shear decrease.（2）The water vapor flux toward the typhoon’s center at lowerlevels increased magnificently during the rapid intensify stage; the heat flux, latent heat flux and moisture flux, at the sea surface were growing constantly, and the contribution of latent heat flux was greater than that of heat flux. (3) The mechanism of conditional symmtrical instability excited the tilted updraft; the development of slantwise vorticity induced the significant increment of relative vorticity near the typhoon center and promoted the strengthening process.
A 72hour numerical simulation of Typhoon Damrey is performed by using WRF (V311). The possible mechanism resulted in the rapid intensification is explored. The results show that: (1) Interaction between easterly waves and typhoon’s circulation at upperlevels during the slowly intensify stage induced a broad range of northeastsouthwest direction outflow channel, which increased divergence at upperlevels and was favorable to the intensification; the vertical wind shear reduced in the first 12 hours, and the rapid intensification lagged behind the vertical wind shear decrease.（2）The water vapor flux toward the typhoon’s center at lowerlevels increased magnificently during the rapid intensify stage; the heat flux, latent heat flux and moisture flux, at the sea surface were growing constantly, and the contribution of latent heat flux was greater than that of heat flux. (3) The mechanism of conditional symmtrical instability excited the tilted updraft; the development of slantwise vorticity induced the significant increment of relative vorticity near the typhoon center and promoted the strengthening process.
2012, 40(2):249-255.
Abstract:
The track data of tropical cyclones (TC) provided by the Chinese Meteorological Administrator from 1949 to 2009 are employed to analyze the climatic characteristics of TC activities over the Northwest Pacific，including the temporalspatial variations of TC sources, the interannual and intermonthly variation of the TCs formed and landed on China, the distribution of TCs intensity and tracks, etc. The results show that the number of TCs formed on China has been decreased for more than 60 years, although there was little change in the number of landfall TCs, but the highintensity TCs increased in recent 10 years, with the peak period being from June to October, especially in August; the greater the intensity was, the later the TC occurred; the average life period of TCs increased with increasing TC intensity, with a singlepeak pattern; as for the geographical distribution of TC occurrence frequency, TCs were mainly concentrated around the South China Sea and the ocean area east of Philippines, decreasing radially outward; however, the TCs tended to stretch westward with the intensity slightly increasing in recent 10 years.
The track data of tropical cyclones (TC) provided by the Chinese Meteorological Administrator from 1949 to 2009 are employed to analyze the climatic characteristics of TC activities over the Northwest Pacific，including the temporalspatial variations of TC sources, the interannual and intermonthly variation of the TCs formed and landed on China, the distribution of TCs intensity and tracks, etc. The results show that the number of TCs formed on China has been decreased for more than 60 years, although there was little change in the number of landfall TCs, but the highintensity TCs increased in recent 10 years, with the peak period being from June to October, especially in August; the greater the intensity was, the later the TC occurred; the average life period of TCs increased with increasing TC intensity, with a singlepeak pattern; as for the geographical distribution of TC occurrence frequency, TCs were mainly concentrated around the South China Sea and the ocean area east of Philippines, decreasing radially outward; however, the TCs tended to stretch westward with the intensity slightly increasing in recent 10 years.
2012, 40(2):256-261.
Abstract:
Utilizing the monthly average temperature data of 160 stations, MICAPS data (two times per day) and NCEP 1°×1°data (four times per day) of May to August from 1999 to 2008, the conceptual model of severe convection associated with the cold vortex is devised, and the anomalies of the subtropical high pressure, East Asian monsoon, highaltitude jet, and lowlevel vertical motion are studied in the anomalous years of the cold vortex in summer. The results indicate that in the strong anomalous years of summer NCCVI (Nouth China Cold Vortex Index), there is a cyclonic circulation developed at 500 hPa over Lake Baikal, an upper trough from Lake Baikal to North China, and more active cold air; North China is affected by the southspreading steering flow after the trough. Various levels of the troposphere are warmer and wetter; the highaltitude jet in 200 hPa is stronger; the northerly air stream in the rear cold vortex at 700 hPa strengthens at high latitudes, and southerly air stream strengthens at low latitudes; the cold air and warm air converges in North China; ascending motion at lower levels develops over North China and North East. Over the same period, the subtropical high pressure is stronger and more southern; East Asian summer monsoon is stronger, which increases the transport of water vapor.In the weak anomalous years of summer NCCVI, these are on the contrary.
Utilizing the monthly average temperature data of 160 stations, MICAPS data (two times per day) and NCEP 1°×1°data (four times per day) of May to August from 1999 to 2008, the conceptual model of severe convection associated with the cold vortex is devised, and the anomalies of the subtropical high pressure, East Asian monsoon, highaltitude jet, and lowlevel vertical motion are studied in the anomalous years of the cold vortex in summer. The results indicate that in the strong anomalous years of summer NCCVI (Nouth China Cold Vortex Index), there is a cyclonic circulation developed at 500 hPa over Lake Baikal, an upper trough from Lake Baikal to North China, and more active cold air; North China is affected by the southspreading steering flow after the trough. Various levels of the troposphere are warmer and wetter; the highaltitude jet in 200 hPa is stronger; the northerly air stream in the rear cold vortex at 700 hPa strengthens at high latitudes, and southerly air stream strengthens at low latitudes; the cold air and warm air converges in North China; ascending motion at lower levels develops over North China and North East. Over the same period, the subtropical high pressure is stronger and more southern; East Asian summer monsoon is stronger, which increases the transport of water vapor.In the weak anomalous years of summer NCCVI, these are on the contrary.
2012, 40(2):262-267.
Abstract:
Using the observation data from 59 stations from 1961 to 2006 in Jiangsu Province，an analysis is made of the annual variation characteristics of heavy fog days.A further research on the generation, dissipation, and duration variation characteristics of heavy fog is conducted by means of the data from 8 stations from 1961 to 2006 The results show that the number of annual fog days increased from 1961, reached the peak in the early 1980s, and declined fast afterward; the heavy duration showed a marked increase trend, mainly the postponement of fog dissipation. A compositive impact index, including the effect of fog days and fog duration, is designed to reflect the fact that highimpact heavy fogs become more serious around the Jiangsu region.
Using the observation data from 59 stations from 1961 to 2006 in Jiangsu Province，an analysis is made of the annual variation characteristics of heavy fog days.A further research on the generation, dissipation, and duration variation characteristics of heavy fog is conducted by means of the data from 8 stations from 1961 to 2006 The results show that the number of annual fog days increased from 1961, reached the peak in the early 1980s, and declined fast afterward; the heavy duration showed a marked increase trend, mainly the postponement of fog dissipation. A compositive impact index, including the effect of fog days and fog duration, is designed to reflect the fact that highimpact heavy fogs become more serious around the Jiangsu region.
2012, 40(2):268-273.
Abstract:
An analysis is made of two tornado events in Lingbi and Sixian counties, Anhui Province, by means of the conventional data, NCEP data, intensive observations, and Doppler radar data. The results show: the tornadoes occurred on the left of the low level jet at the intersection point of highhumidity center and vapor convergence center; before tornadoes appeared, the low level vertical wind shear was strong; the tornadoes occurred in the areas where the ground convergence was the strongest; there were clear vortex features and a midlevel cyclone in 10 to 20 minutes before tornado occurred; the Lingbi tornado appeared in the south of the storm with strong radar echoes under 3 km; the Sixian tornado appeared at the center of the banded radar echoes with strong splited and protruded echoes, and the mesocyclone top descended.
An analysis is made of two tornado events in Lingbi and Sixian counties, Anhui Province, by means of the conventional data, NCEP data, intensive observations, and Doppler radar data. The results show: the tornadoes occurred on the left of the low level jet at the intersection point of highhumidity center and vapor convergence center; before tornadoes appeared, the low level vertical wind shear was strong; the tornadoes occurred in the areas where the ground convergence was the strongest; there were clear vortex features and a midlevel cyclone in 10 to 20 minutes before tornado occurred; the Lingbi tornado appeared in the south of the storm with strong radar echoes under 3 km; the Sixian tornado appeared at the center of the banded radar echoes with strong splited and protruded echoes, and the mesocyclone top descended.
2012, 40(2):274-279.
Abstract:
Based on the routine weather chart data, the rainfall characteristics and circulation features of a continuous rainfall in the southern Jiangsu Province in early spring of 2009 are analyzed. It is shown that the consecutive rainfall had some unusual characteristics, such as prolonged duration, enormous precipitation, low maximum air temperature, and frequent thunderstorms. During the rainfall event, the upperlevel circulation over Eurasia in the middle or high latitudes came through three stages: Baikal trough type, blocking type, and one trough and one ridge type. Several shortwave troughs split up and moved toward east in midlatitudes of Asia, which ensured the sources of cold air. The Bengal trough was active; the subtropical high over the West Pacific was farther northern than normal; and the water vapor was transported mainly by the outer edge air flow of the subtropical high from the South China Sea and Philippine Sea. As cold and warm air interacted constantly on the lower Yangtze Valley, the consecutive rainfall event of 21 days long formed.
Based on the routine weather chart data, the rainfall characteristics and circulation features of a continuous rainfall in the southern Jiangsu Province in early spring of 2009 are analyzed. It is shown that the consecutive rainfall had some unusual characteristics, such as prolonged duration, enormous precipitation, low maximum air temperature, and frequent thunderstorms. During the rainfall event, the upperlevel circulation over Eurasia in the middle or high latitudes came through three stages: Baikal trough type, blocking type, and one trough and one ridge type. Several shortwave troughs split up and moved toward east in midlatitudes of Asia, which ensured the sources of cold air. The Bengal trough was active; the subtropical high over the West Pacific was farther northern than normal; and the water vapor was transported mainly by the outer edge air flow of the subtropical high from the South China Sea and Philippine Sea. As cold and warm air interacted constantly on the lower Yangtze Valley, the consecutive rainfall event of 21 days long formed.
2012, 40(2):280-284.
Abstract:
The data from the SinoJapanese cooperational experiment on atmosphereland interaction processes at Shouxian in the Huaihe River Basin are used to analysis the variations of wind speed, air temperature, relative humidity, and radiation before and during rainy season. Some micrometeorological properties in the nearsurface layer are studied. The results show that there was obvious diurnal variation in both air temperature and relative humidity with one peak pattern in dry season. With the onset of rainy season, the air temperature decreased, relative humidity increased, wind speed fluctuated significantly, and the diurnal variation of meteorological elements became less obvious. It is clearly shown that the latent heat flux was far larger than the sensible heat flux over the middle of the Huaihe River basin. The clear variation trends of micrometeorological elements in dry and rainy season have certain indicative significance for forecasting the beginning and ending of rainy season.
The data from the SinoJapanese cooperational experiment on atmosphereland interaction processes at Shouxian in the Huaihe River Basin are used to analysis the variations of wind speed, air temperature, relative humidity, and radiation before and during rainy season. Some micrometeorological properties in the nearsurface layer are studied. The results show that there was obvious diurnal variation in both air temperature and relative humidity with one peak pattern in dry season. With the onset of rainy season, the air temperature decreased, relative humidity increased, wind speed fluctuated significantly, and the diurnal variation of meteorological elements became less obvious. It is clearly shown that the latent heat flux was far larger than the sensible heat flux over the middle of the Huaihe River basin. The clear variation trends of micrometeorological elements in dry and rainy season have certain indicative significance for forecasting the beginning and ending of rainy season.
2012, 40(2):285-292.
Abstract:
Based on the statistical results of strong winds (above Grade 8 in Beaufort scale ) from 15 meteorological observation stations from 2000 to 2009, the spatialtemporal distribution feature of wind turbulence intensity at the Lianyungang’s coastal region is discussed with wind data from 6 wind gradient towers around the coastal region of Lianyungang from 2005 to 2007 The characteristics of strong wind turbulence intensity caused by different weather systems and their influence on wind farm are analyzed. The results show that the wind turbulence intensity has obvious seasonal change，larger in summer and smaller in winter, decreasing with increasing altitude; the influence of surface roughness over the sea on strong turbulence is different from that over land with breeze; wind and turbulence intensity may change suddenly in the same time in the tropical cyclone region; the strong turbulence appears usually above the altitude of 30 m over sea and near the ground on land respectively, which is also found in strong wind turbulence caused by different weather systems; and the characteristic value of 21% to 38% turbulence intensity exceeds the design criterion of the maximum turbulence intensity for fans at the altitude of fan wheels, which suggests that the parameter of fan maximum turbulence intensity should be adjusted to 0.31 to 0.41 around the coastal region of the central and northern parts of East China.
Based on the statistical results of strong winds (above Grade 8 in Beaufort scale ) from 15 meteorological observation stations from 2000 to 2009, the spatialtemporal distribution feature of wind turbulence intensity at the Lianyungang’s coastal region is discussed with wind data from 6 wind gradient towers around the coastal region of Lianyungang from 2005 to 2007 The characteristics of strong wind turbulence intensity caused by different weather systems and their influence on wind farm are analyzed. The results show that the wind turbulence intensity has obvious seasonal change，larger in summer and smaller in winter, decreasing with increasing altitude; the influence of surface roughness over the sea on strong turbulence is different from that over land with breeze; wind and turbulence intensity may change suddenly in the same time in the tropical cyclone region; the strong turbulence appears usually above the altitude of 30 m over sea and near the ground on land respectively, which is also found in strong wind turbulence caused by different weather systems; and the characteristic value of 21% to 38% turbulence intensity exceeds the design criterion of the maximum turbulence intensity for fans at the altitude of fan wheels, which suggests that the parameter of fan maximum turbulence intensity should be adjusted to 0.31 to 0.41 around the coastal region of the central and northern parts of East China.
2012, 40(2):293-298.
Abstract:
Based on the data of sunshine duration， cloud amount， surface vapor pressure， and precipitation of 11 meteorological stations in Shanghai， the temporal and spatial variation characteristics of sunshine duration and the influencing factors from 1960 to 2009 are analyzed using the linear trend， MannKendall test and other methods. The results indicate that annual sunshine duration in Shanghai reduced significantly in recent 50 years. In summer， autumn and winter， sunshine duration reduced significantly， but in spring， it changed insignificantly. The sunshine duration had an abrupt change in 1980. From 1983， the sunshine duration reduced significantly in Shanghai. Spatially， the sunshine duration reduced in the whole area in recent 50 years， more obvious in the northern parts than in the southern parts of Shanghai. There was significant negative correlation between annual sunshine duration and annual precipitation as well as annual precipitation days， so the increase of annual precipitation amount might contribute to the reduction of annual sunshine duration. There was basically significant negative correlation between seasonal sunshine duration and seasonal cloud amount， surface vapor pressure， and precipitation in four seasons. The increase of summer precipitation amount might contribute to the reduction of summer sunshine duration， and the increase of winter precipitation amount and surface vapor pressure might contribute to the reduction of winter sunshine duration.
Based on the data of sunshine duration， cloud amount， surface vapor pressure， and precipitation of 11 meteorological stations in Shanghai， the temporal and spatial variation characteristics of sunshine duration and the influencing factors from 1960 to 2009 are analyzed using the linear trend， MannKendall test and other methods. The results indicate that annual sunshine duration in Shanghai reduced significantly in recent 50 years. In summer， autumn and winter， sunshine duration reduced significantly， but in spring， it changed insignificantly. The sunshine duration had an abrupt change in 1980. From 1983， the sunshine duration reduced significantly in Shanghai. Spatially， the sunshine duration reduced in the whole area in recent 50 years， more obvious in the northern parts than in the southern parts of Shanghai. There was significant negative correlation between annual sunshine duration and annual precipitation as well as annual precipitation days， so the increase of annual precipitation amount might contribute to the reduction of annual sunshine duration. There was basically significant negative correlation between seasonal sunshine duration and seasonal cloud amount， surface vapor pressure， and precipitation in four seasons. The increase of summer precipitation amount might contribute to the reduction of summer sunshine duration， and the increase of winter precipitation amount and surface vapor pressure might contribute to the reduction of winter sunshine duration.
2012, 40(2):299-303.
Abstract:
Based on the data from 1982 to 2007 of air temperature and phenophases in Huhhot and Wuchuan, an analysis is made of the variation trends of plants, animals and the related hydrometeorological phenophases in spring and autumn, and their relations to climate warming. The results show: (1) The spring soil thaw was later in Huhhot than in Wuchuan, and other phenophase was earlier in Huhhot than in Wuchuan; but in autumn, the phenophases in Wuchuan were earlier than in Huhhot. The phenophase difference between Huhhot and Wuchuan was: Douyan appearance (disappearance) ＞hydrometeorological factors＞florescence (defoliation); the relationship between florescence (defoliation) dates in Huhhot and Wuchuan was positive significantly, and that of Douyan appearance (disappearance) was negative significantly, while that of hydrometeorological phenophases was not significant. (2) From 1982 to 2007, air temperature increased, the first flowering dates of plants advanced and the defoliating dates postponed, which have a strong relationship with temperature; the first appearance dates of Douyan in Huhhot advanced and the last appearance dates postponed, On the contrary in Wuchuan, there was a certain extent relationship with temperature; hydrometeorological phenophases also advanced in Spring and postponed in Autumn; and the relationship with temperature was not significant.
Based on the data from 1982 to 2007 of air temperature and phenophases in Huhhot and Wuchuan, an analysis is made of the variation trends of plants, animals and the related hydrometeorological phenophases in spring and autumn, and their relations to climate warming. The results show: (1) The spring soil thaw was later in Huhhot than in Wuchuan, and other phenophase was earlier in Huhhot than in Wuchuan; but in autumn, the phenophases in Wuchuan were earlier than in Huhhot. The phenophase difference between Huhhot and Wuchuan was: Douyan appearance (disappearance) ＞hydrometeorological factors＞florescence (defoliation); the relationship between florescence (defoliation) dates in Huhhot and Wuchuan was positive significantly, and that of Douyan appearance (disappearance) was negative significantly, while that of hydrometeorological phenophases was not significant. (2) From 1982 to 2007, air temperature increased, the first flowering dates of plants advanced and the defoliating dates postponed, which have a strong relationship with temperature; the first appearance dates of Douyan in Huhhot advanced and the last appearance dates postponed, On the contrary in Wuchuan, there was a certain extent relationship with temperature; hydrometeorological phenophases also advanced in Spring and postponed in Autumn; and the relationship with temperature was not significant.
2012, 40(2):304-309.
Abstract:
The operational system for thunder/lightning potential forecasting based on similar deviation is established by using VB and VC programming languages and MS SQL Server Database， on the basis of the thunder/lightning observation data of Ningxia and the forecasting products of ECMWF and T213. This operational system can give a similar discrimination of physical factors based on the objectively analogue circulation and affecting system automatic recognition. It can produce the forecasting results of circulation patterns and physical quantities in the coming 168 hours， in which the first 10/20 cases with minimum similar deviation were used as the “blueprint” for forecasting; and the system can also accomplish the making and distribution of thunder/lightning potential forecasting products by humanmachine interaction， which enhances the objectivity and automation of the thunder/lightning potential forecasting system. Moreover， it has the functions of thunder/lightning data querying， calculating， outputting， saving， loading， displaying， and so on. This system has become the main operational platform for the making and distribution of thunder/lightning potential forecasting in Ningxia.
The operational system for thunder/lightning potential forecasting based on similar deviation is established by using VB and VC programming languages and MS SQL Server Database， on the basis of the thunder/lightning observation data of Ningxia and the forecasting products of ECMWF and T213. This operational system can give a similar discrimination of physical factors based on the objectively analogue circulation and affecting system automatic recognition. It can produce the forecasting results of circulation patterns and physical quantities in the coming 168 hours， in which the first 10/20 cases with minimum similar deviation were used as the “blueprint” for forecasting; and the system can also accomplish the making and distribution of thunder/lightning potential forecasting products by humanmachine interaction， which enhances the objectivity and automation of the thunder/lightning potential forecasting system. Moreover， it has the functions of thunder/lightning data querying， calculating， outputting， saving， loading， displaying， and so on. This system has become the main operational platform for the making and distribution of thunder/lightning potential forecasting in Ningxia.
2012, 40(2):310-314.
Abstract:
Taking a fire accident in at a pharmacy company in Chongqing on the September 2006 as an example, the causes of the electrostatic fire accident are analyzed by using the meteorological ground observation data and water vapor content inferred from GPS/MAT data, in combination with the production processes of the company. The results show that the extreme weather condition of high temperature and low moisture (air vapour content being 0.5 g/cm3, and surface temperature above 40 ℃) is the precondition for the electrostatic fire; another important cause is the incorrect measures for electrostatic prevention, which made a great deal of static electricity accumulated, produced spark discharge, and then led to the burning of a large amount of volatile petroleum aether vapour. In order to decrease the occurrences of the like electrostatic fire accidents, some precaution suggestions are given.
Taking a fire accident in at a pharmacy company in Chongqing on the September 2006 as an example, the causes of the electrostatic fire accident are analyzed by using the meteorological ground observation data and water vapor content inferred from GPS/MAT data, in combination with the production processes of the company. The results show that the extreme weather condition of high temperature and low moisture (air vapour content being 0.5 g/cm3, and surface temperature above 40 ℃) is the precondition for the electrostatic fire; another important cause is the incorrect measures for electrostatic prevention, which made a great deal of static electricity accumulated, produced spark discharge, and then led to the burning of a large amount of volatile petroleum aether vapour. In order to decrease the occurrences of the like electrostatic fire accidents, some precaution suggestions are given.
2012, 40(2):315-318.
Abstract:
For lacking an accurate method of protection range calculation for the rolling sphere method in the lighting protection standards, a simple calculation method is presented, which is more precise, and easier and more convenient to use, better than the graphing method. A thorough analysis is made of the judgment of the protection range of the double lightning rods for any point from the aspects of both the influence scope of a single lightning rod and the coaction scope of the doublerod lightning protection. The method is devised through analyzing the judgment methods of protection range of two lightning arresters on buildings by means of both distance comparison and angle comparison methods. The calculation method can be applied easily in lighting protection service.
For lacking an accurate method of protection range calculation for the rolling sphere method in the lighting protection standards, a simple calculation method is presented, which is more precise, and easier and more convenient to use, better than the graphing method. A thorough analysis is made of the judgment of the protection range of the double lightning rods for any point from the aspects of both the influence scope of a single lightning rod and the coaction scope of the doublerod lightning protection. The method is devised through analyzing the judgment methods of protection range of two lightning arresters on buildings by means of both distance comparison and angle comparison methods. The calculation method can be applied easily in lighting protection service.
2012, 40(2):319-320.
Abstract:
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.