Volume 43,Issue 1,2015 Table of Contents
2015, 43(1):1-7.
Abstract:
Making use of rainfall attenuation in microwave links is a brand new way to detect rainfall intensity, which can collect abundant meteorological observation information relying on the worldwide microwave communication networks. On the basis of analyzing rainfall attenuation, the 15〖CD*2〗20 GHz microwave link rainfall measurement experiment was conducted, in which the microwave communication link distance of 6 km and the mean values of receiving level before the rainfall are chosen as reference values. The rain attenuation is calculated by means of the reference value and the actual receiving level. The result shows that the 15〖CD*2〗20 GHz microwave can be used to measure the instantaneous rainfall rate at a more detailed temporal resolution; the rainfall attenuation can be exactly detected when the rainfall intensity is between 2 and 70 mm/h. The retrieved rain attenuation values are correlated with the actual measurements. The errors and their reasons in this experiment are also analyzed, which provide references for the further research, such as forward modeling.
Making use of rainfall attenuation in microwave links is a brand new way to detect rainfall intensity, which can collect abundant meteorological observation information relying on the worldwide microwave communication networks. On the basis of analyzing rainfall attenuation, the 15〖CD*2〗20 GHz microwave link rainfall measurement experiment was conducted, in which the microwave communication link distance of 6 km and the mean values of receiving level before the rainfall are chosen as reference values. The rain attenuation is calculated by means of the reference value and the actual receiving level. The result shows that the 15〖CD*2〗20 GHz microwave can be used to measure the instantaneous rainfall rate at a more detailed temporal resolution; the rainfall attenuation can be exactly detected when the rainfall intensity is between 2 and 70 mm/h. The retrieved rain attenuation values are correlated with the actual measurements. The errors and their reasons in this experiment are also analyzed, which provide references for the further research, such as forward modeling.
2015, 43(1):8-14.
Abstract:
Vertical gradient observation is one of the most prominent characteristics for automatic farmland microclimate observation. There are different vertical gradient design schemes, which result in the observed data comparability and value reduced in the agrometeorological operational observation, because of the wide variety of farmland microclimate and complex surface vegetation conditions in the theoretical and applied research fields. Based on the observed data of microclimate stations during the whole winter wheat and maize growth periods in 2012 in Tyan and Zhengzhou, the vertical gradient variation characteristics of temperature and bare temperature and vertical gradient design standards for farmland microclimate are studied. The results indicate that the vertical gradient characteristics of temperature have a good consistency with bare temperature in time and space. According to the bare temperature vertical gradient variation in the wheat and maize fields, taking into account the restrictions of radiation shield heights, the observation heights should be set at 25 cm, 50 cm and 150 cm above the ground for wheat fields, respectively, while the observation heights should be set at 25 cm, 50 cm ,150 cm and 300 cm above the ground for maize fields.
Vertical gradient observation is one of the most prominent characteristics for automatic farmland microclimate observation. There are different vertical gradient design schemes, which result in the observed data comparability and value reduced in the agrometeorological operational observation, because of the wide variety of farmland microclimate and complex surface vegetation conditions in the theoretical and applied research fields. Based on the observed data of microclimate stations during the whole winter wheat and maize growth periods in 2012 in Tyan and Zhengzhou, the vertical gradient variation characteristics of temperature and bare temperature and vertical gradient design standards for farmland microclimate are studied. The results indicate that the vertical gradient characteristics of temperature have a good consistency with bare temperature in time and space. According to the bare temperature vertical gradient variation in the wheat and maize fields, taking into account the restrictions of radiation shield heights, the observation heights should be set at 25 cm, 50 cm and 150 cm above the ground for wheat fields, respectively, while the observation heights should be set at 25 cm, 50 cm ,150 cm and 300 cm above the ground for maize fields.
2015, 43(1):15-21.
Abstract:
The original commutator design flaws of CIRAD/SA(B) are analyzed, aiming at the rectifier unit of transmitters designed unreasonably, which led to higher transmitter faults. The flaws include：the lack of open phase monitoring function, which results in burn out fuse by high voltage power supply, being undetectable; high voltage striking is prone to happen if the impulse current is larger at the moment of applying high voltage; it is inconvenient to repair and cannot locate the fault of high/low voltage circuits rapidly. The new type of rectifier unit is developed, which improves the design of the unreasonable circuit and adds such new functions as rotary switch with repairing function, step stress outputting, and open phase and phase sequence protection, which can reduce transmitter lighter faults and improve the repairing efficiency of high voltage striking faults in a radar transmitter.
The original commutator design flaws of CIRAD/SA(B) are analyzed, aiming at the rectifier unit of transmitters designed unreasonably, which led to higher transmitter faults. The flaws include：the lack of open phase monitoring function, which results in burn out fuse by high voltage power supply, being undetectable; high voltage striking is prone to happen if the impulse current is larger at the moment of applying high voltage; it is inconvenient to repair and cannot locate the fault of high/low voltage circuits rapidly. The new type of rectifier unit is developed, which improves the design of the unreasonable circuit and adds such new functions as rotary switch with repairing function, step stress outputting, and open phase and phase sequence protection, which can reduce transmitter lighter faults and improve the repairing efficiency of high voltage striking faults in a radar transmitter.
2015, 43(1):22-29.
Abstract:
The antenna servo system is a key part of CINRAD/SA weather radar, which works continuously and has complex circuits, so it has a relatively high failure rate in CINRAD/SA radar, especially code jumping malfunction. Conclusions are obtained from 68 cases acquired from nationwide CINRAD/SA radar stations by the project team. The code jumping may be caused by the motor, resolver, collector ring, encoder, fiber link, and digital control unit. Combining with the flow direction of antenna angle codes in the servo system and the parameter characteristics of key components, an analysis is made of the factors that lead to jumping codes, and the method to diagnose jumping codes is summarized. In addition, five representative cases are analyzed. According to the statistics of sample fault attribution, some recommendations for the time sequence of component checking in code jumping failure are given, which provides guidance for removing such malfunction quickly and has a beneficial reference for other Servo faults.
The antenna servo system is a key part of CINRAD/SA weather radar, which works continuously and has complex circuits, so it has a relatively high failure rate in CINRAD/SA radar, especially code jumping malfunction. Conclusions are obtained from 68 cases acquired from nationwide CINRAD/SA radar stations by the project team. The code jumping may be caused by the motor, resolver, collector ring, encoder, fiber link, and digital control unit. Combining with the flow direction of antenna angle codes in the servo system and the parameter characteristics of key components, an analysis is made of the factors that lead to jumping codes, and the method to diagnose jumping codes is summarized. In addition, five representative cases are analyzed. According to the statistics of sample fault attribution, some recommendations for the time sequence of component checking in code jumping failure are given, which provides guidance for removing such malfunction quickly and has a beneficial reference for other Servo faults.
2015, 43(1):30-35.
Abstract:
A self developed hypobaric chamber and its technological parameters, as well as the performance tests and preliminary application, are introduced. The chamber is cylindrical shaped with the dimension of 600 mm in length and 550〖CD*2〗600 mm in diameter. The internal pressure of chamber can be reduced in an automatic or manual mode, and the lowest value can be 21 hPa. Performance testing results show that the average pumping rate of the chamber is 41 hPa/s. The logarithm of pressure in chamber varies linearly with suction time within effective pressure range. The chamber pressure response curve decreases with decreasing pressure, and the average deflation rate of the chamber pressure is 66 hPa/s. The deflation efficiency maximum value is around 100 hPa, with the efficiency reducing from 100 hPa in the higher or lower direction. The static response tests show that the chamber air pressure variability is 22% to 36% in 10〖CD*2〗60 s, and 36±18% in 1〖CD*2〗10 min. The average air leak rate of the chamber is 04 Pa/min in 10 min, and the actual pressure deviations in 10, 20, 40 min and 1 hour is 004, 01, 019, and 025 hPa, respectively. The hypobaric chamber is used for testing the SPC 6A ozonesonde pump efficiency in a low pressure environment. The results show that the deviation of pump efficiency correction factor is <25%, <5%, <6%, and <5%, 〖JP2〗respectively, when the corresponding air pressure is >70 hPa, 70〖CD*2〗35 hPa, 35〖CD*2〗20 hPa, and <20 hPa. These measured pump efficiency correction factors are consist with the original values provided by the manufacture. The hypobaric chamber is expected to provide a low pressure environment for correlative meteorological instrument performance testing.
A self developed hypobaric chamber and its technological parameters, as well as the performance tests and preliminary application, are introduced. The chamber is cylindrical shaped with the dimension of 600 mm in length and 550〖CD*2〗600 mm in diameter. The internal pressure of chamber can be reduced in an automatic or manual mode, and the lowest value can be 21 hPa. Performance testing results show that the average pumping rate of the chamber is 41 hPa/s. The logarithm of pressure in chamber varies linearly with suction time within effective pressure range. The chamber pressure response curve decreases with decreasing pressure, and the average deflation rate of the chamber pressure is 66 hPa/s. The deflation efficiency maximum value is around 100 hPa, with the efficiency reducing from 100 hPa in the higher or lower direction. The static response tests show that the chamber air pressure variability is 22% to 36% in 10〖CD*2〗60 s, and 36±18% in 1〖CD*2〗10 min. The average air leak rate of the chamber is 04 Pa/min in 10 min, and the actual pressure deviations in 10, 20, 40 min and 1 hour is 004, 01, 019, and 025 hPa, respectively. The hypobaric chamber is used for testing the SPC 6A ozonesonde pump efficiency in a low pressure environment. The results show that the deviation of pump efficiency correction factor is <25%, <5%, <6%, and <5%, 〖JP2〗respectively, when the corresponding air pressure is >70 hPa, 70〖CD*2〗35 hPa, 35〖CD*2〗20 hPa, and <20 hPa. These measured pump efficiency correction factors are consist with the original values provided by the manufacture. The hypobaric chamber is expected to provide a low pressure environment for correlative meteorological instrument performance testing.
2015, 43(1):36-42.
Abstract:
Based on the lightning protective experiments of automatic weather stations, the characteristics of lightning induced voltage in power cables with different burying situations are analyzed.The results show that soil has significant shielding effect on LEMP (Lightning ElectroMagnetic Pulse) of return strokes. Compared with the peak lightning induced voltage in the power cable on the ground, the peak value of the induced voltage under the depth of 05 meters is 522%. The induced voltage shows an oscillation waveform with a tendency of attenuation. At the same time, the induced voltages of buried power cables show a smaller amplitude in the frequency from 50 kHz to 5 MHz. The decreasing in the frequency from 9055 kHz to 1535 MHz is more obvious.
Based on the lightning protective experiments of automatic weather stations, the characteristics of lightning induced voltage in power cables with different burying situations are analyzed.The results show that soil has significant shielding effect on LEMP (Lightning ElectroMagnetic Pulse) of return strokes. Compared with the peak lightning induced voltage in the power cable on the ground, the peak value of the induced voltage under the depth of 05 meters is 522%. The induced voltage shows an oscillation waveform with a tendency of attenuation. At the same time, the induced voltages of buried power cables show a smaller amplitude in the frequency from 50 kHz to 5 MHz. The decreasing in the frequency from 9055 kHz to 1535 MHz is more obvious.
2015, 43(1):43-48.
Abstract:
The generation and composition of the monthly data files of radiosonde measurements are briefly introduced. The calculation method of the data processing software for the L band radar observation system in dealing with the radiosonde data，the existing radiosonde measurements，and the functions of quality control software for the monthly data files of radiosonde measurements are disscussed, and it points out that the key to control the quality of monthly data files of radiosonde measurements is the quality control of the original second data of the basic data files of radiosonde measurements (second data file). The second data file is the encoded data of radar signals，and it is necessary to integrate the functions of the quality control software of the monthly data files for radiosonde measurements with the L band radar data processing software. Some typical examples are given. It is pointed out that the existing parameter database for the monthly data files of radiosonde measurements presently used has defects compared with the observational data.
The generation and composition of the monthly data files of radiosonde measurements are briefly introduced. The calculation method of the data processing software for the L band radar observation system in dealing with the radiosonde data，the existing radiosonde measurements，and the functions of quality control software for the monthly data files of radiosonde measurements are disscussed, and it points out that the key to control the quality of monthly data files of radiosonde measurements is the quality control of the original second data of the basic data files of radiosonde measurements (second data file). The second data file is the encoded data of radar signals，and it is necessary to integrate the functions of the quality control software of the monthly data files for radiosonde measurements with the L band radar data processing software. Some typical examples are given. It is pointed out that the existing parameter database for the monthly data files of radiosonde measurements presently used has defects compared with the observational data.
2015, 43(1):49-52.
Abstract:
The observed precipitation and high resolution grid data of precipitation estimated quantitatively with radar are analyzed and compared, and it is found that the ratios of the precipitation estimation with radar and observed precipitation obey normal distribution. Credibility of observed precipitation can be derived from above regularities, and moreover, the distortion of observed rainfall can be estimated by building a regression equation. The precipitation during Typhoon Fitow is analyzed and calculated, and results show that good effect is achieved in the quality control of the observed precipitation actually by using radar precipitation estimation. This topic is worth further study.
The observed precipitation and high resolution grid data of precipitation estimated quantitatively with radar are analyzed and compared, and it is found that the ratios of the precipitation estimation with radar and observed precipitation obey normal distribution. Credibility of observed precipitation can be derived from above regularities, and moreover, the distortion of observed rainfall can be estimated by building a regression equation. The precipitation during Typhoon Fitow is analyzed and calculated, and results show that good effect is achieved in the quality control of the observed precipitation actually by using radar precipitation estimation. This topic is worth further study.
2015, 43(1):53-58.
Abstract:
Guangzhou meteorological satellite ground station upgraded the receiving system of the polar orbit satellite of FY 3 It helps the receiving system of FY 3 to have the ability to receive the broadcast data from the Suomi NPP satellite of USA. The capacity for receiving of the existing operational system at the Guangzhou ground station is evaluated. A retrofit project of NPOESS (National Polar orbiting Operational Environmental Satellite System) data reception is put forward. The data acquisition subcontract subsystem is rebuilt. The NPP Receive Scheme is successfully applied in Urumqi and Jiamusi meteorological satellite ground stations. An introduction to the RT STPS and IPOPP is given. The processing of NPP data is completed from Level 0 to Level 1
Guangzhou meteorological satellite ground station upgraded the receiving system of the polar orbit satellite of FY 3 It helps the receiving system of FY 3 to have the ability to receive the broadcast data from the Suomi NPP satellite of USA. The capacity for receiving of the existing operational system at the Guangzhou ground station is evaluated. A retrofit project of NPOESS (National Polar orbiting Operational Environmental Satellite System) data reception is put forward. The data acquisition subcontract subsystem is rebuilt. The NPP Receive Scheme is successfully applied in Urumqi and Jiamusi meteorological satellite ground stations. An introduction to the RT STPS and IPOPP is given. The processing of NPP data is completed from Level 0 to Level 1
2015, 43(1):59-64.
Abstract:
In August 2012, an experiment was carried out on the new GPS radiosonde sounding system, an automatic sounding system，and the accuracy after its technology improvement is compared and analyzed. The results show that the temperature of new GPS radiosondes is significantly better than that of GTS1 2 radiosondes. The humidity results are consistent with those from RS92 radiosondes. The system error is 15%; the standard deviation is less than 12%. The system error of pressure is within ± 10 hPa; the standard deviation is less than 08 hPa. The system error of geopotential height is within ± 20 gpm; the standard deviation is less than 70 gpm. The results of wind measurement are better than those of GTS1 2A.
In August 2012, an experiment was carried out on the new GPS radiosonde sounding system, an automatic sounding system，and the accuracy after its technology improvement is compared and analyzed. The results show that the temperature of new GPS radiosondes is significantly better than that of GTS1 2 radiosondes. The humidity results are consistent with those from RS92 radiosondes. The system error is 15%; the standard deviation is less than 12%. The system error of pressure is within ± 10 hPa; the standard deviation is less than 08 hPa. The system error of geopotential height is within ± 20 gpm; the standard deviation is less than 70 gpm. The results of wind measurement are better than those of GTS1 2A.
2015, 43(1):65-69.
Abstract:
Based on the calibration method of rainfall sensors, an evaluating method of measurement uncertainty for errors of SL3 rainfall sensors is described. A measurement model is established, and the error sources of measurement uncertainty are analyzed based on the propagation theorem of measurement uncertainty. According to different evaluation methods, the components of measurement uncertainty are evaluated rationally. An evaluation example of measurement uncertainty for the errors of SL3 rainfall sensors is given in combination with practice. The factors affecting measurement uncertainty are analyzed. The results show that the expanded uncertainty of the errors for rainfall sensors is 01 mm (〖WTBX〗k〖WTBZ〗=2). The standard uncertainty introducing from repeatability of rainfall sensors is the main factor affecting the measurement uncertainty, and the resolution of the rainfall sensors and the counting devices are the next importance factors. The standard uncertainty introducing from the simulation accuracy of automatic rainfall calibrators is the minimal factor.
Based on the calibration method of rainfall sensors, an evaluating method of measurement uncertainty for errors of SL3 rainfall sensors is described. A measurement model is established, and the error sources of measurement uncertainty are analyzed based on the propagation theorem of measurement uncertainty. According to different evaluation methods, the components of measurement uncertainty are evaluated rationally. An evaluation example of measurement uncertainty for the errors of SL3 rainfall sensors is given in combination with practice. The factors affecting measurement uncertainty are analyzed. The results show that the expanded uncertainty of the errors for rainfall sensors is 01 mm (〖WTBX〗k〖WTBZ〗=2). The standard uncertainty introducing from repeatability of rainfall sensors is the main factor affecting the measurement uncertainty, and the resolution of the rainfall sensors and the counting devices are the next importance factors. The standard uncertainty introducing from the simulation accuracy of automatic rainfall calibrators is the minimal factor.
2015, 43(1):70-75.
Abstract:
The automation of some traditional artificial observations such as clouds and weather phenomena has profound influence on the daily observation operation, which affects data storage and data exchange as well. The characteristics of the World Meteorological Organization code table 4680 are discussed, and it is discovered that it is more suitable for automatic weather observation. Based on the newly formed rules and regulations in atmospheric observation, the automatic coding of present weather and past weather is designed. Taking the coding principles and weather characteristics into accounts, the antomatic coding of 46 codes is realized automatically.
The automation of some traditional artificial observations such as clouds and weather phenomena has profound influence on the daily observation operation, which affects data storage and data exchange as well. The characteristics of the World Meteorological Organization code table 4680 are discussed, and it is discovered that it is more suitable for automatic weather observation. Based on the newly formed rules and regulations in atmospheric observation, the automatic coding of present weather and past weather is designed. Taking the coding principles and weather characteristics into accounts, the antomatic coding of 46 codes is realized automatically.
2015, 43(1):76-81.
Abstract:
In order to meet the changing needs of meteorological service, the Hainan Meteorological Service Centre designed the provincial meteorological service product distribution system. The system is a desktop operation system with more perfect functions; by integrating the existing operational systems, it includes four processes: acquisition, production, distribution, and monitoring. The local caching mechanism and intelligent text generation technology are applied to improve the system efficiency, operation process automation, product quality control, and monitoring system running status. After putting into operation, the service efficiency of the system is improved obviously, and oversights in work are reduced. The system can provide real time and accurate meteorological service products to users.
In order to meet the changing needs of meteorological service, the Hainan Meteorological Service Centre designed the provincial meteorological service product distribution system. The system is a desktop operation system with more perfect functions; by integrating the existing operational systems, it includes four processes: acquisition, production, distribution, and monitoring. The local caching mechanism and intelligent text generation technology are applied to improve the system efficiency, operation process automation, product quality control, and monitoring system running status. After putting into operation, the service efficiency of the system is improved obviously, and oversights in work are reduced. The system can provide real time and accurate meteorological service products to users.
2015, 43(1):82-86.
Abstract:
A description of the Ningbo meteorological fax issuing service system is given, including the way of design, technical framework, key techniques, and practical application. The Web enabled fax service is developed to meet the current demands of meteorological services on Web pages, providing the query functions of fax, receipt, and failure retry records as well, which makes it possible to update meteorological terminal products timely. As terminal clients for weather services, such as meteorology warnings, are relatively stable, default fax configurations have been set up to realize the dynamic matching of products and default fax receivers. The system can send faxes as many as 100 per minute, which is playing an important role in meteorological disaster prevention and mitigation with timely warnings.
A description of the Ningbo meteorological fax issuing service system is given, including the way of design, technical framework, key techniques, and practical application. The Web enabled fax service is developed to meet the current demands of meteorological services on Web pages, providing the query functions of fax, receipt, and failure retry records as well, which makes it possible to update meteorological terminal products timely. As terminal clients for weather services, such as meteorology warnings, are relatively stable, default fax configurations have been set up to realize the dynamic matching of products and default fax receivers. The system can send faxes as many as 100 per minute, which is playing an important role in meteorological disaster prevention and mitigation with timely warnings.
2015, 43(1):87-90.
Abstract:
According to the current situation of county level meteorological service development, the production principles of television weather forecast program are discussed, and the equipment layout and signal flow diagram of the weather video production system are designed. Also the principles and configuration of the related core equipment, the production processes and working procedures of the county level video weather forecast programs are described. Combined with the actual situation of county level meteorological television production, a prefectural level meteorological video production system is designed, which includes such parts as moderator’s commentary collection, site recording and dubbing, program data compression, and transmission. The system achieves the centralized production and rapid transmission of county level television weather forecast programs, and improves working efficiency effectively.
According to the current situation of county level meteorological service development, the production principles of television weather forecast program are discussed, and the equipment layout and signal flow diagram of the weather video production system are designed. Also the principles and configuration of the related core equipment, the production processes and working procedures of the county level video weather forecast programs are described. Combined with the actual situation of county level meteorological television production, a prefectural level meteorological video production system is designed, which includes such parts as moderator’s commentary collection, site recording and dubbing, program data compression, and transmission. The system achieves the centralized production and rapid transmission of county level television weather forecast programs, and improves working efficiency effectively.
2015, 43(1):91-96.
Abstract:
Clear Air Turbulence (CAT) is one of extremely dangerous weather for aviation safety. CAT often takes place without visual weather phenomenon and cannot be detected by present airborne radar. CAT poses so great threat on aviation safety that researches on formation mechanisms and early warning and forecasting of CAT becomes quite necessary. The recent advances in CAT researches are reviewed and summarized by classified into three aspects: formation mechanisms, observing measures, and forecasting methods. There are some significant advances such as the important role of inertia gravity waves in CAT formation, valuable observations provided by new detecting methods, CAT numerical forecasting based on turbulence indices, and so on. Then, aspects which need to be improved further are analyzed, and the trends of researches on CAT are also prospected.
Clear Air Turbulence (CAT) is one of extremely dangerous weather for aviation safety. CAT often takes place without visual weather phenomenon and cannot be detected by present airborne radar. CAT poses so great threat on aviation safety that researches on formation mechanisms and early warning and forecasting of CAT becomes quite necessary. The recent advances in CAT researches are reviewed and summarized by classified into three aspects: formation mechanisms, observing measures, and forecasting methods. There are some significant advances such as the important role of inertia gravity waves in CAT formation, valuable observations provided by new detecting methods, CAT numerical forecasting based on turbulence indices, and so on. Then, aspects which need to be improved further are analyzed, and the trends of researches on CAT are also prospected.
2015, 43(1):97-102.
Abstract:
Based on China Meteorological Administration (CMA) ensemble numerical forecast products from the TIGGE data, the probability forecast experiments of the surface temperature are carried out. The results show that by using the methods of Downscaling (D), Systemic deviation (S), and combination of Downscaling and Systemic deviation (D S), through the Brier Score (BS) and Relative Operating Characteristic (ROC) tests, forecast skills have great improvement in 24〖CD*2〗 to 240〖CD*2〗hour forecasts. Particularly, the method D S is much better than methods D and S. Calculations of ranked probability score (RPS) indicate that the result of the method D S is greater than those of methods D and S before 168 hour forecasts； after 168 hours, the method D S is much less than that of the method S but better than the of the method D. Averagely, the probability forecasts of three methods are all skillful for surface temperature. The skill of probability forecast for surface temperature before 168 hours is greater than the skill for the later 168 hours.
Based on China Meteorological Administration (CMA) ensemble numerical forecast products from the TIGGE data, the probability forecast experiments of the surface temperature are carried out. The results show that by using the methods of Downscaling (D), Systemic deviation (S), and combination of Downscaling and Systemic deviation (D S), through the Brier Score (BS) and Relative Operating Characteristic (ROC) tests, forecast skills have great improvement in 24〖CD*2〗 to 240〖CD*2〗hour forecasts. Particularly, the method D S is much better than methods D and S. Calculations of ranked probability score (RPS) indicate that the result of the method D S is greater than those of methods D and S before 168 hour forecasts； after 168 hours, the method D S is much less than that of the method S but better than the of the method D. Averagely, the probability forecasts of three methods are all skillful for surface temperature. The skill of probability forecast for surface temperature before 168 hours is greater than the skill for the later 168 hours.
2015, 43(1):103-107.
Abstract:
By means of the daily observations data of 16 meteorological stations over Hulun Buir from 1973 to 2012, the day to day meteorological drought Composite Index (CI) in the growth season (from April to October) is calculated, and the characteristics of drought strength in Hulun Buir are analyzed. Using the methods of linear regression, signal to noise ratio test, M K mutation testing, and wavelet analysis, the spatial distribution, variation with time, mutation, and periodicity of drought intensity are studied. Analysis shows that meteorological droughts occur most frequently in the pastoral areas, with the strength decreasing from the southwest pastoral area to the northeast forest area; spring droughts have a decreasing trend, while summer, autumn droughts aggravating trends, particularly in the pastoral area in autumn; the variation periods in the agricultural areas are longer, 19 to 24 years, and those in the forest and pastoral areas are shorter, 5 to 12 years and 7 to 12 years.
By means of the daily observations data of 16 meteorological stations over Hulun Buir from 1973 to 2012, the day to day meteorological drought Composite Index (CI) in the growth season (from April to October) is calculated, and the characteristics of drought strength in Hulun Buir are analyzed. Using the methods of linear regression, signal to noise ratio test, M K mutation testing, and wavelet analysis, the spatial distribution, variation with time, mutation, and periodicity of drought intensity are studied. Analysis shows that meteorological droughts occur most frequently in the pastoral areas, with the strength decreasing from the southwest pastoral area to the northeast forest area; spring droughts have a decreasing trend, while summer, autumn droughts aggravating trends, particularly in the pastoral area in autumn; the variation periods in the agricultural areas are longer, 19 to 24 years, and those in the forest and pastoral areas are shorter, 5 to 12 years and 7 to 12 years.
2015, 43(1):108-115.
Abstract:
By means of the conventional weather charts and NCEP/NCAR 1°×1° reanalysis data， analyses are made of the climatic features, circulation patterns, rainfall distributions, and spatial structures of typical shear lines in Shandong Province. The results show that shear lines can be divided into cold and warm ones according to their thermodynamic properties. Cold shear lines can be divided into meridional and zonal ones according to the wind field structure. Shear lines appear frequently in July and August in a year. The occurrence of typical shear lines is closely related to the Subtropical High during rainy season. The occurrence of a meridional shear line is often accompanied by the stronger cell shaped Subtropical High when the eastward trough is blocked, and zonal one by the band shaped one, while westerly troughs are transformed into shear lines. Shear lines are associated with the positive vorticity column in profile, and the strongest vorticity is often found on shear lines. There are θse energy frontal zones on shear lines, with the cold shear lines tending toward the warm side and the warm lines in the middle. The ascending motion areas locate on shear lines and the warm side. For cold shear lines, the convergence of water vapor locates on a shear line and the cold air side, but the occurrence of water vapor convergence is mainly on a shear line for warm shear lines. The rainfall area lies in the northerly flow in the rear of the ground stationary front for cold shear lines, but lies in the easterly flow of the ground inverted trough for warm shear lines, both with a trough in the 500 hPa layer as the border. Relatively large precipitation occurs in the area between the ground projections of the shear line in the layer of 700 to 850 hPa. The shear line warm air mass or relatively warm air mass may also bring the dispersive short duration precipitation in appropriate triggering conditions.
By means of the conventional weather charts and NCEP/NCAR 1°×1° reanalysis data， analyses are made of the climatic features, circulation patterns, rainfall distributions, and spatial structures of typical shear lines in Shandong Province. The results show that shear lines can be divided into cold and warm ones according to their thermodynamic properties. Cold shear lines can be divided into meridional and zonal ones according to the wind field structure. Shear lines appear frequently in July and August in a year. The occurrence of typical shear lines is closely related to the Subtropical High during rainy season. The occurrence of a meridional shear line is often accompanied by the stronger cell shaped Subtropical High when the eastward trough is blocked, and zonal one by the band shaped one, while westerly troughs are transformed into shear lines. Shear lines are associated with the positive vorticity column in profile, and the strongest vorticity is often found on shear lines. There are θse energy frontal zones on shear lines, with the cold shear lines tending toward the warm side and the warm lines in the middle. The ascending motion areas locate on shear lines and the warm side. For cold shear lines, the convergence of water vapor locates on a shear line and the cold air side, but the occurrence of water vapor convergence is mainly on a shear line for warm shear lines. The rainfall area lies in the northerly flow in the rear of the ground stationary front for cold shear lines, but lies in the easterly flow of the ground inverted trough for warm shear lines, both with a trough in the 500 hPa layer as the border. Relatively large precipitation occurs in the area between the ground projections of the shear line in the layer of 700 to 850 hPa. The shear line warm air mass or relatively warm air mass may also bring the dispersive short duration precipitation in appropriate triggering conditions.
2015, 43(1):116-124.
Abstract:
The environmental conditions, trigger mechanisms, and Doppler radar echo characteristics of a local strong hailstorm occurred in the central Zhejiang province on 29 May 2013 are analyzed based on the data of NCEP reanalysis, conventional weather observation and regional automatic weather station, lighting and Doppler radar measurements. The results show that the local severe convective weather occurred in the background of the northeast cold vortex; the convective instability of the atmosphere increased while the cold advection in the upper layer moved southward and the warm advection in the lower layer moved northward; the sheer line, cold air, and surface convergence lines were important trigger mechanisms for the severe convective weather while the instability of thermal energy increased, at the same time; the convergence line of the surface also played the role of organizing strong convection. The higher potential vorticity in the isentropic surface contributed to the genesis and development of the super cell storm. The revised sounding data indicate that it is favorable for local hailstorm weather happened when the strong potential instability， moderate vertical wind shear, and sufficient water vapor in the lower layer appeared with a higher height of the 0 ℃ layer in early summer. The warm moist air in the lower layer flowed into the updraft area by the increased flow suction effect, and accelerated, leading to the ground wind generation. The super cell storm was formed, resulted from the organized multiple strong convective echo centers by a meso cyclone, inducing the local severe hailstorm weather.
The environmental conditions, trigger mechanisms, and Doppler radar echo characteristics of a local strong hailstorm occurred in the central Zhejiang province on 29 May 2013 are analyzed based on the data of NCEP reanalysis, conventional weather observation and regional automatic weather station, lighting and Doppler radar measurements. The results show that the local severe convective weather occurred in the background of the northeast cold vortex; the convective instability of the atmosphere increased while the cold advection in the upper layer moved southward and the warm advection in the lower layer moved northward; the sheer line, cold air, and surface convergence lines were important trigger mechanisms for the severe convective weather while the instability of thermal energy increased, at the same time; the convergence line of the surface also played the role of organizing strong convection. The higher potential vorticity in the isentropic surface contributed to the genesis and development of the super cell storm. The revised sounding data indicate that it is favorable for local hailstorm weather happened when the strong potential instability， moderate vertical wind shear, and sufficient water vapor in the lower layer appeared with a higher height of the 0 ℃ layer in early summer. The warm moist air in the lower layer flowed into the updraft area by the increased flow suction effect, and accelerated, leading to the ground wind generation. The super cell storm was formed, resulted from the organized multiple strong convective echo centers by a meso cyclone, inducing the local severe hailstorm weather.
2015, 43(1):125-132.
Abstract:
To establish the meteorological index for farming activities of wheat, the precipitation and soil moisture indexes for the main mechanized farming activities in Anhui Huaibei Plain are designed though qualitative and quantitative statistical analysis, based on the historical data of farming activities and contemporaneous precipitation and soil moisture data of many years. The results show that in wheat fields, the suitable soil moisture indexes for soil preparation (fertilization), sowing, and harvesting are 578% to 870%, 643% to 899%, and ≤467%, respectively. When the soil moisture index is between 50% and 55%, after a rainfall process, the suitable precipitation indexes for soil preparation (fertilization), sowing and harvesting are 10 to 25 mm, 20 to 25 mm, and ≤3 mm, as well as 3 to 20 mm, 5 to 25 mm, and ≤3 mm, respectively. When the soil moisture is 70%, the precipitation indexes for soil preparation and sowing are 3 to 5 mm and 3 to 10 mm. However, when the soil moisture is 70% to 80%, no matter how much the precipitation is, it is not suitable for harvesting, sowing, and soil preparation.
To establish the meteorological index for farming activities of wheat, the precipitation and soil moisture indexes for the main mechanized farming activities in Anhui Huaibei Plain are designed though qualitative and quantitative statistical analysis, based on the historical data of farming activities and contemporaneous precipitation and soil moisture data of many years. The results show that in wheat fields, the suitable soil moisture indexes for soil preparation (fertilization), sowing, and harvesting are 578% to 870%, 643% to 899%, and ≤467%, respectively. When the soil moisture index is between 50% and 55%, after a rainfall process, the suitable precipitation indexes for soil preparation (fertilization), sowing and harvesting are 10 to 25 mm, 20 to 25 mm, and ≤3 mm, as well as 3 to 20 mm, 5 to 25 mm, and ≤3 mm, respectively. When the soil moisture is 70%, the precipitation indexes for soil preparation and sowing are 3 to 5 mm and 3 to 10 mm. However, when the soil moisture is 70% to 80%, no matter how much the precipitation is, it is not suitable for harvesting, sowing, and soil preparation.
2015, 43(1):133-137.
Abstract:
As for freezing injury prevention in greenhouse vegetables， the temperature adjusting method by building sheds and covering multi layer plastic films is used widely. Temperature observation of microclimate environment in greenhouse with this multi layer plastic film covers was conducted, and temperature correlativity inside and outside the greenhouse is analyzed. The unary linear regression forecast models of daily minimum temperature in greenhouse are built, and daily minimum temperature in greenhouse is predicted by using the models and the daily minimum temperature of weather forecasts. The number of plastic film covers was determined on the basis of the forecast results and vegetable freezing injury indexes, and the countermeasure with the plastic film cover method is proposed to prevent freezing injury for greenhouse vegetables, which give references for the safe production of facility agriculture.
As for freezing injury prevention in greenhouse vegetables， the temperature adjusting method by building sheds and covering multi layer plastic films is used widely. Temperature observation of microclimate environment in greenhouse with this multi layer plastic film covers was conducted, and temperature correlativity inside and outside the greenhouse is analyzed. The unary linear regression forecast models of daily minimum temperature in greenhouse are built, and daily minimum temperature in greenhouse is predicted by using the models and the daily minimum temperature of weather forecasts. The number of plastic film covers was determined on the basis of the forecast results and vegetable freezing injury indexes, and the countermeasure with the plastic film cover method is proposed to prevent freezing injury for greenhouse vegetables, which give references for the safe production of facility agriculture.
2015, 43(1):138-144.
Abstract:
The multi year spatial distribution and variations of liquid water content and particle effective radiuses in Southwest China are analyzed by using MODIS data from NASA Goddard Earth Science DAAC from 2000 to 2010 The results show that annual and seasonal liquid water content at high latitudes is greater than that at low latitudes; the annual and seasonal particle effective radiuses have the opposite distributions. Liquid water content has seasonal difference, higher in autumn and summer, and lower in spring and winter; particle effective radiuses have smaller seasonal difference. There is a decreasing trend in annual liquid water content from 2000 to 2010, as well as in spring and winter, and there is no obvious trend in particle effective radius.
The multi year spatial distribution and variations of liquid water content and particle effective radiuses in Southwest China are analyzed by using MODIS data from NASA Goddard Earth Science DAAC from 2000 to 2010 The results show that annual and seasonal liquid water content at high latitudes is greater than that at low latitudes; the annual and seasonal particle effective radiuses have the opposite distributions. Liquid water content has seasonal difference, higher in autumn and summer, and lower in spring and winter; particle effective radiuses have smaller seasonal difference. There is a decreasing trend in annual liquid water content from 2000 to 2010, as well as in spring and winter, and there is no obvious trend in particle effective radius.
2015, 43(1):145-150.
Abstract:
Forecasting indexes of dense fog formation and dissipation along highway are summarized by analyzing the meteorological element features of 84 observation samples from the traffic meteorological observation data along the Beijing Qinhuangdao Highway. The visibility during the dense fogs almost keeps unchanged. Small rise during the decline of temperature provides a good indicator of sudden visibility decreasing. The relative humidity can be up to greater than 80% in an hour before the sudden visibility decreasing. General dense fogs mostly appear during the continuous linear decreasing period of temperature after temperature fluctuation. The relative humidity can reach up to greater than 90%, which happens 15 hour before the visibility decreases to less than 500 m, and the relative humidity reaches the saturated state before the visibility decreases to less than 50 m. When fog dissipation is caused by cold air, forecast should focus on the time when the cold front reaches the highway; when fog dissipation is caused by radiative temperature rise, forecast should focus on the judgment of weather conditions and temperature increasing speed.
Forecasting indexes of dense fog formation and dissipation along highway are summarized by analyzing the meteorological element features of 84 observation samples from the traffic meteorological observation data along the Beijing Qinhuangdao Highway. The visibility during the dense fogs almost keeps unchanged. Small rise during the decline of temperature provides a good indicator of sudden visibility decreasing. The relative humidity can be up to greater than 80% in an hour before the sudden visibility decreasing. General dense fogs mostly appear during the continuous linear decreasing period of temperature after temperature fluctuation. The relative humidity can reach up to greater than 90%, which happens 15 hour before the visibility decreases to less than 500 m, and the relative humidity reaches the saturated state before the visibility decreases to less than 50 m. When fog dissipation is caused by cold air, forecast should focus on the time when the cold front reaches the highway; when fog dissipation is caused by radiative temperature rise, forecast should focus on the judgment of weather conditions and temperature increasing speed.
2015, 43(1):151-155.
Abstract:
By using the hourly visibility and runway visual range (RVR) observation of nearly 20 years (1996〖CD*2〗2013), the annual, seasonal, and daily variation characteristics of low visibility (＜800 m) and low RVR (＜550 m) in the Shanghai Hongqiao International Airport are analyzed. Results show that low visibility appeared more frequently than low RVR in almost all years except 2002 From 1996 to 2013, the numbers of both low visibility and low RVR events showed decreasing trends by the rate of 57 times/year and 26 times/year, respectively. The low visibility and low RVR appeared most frequently in December, while the least in September. For both, November to February was the high frequency period and May to September is the low frequency period. As for daily variation characteristics, low visibility and low RVR events occur usually in 19:00〖CD*2〗01:00 UTC with the peak at 23:00 UTC. During the night, the appearing rates of low visibility are greater first, and afterwards the impaction of low RVR events becomes prominent gradually from midnight to early morning. Along with the decreasing of visibility, the number of low visibility events decreases at first then increases. Meanwhile, the number of low RVR events is relatively greater in the ranges of 150〖CD*2〗200 m and 0〖CD*2〗50 m.
By using the hourly visibility and runway visual range (RVR) observation of nearly 20 years (1996〖CD*2〗2013), the annual, seasonal, and daily variation characteristics of low visibility (＜800 m) and low RVR (＜550 m) in the Shanghai Hongqiao International Airport are analyzed. Results show that low visibility appeared more frequently than low RVR in almost all years except 2002 From 1996 to 2013, the numbers of both low visibility and low RVR events showed decreasing trends by the rate of 57 times/year and 26 times/year, respectively. The low visibility and low RVR appeared most frequently in December, while the least in September. For both, November to February was the high frequency period and May to September is the low frequency period. As for daily variation characteristics, low visibility and low RVR events occur usually in 19:00〖CD*2〗01:00 UTC with the peak at 23:00 UTC. During the night, the appearing rates of low visibility are greater first, and afterwards the impaction of low RVR events becomes prominent gradually from midnight to early morning. Along with the decreasing of visibility, the number of low visibility events decreases at first then increases. Meanwhile, the number of low RVR events is relatively greater in the ranges of 150〖CD*2〗200 m and 0〖CD*2〗50 m.
2015, 43(1):156-161.
Abstract:
Based on the recent 32 year meteorological data from Wuhan Observatory and 5 year data from regional encryption weather stations, the first day of each season and their lengths for the past decade in Wuhan are calculated and compared with the variation characteristics of four seasons in the past years. The human settlement climate suitability evaluation index system based on temperature and humidity index, wind effect index, and apparent temperature index is adopted for human settlement climate suitability zoning in a typical low carbon livable community in Wuhan. The results show that in the last decade, summer becomes longer while spring, autumn, and winter are slightly shorter in Wuhan, so that the number of climate suitable days for urban human settlement is reducing; in a typical low carbon livable community, the length of recent 10 year average climate suitable season is 129 days, while that of cooling season 72 days, dehumidification season 74 days, cold season 34 days and heating season 132 days. The evaluation results of community human settlement climate suitability can provide a basis for scientific scheduling of community energy and the rational use of natural climate resources.
Based on the recent 32 year meteorological data from Wuhan Observatory and 5 year data from regional encryption weather stations, the first day of each season and their lengths for the past decade in Wuhan are calculated and compared with the variation characteristics of four seasons in the past years. The human settlement climate suitability evaluation index system based on temperature and humidity index, wind effect index, and apparent temperature index is adopted for human settlement climate suitability zoning in a typical low carbon livable community in Wuhan. The results show that in the last decade, summer becomes longer while spring, autumn, and winter are slightly shorter in Wuhan, so that the number of climate suitable days for urban human settlement is reducing; in a typical low carbon livable community, the length of recent 10 year average climate suitable season is 129 days, while that of cooling season 72 days, dehumidification season 74 days, cold season 34 days and heating season 132 days. The evaluation results of community human settlement climate suitability can provide a basis for scientific scheduling of community energy and the rational use of natural climate resources.
2015, 43(1):162-167.
Abstract:
Based on the 10 minute maximum wind speed data of 48 weather stations over the eastern Inner Mongolia, the distribution maps of extreme wind speed of 30 , 50 , and 100 year return periods, which are calculated by using the type Ⅰextreme distribution function, are drawn and analyzed. The characteristics of maximum wind speed in 1980-2010 are also analyzed. The results show that the annual maximum wind displayed a phased downward trend in the past 42 years, with the decreasing rate being 14 m/s per 10 years. The annual variation of maximum wind shows a double peak curve with the annual maximum wind in spring mainly. 〖JP2〗The annual maximum wind speed mainly appears in west direction (W to NNW) with a frequency of 70%. In general, the distributions of maximum wind and extreme wind speeds show a decreasing trend from west to east, but has obvious regional characteristics. The results can provide important references for the design, operation, and maintenance of the eastern Inner Mongolia power grid.
Based on the 10 minute maximum wind speed data of 48 weather stations over the eastern Inner Mongolia, the distribution maps of extreme wind speed of 30 , 50 , and 100 year return periods, which are calculated by using the type Ⅰextreme distribution function, are drawn and analyzed. The characteristics of maximum wind speed in 1980-2010 are also analyzed. The results show that the annual maximum wind displayed a phased downward trend in the past 42 years, with the decreasing rate being 14 m/s per 10 years. The annual variation of maximum wind shows a double peak curve with the annual maximum wind in spring mainly. 〖JP2〗The annual maximum wind speed mainly appears in west direction (W to NNW) with a frequency of 70%. In general, the distributions of maximum wind and extreme wind speeds show a decreasing trend from west to east, but has obvious regional characteristics. The results can provide important references for the design, operation, and maintenance of the eastern Inner Mongolia power grid.
2015, 43(1):168-171.
Abstract:
The observation sites generally located in open areas, and wind sensors are installed at the altitude of 10 meters, so it is easily damaged by lightning. The circuit diagram is drawn according to the wind direction sensor, and the working principles are analyzed. A gray code detection circuit is designed, which can conveniently and intuitively identify the failure bit in the 7 bit LEDs, so to find the reason and related components for failure. A simple method of replacing patch chips, in case of no special tool, is introduced, and some examples are given.
The observation sites generally located in open areas, and wind sensors are installed at the altitude of 10 meters, so it is easily damaged by lightning. The circuit diagram is drawn according to the wind direction sensor, and the working principles are analyzed. A gray code detection circuit is designed, which can conveniently and intuitively identify the failure bit in the 7 bit LEDs, so to find the reason and related components for failure. A simple method of replacing patch chips, in case of no special tool, is introduced, and some examples are given.
2015, 43(1):172-174.
Abstract:
In order to make the field calibration specifications for AWS evaporation sensors suitable for the actual work better, according to the characteristics of ultrasonic evaporation sensors, work experiences from field calibration, and some experimental data, some problems existed in calibration procedures of AWS evaporation sensors are discovered and analyzed, and some suggestions are proposed, such as making repeatable measurements, changing maximum permissible error to ± (01 mm+15% H), and describing the calibration method clearly in use of the whole standard modules, so to improve the field calibration indexes and methods of ultrasonic evaporation sensors. It provides references for the preparation of new calibration specifications.
In order to make the field calibration specifications for AWS evaporation sensors suitable for the actual work better, according to the characteristics of ultrasonic evaporation sensors, work experiences from field calibration, and some experimental data, some problems existed in calibration procedures of AWS evaporation sensors are discovered and analyzed, and some suggestions are proposed, such as making repeatable measurements, changing maximum permissible error to ± (01 mm+15% H), and describing the calibration method clearly in use of the whole standard modules, so to improve the field calibration indexes and methods of ultrasonic evaporation sensors. It provides references for the preparation of new calibration specifications.
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.