Volume 38,Issue 5,2010 Table of Contents
2010, 38(5):533-536.
Abstract:
The super typhoon “Saomai” (No.0608) landed at the coast of Cangnan County，Zhejiang Province on 10 August 2006， with the maximum wind force being up to 17 in the vicinity of its center and the central pressure being 920 hPa． It is the most powerful typhoon landed in Mainland China since 1949. A great deal of researches reveal that the weak environmental vertical wind speed shear, high sea surface temperature (SST), strong divergence at the upper level and remarkable vorticity near the center of Saomai, etc., play important roles in the rapidly intensifying process. Some researchers conducted invaluable work such as observational study, numerical simulation, and the causes of sudden intensity increase, etc. A review is made of the previous achievements, and the problems existing presently in this field are discussed.
The super typhoon “Saomai” (No.0608) landed at the coast of Cangnan County，Zhejiang Province on 10 August 2006， with the maximum wind force being up to 17 in the vicinity of its center and the central pressure being 920 hPa． It is the most powerful typhoon landed in Mainland China since 1949. A great deal of researches reveal that the weak environmental vertical wind speed shear, high sea surface temperature (SST), strong divergence at the upper level and remarkable vorticity near the center of Saomai, etc., play important roles in the rapidly intensifying process. Some researchers conducted invaluable work such as observational study, numerical simulation, and the causes of sudden intensity increase, etc. A review is made of the previous achievements, and the problems existing presently in this field are discussed.
2010, 38(5):537-542.
Abstract:
Using the summer (June to August) temperature data from 1951 to 2008, the temporal and spatial distribution features are studied by applying the methods of EOF， REOF， MannKendall trend test, etc. The results show that: (1) the eastern region of China in summer can be divided into three main types of spatial characteristic fields: uniform type, reverse northsouth type, positivenegativepositive type. (2) The summer mean temperature field can be divided into seven major regions: North China, Jianghuai region, Southeast China, South China, Southwest China, Northwest China, Northeast China. (3) Summer temperature in the eastern region of China showed an increasing trend after the first drop. (4) Summer temperature in the entire eastern region had a sudden change in 1997, with the temperature going up, and there were sudden changes in different years in each subregions.
Using the summer (June to August) temperature data from 1951 to 2008, the temporal and spatial distribution features are studied by applying the methods of EOF， REOF， MannKendall trend test, etc. The results show that: (1) the eastern region of China in summer can be divided into three main types of spatial characteristic fields: uniform type, reverse northsouth type, positivenegativepositive type. (2) The summer mean temperature field can be divided into seven major regions: North China, Jianghuai region, Southeast China, South China, Southwest China, Northwest China, Northeast China. (3) Summer temperature in the eastern region of China showed an increasing trend after the first drop. (4) Summer temperature in the entire eastern region had a sudden change in 1997, with the temperature going up, and there were sudden changes in different years in each subregions.
2010, 38(5):543-549.
Abstract:
By using the data from AWS stations, radar observations, reanalysed data of NCEP 1°×1°, adopting the relative coordinate system with Matsa moving, a case study is made of the abnormal rainstorm process for typhoon Matsa in August 2005. The results indicate: (1) The structure of typhoon Matsa is quite different from common typhoons, and the unusual distribution of rainfall is closely related with the special situation. (2) There was a number of rain clusters reproduced and moved in the first and second quadrant of the typhoon system, which were corresponding to the areas where there were strongweak interweaved radar echoes for updrafts and downdrafts occurred alternately; the frequent appearing and movement of mesoscale “rain cells” were key mechanisms for the generation of the severe rainstorm. (3) The areas where local unusual variability occurred due to special structure changes in certain quadrants of the typhoon system can be a significant indicator for the monitoring and forecasting of typhoon heavy rainfall.
By using the data from AWS stations, radar observations, reanalysed data of NCEP 1°×1°, adopting the relative coordinate system with Matsa moving, a case study is made of the abnormal rainstorm process for typhoon Matsa in August 2005. The results indicate: (1) The structure of typhoon Matsa is quite different from common typhoons, and the unusual distribution of rainfall is closely related with the special situation. (2) There was a number of rain clusters reproduced and moved in the first and second quadrant of the typhoon system, which were corresponding to the areas where there were strongweak interweaved radar echoes for updrafts and downdrafts occurred alternately; the frequent appearing and movement of mesoscale “rain cells” were key mechanisms for the generation of the severe rainstorm. (3) The areas where local unusual variability occurred due to special structure changes in certain quadrants of the typhoon system can be a significant indicator for the monitoring and forecasting of typhoon heavy rainfall.
2010, 38(5):550-557.
Abstract:
Based on the NCEP 1°×1°reanalysis data and Tianjin Doppler data, the causes of the heavy rainfall happened in Tangshan and Tianjin between 14 and 15 July 2008 is analyzed, and the simulation with the PSU/NCAR MM5 model is made to verify the precision of the analysis. The results show that the heavy rainfall event occurred under the background of the interaction of mid and lowlatitude systems, caused by the upper trough on 700 hPa, low vortex on 850 hPa, and mesoscale convergence line in the boundarylayer. The vapor was delivered mainly by the low jet. The lowlevel convergence, upperlevel divergence, and lifting motion near the front were dynamical mechanisms that make the low vortex developed. The pulsatory strengthening of the southwest jet stream caused by the cold air from the midlevel was related to the amplifying of heavy rainfall. The major precipitation echoes of the heavy rainfall were eddy and band echoes.
Based on the NCEP 1°×1°reanalysis data and Tianjin Doppler data, the causes of the heavy rainfall happened in Tangshan and Tianjin between 14 and 15 July 2008 is analyzed, and the simulation with the PSU/NCAR MM5 model is made to verify the precision of the analysis. The results show that the heavy rainfall event occurred under the background of the interaction of mid and lowlatitude systems, caused by the upper trough on 700 hPa, low vortex on 850 hPa, and mesoscale convergence line in the boundarylayer. The vapor was delivered mainly by the low jet. The lowlevel convergence, upperlevel divergence, and lifting motion near the front were dynamical mechanisms that make the low vortex developed. The pulsatory strengthening of the southwest jet stream caused by the cold air from the midlevel was related to the amplifying of heavy rainfall. The major precipitation echoes of the heavy rainfall were eddy and band echoes.
2010, 38(5):558-564.
Abstract:
The conventional observation, ECMWF model， and NCEP/NCAR data are used in the diagnostic analysis of the circulation pattern and the frontogenesis function for the longduration, highintensity and widerange frozen weather occurred in January and February 2008. The results show that the continuous frozen disaster was a process of strong frontogenesis resulted from the cold front moving to Guizhou from north, northeast, or northwest, persisted for long time steadily, under the general circulation of two blocking highs over the Ural and Aleutian at the midhigh latitudes in the Northern Hemisphere. The north and south branch fronts were further south and favorite to the cold air moving to the south, so the quasistationary front produced frontogenesis ceaselessly and remained in the western Guizhou. The dynamic mechanisms of causing snowstorms in the eastern Guizhou include upperlevel divergence, lowerlevel convergence, and their responses to strong ascending motion and cyclonic vorticity. The southwest air current in front of Southern Trough and the terrainblocked movement of cold air are important for the emergence and development of the process.
The conventional observation, ECMWF model， and NCEP/NCAR data are used in the diagnostic analysis of the circulation pattern and the frontogenesis function for the longduration, highintensity and widerange frozen weather occurred in January and February 2008. The results show that the continuous frozen disaster was a process of strong frontogenesis resulted from the cold front moving to Guizhou from north, northeast, or northwest, persisted for long time steadily, under the general circulation of two blocking highs over the Ural and Aleutian at the midhigh latitudes in the Northern Hemisphere. The north and south branch fronts were further south and favorite to the cold air moving to the south, so the quasistationary front produced frontogenesis ceaselessly and remained in the western Guizhou. The dynamic mechanisms of causing snowstorms in the eastern Guizhou include upperlevel divergence, lowerlevel convergence, and their responses to strong ascending motion and cyclonic vorticity. The southwest air current in front of Southern Trough and the terrainblocked movement of cold air are important for the emergence and development of the process.
2010, 38(5):565-571.
Abstract:
To provide reference for rainstorm forecast, two torrential rain cases happened in the western Guangdong Province are diagnosed on the basis of NCEP/NCAR reanalysis data and observational data. The results indicate: Both of the two processes happened at a favorable circulation background, integrating with rich water vapor, strong vertical ascending motion， and unstable atmosphere stratification. The rainstorm area corresponded well with the negative center of vapor flux divergence, the highvalue area and the denseisoline zone of 〖WTBX〗θ〖WTBZ〗se at 850 hPa, and the highvalue centers of the vertical helicity and the vertical velocity. The storm intensity also matched quite well with the physical quantities in the two rains.
To provide reference for rainstorm forecast, two torrential rain cases happened in the western Guangdong Province are diagnosed on the basis of NCEP/NCAR reanalysis data and observational data. The results indicate: Both of the two processes happened at a favorable circulation background, integrating with rich water vapor, strong vertical ascending motion， and unstable atmosphere stratification. The rainstorm area corresponded well with the negative center of vapor flux divergence, the highvalue area and the denseisoline zone of 〖WTBX〗θ〖WTBZ〗se at 850 hPa, and the highvalue centers of the vertical helicity and the vertical velocity. The storm intensity also matched quite well with the physical quantities in the two rains.
2010, 38(5):572-576.
Abstract:
By using the data from automatic ground stations, radar and NCEP reanalysis，the causes and thermodynamic conditions of a heavy rainfall event occurred in the centralsouthern Fujian on 19 April 2009 are analyzed. The results show that there were active mesoscale rain bands during this process; the mesoscale convergence zone at ground was a direct influencing factor; the southwest lowlevel jet provided water vapor for the occurrence and development of strong convection in the warm zone; the lowlevel warm air advection and highlevel cold air advection made unstable energy built up, and provided necessary energy for convection to develop.
By using the data from automatic ground stations, radar and NCEP reanalysis，the causes and thermodynamic conditions of a heavy rainfall event occurred in the centralsouthern Fujian on 19 April 2009 are analyzed. The results show that there were active mesoscale rain bands during this process; the mesoscale convergence zone at ground was a direct influencing factor; the southwest lowlevel jet provided water vapor for the occurrence and development of strong convection in the warm zone; the lowlevel warm air advection and highlevel cold air advection made unstable energy built up, and provided necessary energy for convection to develop.
2010, 38(5):577-580.
Abstract:
Using the conventional meteorological data, the NCEP reanalyzed data, in combination with Huangshan Doppler radar observational data, the hailstorm occurred in February 2009 in the Huangshan Mountain area is studied. The results indicate: (1) The hailstorm, having the feature of multiple convective cells, was induced by an upperlevel jet and a merging process of cumulus clouds. (2) The hailstorms occurring in early in spring have common features of hailstorms, and also have obvious seasonal feature: the combination emissivity is also very high, but because the column temperature is relatively low, compared with early summer hailstorms, the vertical liquid water content is smaller, and the height of -20 ℃ was 1 to 2 kilometers lower.
Using the conventional meteorological data, the NCEP reanalyzed data, in combination with Huangshan Doppler radar observational data, the hailstorm occurred in February 2009 in the Huangshan Mountain area is studied. The results indicate: (1) The hailstorm, having the feature of multiple convective cells, was induced by an upperlevel jet and a merging process of cumulus clouds. (2) The hailstorms occurring in early in spring have common features of hailstorms, and also have obvious seasonal feature: the combination emissivity is also very high, but because the column temperature is relatively low, compared with early summer hailstorms, the vertical liquid water content is smaller, and the height of -20 ℃ was 1 to 2 kilometers lower.
2010, 38(5):581-587.
Abstract:
The atmospheric water vapor retrieval technology based on the 940nm nearinfrared (NIR) absorption region and near window bands began in the 1980s. The algorithm of water vapor derivations is mainly based on the absorption difference theory. The characteristics and problems of this algorithm developed by several researchers are summarized, and some experiments on NIR water vapor retrieval are conducted by using the China’s satellite data. Of these results, the smallest error is 0.04 g/cm2. This provides a compact basis for the operational algorithm developing of total precipitation water (TPW) over land based on the future FY3/MERSI.
The atmospheric water vapor retrieval technology based on the 940nm nearinfrared (NIR) absorption region and near window bands began in the 1980s. The algorithm of water vapor derivations is mainly based on the absorption difference theory. The characteristics and problems of this algorithm developed by several researchers are summarized, and some experiments on NIR water vapor retrieval are conducted by using the China’s satellite data. Of these results, the smallest error is 0.04 g/cm2. This provides a compact basis for the operational algorithm developing of total precipitation water (TPW) over land based on the future FY3/MERSI.
2010, 38(5):588-593.
Abstract:
Precipitation is a common phenomenon in the atmosphere. Owing to the difficulty of high spatial and temporal resolution cloud monitoring on ground, various remote sensing techniques are used in precipitation cloud monitoring. An introduction is made to the principles, techniques, and methods of rainfall cloud detection techniques, mainly the groundbased Doppler weather radar, and meteorological satellites. The findings and advances in the researches on the identification of cloud systems/clusters for different types of precipitation (including convective, stratoformcloud, and mixingcloud precipitation) with neural network, threshold, and wavelet analysis methods in China and abroad are reviewed, with emphasis on the threshold method. The problems encountered in use of both radar and satellite detection data are discussed.
Precipitation is a common phenomenon in the atmosphere. Owing to the difficulty of high spatial and temporal resolution cloud monitoring on ground, various remote sensing techniques are used in precipitation cloud monitoring. An introduction is made to the principles, techniques, and methods of rainfall cloud detection techniques, mainly the groundbased Doppler weather radar, and meteorological satellites. The findings and advances in the researches on the identification of cloud systems/clusters for different types of precipitation (including convective, stratoformcloud, and mixingcloud precipitation) with neural network, threshold, and wavelet analysis methods in China and abroad are reviewed, with emphasis on the threshold method. The problems encountered in use of both radar and satellite detection data are discussed.
2010, 38(5):594-598.
Abstract:
Based on the lightning activity characteristics of Qingdao, as well as comprehensive lightning monitoring and warning technology, the Nanjing University of Information Science & Technology and the Qingdao Meteorological Bureau developed cooperatively a lightning monitoring and warning system (NUISTLMWS). The functions of the system include the realtime monitoring and the 0 to 1 hour lightning warning, as well as the management of historical data. During the 2008 Beijing Olympic Games, in the Qingdao sailing venue, NUISTLMWS was put to use experimentally and provided useful service information for meteorological support. The warning results of three thunderstorms are analyzed, and the results show that this system performed satisfactorily in the 0 to 1 hour lightning warning.
Based on the lightning activity characteristics of Qingdao, as well as comprehensive lightning monitoring and warning technology, the Nanjing University of Information Science & Technology and the Qingdao Meteorological Bureau developed cooperatively a lightning monitoring and warning system (NUISTLMWS). The functions of the system include the realtime monitoring and the 0 to 1 hour lightning warning, as well as the management of historical data. During the 2008 Beijing Olympic Games, in the Qingdao sailing venue, NUISTLMWS was put to use experimentally and provided useful service information for meteorological support. The warning results of three thunderstorms are analyzed, and the results show that this system performed satisfactorily in the 0 to 1 hour lightning warning.
2010, 38(5):599-604.
Abstract:
By analyzing the synchronously observed temperature data (January, April, July 2008) from the new and old meteorological observation stations in Dong’e, it is found out that temperature in the old station was higher than that in the new station because of urban heat island effect, which was more obvious at night than in the daytime, more obvious in winter， spring， and autumn than in summer. The urban heat island effect decreased minimum temperature and so reduced the diurnal temperature range at the old station, which thus increased the statistical temperature. The analysis shows that temperature in the old station had a positive correlation with that in the new station; meanwhile there was obvious difference between temperatures in the old and new stations. As a result, there is discontinuity in the air temperature data from the old and new stations. The old temperature measurements cannot be used along with the new to represent the temperature of Dong’e without appropriate correction.
By analyzing the synchronously observed temperature data (January, April, July 2008) from the new and old meteorological observation stations in Dong’e, it is found out that temperature in the old station was higher than that in the new station because of urban heat island effect, which was more obvious at night than in the daytime, more obvious in winter， spring， and autumn than in summer. The urban heat island effect decreased minimum temperature and so reduced the diurnal temperature range at the old station, which thus increased the statistical temperature. The analysis shows that temperature in the old station had a positive correlation with that in the new station; meanwhile there was obvious difference between temperatures in the old and new stations. As a result, there is discontinuity in the air temperature data from the old and new stations. The old temperature measurements cannot be used along with the new to represent the temperature of Dong’e without appropriate correction.
2010, 38(5):605-608.
Abstract:
By means of 3D visualization technology, the 3D surface reconstruction algorithm and the 3D body reconstruction algorithm are introduced into the analysis of weather radar echo images, and in combination with the weather radar 3D networking mosaic products developed by the State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Science, the 3D display of the typhoon “Sepat” is realized. The results indicate that compared with single radar products, the 3D mosaic products have wider coverage in time and space; compared with 2D display, 3D Visualization has greater advantages in analyzing the spatial distribution of radar echoes, especially in analyzing the structure of radar echoes. The 3D visualization technology combined with 3D mosaic products provides a more comprehensive way for radar echo analysis.
By means of 3D visualization technology, the 3D surface reconstruction algorithm and the 3D body reconstruction algorithm are introduced into the analysis of weather radar echo images, and in combination with the weather radar 3D networking mosaic products developed by the State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Science, the 3D display of the typhoon “Sepat” is realized. The results indicate that compared with single radar products, the 3D mosaic products have wider coverage in time and space; compared with 2D display, 3D Visualization has greater advantages in analyzing the spatial distribution of radar echoes, especially in analyzing the structure of radar echoes. The 3D visualization technology combined with 3D mosaic products provides a more comprehensive way for radar echo analysis.
2010, 38(5):609-612.
Abstract:
The PCVSAT singlestation receiving system is used widely in meteorological stations at all levels in China to receive meteorological satellite broadcast information. A failure of the singlestation receiving system will affect the normal reception of meteorological data, leading to the loss of meteorological data. In order to ensure the timely and complete receiving of meteorological data, an automatic meteorological data downloading system was developed. The system is based on a modern broadband network transmission system, using the C/S model to build. In case of receiving system failure, the downloading system can recover timely and rapidly meteorological data. In addition, for the stations without the singlestation receiving system, the system can be used to receive in real time the meteorological data of the system.
The PCVSAT singlestation receiving system is used widely in meteorological stations at all levels in China to receive meteorological satellite broadcast information. A failure of the singlestation receiving system will affect the normal reception of meteorological data, leading to the loss of meteorological data. In order to ensure the timely and complete receiving of meteorological data, an automatic meteorological data downloading system was developed. The system is based on a modern broadband network transmission system, using the C/S model to build. In case of receiving system failure, the downloading system can recover timely and rapidly meteorological data. In addition, for the stations without the singlestation receiving system, the system can be used to receive in real time the meteorological data of the system.
2010, 38(5):613-619.
Abstract:
Using the radiosonde data from 11 meteorological stations and precipitation data from 84 meteorological stations over Jiangxi Province from 1959 to 2007, according to the synoptic meteorological principles, computation and analysis are conducted with the mathematical statistic method on the total water vapor, total cloud water, the number of water vapor exchanges, water vapor turnover rate, actual total precipitation, etc. The results indicate that the maximum value of total water vapor and total cloud water appeared in June (in 1975), the minimum value appeared in December (in 1963); maximum total cloud water was found in the area with moderate drought frequency, and minimum total cloud water in the area with low drought frequency. The number of water vapor exchanges was averagely 7.23 times per each month, and the water vapor turnover rate was averagely 4.22 days for each time. The correlations between total precipitation and total water vapor, total cloud water are good, and the annual variation exhibited a multipeak pattern. The geographic distribution of the total water vapor and total cloud water shows a tendency of high in the north and low in the south.
Using the radiosonde data from 11 meteorological stations and precipitation data from 84 meteorological stations over Jiangxi Province from 1959 to 2007, according to the synoptic meteorological principles, computation and analysis are conducted with the mathematical statistic method on the total water vapor, total cloud water, the number of water vapor exchanges, water vapor turnover rate, actual total precipitation, etc. The results indicate that the maximum value of total water vapor and total cloud water appeared in June (in 1975), the minimum value appeared in December (in 1963); maximum total cloud water was found in the area with moderate drought frequency, and minimum total cloud water in the area with low drought frequency. The number of water vapor exchanges was averagely 7.23 times per each month, and the water vapor turnover rate was averagely 4.22 days for each time. The correlations between total precipitation and total water vapor, total cloud water are good, and the annual variation exhibited a multipeak pattern. The geographic distribution of the total water vapor and total cloud water shows a tendency of high in the north and low in the south.
2010, 38(5):620-624.
Abstract:
With the climatographies and MICAPS conventional weather charts from 34 meteorological stations from 1980 to 2004, the spatial and temporal distribution, circulation patterns, and moving paths of hail are analyzed．The results show that the eastern part of Chongqing had more hails than the western part，and the northeastern part had the most; the number of hail days varied unevenly in the past 50 years, with significant increasing after the 1980s; the intermonthly variation showed a doublepeak pattern, one peak between April and May and the other between July and August. Hails in Chongqing can mainly attribute to local convection, and then to systematic convection. The circulation background patterns for systematic convection can be divided into three types: vortex, northwest airflow, and upper trough, among which the northwest airflow is the major influencing system (accounting for about 62%). The moving paths of hails and some suggestions for improving the effectiveness of weather modification are given.
With the climatographies and MICAPS conventional weather charts from 34 meteorological stations from 1980 to 2004, the spatial and temporal distribution, circulation patterns, and moving paths of hail are analyzed．The results show that the eastern part of Chongqing had more hails than the western part，and the northeastern part had the most; the number of hail days varied unevenly in the past 50 years, with significant increasing after the 1980s; the intermonthly variation showed a doublepeak pattern, one peak between April and May and the other between July and August. Hails in Chongqing can mainly attribute to local convection, and then to systematic convection. The circulation background patterns for systematic convection can be divided into three types: vortex, northwest airflow, and upper trough, among which the northwest airflow is the major influencing system (accounting for about 62%). The moving paths of hails and some suggestions for improving the effectiveness of weather modification are given.
17 Effect of Winds on Trajectory of BL1A HailSuppressing/RainEnhancing Rockets and Its Correction
2010, 38(5):625-628.
Abstract:
The actual trajectory of the BL1A hailsuppressing/rainenhancing rocket has a major deviation from the curve provided by its manufacturer at high wind speed: the elevation angle of the shell body will increase when the rocket is launched downwind and decrease when the rocket is launched upwind; the shell body will slip rightward when there is crosswind from right side, and slip leftward when there is crosswind from left side. Also, the drifting of rockets in flight at high wind speeds will lead to the failure of rocket seeding into the effective part of the clouds. There are even cases in which rockets went beyond their safe limits, resulting in potential safety problems. A BL1A rocket ballistic curve corresponding to the standardized angle of departure is presented based on the experiences from operations carried out in recent years, and the wind correction is conducted by adjusting the angle of departure and the azimuth according to the condition of the ground and upperlevel wind speed and direction. The revised angle of departure can reach such accuracy that the flying altitude and the direction of the rocket can meet the requirements of the operations when catalyst is being seeded, and its selfdestruction point can be controlled within the expected range.
The actual trajectory of the BL1A hailsuppressing/rainenhancing rocket has a major deviation from the curve provided by its manufacturer at high wind speed: the elevation angle of the shell body will increase when the rocket is launched downwind and decrease when the rocket is launched upwind; the shell body will slip rightward when there is crosswind from right side, and slip leftward when there is crosswind from left side. Also, the drifting of rockets in flight at high wind speeds will lead to the failure of rocket seeding into the effective part of the clouds. There are even cases in which rockets went beyond their safe limits, resulting in potential safety problems. A BL1A rocket ballistic curve corresponding to the standardized angle of departure is presented based on the experiences from operations carried out in recent years, and the wind correction is conducted by adjusting the angle of departure and the azimuth according to the condition of the ground and upperlevel wind speed and direction. The revised angle of departure can reach such accuracy that the flying altitude and the direction of the rocket can meet the requirements of the operations when catalyst is being seeded, and its selfdestruction point can be controlled within the expected range.
2010, 38(5):629-634.
Abstract:
The design ideas， technical framework， main functions， and application of the Shenzhen Localized Warning System (LWS) for Severe Weather is introduced The system can display a wide range of integrated exploration data and nowcasting products， check and rank (meritbased) the quantitative precipitation forecast products， prompt automatically the formation of LWS areas in accordance with the observation and extrapolation forecasting， forming the LWS areas by free combination of subareas The system links the distribution channels automatically， producing LWS products simultaneously and releasing products through different distribution channels at the same time The system realized the highdegree integration of weather forecasting/earlywarning technology， the earlywarning product development platform， and the earlywarning product distribution system
The design ideas， technical framework， main functions， and application of the Shenzhen Localized Warning System (LWS) for Severe Weather is introduced The system can display a wide range of integrated exploration data and nowcasting products， check and rank (meritbased) the quantitative precipitation forecast products， prompt automatically the formation of LWS areas in accordance with the observation and extrapolation forecasting， forming the LWS areas by free combination of subareas The system links the distribution channels automatically， producing LWS products simultaneously and releasing products through different distribution channels at the same time The system realized the highdegree integration of weather forecasting/earlywarning technology， the earlywarning product development platform， and the earlywarning product distribution system
2010, 38(5):635-639.
Abstract:
A regional refined atmospheric environmental emergency response system, targeting at the sudden diffusion of atmospheric pollutants, such as chemical accidents, was developed by the National Meteorological Center. The modelling system, based on the atmosphere dispersion model HYSPLIT_4 and the numerical model WRF, can produce such forecast products as trajectory, concentration, and deposition forecasts with the refined GIS information. The modelling system is available for running on demand and maintained in a state of readiness so that the requests for products can be satisfied quickly. An example of atmospheric environmental emergency response is given, and the results show that the modelling system is able to provide instructive products in case of emergency, such as an accident of toxicgas teakage.
A regional refined atmospheric environmental emergency response system, targeting at the sudden diffusion of atmospheric pollutants, such as chemical accidents, was developed by the National Meteorological Center. The modelling system, based on the atmosphere dispersion model HYSPLIT_4 and the numerical model WRF, can produce such forecast products as trajectory, concentration, and deposition forecasts with the refined GIS information. The modelling system is available for running on demand and maintained in a state of readiness so that the requests for products can be satisfied quickly. An example of atmospheric environmental emergency response is given, and the results show that the modelling system is able to provide instructive products in case of emergency, such as an accident of toxicgas teakage.
2010, 38(5):640-644.
Abstract:
To study the atmospheric wind field characteristics in the 100km Gale Area in Xinjiang, the Institute of Urumqi Desert Meteorology of the China Meteorological Administration carried out an observation experiment from 25 March to 8 April 2009 at Shisanjianfang Station, which is within the 100km Gale Area in Xinjiang. The diurnal and daytoday variations of the lowerlevel wind fields are analyzed by using the wind profile data from the Airda3000Q windprofiler radar system. The results show:（1） in this area, west and north winds prevailed, and longitudedirection winds were evidently greater than latitudedirection winds on the same time; (2) the horizontal wind speeds below 1500 meters were in general obviously greater that those above 1500 meters, influenced by the funneling effect of the Qijiaojing pass; (3) the analysis of the average profiles in day and night time shows that the nighttime wind speed was greater than that of the whole day, but the change trends with height were basically same for both, with the wind speed being decreasing with the increasing height below 1500 meters and increasing above 1500 meters; (4) the high temporalspatial resolution data of wind profiles were obtained by means of the Airda3000Q boundary layer wind profiler radar, which can be used to monitor the occurrence and change processes of gale weather.
To study the atmospheric wind field characteristics in the 100km Gale Area in Xinjiang, the Institute of Urumqi Desert Meteorology of the China Meteorological Administration carried out an observation experiment from 25 March to 8 April 2009 at Shisanjianfang Station, which is within the 100km Gale Area in Xinjiang. The diurnal and daytoday variations of the lowerlevel wind fields are analyzed by using the wind profile data from the Airda3000Q windprofiler radar system. The results show:（1） in this area, west and north winds prevailed, and longitudedirection winds were evidently greater than latitudedirection winds on the same time; (2) the horizontal wind speeds below 1500 meters were in general obviously greater that those above 1500 meters, influenced by the funneling effect of the Qijiaojing pass; (3) the analysis of the average profiles in day and night time shows that the nighttime wind speed was greater than that of the whole day, but the change trends with height were basically same for both, with the wind speed being decreasing with the increasing height below 1500 meters and increasing above 1500 meters; (4) the high temporalspatial resolution data of wind profiles were obtained by means of the Airda3000Q boundary layer wind profiler radar, which can be used to monitor the occurrence and change processes of gale weather.
2010, 38(5):645-648.
Abstract:
The features of VDRAS products at the initial stage of thunderstorms during the 2008 Olympic Games are analyzed. It is concluded that collision among gust fronts can cause thunderstorms. The strong temperature gradients of VDRAS mean that a gust front will be separated from its major cell. Meanwhile, the intensified cold center means that the thunderstorm will develop. The VDRAS products are verified by means of the wind profile and AWS (Automatic Weather Station) data from Haidian. The results indicate that the wind direction of VDRAS from 0.18 to 1.6 km of height were the same as the profile, but the wind speed was smaller. Wind direction and wind speed from 1.6 to 2.8 km were the same as the profile. The wind direction of VDRAS from 2.8 to 3.5 km was also the same as the profile, but the speed was sometime smaller. In addition, the temperature of VDRAS was about 3 to 4 ℃ higher than that of AWS.
The features of VDRAS products at the initial stage of thunderstorms during the 2008 Olympic Games are analyzed. It is concluded that collision among gust fronts can cause thunderstorms. The strong temperature gradients of VDRAS mean that a gust front will be separated from its major cell. Meanwhile, the intensified cold center means that the thunderstorm will develop. The VDRAS products are verified by means of the wind profile and AWS (Automatic Weather Station) data from Haidian. The results indicate that the wind direction of VDRAS from 0.18 to 1.6 km of height were the same as the profile, but the wind speed was smaller. Wind direction and wind speed from 1.6 to 2.8 km were the same as the profile. The wind direction of VDRAS from 2.8 to 3.5 km was also the same as the profile, but the speed was sometime smaller. In addition, the temperature of VDRAS was about 3 to 4 ℃ higher than that of AWS.
22 Characteristics of Climate Change in Ankang Reservoir Upstream Basin before and after Impoundment
2010, 38(5):649-654.
Abstract:
Based on the data of precipitation, temperature, evaporation, etc., from meteorological stations over the drainage areas of the Shaanxi Ankang Reservoir, an analysis is made of the characteristics of climate change over in the drainage areas of the reservoir. The results indicate that annual precipitation reduced year by year; annual average temperature was increasing year by year; annual evapotranspiration had a negative trend; annual and main flood season precipitation, rainy days, heavy rain days, the probability of extreme heavy precipitation and evapotranspiration appeared much less after reservoir impoundment than before. The extent of warming in winter was most obvious. The main flood season and annual precipitation, average temperature, and evapotranspiration in winter before and after impoundment show significant differences. The natural runoff of the Hanjiang River had a negative trend in the past 45 years and rainfall influenced runoff significantly.
Based on the data of precipitation, temperature, evaporation, etc., from meteorological stations over the drainage areas of the Shaanxi Ankang Reservoir, an analysis is made of the characteristics of climate change over in the drainage areas of the reservoir. The results indicate that annual precipitation reduced year by year; annual average temperature was increasing year by year; annual evapotranspiration had a negative trend; annual and main flood season precipitation, rainy days, heavy rain days, the probability of extreme heavy precipitation and evapotranspiration appeared much less after reservoir impoundment than before. The extent of warming in winter was most obvious. The main flood season and annual precipitation, average temperature, and evapotranspiration in winter before and after impoundment show significant differences. The natural runoff of the Hanjiang River had a negative trend in the past 45 years and rainfall influenced runoff significantly.
2010, 38(5):655-658.
Abstract:
It is always difficult to observe clouds at night with the naked eye when there is no light, starlight or moonlight. The routine cloud observation at night is to observe clouds in accordance with the observer’s vision in combination with the density of starlight, air clarity, cloud color and movement speed, weather phenomena and measured cloud height, as well as the observation of cloud condition at dusk. In order to identify the cloud condition at the located meteorological station rapidly and accurately at night, an introduction is made to the application of advanced apparatuses in assisting cloud observation, such as the data of atmospheric radiation, atmospheric electric field, meteorological satellite cloud pictures, and Doppler weather radar echoes, which can better cover the shortages in cloud observation during night time with the naked eye.
It is always difficult to observe clouds at night with the naked eye when there is no light, starlight or moonlight. The routine cloud observation at night is to observe clouds in accordance with the observer’s vision in combination with the density of starlight, air clarity, cloud color and movement speed, weather phenomena and measured cloud height, as well as the observation of cloud condition at dusk. In order to identify the cloud condition at the located meteorological station rapidly and accurately at night, an introduction is made to the application of advanced apparatuses in assisting cloud observation, such as the data of atmospheric radiation, atmospheric electric field, meteorological satellite cloud pictures, and Doppler weather radar echoes, which can better cover the shortages in cloud observation during night time with the naked eye.
2010, 38(5):659-660.
Abstract:
Based on the parallel observation data of manual and automatic observations from 5 basic stations from 2003 to 2007, the influence of calibration/replacement of temperature and humidity sensors on the differences between automaticmanual observations is studied. The results indicate: there were two different differences after calibrating or replacing temperature and humidity sensors. It is essential for singlestation data correction to find the abrupt change points of these differences.
Based on the parallel observation data of manual and automatic observations from 5 basic stations from 2003 to 2007, the influence of calibration/replacement of temperature and humidity sensors on the differences between automaticmanual observations is studied. The results indicate: there were two different differences after calibrating or replacing temperature and humidity sensors. It is essential for singlestation data correction to find the abrupt change points of these differences.
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.