Volume 37,Issue 4,2009 Table of Contents
2009, 37(4):385-391.
Abstract:
The influence of middlelatitude cold air and topographic forcing on the abnormally severe rainfall event induced by a typhoon depression in Jiangxi Province on 2 to 4 September 2005 is analyzed by using the conventional and intensive observational data, the new atmospheric probing data (including automatic weather station data, lightning localization data, radar images, satellite images), and NCEP reanalysis data. The results show that under the background condition of the subtropical high confronting the land high in the Western China, the middlelatitude weak cold air invading the northern part of the typhoon depression from below unceasingly at the 850 hPa level led to the strengthening of the NE current on its north side; with the main cold air entering the area south of Jiangsu and Anhui provinces from the middle latitude, its barotropic structure transformed slowly into the baroclinic state of “warm in the east and cold west”, and the horizontal distribution of the total energy also changed from spiral vortex to NESW structure, which confirms that the supplement of baroclinic disturbance energy is advantageous to the longtime maintenance of the typhoon low; the analysis of the barotropic part of wet potential vorticity indicates that it changed from the convective stability to the convective instability during the disappearing period of the typhoon low; the strengthening of the energy front in the planet boundarylayer triggered the generation of the mesoβ scale convection system, which produced the severe thunderstorm weather; the severe precipitation mainly distributed on the windward slope east of the Dabie and Jiuling mountains, which demonstrates that the orographic lifting and convergence effect contributed greatly to precipitation enhancement.
The influence of middlelatitude cold air and topographic forcing on the abnormally severe rainfall event induced by a typhoon depression in Jiangxi Province on 2 to 4 September 2005 is analyzed by using the conventional and intensive observational data, the new atmospheric probing data (including automatic weather station data, lightning localization data, radar images, satellite images), and NCEP reanalysis data. The results show that under the background condition of the subtropical high confronting the land high in the Western China, the middlelatitude weak cold air invading the northern part of the typhoon depression from below unceasingly at the 850 hPa level led to the strengthening of the NE current on its north side; with the main cold air entering the area south of Jiangsu and Anhui provinces from the middle latitude, its barotropic structure transformed slowly into the baroclinic state of “warm in the east and cold west”, and the horizontal distribution of the total energy also changed from spiral vortex to NESW structure, which confirms that the supplement of baroclinic disturbance energy is advantageous to the longtime maintenance of the typhoon low; the analysis of the barotropic part of wet potential vorticity indicates that it changed from the convective stability to the convective instability during the disappearing period of the typhoon low; the strengthening of the energy front in the planet boundarylayer triggered the generation of the mesoβ scale convection system, which produced the severe thunderstorm weather; the severe precipitation mainly distributed on the windward slope east of the Dabie and Jiuling mountains, which demonstrates that the orographic lifting and convergence effect contributed greatly to precipitation enhancement.
2009, 37(4):392-397.
Abstract:
Numerical simulation is made on the heavy rainfall over the Huaihe valley on 3 to 4 July 2003 using the PSU/NCAR MM5 model. It is revealed that the MM5 model performed quite well in simulating and can provide highresolution data for diagnosis. The mesoαscale and mesoβscale convective systems of about 100 km can be simulated out by the MM5 model, but the model has a limited capability in simulating the mesoβ(γ)scale systems of smaller scales or more strongly developed systems. The direct reason of the heavy rainfall event is the rapid development of the about 100 km long mesoβscale convergence zone at the lower levels, which is validated by the highresolution data provided by the MM5 model. The mechanisms and the 3D structure of the mesoscale convergence zone are obtained by the diagnostic analysis of the physical quantity field characteristics.
Numerical simulation is made on the heavy rainfall over the Huaihe valley on 3 to 4 July 2003 using the PSU/NCAR MM5 model. It is revealed that the MM5 model performed quite well in simulating and can provide highresolution data for diagnosis. The mesoαscale and mesoβscale convective systems of about 100 km can be simulated out by the MM5 model, but the model has a limited capability in simulating the mesoβ(γ)scale systems of smaller scales or more strongly developed systems. The direct reason of the heavy rainfall event is the rapid development of the about 100 km long mesoβscale convergence zone at the lower levels, which is validated by the highresolution data provided by the MM5 model. The mechanisms and the 3D structure of the mesoscale convergence zone are obtained by the diagnostic analysis of the physical quantity field characteristics.
2009, 37(4):398-406.
Abstract:
An analysis is made of the structural characteristics of the convective clouds and precipitation on 25 to 26 June in 2005, by using a variety of observation and remote sensing data and the favorable surrounding conditions by using NCEP reanalysis data and real wind data. The results show that some mesoscale convective cloud clusters underwent the development of more than 10 hours, and TBB decreased to －90 degrees，which led to the inhomogeneous rainfall distribution in both time and space. The convective clouds had prominent microphysical structural characteristics, which had the high content of ice particles at the upper level and more plentiful cloud water. The seederfeeder mechanism was playing the major role. The “doublepeek” profile structure of convective precipitation shows that the warm rain process was very strong in MCC. The surrounding conditions were very useful for the formation of MCC and the convective storm： the water vapor transmitted and converged by the strong southwest low level jet and the interaction of high and low level jet provided vapor and unstable conditions；the strong vertical upward motion in the unstable areas was the necessary dynamic condition；the middlescale convergence system directly caused the convective process.
An analysis is made of the structural characteristics of the convective clouds and precipitation on 25 to 26 June in 2005, by using a variety of observation and remote sensing data and the favorable surrounding conditions by using NCEP reanalysis data and real wind data. The results show that some mesoscale convective cloud clusters underwent the development of more than 10 hours, and TBB decreased to －90 degrees，which led to the inhomogeneous rainfall distribution in both time and space. The convective clouds had prominent microphysical structural characteristics, which had the high content of ice particles at the upper level and more plentiful cloud water. The seederfeeder mechanism was playing the major role. The “doublepeek” profile structure of convective precipitation shows that the warm rain process was very strong in MCC. The surrounding conditions were very useful for the formation of MCC and the convective storm： the water vapor transmitted and converged by the strong southwest low level jet and the interaction of high and low level jet provided vapor and unstable conditions；the strong vertical upward motion in the unstable areas was the necessary dynamic condition；the middlescale convergence system directly caused the convective process.
2009, 37(4):407-410.
Abstract:
Based on the Doppler radar basic reflectivity and rain gauge data, the estimated and predicted precipitation products are produced by means of the precipitation algorithm, the optimal interpolation method, and the crosscorrelation method. The verification indicates that the estimated and predicted rainfall is more accurate. With the two kinds of precipitation products, the accumulated precipitation products for different periods were generated and applied in the nowcasting services of the typhoon Bilis (200604), and some other severe rainfall events (070608, 080612 and 200803) induced by lowpressure vortex shears. On the basis of the accumulated precipitation products, the yellow and orange rainstorm warnings were issued on these processes timely and effectively. The results show that the accumulated precipitation products play an important role in determining the grades and the issuing time of warning on continuous heavy precipitation processes. In the region without automatic meteorological stations, the significance is even more prominent.
Based on the Doppler radar basic reflectivity and rain gauge data, the estimated and predicted precipitation products are produced by means of the precipitation algorithm, the optimal interpolation method, and the crosscorrelation method. The verification indicates that the estimated and predicted rainfall is more accurate. With the two kinds of precipitation products, the accumulated precipitation products for different periods were generated and applied in the nowcasting services of the typhoon Bilis (200604), and some other severe rainfall events (070608, 080612 and 200803) induced by lowpressure vortex shears. On the basis of the accumulated precipitation products, the yellow and orange rainstorm warnings were issued on these processes timely and effectively. The results show that the accumulated precipitation products play an important role in determining the grades and the issuing time of warning on continuous heavy precipitation processes. In the region without automatic meteorological stations, the significance is even more prominent.
2009, 37(4):411-414.
Abstract:
An analysis of a heavy rainfall event on 2 June 2008 in Dali, Yunnan Province, is made with wind profiler radar products and hourly rainfall data. The results show that the event is characterized with apparent mesoscale features; the vertical structure can be clearly revealed by the horizontal wind profiler products; the downward disturbance at the upper atmosphere is closely related with the enhancement of rainfall; the products of wind profiler radar (such as vertical velocity, refractivity structure constant, signal to noise ratio) can be used to determine the beginning, ending and intensity of rainfall.
An analysis of a heavy rainfall event on 2 June 2008 in Dali, Yunnan Province, is made with wind profiler radar products and hourly rainfall data. The results show that the event is characterized with apparent mesoscale features; the vertical structure can be clearly revealed by the horizontal wind profiler products; the downward disturbance at the upper atmosphere is closely related with the enhancement of rainfall; the products of wind profiler radar (such as vertical velocity, refractivity structure constant, signal to noise ratio) can be used to determine the beginning, ending and intensity of rainfall.
2009, 37(4):415-419.
Abstract:
By means of the outputs of 13 GCM models provided by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCCAR4), the situations of climate change in Chongqing in the next 100 years under different greenhouse gas emission scenarios (SRES A2, SRES A1B and SRES B1) are analyzed. The results show that the climate in Chongqing would have a warming and wetting tendency in the 21st century; the linear tendency of temperature changes would range from 2.3 to 4.2 ℃ per 100 years; precipitation increase would range from 5.9% to 8.8% per 100 years. The largest range of warming would be in winter, while the largest increase of precipitation would be in spring and the largest decrease of precipitation would be in autumn. Considering the effect of SRES A2, SRES A1B, and SRES B1, temperature in Chongqing would increase by 3.68 ℃, 3.28 ℃ and 2.26 ℃, respectively and precipitation would increase by 5.24%, 5.77%, and 3.43% at the end of the 21st century.
By means of the outputs of 13 GCM models provided by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCCAR4), the situations of climate change in Chongqing in the next 100 years under different greenhouse gas emission scenarios (SRES A2, SRES A1B and SRES B1) are analyzed. The results show that the climate in Chongqing would have a warming and wetting tendency in the 21st century; the linear tendency of temperature changes would range from 2.3 to 4.2 ℃ per 100 years; precipitation increase would range from 5.9% to 8.8% per 100 years. The largest range of warming would be in winter, while the largest increase of precipitation would be in spring and the largest decrease of precipitation would be in autumn. Considering the effect of SRES A2, SRES A1B, and SRES B1, temperature in Chongqing would increase by 3.68 ℃, 3.28 ℃ and 2.26 ℃, respectively and precipitation would increase by 5.24%, 5.77%, and 3.43% at the end of the 21st century.
2009, 37(4):420-424.
Abstract:
The daily thunderstorm data from the Capital Airport (Beijing) from 1958 to 2007 are used to perform the analysis of the temporal variations of summer thunderstorms, and the wavelet analysis is used to disclose its interannual and interdecadal variations. The results show that there was obvious daily variation in thunderstorm weather from July to September in the recent 50 years; there was a decline tendency in thunderstorm days, especially in July and August; obvious 1 to 2, 4 to 6, and quasi10 year oscillations can be found in summer thunderstorm days at the Capital Airport, among which 1 to 2 year oscillations are most significant; meanwhile,the quasi10 year oscillation is also obvious.
The daily thunderstorm data from the Capital Airport (Beijing) from 1958 to 2007 are used to perform the analysis of the temporal variations of summer thunderstorms, and the wavelet analysis is used to disclose its interannual and interdecadal variations. The results show that there was obvious daily variation in thunderstorm weather from July to September in the recent 50 years; there was a decline tendency in thunderstorm days, especially in July and August; obvious 1 to 2, 4 to 6, and quasi10 year oscillations can be found in summer thunderstorm days at the Capital Airport, among which 1 to 2 year oscillations are most significant; meanwhile,the quasi10 year oscillation is also obvious.
2009, 37(4):425-428.
Abstract:
Based on the results simulated by PRECIS (Providing Regional Climates for Impacts Studies), which is developed by the Hadley Centre for Climate Prediction and Research, the changes of floodseason heavy rainfall under tthe SRES B2 scenario over South China during 2071〖CD*2〗2100 are analyzed. It is shown that PRECIS has the capability to simulate floodseason severe heavy rainfall. The percentage of severe heavy rainfall to total rainfall in 2071〖CD*2〗2100 would increase relative to 1961〖CD*2〗1990 (the baseline). The percentage of the number of severe rainnig days in 2071〖CD*2〗2100 is analyzed, and the results show that there would be a maximum center in the centralnorth part of Guangxi and the northern Fujian during the earlier floodseason, and there would be a maximum center in Guangdong and Fujian during the later floodseason. The change percentage in each month during flood season is positive over South China except for Hainan. The occurrence frequency of floodseason severe precipitation events in 2071〖CD*2〗2100 would increase obviously.
Based on the results simulated by PRECIS (Providing Regional Climates for Impacts Studies), which is developed by the Hadley Centre for Climate Prediction and Research, the changes of floodseason heavy rainfall under tthe SRES B2 scenario over South China during 2071〖CD*2〗2100 are analyzed. It is shown that PRECIS has the capability to simulate floodseason severe heavy rainfall. The percentage of severe heavy rainfall to total rainfall in 2071〖CD*2〗2100 would increase relative to 1961〖CD*2〗1990 (the baseline). The percentage of the number of severe rainnig days in 2071〖CD*2〗2100 is analyzed, and the results show that there would be a maximum center in the centralnorth part of Guangxi and the northern Fujian during the earlier floodseason, and there would be a maximum center in Guangdong and Fujian during the later floodseason. The change percentage in each month during flood season is positive over South China except for Hainan. The occurrence frequency of floodseason severe precipitation events in 2071〖CD*2〗2100 would increase obviously.
9 Comparative Analyses of Turbulence Characteristics in NearSurface Layer in Dry/Wet Periods at Dali
2009, 37(4):429-433.
Abstract:
Based on the data of the PBL observation system at Dali from March to December 2007, the characteristics of turbulent intensity, turbulent variances and turbulent flux are analyzed by using the eddy correlation method. The results show that the turbulent intensity in the dry period is much higher than that in the wet period. The relation between the normalized variance of 3D winds and 〖WTBX〗z/L〖WTBZ〗 satisfies the law of 1/3 fractional power. In the case of stable stratification, the relation of the variance to z/L is dispersed in the horizontal direction. Turbulent flux shows obvious diurnal variation. The values of sensible heat flux and momentum flux are larger in the dry period, but the latent heat flux is lager in the wet period. The latent heat flux is greater in both dry and wet periods.
Based on the data of the PBL observation system at Dali from March to December 2007, the characteristics of turbulent intensity, turbulent variances and turbulent flux are analyzed by using the eddy correlation method. The results show that the turbulent intensity in the dry period is much higher than that in the wet period. The relation between the normalized variance of 3D winds and 〖WTBX〗z/L〖WTBZ〗 satisfies the law of 1/3 fractional power. In the case of stable stratification, the relation of the variance to z/L is dispersed in the horizontal direction. Turbulent flux shows obvious diurnal variation. The values of sensible heat flux and momentum flux are larger in the dry period, but the latent heat flux is lager in the wet period. The latent heat flux is greater in both dry and wet periods.
2009, 37(4):434-438.
Abstract:
Based on the 4105A grounding resistance measuring meter, a longdistance automatic soil resistivity measuring device was developed independently to solve the problem that soil resistivity measuring instruments has to be operated manually. The measurement principles, structure, and work processes of the device are described, and the design ideas are discussed. The oneyear field experiment indicates that the system is simple and easy to use, has light weight, runs steadily, and provides quality data, being suitable for the longterm, continuous, and automatic measurement of soil resistivity.
Based on the 4105A grounding resistance measuring meter, a longdistance automatic soil resistivity measuring device was developed independently to solve the problem that soil resistivity measuring instruments has to be operated manually. The measurement principles, structure, and work processes of the device are described, and the design ideas are discussed. The oneyear field experiment indicates that the system is simple and easy to use, has light weight, runs steadily, and provides quality data, being suitable for the longterm, continuous, and automatic measurement of soil resistivity.
2009, 37(4):439-443.
Abstract:
A comprehensive malfunction in the CINRAD/SA weather radar servo system at Jinan occurred from 21:00 28 May to 13:00 31 May 2008, involved the digital control unit (DCU), fiber communication link and data attainment unit (DAU) of the antenna servo system. By means of the conventional approaches, the malfunction can not be removed. Through taking the digital control unit state display and corner brace display as key points, the causes of the malfunction were reexamined one by one, so to make the radar return to normal. The causes and inspection and repair ideas of the malfunction are discussed, and the results can be used as references in improving the capability of the radar maintenance staff.
A comprehensive malfunction in the CINRAD/SA weather radar servo system at Jinan occurred from 21:00 28 May to 13:00 31 May 2008, involved the digital control unit (DCU), fiber communication link and data attainment unit (DAU) of the antenna servo system. By means of the conventional approaches, the malfunction can not be removed. Through taking the digital control unit state display and corner brace display as key points, the causes of the malfunction were reexamined one by one, so to make the radar return to normal. The causes and inspection and repair ideas of the malfunction are discussed, and the results can be used as references in improving the capability of the radar maintenance staff.
2009, 37(4):444-447.
Abstract:
An introduction is made to the application of the RS485 bus in the nearsurface layer flux observation system at Zhangye, as well as the characteristics, working mode, and networking of the RS485 bus, which consists of there subsystems: eddy covariance system, gradient system and wind energy observation system. About oneyear application of the RS485 bus at the Zhangye National Climatological Observatory indicates that it is stable, has good antinoise capability, and can be used in longdistance data transfer.
An introduction is made to the application of the RS485 bus in the nearsurface layer flux observation system at Zhangye, as well as the characteristics, working mode, and networking of the RS485 bus, which consists of there subsystems: eddy covariance system, gradient system and wind energy observation system. About oneyear application of the RS485 bus at the Zhangye National Climatological Observatory indicates that it is stable, has good antinoise capability, and can be used in longdistance data transfer.
2009, 37(4):448-451.
Abstract:
ORACLE, being powerful and complicated, is one of the most popular business database software systems. The emphasis of the study is put on the configuration connection method. The structure of ORACLE database and its communication mode between client and server are discussed, based on which the connection method between ORACLE client and server is explained by networking and process communication modes, respectively. The configurations from client side and server side under the different connection modes are described. Two solutions to connection malfunctions are given as examples.
ORACLE, being powerful and complicated, is one of the most popular business database software systems. The emphasis of the study is put on the configuration connection method. The structure of ORACLE database and its communication mode between client and server are discussed, based on which the connection method between ORACLE client and server is explained by networking and process communication modes, respectively. The configurations from client side and server side under the different connection modes are described. Two solutions to connection malfunctions are given as examples.
2009, 37(4):452-456.
Abstract:
The operational flow setting in the whole qualitycontrol system of regional rainfall data in Shijiazhuang is given, and the quality control techniques and quality control information are introduced, considering the errors of tippingbucket raingauges. The techniques for checking averages, ranges, spatial consistency, including time consistency and internal consistency, are presented. The system is highly automatic with a friendly and convenient interface, can help ensure the rainfall data quality in meteorological services.
The operational flow setting in the whole qualitycontrol system of regional rainfall data in Shijiazhuang is given, and the quality control techniques and quality control information are introduced, considering the errors of tippingbucket raingauges. The techniques for checking averages, ranges, spatial consistency, including time consistency and internal consistency, are presented. The system is highly automatic with a friendly and convenient interface, can help ensure the rainfall data quality in meteorological services.
2009, 37(4):457-461.
Abstract:
In order to get further insight into disastrous weather in Changzhou for forecasters, the Webbased multifunction automatic inquiry system of disastrous weather (including heavy rain, cold waves, typhoons, etc.) is established, which make full use of various information sources, including data on the surface, lowerlevel and upperlevel atmospheric circulation patterns, and typhoon tracks, as well as satellite cloud pictures, Doppler radar echo images, recording data, and disaster reports relevant to weather disasters from 1974 to 2007. The system is practical, fast, interface friendly, easy to use, and suitable for meteorological stations of various levels
In order to get further insight into disastrous weather in Changzhou for forecasters, the Webbased multifunction automatic inquiry system of disastrous weather (including heavy rain, cold waves, typhoons, etc.) is established, which make full use of various information sources, including data on the surface, lowerlevel and upperlevel atmospheric circulation patterns, and typhoon tracks, as well as satellite cloud pictures, Doppler radar echo images, recording data, and disaster reports relevant to weather disasters from 1974 to 2007. The system is practical, fast, interface friendly, easy to use, and suitable for meteorological stations of various levels
2009, 37(4):462-465.
Abstract:
The Intelligent Management System of Meteorological Detection Facility Information in the Chengdu (Southwest) region achieved the realtime monitoring, audio warning, and SMS warning of meteorological detecting devices and the macrocontrolling and intelligent management of the storage, purchase, and maintenance of devices, as well as the statistical analysis of the related usage information. The Webbased system adopts “threetier architecture” and B/S (Browser/server) modes using the Windows service technology and SQL Server 2000 database platform. The detection facilities include the nextgeneration weather radar, Lband radar and radiosonde, and automatic weather stations. This system has the features of lowcost and high effectiveness and efficiency, which helps reduce the workload of operators on duty and can be used as an information exchange platform for the development and renovation of atmospheric detection facilities.
The Intelligent Management System of Meteorological Detection Facility Information in the Chengdu (Southwest) region achieved the realtime monitoring, audio warning, and SMS warning of meteorological detecting devices and the macrocontrolling and intelligent management of the storage, purchase, and maintenance of devices, as well as the statistical analysis of the related usage information. The Webbased system adopts “threetier architecture” and B/S (Browser/server) modes using the Windows service technology and SQL Server 2000 database platform. The detection facilities include the nextgeneration weather radar, Lband radar and radiosonde, and automatic weather stations. This system has the features of lowcost and high effectiveness and efficiency, which helps reduce the workload of operators on duty and can be used as an information exchange platform for the development and renovation of atmospheric detection facilities.
2009, 37(4):466-468.
Abstract:
The traditional surface manual meteorological observations are gradually replaced by the automatic observation systems, but the electronic equipments of Automatic Weather Stations (AWS) are easily be influenced by thunders and lightning electromagnetic pulses，leading to equipment damage, operation interruption, observation data missing. It is necessary for observers to master the technical means of remedying damaged or missing data induced by lightning strikes to ensure data integrity. The causes and countermeasures of AWS data missing are discussed, with the emphasis on the processing of routine observation data, hourly upload files, daily and monthly extreme value data, missing data, etc.
The traditional surface manual meteorological observations are gradually replaced by the automatic observation systems, but the electronic equipments of Automatic Weather Stations (AWS) are easily be influenced by thunders and lightning electromagnetic pulses，leading to equipment damage, operation interruption, observation data missing. It is necessary for observers to master the technical means of remedying damaged or missing data induced by lightning strikes to ensure data integrity. The causes and countermeasures of AWS data missing are discussed, with the emphasis on the processing of routine observation data, hourly upload files, daily and monthly extreme value data, missing data, etc.
2009, 37(4):469-471.
Abstract:
The construction and the reliability of an automatic weather station in the extreme circumstance of the Everest region are discussed. The Compass Navigation Satellite System was adopted in establishing the automatic weather station in the Everest region. A brief analysis and comparison of the data transmission methods commonly used are conducted. The communication control system and communication solution are designed to fit in with the Compass Navigation Satellite System. The hierarchy idea is applied to improve the expansibility and maintainability, and the mechanisms such as reconnection, receipt, resending and verification are utilized to guarantee the stability and reliability of the system.
The construction and the reliability of an automatic weather station in the extreme circumstance of the Everest region are discussed. The Compass Navigation Satellite System was adopted in establishing the automatic weather station in the Everest region. A brief analysis and comparison of the data transmission methods commonly used are conducted. The communication control system and communication solution are designed to fit in with the Compass Navigation Satellite System. The hierarchy idea is applied to improve the expansibility and maintainability, and the mechanisms such as reconnection, receipt, resending and verification are utilized to guarantee the stability and reliability of the system.
2009, 37(4):472-477.
Abstract:
Integrated observations were made of the solar radiation, including photosynthetically active radiation (PAR), visible radiation (VIS), global radiation (Q), etc, and meteorological parameters at Xinglong, Hebei Province, from 11 September 2005 to 2 September 2006. The variation characteristics of PAR and VIS were obtained. The results show that the ratios of hourly sum of PAR to Q, VIS to Q, and PAR to VIS are relatively stable, and their averages are 2.03 (mol/MJ), 0.42 and 4.89 (mol/MJ), respectively,which indicate the obvious diurnal, daily and seasonal variations, being influenced by water vapor, aerosol, clouds, etc. The empirical formulas under all sky conditions for calculating the hourly sums of PAR and VIS, and the conversion relationship between hourly sums of PAR and VIS are built. The calculated PAR and VIS are in good agreement with the measured, and their relative biases are 13.3% and 12.1%, respectively, when the water vapor and scattering factor are considered. Concerning the actual condition, when only water vapor factor was considered, their relative biases are 13.8% and 12.4%, respectively. In view of the transmission and calculation of PAR and VIS, the water vapor factor plays an important role, and the role of aerosol is not as important as water vapor, but it should still be considered.
Integrated observations were made of the solar radiation, including photosynthetically active radiation (PAR), visible radiation (VIS), global radiation (Q), etc, and meteorological parameters at Xinglong, Hebei Province, from 11 September 2005 to 2 September 2006. The variation characteristics of PAR and VIS were obtained. The results show that the ratios of hourly sum of PAR to Q, VIS to Q, and PAR to VIS are relatively stable, and their averages are 2.03 (mol/MJ), 0.42 and 4.89 (mol/MJ), respectively,which indicate the obvious diurnal, daily and seasonal variations, being influenced by water vapor, aerosol, clouds, etc. The empirical formulas under all sky conditions for calculating the hourly sums of PAR and VIS, and the conversion relationship between hourly sums of PAR and VIS are built. The calculated PAR and VIS are in good agreement with the measured, and their relative biases are 13.3% and 12.1%, respectively, when the water vapor and scattering factor are considered. Concerning the actual condition, when only water vapor factor was considered, their relative biases are 13.8% and 12.4%, respectively. In view of the transmission and calculation of PAR and VIS, the water vapor factor plays an important role, and the role of aerosol is not as important as water vapor, but it should still be considered.
2009, 37(4):478-485.
Abstract:
By means of the hierarchical analysis method, taking Maduo County (a typical area of the QinghaiTibet Plateau) as an example, the structure and functions of the plateau ecological environment, the dynamic changes and interactive mechanisms of the geographic landscapes, and the heterogeneity, abundance, and fragmentation of the landscape structure are explored. An assessing index system and an assessing method of ecological environment quality for the QinghaiTibet Plateau are established, and an assessment is conducted on the ecological environment in Maduo County. The results show that the ecological environment quality of Maduo County is at a worse level in 2004, which reflects basically the ecological environment situation in Maduo County. The ecological pattern optimization (0.4228) and prosperous variation (0.4180) are at a normal level; the function intensity (0.2764, the smallest among four assessing indexes) is at a worse level, but anthropogenic stress (0.7037, the greatest) is in a good condition, which shows that the ecological environment is hardly disturbed by human being. The deterioration of the ecological environment this region is attributed mainly to its natural environment conditions.
By means of the hierarchical analysis method, taking Maduo County (a typical area of the QinghaiTibet Plateau) as an example, the structure and functions of the plateau ecological environment, the dynamic changes and interactive mechanisms of the geographic landscapes, and the heterogeneity, abundance, and fragmentation of the landscape structure are explored. An assessing index system and an assessing method of ecological environment quality for the QinghaiTibet Plateau are established, and an assessment is conducted on the ecological environment in Maduo County. The results show that the ecological environment quality of Maduo County is at a worse level in 2004, which reflects basically the ecological environment situation in Maduo County. The ecological pattern optimization (0.4228) and prosperous variation (0.4180) are at a normal level; the function intensity (0.2764, the smallest among four assessing indexes) is at a worse level, but anthropogenic stress (0.7037, the greatest) is in a good condition, which shows that the ecological environment is hardly disturbed by human being. The deterioration of the ecological environment this region is attributed mainly to its natural environment conditions.
2009, 37(4):486-491.
Abstract:
Weather radar is most direct and effective detection and command tool in the domestic weather modification operations, especially in ground hail suppression operation command systems, but the detection products from various radars, which have different types and detection modes, are hard to be used effectively. Considering the needs of hail suppression operations at the prefectural/county level, a ground Artificial Hail Suppression Operation Command System (AHSOCS) is designed and developed based on multiradar products using VC and VB language and graphic image processing, GIS, clientserver, database, and multimedia technology. The system composition, running procedure and the related technologies are discussed, and the corresponding criterions and indexes of operation command are given. The case analysis shows that the mutual complementation of various detection products from different types of weather radar in hail suppression operations is achieved through AHSOCS, which can improve the level of artificial hail suppression operation command.
Weather radar is most direct and effective detection and command tool in the domestic weather modification operations, especially in ground hail suppression operation command systems, but the detection products from various radars, which have different types and detection modes, are hard to be used effectively. Considering the needs of hail suppression operations at the prefectural/county level, a ground Artificial Hail Suppression Operation Command System (AHSOCS) is designed and developed based on multiradar products using VC and VB language and graphic image processing, GIS, clientserver, database, and multimedia technology. The system composition, running procedure and the related technologies are discussed, and the corresponding criterions and indexes of operation command are given. The case analysis shows that the mutual complementation of various detection products from different types of weather radar in hail suppression operations is achieved through AHSOCS, which can improve the level of artificial hail suppression operation command.
2009, 37(4):492-495.
Abstract:
The areal rainfall over the target areas for two different precipitation processes in Beijing are calculated with the data from climate stations only or from both climate stations and automatic precipitation stations by using the arithmetic and Thiessen polygon methods respectively. The results show that the Thiessen polygon method is advantageous in analyzing different kinds of precipitation events. The areal rainfall calculated with the data from both climate stations and automatic precipitation stations is much more accurate than that from climate stations only. For the assessment of precipitation enhancement effectiveness, a statistical correction method is proposed to calculate more accurately the areal rainfall over the target areas (including the control area) by using the historical rainfall data, which is highly important for improving the precision in the assessment of precipitation enhancement effectiveness.
The areal rainfall over the target areas for two different precipitation processes in Beijing are calculated with the data from climate stations only or from both climate stations and automatic precipitation stations by using the arithmetic and Thiessen polygon methods respectively. The results show that the Thiessen polygon method is advantageous in analyzing different kinds of precipitation events. The areal rainfall calculated with the data from both climate stations and automatic precipitation stations is much more accurate than that from climate stations only. For the assessment of precipitation enhancement effectiveness, a statistical correction method is proposed to calculate more accurately the areal rainfall over the target areas (including the control area) by using the historical rainfall data, which is highly important for improving the precision in the assessment of precipitation enhancement effectiveness.
2009, 37(4):496-502.
Abstract:
The weatherbased appraisal model of low temperature, rain/snow, and freezes disaster influence in the Southeast Guizhou is built and the damage degrees of 206 villages (towns) in Southeast Guizhou are calculated by using the weighted average method and the related meteorological factors of 16 weather stations in Southeast Guizhou during the disaster period. The results show that the low temperature, rain/snow, and freezing disaster caused great damages in Southeast Guizhou with varying degrees in different areas; there are 16 villages (towns) suffered the first grade freezing, mainly in the areas with medium elevation in the eastern part; the second grade freezing occurred mainly in the eastern part, the northern mountainous area and the western border areas; the freezing degree was relatively low over the lowlying river valley areas. Through the analysis, it is found out that the influence of the freezing disaster is related to not only the abnormal atmospheric circulation situation, but also the special terrain of Southeast Guizhou.
The weatherbased appraisal model of low temperature, rain/snow, and freezes disaster influence in the Southeast Guizhou is built and the damage degrees of 206 villages (towns) in Southeast Guizhou are calculated by using the weighted average method and the related meteorological factors of 16 weather stations in Southeast Guizhou during the disaster period. The results show that the low temperature, rain/snow, and freezing disaster caused great damages in Southeast Guizhou with varying degrees in different areas; there are 16 villages (towns) suffered the first grade freezing, mainly in the areas with medium elevation in the eastern part; the second grade freezing occurred mainly in the eastern part, the northern mountainous area and the western border areas; the freezing degree was relatively low over the lowlying river valley areas. Through the analysis, it is found out that the influence of the freezing disaster is related to not only the abnormal atmospheric circulation situation, but also the special terrain of Southeast Guizhou.
2009, 37(4):503-507.
Abstract:
The average characteristics of wind fields and sea conditions in 2006, 2007, and 2008 and sea conditions on South China Sea (SCS) in winter (January) are analyzed by using the merged data from four satellite altimeters. Both wind force and wave heights were the biggest on the northeastern SCS, the Taiwan strait and the Bashi strait, and the second in the southwestern SCS. According to these characteristics, considering the security and economy, four routes are designed for vessels: (1) the shortest route, from the Malacca strait to the Taiwan strait directly; (2) the route to avoid the gales and high waves on the southwestern SCS and the sea area south of Taiwan; (3) the route bypassing Taiwan from east to avoid the gales on the Taiwan strait; (4) the safest but farthest route. It is obvious from the example of the ship MV H that gales and high waves affect greatly the security of the vessels.
The average characteristics of wind fields and sea conditions in 2006, 2007, and 2008 and sea conditions on South China Sea (SCS) in winter (January) are analyzed by using the merged data from four satellite altimeters. Both wind force and wave heights were the biggest on the northeastern SCS, the Taiwan strait and the Bashi strait, and the second in the southwestern SCS. According to these characteristics, considering the security and economy, four routes are designed for vessels: (1) the shortest route, from the Malacca strait to the Taiwan strait directly; (2) the route to avoid the gales and high waves on the southwestern SCS and the sea area south of Taiwan; (3) the route bypassing Taiwan from east to avoid the gales on the Taiwan strait; (4) the safest but farthest route. It is obvious from the example of the ship MV H that gales and high waves affect greatly the security of the vessels.
2009, 37(4):508-510.
Abstract:
2009, 37(4):511-512.
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.
Supported by:Beijing E-Tiller Technology Development Co., Ltd.