Volume 42,Issue 6,2014 Table of Contents
2014, 42(6):951-956.
Abstract:
An analysis is made of the calibration principles and limitations for differential reflectivity （〖WTBX〗Z〖WTBZ〗dr） of dual polarization weather radar using external targets such as drizzle, sun, Bragg scattering at the top of the convective boundary layer and ground clutter. An engineering calibration method that can obtain the〖WTBX〗 Z〖WTBZ〗dr bias induced by transmitter, receiver, and antenna online is presented. In addition, a method is put forward to improve 〖WTBX〗Z〖WTBZ〗dr measurement accuracy, which compensates variations in transmitted power and receiver gain by measuring coupled transmitted power and backscattered power of meteorological targets at the output of digital receiver during each pulse repetition time in horizontal and vertical channels, respectively. These two engineering calibration methods are applicable to radar that simultaneously transmit and receive waves in horizontal and vertical polarization channels and can satisfy operational requirements for online calibration.
An analysis is made of the calibration principles and limitations for differential reflectivity （〖WTBX〗Z〖WTBZ〗dr） of dual polarization weather radar using external targets such as drizzle, sun, Bragg scattering at the top of the convective boundary layer and ground clutter. An engineering calibration method that can obtain the〖WTBX〗 Z〖WTBZ〗dr bias induced by transmitter, receiver, and antenna online is presented. In addition, a method is put forward to improve 〖WTBX〗Z〖WTBZ〗dr measurement accuracy, which compensates variations in transmitted power and receiver gain by measuring coupled transmitted power and backscattered power of meteorological targets at the output of digital receiver during each pulse repetition time in horizontal and vertical channels, respectively. These two engineering calibration methods are applicable to radar that simultaneously transmit and receive waves in horizontal and vertical polarization channels and can satisfy operational requirements for online calibration.
2014, 42(6):957-963.
Abstract:
Unusual echoes on 3 April and 3 July, 2013 are studied by CINRAD/SA and radiosonde data. The results indicate that radar servo system faults resulted in the dislocation of scan line azimuth, which led to the silk shaped echoes on 3 April 2013 The unusual echoes on 3 July contain cloud and super refraction radar echoes. The reason why the area of 15° was greater than 05° is that the engineer did not adjust time appropriately, and the radar system was adjusted by using wrong calculation data while calibrating radar beam pointing on April 6 The formula and algorithm of parameters for the calibration of radar azimuth and elevation by the solar method are given, and the fault phenomenon is imitated. It is pointed out that the error data generated by radar hardware faults and calibration errors have influence on forecasters in analyzing weather correctly. The data quality control method for silk shaped echoes is introduced. It is suggested that a high precision time service system should be equipped at radar sites, which can provide experiences and scientific evidences for super refraction echo identification and radar routine maintenance.
Unusual echoes on 3 April and 3 July, 2013 are studied by CINRAD/SA and radiosonde data. The results indicate that radar servo system faults resulted in the dislocation of scan line azimuth, which led to the silk shaped echoes on 3 April 2013 The unusual echoes on 3 July contain cloud and super refraction radar echoes. The reason why the area of 15° was greater than 05° is that the engineer did not adjust time appropriately, and the radar system was adjusted by using wrong calculation data while calibrating radar beam pointing on April 6 The formula and algorithm of parameters for the calibration of radar azimuth and elevation by the solar method are given, and the fault phenomenon is imitated. It is pointed out that the error data generated by radar hardware faults and calibration errors have influence on forecasters in analyzing weather correctly. The data quality control method for silk shaped echoes is introduced. It is suggested that a high precision time service system should be equipped at radar sites, which can provide experiences and scientific evidences for super refraction echo identification and radar routine maintenance.
2014, 42(6):964-968.
Abstract:
The method of Mean Time Between Failures (MTBF) is used commonly to evaluate the status of CINRAD/SA radar operation, which ignores the fact that different parts have different influences on the operation status of radar. However, only numerical degrees cannot reflect the quality of maintenance work. A new method is proposed, in which CINRAD/SA radar is divided into parts according to the radar structure, and after each part is given a weight on the basis of its influence on the operation of radar, the ranking of radar operation and its grade of membership are computed by means of membership function. Simulation using the operation logs of 8 CINRAD/SA radar shows that the algorithm is more accurate and effective than MTBF approach.
The method of Mean Time Between Failures (MTBF) is used commonly to evaluate the status of CINRAD/SA radar operation, which ignores the fact that different parts have different influences on the operation status of radar. However, only numerical degrees cannot reflect the quality of maintenance work. A new method is proposed, in which CINRAD/SA radar is divided into parts according to the radar structure, and after each part is given a weight on the basis of its influence on the operation of radar, the ranking of radar operation and its grade of membership are computed by means of membership function. Simulation using the operation logs of 8 CINRAD/SA radar shows that the algorithm is more accurate and effective than MTBF approach.
2014, 42(6):969-972.
Abstract:
The operating process of the Discharge Trigger Controller 3A11 is discussed in details，and the electronic circuits, and the corresponding protection functions with the functional block diagram are analyzed. The test method of key point waveforms is described and the relationship of the trigger control signal and protection signal to sample feedback signal is clarified. The adjustment methods of the relevant working point are introduced in tabular form. From the radar system maintenance experiences, some basic electronic trouble shooting thoughts and effective maintenance methods are discussed and summarized with the relevant alarm massages and the corresponding case analyses.
The operating process of the Discharge Trigger Controller 3A11 is discussed in details，and the electronic circuits, and the corresponding protection functions with the functional block diagram are analyzed. The test method of key point waveforms is described and the relationship of the trigger control signal and protection signal to sample feedback signal is clarified. The adjustment methods of the relevant working point are introduced in tabular form. From the radar system maintenance experiences, some basic electronic trouble shooting thoughts and effective maintenance methods are discussed and summarized with the relevant alarm massages and the corresponding case analyses.
2014, 42(6):973-977.
Abstract:
The measuring performance of GE Dew Point Analyzer is studied. By studying the problems encountered in use, operating requirements, such as the choice of probes, the installation place of a probe, gas tightness, and control of flow, are summarized. Many static tests were conducted with the two pressure humidity generator as the standard. The results show that the relative humidity measured by GE Dew Point Analyzer is lower than that by the two pressure humidity generator; for low temperature, the measurement error is larger and more dispersive. As temperature decreases, the sensitivity declines and the repeatability characteristic becomes worse. At -10 ℃, its performance decreases significantly. The findings are of significance for determining the measuring performance and improving the accuracy and reliability of Dew Point Analyzer.
The measuring performance of GE Dew Point Analyzer is studied. By studying the problems encountered in use, operating requirements, such as the choice of probes, the installation place of a probe, gas tightness, and control of flow, are summarized. Many static tests were conducted with the two pressure humidity generator as the standard. The results show that the relative humidity measured by GE Dew Point Analyzer is lower than that by the two pressure humidity generator; for low temperature, the measurement error is larger and more dispersive. As temperature decreases, the sensitivity declines and the repeatability characteristic becomes worse. At -10 ℃, its performance decreases significantly. The findings are of significance for determining the measuring performance and improving the accuracy and reliability of Dew Point Analyzer.
2014, 42(6):978-982.
Abstract:
For wiring difficulties and poor mobility problems of temperature and humidity, dew point, and other measuring instruments in agro meteorological monitoring, a temperature and humidity node is designed based on WSN, which is constituted by the high precision temperature and humidity sensor SHT75, CC2530 wireless processor, SD2003A clock chip, GPS module TU 30, and other circuits, and the peripheral circuit design of each functional module is completed. Using the Zigbee protocol for networking, after the testing procedures of temperature and humidity, the node sends the data to the network through wireless. This node can be used as a network node arranged in different positions in farmlands, greenhouses or granary, constructing the monitoring system for agricultural services together with other meteorological network nodes and achieving the measurement of temperature, humidity, etc.
For wiring difficulties and poor mobility problems of temperature and humidity, dew point, and other measuring instruments in agro meteorological monitoring, a temperature and humidity node is designed based on WSN, which is constituted by the high precision temperature and humidity sensor SHT75, CC2530 wireless processor, SD2003A clock chip, GPS module TU 30, and other circuits, and the peripheral circuit design of each functional module is completed. Using the Zigbee protocol for networking, after the testing procedures of temperature and humidity, the node sends the data to the network through wireless. This node can be used as a network node arranged in different positions in farmlands, greenhouses or granary, constructing the monitoring system for agricultural services together with other meteorological network nodes and achieving the measurement of temperature, humidity, etc.
2014, 42(6):983-985.
Abstract:
Measurement uncertainty is a parameter that shows the credibility of calibration results. In order to ensure that the results of pressure sensors are correct and reliable, according to the requirements of the Standards JJG (meteorology) 001 2011 Pressure Sensor of Automatic Meteorological Station and JJF 10591 2012 Evaluation and Expression of Uncertainty in Measurement, using the MODEL 745 pressure calibrator as a standard device to calibrate a Vaisala PTB220 pressure sensor, a mathematical model is built, and the uncertainty sources, 〖JP2〗which have significant effects on the measurement results, are analyzed and listed. The pressure sensor test is conducted, and the uncertainty of its calibration results (02 hPa) is analyzed. The uncertainty evaluation method is of significance and reference value to other kinds of sensors.
Measurement uncertainty is a parameter that shows the credibility of calibration results. In order to ensure that the results of pressure sensors are correct and reliable, according to the requirements of the Standards JJG (meteorology) 001 2011 Pressure Sensor of Automatic Meteorological Station and JJF 10591 2012 Evaluation and Expression of Uncertainty in Measurement, using the MODEL 745 pressure calibrator as a standard device to calibrate a Vaisala PTB220 pressure sensor, a mathematical model is built, and the uncertainty sources, 〖JP2〗which have significant effects on the measurement results, are analyzed and listed. The pressure sensor test is conducted, and the uncertainty of its calibration results (02 hPa) is analyzed. The uncertainty evaluation method is of significance and reference value to other kinds of sensors.
2014, 42(6):986-991.
Abstract:
The AWS equipment in China is running daily, lacking of information reflecting its running status. In order to test the running status of the pressure sensor, a pressure forecasting model based on the time series analysis is proposed. Through this model, the next value can be estimated reasonably by using the latest values together with a confidence interval, and then compared with the actual data. If the actual data deviate from the confidence interval, then the pressure sensor is considered failed. The validity of the model 〖JP2〗ARMA is verified by the results of one forecasting example, and the best model is ARMA (2, 1) 〖JP〗with the forecast error being 0.
The AWS equipment in China is running daily, lacking of information reflecting its running status. In order to test the running status of the pressure sensor, a pressure forecasting model based on the time series analysis is proposed. Through this model, the next value can be estimated reasonably by using the latest values together with a confidence interval, and then compared with the actual data. If the actual data deviate from the confidence interval, then the pressure sensor is considered failed. The validity of the model 〖JP2〗ARMA is verified by the results of one forecasting example, and the best model is ARMA (2, 1) 〖JP〗with the forecast error being 0.
2014, 42(6):992-996.
Abstract:
Soil moisture monitoring plays an important role in agricultural production and scientific researches, so automatic soil moisture measurements are widely applied. The operational verification process of the new DZN3 type automatic soil moisture station is introduced. The report rate of automatic observation data and the determination of soil constant are analyzed and compared with the manual observation data in detail. Automatic soil moisture observation stations that can put into operation are confirmed through the way of contrast testing. The reasons for failing to pass the test are also analyzed, and some suggestions are given for future operational tests.
Soil moisture monitoring plays an important role in agricultural production and scientific researches, so automatic soil moisture measurements are widely applied. The operational verification process of the new DZN3 type automatic soil moisture station is introduced. The report rate of automatic observation data and the determination of soil constant are analyzed and compared with the manual observation data in detail. Automatic soil moisture observation stations that can put into operation are confirmed through the way of contrast testing. The reasons for failing to pass the test are also analyzed, and some suggestions are given for future operational tests.
2014, 42(6):997-1001.
Abstract:
With the increasing importance of equipment support services in the meteorological department, to study the assessment methods of equipment support and to evaluate scientifically the support quality become important. Three independent evaluation systems of the equipment support services are established, and based on the independence of monitoring, maintenance， and repair work, an assessment method of comprehensive performance for equipment support is put forward, in which the weighted average of monitoring rate, failure rate, and repair rate is used to evaluate the comprehensive performance of equipment support, depending on the responsibility of the department. The evaluation indicators and ideas have a certain reference value in establishing an evaluation system for meteorological equipment support services.
With the increasing importance of equipment support services in the meteorological department, to study the assessment methods of equipment support and to evaluate scientifically the support quality become important. Three independent evaluation systems of the equipment support services are established, and based on the independence of monitoring, maintenance， and repair work, an assessment method of comprehensive performance for equipment support is put forward, in which the weighted average of monitoring rate, failure rate, and repair rate is used to evaluate the comprehensive performance of equipment support, depending on the responsibility of the department. The evaluation indicators and ideas have a certain reference value in establishing an evaluation system for meteorological equipment support services.
2014, 42(6):1002-1008.
Abstract:
By using such five methods as Inverse Distance Weighted (IDW), Ordinary Kriging (OK), Radial Basis Function (RBF), Three Dimensional and Quadratic Trend Surface, and Geographically Weighted Regression (GWR), the spatial distributions of the average temperature for 30 years （January, April, July, October and anniversary） in Yunnan Province are interpolated and contrastively analyzed on the basis of the data of 125 weather stations from 1981 to 2010 The results show that the simulation accuracies of the interpolation for three conventional methods (namely IDW, OK and RBF) are unsatisfactory under the condition of complicated geographical environments in Yunnan; the simulation results of three dimensional and quadratic trend surface and GWR to interpolate the spatial distribution of temperature are preferable. The mean absolute errors （MAE） of cross check results for three dimensional and quadratic trend surface are 043 to 102 ℃, with the root mean square errors （RMSE） being 067 to 177 ℃. MAE of the interpolation results of GWR models are less than 065 ℃ and its RMSE is below 08 ℃. The cross check results indicate that the simulation error of GWR model to simulate the spatial distribution of average temperature in Yunnan was the smallest among the five single interpolation methods. Further, by using the superposition method of “GWR interpolation + IDW residual interpolation,” the absolute errors of 64% interpolation results for tested weather stations, including monthly values and annual values, are less than 05 ℃ and the relative errors of 74% interpolation results are below 5%. Meanwhile, the determination coefficients (R2) of the regression relation between measured and interpolated values are above 09 under the condition of using the superposition method.
By using such five methods as Inverse Distance Weighted (IDW), Ordinary Kriging (OK), Radial Basis Function (RBF), Three Dimensional and Quadratic Trend Surface, and Geographically Weighted Regression (GWR), the spatial distributions of the average temperature for 30 years （January, April, July, October and anniversary） in Yunnan Province are interpolated and contrastively analyzed on the basis of the data of 125 weather stations from 1981 to 2010 The results show that the simulation accuracies of the interpolation for three conventional methods (namely IDW, OK and RBF) are unsatisfactory under the condition of complicated geographical environments in Yunnan; the simulation results of three dimensional and quadratic trend surface and GWR to interpolate the spatial distribution of temperature are preferable. The mean absolute errors （MAE） of cross check results for three dimensional and quadratic trend surface are 043 to 102 ℃, with the root mean square errors （RMSE） being 067 to 177 ℃. MAE of the interpolation results of GWR models are less than 065 ℃ and its RMSE is below 08 ℃. The cross check results indicate that the simulation error of GWR model to simulate the spatial distribution of average temperature in Yunnan was the smallest among the five single interpolation methods. Further, by using the superposition method of “GWR interpolation + IDW residual interpolation,” the absolute errors of 64% interpolation results for tested weather stations, including monthly values and annual values, are less than 05 ℃ and the relative errors of 74% interpolation results are below 5%. Meanwhile, the determination coefficients (R2) of the regression relation between measured and interpolated values are above 09 under the condition of using the superposition method.
2014, 42(6):1009-1013.
Abstract:
Several methods such as the typical radiation data quality method, radiation data variation analysis, comparison of Sunshine duration between the manual and instrument measurements, and statistical analysis of solar global radiation and the other radiation are used to analyze the quality of the solar radiation data in the Baodi Meteorological Station (54525). The results show that during the test run, there was few missing data; 100% of global radiation and diffuse radiation and 85% of direct radiation passed the BSRN recommended QC tests and 100% net radiation passed the equipment observation threshold test; the solar radiation variation corresponds to reality; the manual and instrument sunshine duration measurements have good consistency; the linear changes among the global radiation, diffuse radiation, and the sunshine duration are the same with the classic study results. Overall, the data of this radiation observing system has high availability and can fulfill the daily business needs.
Several methods such as the typical radiation data quality method, radiation data variation analysis, comparison of Sunshine duration between the manual and instrument measurements, and statistical analysis of solar global radiation and the other radiation are used to analyze the quality of the solar radiation data in the Baodi Meteorological Station (54525). The results show that during the test run, there was few missing data; 100% of global radiation and diffuse radiation and 85% of direct radiation passed the BSRN recommended QC tests and 100% net radiation passed the equipment observation threshold test; the solar radiation variation corresponds to reality; the manual and instrument sunshine duration measurements have good consistency; the linear changes among the global radiation, diffuse radiation, and the sunshine duration are the same with the classic study results. Overall, the data of this radiation observing system has high availability and can fulfill the daily business needs.
2014, 42(6):1014-1018.
Abstract:
The Automated Weather Phenomenon Observation System can observe condensation and record the occurring time of weather phenomena by using image identification technology. The time of condensation occurrrsing and the data of soil moisture in the shallow soil layer are analyzed, and the relationship is established by using the data of the automatedic present weather observation system and the soil moisture observation equipment installed at Pinggu Station in Beijing from April to September in 2011 The condensation phenomenon appears earlier when the soil moisture of 0 to 10 cm layer is higher. On the contrary, the condensation phenomenon appears later when the soil moisture of 0 to 10 cm layer is lower, and the condensation phenomenon does not appear when the soil moisture of 0 to 10 cm layer is too low. In order to everify the the certain relationship between the condensation time and soil moisture, the relationship between the condensation time and the number of days after the rainfall in Huairou, Mentougou, Chaoyang, Daxing, and Yanqing stations of Beijing are analyzed.
The Automated Weather Phenomenon Observation System can observe condensation and record the occurring time of weather phenomena by using image identification technology. The time of condensation occurrrsing and the data of soil moisture in the shallow soil layer are analyzed, and the relationship is established by using the data of the automatedic present weather observation system and the soil moisture observation equipment installed at Pinggu Station in Beijing from April to September in 2011 The condensation phenomenon appears earlier when the soil moisture of 0 to 10 cm layer is higher. On the contrary, the condensation phenomenon appears later when the soil moisture of 0 to 10 cm layer is lower, and the condensation phenomenon does not appear when the soil moisture of 0 to 10 cm layer is too low. In order to everify the the certain relationship between the condensation time and soil moisture, the relationship between the condensation time and the number of days after the rainfall in Huairou, Mentougou, Chaoyang, Daxing, and Yanqing stations of Beijing are analyzed.
2014, 42(6):1019-1022.
Abstract:
Based on the group sending function of the micro message public service platform, a micro message virtual server for meteorological early warning information release is created. The meteorological early warning information release system is established in combination with the existing meteorological information in the Qianjiang Meteorological Service, which realizes the function of text information push, information query, user management, and human computer interaction. The system adopts the multi process parallel computing to release early warning information quickly, and a private Micro Message service number is applied for voice warning messages. The meteorological early warning information release system enhances the capacity of meteorological disaster prevention and mitigation in Qianjiang.
Based on the group sending function of the micro message public service platform, a micro message virtual server for meteorological early warning information release is created. The meteorological early warning information release system is established in combination with the existing meteorological information in the Qianjiang Meteorological Service, which realizes the function of text information push, information query, user management, and human computer interaction. The system adopts the multi process parallel computing to release early warning information quickly, and a private Micro Message service number is applied for voice warning messages. The meteorological early warning information release system enhances the capacity of meteorological disaster prevention and mitigation in Qianjiang.
2014, 42(6):1023-1027.
Abstract:
The hindcast experiments of winter temperature and rainfall over North China from 1991 to 2010 are carried out by using a regional climate model (RegCM_NCC) nested a global atmosphere ocean coupled model (CGCM_NCC). Five operational assessment parameters of the National Climate Center are used to assess the hindcast of winter temperature and rainfall of RegCM_NCC from 1991 to 2010 The results show the averaged P score of the winter temperature is 704, and the scores in most years are greater than 60, those in 11 year are greater than 80 Compared with the random forecast skill and forecast skill of climate 11 years hindcast display positive skill. The P score of winter precipitation in 13 years are greater than 60, and the average is 663 Compared with the random forecast skill, the 8 year hindcast displays positive skill. Compared with the forecast skill of climate, the 11 year hindcast displays also positive skill. Either negative sea surface temperature anomaly in Nino 34 region or negative EA/WR index in winter may enhance the P score of winter temperature.
The hindcast experiments of winter temperature and rainfall over North China from 1991 to 2010 are carried out by using a regional climate model (RegCM_NCC) nested a global atmosphere ocean coupled model (CGCM_NCC). Five operational assessment parameters of the National Climate Center are used to assess the hindcast of winter temperature and rainfall of RegCM_NCC from 1991 to 2010 The results show the averaged P score of the winter temperature is 704, and the scores in most years are greater than 60, those in 11 year are greater than 80 Compared with the random forecast skill and forecast skill of climate 11 years hindcast display positive skill. The P score of winter precipitation in 13 years are greater than 60, and the average is 663 Compared with the random forecast skill, the 8 year hindcast displays positive skill. Compared with the forecast skill of climate, the 11 year hindcast displays also positive skill. Either negative sea surface temperature anomaly in Nino 34 region or negative EA/WR index in winter may enhance the P score of winter temperature.
2014, 42(6):1028-1038.
Abstract:
Various atmospheric systems and the indexes affecting precipitation and temperature in China are examined. The parameters of high independence and high correlation coefficients were chosen as prediction factors to predict the monthly precipitation and temperature of 160 observation stations through downscaling method. By using the filtration method to determine primary prediction factors and establishing the linear regression equations dynamically, the Regional Monthly Climate Forecast Model (RMCFM) is built up, in which the operational interface for communication between people and computer is set up. RMCFM can make monthly climate prediction of monthly precipitation and temperature over 160 stations in China. Practice proved that RMCFM is of high calculating speed and clear structure, and easy to operate. The real time daily grid reanalysis data in NCEP/NCAR were used as pretreatment data for RMCFM. It is proved that RMCFM improved the capability of regional climate prediction.
Various atmospheric systems and the indexes affecting precipitation and temperature in China are examined. The parameters of high independence and high correlation coefficients were chosen as prediction factors to predict the monthly precipitation and temperature of 160 observation stations through downscaling method. By using the filtration method to determine primary prediction factors and establishing the linear regression equations dynamically, the Regional Monthly Climate Forecast Model (RMCFM) is built up, in which the operational interface for communication between people and computer is set up. RMCFM can make monthly climate prediction of monthly precipitation and temperature over 160 stations in China. Practice proved that RMCFM is of high calculating speed and clear structure, and easy to operate. The real time daily grid reanalysis data in NCEP/NCAR were used as pretreatment data for RMCFM. It is proved that RMCFM improved the capability of regional climate prediction.
2014, 42(6):1039-1046.
Abstract:
The major advances in the researches on the dynamic effect of the Tibetan Plateau on weather and climate are summarized. It is concluded: (1) The thermal and dynamic effects of the plateau have seasonal differences. Dynamic effects are stronger in winter and spring. (2) The dynamic effects are embodied mainly in the aspect of the flow around the plateau, especially in bypassing and climbing induced by the plateau in winter and spring, but there is only bypassing effect in summer. (3) The plateau has important influence on weather systems such as cold wave, southwest vortex, and tropical cyclone. (4) Through blocking the climate system and drawing the monsoon, the plateau makes Northwest China dry and South China humid.
The major advances in the researches on the dynamic effect of the Tibetan Plateau on weather and climate are summarized. It is concluded: (1) The thermal and dynamic effects of the plateau have seasonal differences. Dynamic effects are stronger in winter and spring. (2) The dynamic effects are embodied mainly in the aspect of the flow around the plateau, especially in bypassing and climbing induced by the plateau in winter and spring, but there is only bypassing effect in summer. (3) The plateau has important influence on weather systems such as cold wave, southwest vortex, and tropical cyclone. (4) Through blocking the climate system and drawing the monsoon, the plateau makes Northwest China dry and South China humid.
2014, 42(6):1047-1056.
Abstract:
The Typhoon Fitow experienced four rainfall stages: typhoon peripheral precipitation, rainfall caused by the typhoon inverted trough and typhoon itself, rear spiral rain band rainfall, and rainfall originating from the interaction between outside circulation of the residual low pressure and the cold air. Using the data of surface observation, weather radar, and NCEP analysis, the rainstorm circulation forms of Fitow are analyzed. The east and west sides of high pressure, which guided the eastwards movement of typhoon, had different thermal properties. The east side was warm and deep, while the west side was cold and shallow. The shallow cold high pressure prevented the westward movement after landfalling, leading to the persistent rainfall under the typhoon inverted trough and in the rear spiral rain band. The approaching of typhoon Danas was beneficial to the enhancement of water vapor transfer with southeast winds. The interaction between typhoon and the osmotic cold air, which was different from the traditional detaining cold air with large vertical wind shear and a strong upper level jet stream, was discussed. The osmotic cold air invaded from the lower layer and affected the outside circulation of residual low pressure of typhoon. The strong northeast winds formed in the north of outside circulation of low pressure and converged with the east winds from the sea, which formed the coastal front. The spatial asymmetry characteristics of the osmotic cold air were obvious: convective available potential energy was high in the east and low in the west, and the vertical wind shear was high in the northwest and low in the northeast. The cold air had only small influence on the middle layer of the residual low pressure, so the southeast winds in the coastal area existed for a longer time. The interaction between high potential vorticity area in the middle layer and the coastal front on the surface provided good conditions for the residual low pressure rainstorm of extra tropical transition.
The Typhoon Fitow experienced four rainfall stages: typhoon peripheral precipitation, rainfall caused by the typhoon inverted trough and typhoon itself, rear spiral rain band rainfall, and rainfall originating from the interaction between outside circulation of the residual low pressure and the cold air. Using the data of surface observation, weather radar, and NCEP analysis, the rainstorm circulation forms of Fitow are analyzed. The east and west sides of high pressure, which guided the eastwards movement of typhoon, had different thermal properties. The east side was warm and deep, while the west side was cold and shallow. The shallow cold high pressure prevented the westward movement after landfalling, leading to the persistent rainfall under the typhoon inverted trough and in the rear spiral rain band. The approaching of typhoon Danas was beneficial to the enhancement of water vapor transfer with southeast winds. The interaction between typhoon and the osmotic cold air, which was different from the traditional detaining cold air with large vertical wind shear and a strong upper level jet stream, was discussed. The osmotic cold air invaded from the lower layer and affected the outside circulation of residual low pressure of typhoon. The strong northeast winds formed in the north of outside circulation of low pressure and converged with the east winds from the sea, which formed the coastal front. The spatial asymmetry characteristics of the osmotic cold air were obvious: convective available potential energy was high in the east and low in the west, and the vertical wind shear was high in the northwest and low in the northeast. The cold air had only small influence on the middle layer of the residual low pressure, so the southeast winds in the coastal area existed for a longer time. The interaction between high potential vorticity area in the middle layer and the coastal front on the surface provided good conditions for the residual low pressure rainstorm of extra tropical transition.
2014, 42(6):1057-1063.
Abstract:
Based on the conventional weather chart data and NCEP reanalysis data, two cyclone induced rainstorm events on 14 May 2002 and 26 May 2013 in Shandong are analyzed. The results show that: the two processes were affected by the upper level trough, southwest vortex, and surface cyclone, but there were significant differences in the path of cold air, upper and lower level jets and air instability stratification. During the rain process of the former, the invasion of cold air was from bottom to top, and the atmospheric stratification was convective stability; the vertical isentropic surface triggered the growth of vertical vorticity and the energy release of moist symmetrical instability. The latter was cyclone waves resulted from the enhancement of cold/warm advection above a stationary front, in which the convective instability energy released through reducing the lower level stability forces warm air to lift, which was superimposed by the cold air mass above the warm moist air flow.
Based on the conventional weather chart data and NCEP reanalysis data, two cyclone induced rainstorm events on 14 May 2002 and 26 May 2013 in Shandong are analyzed. The results show that: the two processes were affected by the upper level trough, southwest vortex, and surface cyclone, but there were significant differences in the path of cold air, upper and lower level jets and air instability stratification. During the rain process of the former, the invasion of cold air was from bottom to top, and the atmospheric stratification was convective stability; the vertical isentropic surface triggered the growth of vertical vorticity and the energy release of moist symmetrical instability. The latter was cyclone waves resulted from the enhancement of cold/warm advection above a stationary front, in which the convective instability energy released through reducing the lower level stability forces warm air to lift, which was superimposed by the cold air mass above the warm moist air flow.
2014, 42(6):1064-1068.
Abstract:
Southeasterly high winds are forecasted by using WRF model and GFS data. Meanwhile, terrain sensitivity experiments are carried out. The results show that the WRF model has relatively strong capability of forecasting the starting time and duration of winds, wind speeds, etc. Terrain sensitivity experiments show that: (1) the altitude difference （about 300 m) between the Urumqi urban area and the airport has significant influence on wind speeds; (2) the strength of downward movement above the airport is in good correspondence with wind speeds; (3) the variation of wind speeds does not always keep step with the pressure gradient force at the ends of the valley. 〖JP2〗The high winds are the combined result of the low level downward transporting of momentum, tunnel effect, and downslope winds. The downward transporting of momentum mainly occurs below 2000 m (AMSL), 〖JP2〗while downslope winds occur below 935 m.
Southeasterly high winds are forecasted by using WRF model and GFS data. Meanwhile, terrain sensitivity experiments are carried out. The results show that the WRF model has relatively strong capability of forecasting the starting time and duration of winds, wind speeds, etc. Terrain sensitivity experiments show that: (1) the altitude difference （about 300 m) between the Urumqi urban area and the airport has significant influence on wind speeds; (2) the strength of downward movement above the airport is in good correspondence with wind speeds; (3) the variation of wind speeds does not always keep step with the pressure gradient force at the ends of the valley. 〖JP2〗The high winds are the combined result of the low level downward transporting of momentum, tunnel effect, and downslope winds. The downward transporting of momentum mainly occurs below 2000 m (AMSL), 〖JP2〗while downslope winds occur below 935 m.
2014, 42(6):1069-1076.
Abstract:
Three fog events in Beijing were dynamically monitored in real time from the end of October to early December in 2011 using the visibility and relative humidity data from surface AWS (Automated Weather Station) and artificial observation, comparing with fog thickness data detected by satellites. The results show that the processes of fog occurrence, development, and dissipation can be monitored by means of the visibility and relative humidity observation. Comparing with the analysis of satellite data，the visibility and relative humidity data have the same trend and advantages in detecting the life cycle of a fog event.
Three fog events in Beijing were dynamically monitored in real time from the end of October to early December in 2011 using the visibility and relative humidity data from surface AWS (Automated Weather Station) and artificial observation, comparing with fog thickness data detected by satellites. The results show that the processes of fog occurrence, development, and dissipation can be monitored by means of the visibility and relative humidity observation. Comparing with the analysis of satellite data，the visibility and relative humidity data have the same trend and advantages in detecting the life cycle of a fog event.
2014, 42(6):1077-1082.
Abstract:
A rainstorm weather event occurred from 1 to 3 September 2012 in Dali over the northwestern Yunnan Plateau is analyzed based on the new type detection data. The results indicate that during the rainfall, the cloud base height observed by a microwave radiometer always maintained under 1 km, and the larger the liquid water content was, the stronger the rainfall intensity was; air temperature appeared lager fluctuation; the small value area of relative humidity at upper levels corresponded well with heavy precipitation. During precipitation, the detection height from wind profile radar increased; the horizontal wind rotated clockwise from ground to top (warm advection), and the vertical wind speed was less than-4 m/s; the signal to noise ratio was greater than 40 dB, and there was a positive relationship between signal to noise ratio and rainfall intensity. The results are helpful to the monitoring and studies of rainfall weather in details.
A rainstorm weather event occurred from 1 to 3 September 2012 in Dali over the northwestern Yunnan Plateau is analyzed based on the new type detection data. The results indicate that during the rainfall, the cloud base height observed by a microwave radiometer always maintained under 1 km, and the larger the liquid water content was, the stronger the rainfall intensity was; air temperature appeared lager fluctuation; the small value area of relative humidity at upper levels corresponded well with heavy precipitation. During precipitation, the detection height from wind profile radar increased; the horizontal wind rotated clockwise from ground to top (warm advection), and the vertical wind speed was less than-4 m/s; the signal to noise ratio was greater than 40 dB, and there was a positive relationship between signal to noise ratio and rainfall intensity. The results are helpful to the monitoring and studies of rainfall weather in details.
Mao Chengzhong
,
Yu Nailian
,
Du Jiale
,
Yang Ge
,
Leng Pengfei
,
Meng Fang
,
Zhang Ming
,
Xiao Gang
2014, 42(6):1083-1089.
Abstract:
The characteristics of negative oxygen ions are compared and analyzed between typical urban and forest areas by means of the data of the 15 months hour to hour continuous measurements. The results indicate：（1） The average concentration of negative oxygen ions in typical urban areas is 240 cm-3 and 1470 cm-3 in forest areas, and the concentration in forest areas is 5 to 6 times higher than that in typical urban areas； the small ions in negative oxygen ions accounts for about 80 %, the middle ions about 20 % in forest areas， but there is few middle ions in typical urban areas. （2） The changing trend of negative oxygen ion concentration is basically identical between typical urban and forest areas; the high concentration period mainly occurs from midnight to sunset, and the low concentration period mainly from noon to evening, the peaks from 04:00 and 05:00, and the minimum at 13:00 （3） The highest negative oxygen ion concentration seasons in forest areas are spring and winter, but that in typical urban areas in autumn, which may be caused by the abnormal large amount of rainfall in autumn. （4） The negative oxygen ion concentration shows a slight declined tendency in the Dalaoling forest area，and that shows a contrary tendency in typical urban areas. （5） In urban areas, the daily average concentration of negative oxygen ions is higher in foggy days and rainy days than those in thunderstorm days and overcast days，and the minimum is found in sunny days. On the contrary, in forest areas, the daily average concentration of negative oxygen ions is higher in sunny days and thunderstorm days than that in overcast days, and the minimum appears usually in rainy days and foggy days.
The characteristics of negative oxygen ions are compared and analyzed between typical urban and forest areas by means of the data of the 15 months hour to hour continuous measurements. The results indicate：（1） The average concentration of negative oxygen ions in typical urban areas is 240 cm-3 and 1470 cm-3 in forest areas, and the concentration in forest areas is 5 to 6 times higher than that in typical urban areas； the small ions in negative oxygen ions accounts for about 80 %, the middle ions about 20 % in forest areas， but there is few middle ions in typical urban areas. （2） The changing trend of negative oxygen ion concentration is basically identical between typical urban and forest areas; the high concentration period mainly occurs from midnight to sunset, and the low concentration period mainly from noon to evening, the peaks from 04:00 and 05:00, and the minimum at 13:00 （3） The highest negative oxygen ion concentration seasons in forest areas are spring and winter, but that in typical urban areas in autumn, which may be caused by the abnormal large amount of rainfall in autumn. （4） The negative oxygen ion concentration shows a slight declined tendency in the Dalaoling forest area，and that shows a contrary tendency in typical urban areas. （5） In urban areas, the daily average concentration of negative oxygen ions is higher in foggy days and rainy days than those in thunderstorm days and overcast days，and the minimum is found in sunny days. On the contrary, in forest areas, the daily average concentration of negative oxygen ions is higher in sunny days and thunderstorm days than that in overcast days, and the minimum appears usually in rainy days and foggy days.
2014, 42(6):1090-1094.
Abstract:
By means of the PM10 data from 2006 to 2008 obtained at Yan’an, the concentration level and variation are analyzed, and their relationship with meteorological conditions is studied. The annual mean mass concentration of PM10 is 153 μg/m3 at Yan’an, which is two times higher than the limit value of 70 μg/m3 according to the Class 2 Standard of the National Ambient Air Quality Standard (NAAQS). The regional background level of PM10 has an average value of 109 μg/m3, which contributes significantly to the ambient PM10 level in Yan’an. The mass concentration of PM10 is the highest in spring, then in winter, autumn and summer. The number of days with the mass PM10 concentration exceeding the Class 2 limit value (150 μg/m3) of NAAQS accounts for 40% in the whole year and 66% in spring. The diurnal change of PM10 shows a double peak double valley distribution curve, and PM10 concentration has significant negative correlation with the diurnal variation of wind speeds. The scavenging efficiency of 1 mm rainfall on PM10 decreases successively in winter, spring, autumn and summer. The mass concentration of PM10 is the highest under westerly winds, but the highest accumulated contribution to PM10 is the southwest winds, about 40 to 50 μg/m3 higher than that in the other wind directions.
By means of the PM10 data from 2006 to 2008 obtained at Yan’an, the concentration level and variation are analyzed, and their relationship with meteorological conditions is studied. The annual mean mass concentration of PM10 is 153 μg/m3 at Yan’an, which is two times higher than the limit value of 70 μg/m3 according to the Class 2 Standard of the National Ambient Air Quality Standard (NAAQS). The regional background level of PM10 has an average value of 109 μg/m3, which contributes significantly to the ambient PM10 level in Yan’an. The mass concentration of PM10 is the highest in spring, then in winter, autumn and summer. The number of days with the mass PM10 concentration exceeding the Class 2 limit value (150 μg/m3) of NAAQS accounts for 40% in the whole year and 66% in spring. The diurnal change of PM10 shows a double peak double valley distribution curve, and PM10 concentration has significant negative correlation with the diurnal variation of wind speeds. The scavenging efficiency of 1 mm rainfall on PM10 decreases successively in winter, spring, autumn and summer. The mass concentration of PM10 is the highest under westerly winds, but the highest accumulated contribution to PM10 is the southwest winds, about 40 to 50 μg/m3 higher than that in the other wind directions.
2014, 42(6):1095-1099.
Abstract:
In order to minimize the losses caused by continuous rainfall, the day by day precipitation data of 42 weather stations from late August to middle October of 1970 to 2012, the cotton damage data from continuous rainfall, and the economy data in the same period from the Guangzhong Cotton area of Shaanxi Province are used to conduct risking regionalization, with emphasis on the main disaster (continuous rainfall) in cotton boll opening and mature periods in Guangzhong, based on the ARCGIS platform, so as to make full use of agricultural climatic resources and to avoid unfavorable climates conditions and improve the cap ability of responding to continuous rain disasters. The results show that the highest and medium risk areas of continuous rain in cotton boll opening and mature periods in Guanzhong in Shaanxi include Baoji and the southern Xi’An along the northern foot of Qinling Ranges (Zhouzhi, Huxian, Chang’an and Lantian counties), where are unfavorable for growing cotton in large scale. The low risk regions include Weinan, most parts of Xian Yang, Lintong, Yanliang, and Gaoling counties, where climate conditions are suitable for cotton in boll opening and mature stages.
In order to minimize the losses caused by continuous rainfall, the day by day precipitation data of 42 weather stations from late August to middle October of 1970 to 2012, the cotton damage data from continuous rainfall, and the economy data in the same period from the Guangzhong Cotton area of Shaanxi Province are used to conduct risking regionalization, with emphasis on the main disaster (continuous rainfall) in cotton boll opening and mature periods in Guangzhong, based on the ARCGIS platform, so as to make full use of agricultural climatic resources and to avoid unfavorable climates conditions and improve the cap ability of responding to continuous rain disasters. The results show that the highest and medium risk areas of continuous rain in cotton boll opening and mature periods in Guanzhong in Shaanxi include Baoji and the southern Xi’An along the northern foot of Qinling Ranges (Zhouzhi, Huxian, Chang’an and Lantian counties), where are unfavorable for growing cotton in large scale. The low risk regions include Weinan, most parts of Xian Yang, Lintong, Yanliang, and Gaoling counties, where climate conditions are suitable for cotton in boll opening and mature stages.
2014, 42(6):1100-1105.
Abstract:
Using the observation data from 100 regional automatic weather stations and 6 national weather stations in the southern Taihang Mountain, NCEP/NCAR reanalysis data, and the puberty observation data and freeze injury data of the “Luling” walnut planting base, the correlation of temperature indexes between regional automatic weather stations and national weather stations, and the climate characteristics of freeze injury risk are studied. It is found: (1) The indexes between regional automatic weather stations and national weather stations are significantly related, with more than 90% correlation coefficients higher than 09. (2) There is a significant negative correlation between temperature and altitude of regional automatic weather stations; when the temperature of national weather station is lower than 36 ℃, 2 ℃, 04 ℃ and -04 ℃, the altitude of the region where the walnut may be injured, is over 1000 m, 600 m, 200 m and 0 m, respectively. (3) The annual mean number of freeze injury risk days in the critical period of walnut florescence is 34. (4) The freeze injury in walnut florescence is related to the anomalous strong polar vortex and Ural high pressure ridge.
Using the observation data from 100 regional automatic weather stations and 6 national weather stations in the southern Taihang Mountain, NCEP/NCAR reanalysis data, and the puberty observation data and freeze injury data of the “Luling” walnut planting base, the correlation of temperature indexes between regional automatic weather stations and national weather stations, and the climate characteristics of freeze injury risk are studied. It is found: (1) The indexes between regional automatic weather stations and national weather stations are significantly related, with more than 90% correlation coefficients higher than 09. (2) There is a significant negative correlation between temperature and altitude of regional automatic weather stations; when the temperature of national weather station is lower than 36 ℃, 2 ℃, 04 ℃ and -04 ℃, the altitude of the region where the walnut may be injured, is over 1000 m, 600 m, 200 m and 0 m, respectively. (3) The annual mean number of freeze injury risk days in the critical period of walnut florescence is 34. (4) The freeze injury in walnut florescence is related to the anomalous strong polar vortex and Ural high pressure ridge.
2014, 42(6):1106-1113.
Abstract:
At present，there is no special lightning protection standards of designing, construction, and testing aimed at metro systems in China，so that there is no systematical technical standards in lightning protection of metro systems launched in China. An analysis is made of the main ways and approaches in which metro systems are attacked by lightning, and the necessity of lightning protection for metro systems is discussed. On the other hand, aiming at the key point of lightning protection for metro systems, according to the calculation of theoretical analysis, it is assured for the first time that the lightning protection of metro systems should be classified as Class 2，and the key parameter of metro Lightning protection—theoretical value of earthing resistance—is deduced. From the aspects of five elements such as the lightning arrester， earthing， equipotential connection, shield， composite wiring, and surge protection, specific measures of metro lightning protection are analyzed, which can provide references for those who are engaging in designing, construction, and testing of lightning protection for metro systems, and be useful for the formation of technical standards of lightning protection for metro systems.
At present，there is no special lightning protection standards of designing, construction, and testing aimed at metro systems in China，so that there is no systematical technical standards in lightning protection of metro systems launched in China. An analysis is made of the main ways and approaches in which metro systems are attacked by lightning, and the necessity of lightning protection for metro systems is discussed. On the other hand, aiming at the key point of lightning protection for metro systems, according to the calculation of theoretical analysis, it is assured for the first time that the lightning protection of metro systems should be classified as Class 2，and the key parameter of metro Lightning protection—theoretical value of earthing resistance—is deduced. From the aspects of five elements such as the lightning arrester， earthing， equipotential connection, shield， composite wiring, and surge protection, specific measures of metro lightning protection are analyzed, which can provide references for those who are engaging in designing, construction, and testing of lightning protection for metro systems, and be useful for the formation of technical standards of lightning protection for metro systems.
2014, 42(6):1114-1117.
Abstract:
GNSS reference stations are vulnerable to the thunders and lightning. The design of lightning protection devices is of great importance for the establishment of GNSS reference stations. According to the regulations of lightning protection for general buildings and the characteristics of GNSS reference stations, the lightning protection levels of GNSS reference stations are analyzed, and the external and internal protection of lightning arresters, down conductors, grounding, equipotential bonding, shield, reasonable wiring and SPDs are discussed. Practice shows that the method is effective for preventing the reference stations from being stricken by lightning.
GNSS reference stations are vulnerable to the thunders and lightning. The design of lightning protection devices is of great importance for the establishment of GNSS reference stations. According to the regulations of lightning protection for general buildings and the characteristics of GNSS reference stations, the lightning protection levels of GNSS reference stations are analyzed, and the external and internal protection of lightning arresters, down conductors, grounding, equipotential bonding, shield, reasonable wiring and SPDs are discussed. Practice shows that the method is effective for preventing the reference stations from being stricken by lightning.
2014, 42(6):1118-1125.
Abstract:
An analysis is made of the uniqueness and limitation of the collection area calculation formula in the evaluation of lightning disaster risk. The common complex shaped structures are divided into three categories: rectangular building with a high point, podium building, and L shaped building, and the corresponding models are formed. According to the Technical Codes for Protection of Building Electronic Information System against Lighting (GB50343-2012), an appropriate model of collection area is devised by using the Auto CAD software. The corresponding model formula is generalized. Comparing to the empirical method, the results of the calculation method is close to true values, which provides scientific references for the evaluation of lightning disaster risk.
An analysis is made of the uniqueness and limitation of the collection area calculation formula in the evaluation of lightning disaster risk. The common complex shaped structures are divided into three categories: rectangular building with a high point, podium building, and L shaped building, and the corresponding models are formed. According to the Technical Codes for Protection of Building Electronic Information System against Lighting (GB50343-2012), an appropriate model of collection area is devised by using the Auto CAD software. The corresponding model formula is generalized. Comparing to the empirical method, the results of the calculation method is close to true values, which provides scientific references for the evaluation of lightning disaster risk.
2014, 42(6):1126-1130.
Abstract:
The calculation of equivalent collection areas is important for the lightning risk management of structures. Three problems are frequently encountered in practice: (1) how to calculate equivalent collection areas of complex shaped structures? (2) how to distinguish clearly between isolated and non isolated structures? (3) how to calculate equivalent collection areas of non isolated structures? The solutions to these problems are given: (1) through software modeling of structures; (2) if the equivalent collection areas of two structures overlaps, they are considered as non isolated structures, and otherwise isolated structures; (3) a new method is present to solve this problem. An example of several buildings is given to show the advantages of this new method.
The calculation of equivalent collection areas is important for the lightning risk management of structures. Three problems are frequently encountered in practice: (1) how to calculate equivalent collection areas of complex shaped structures? (2) how to distinguish clearly between isolated and non isolated structures? (3) how to calculate equivalent collection areas of non isolated structures? The solutions to these problems are given: (1) through software modeling of structures; (2) if the equivalent collection areas of two structures overlaps, they are considered as non isolated structures, and otherwise isolated structures; (3) a new method is present to solve this problem. An example of several buildings is given to show the advantages of this new method.
2014, 42(6):1131-1136.
Abstract:
The reliability of convective cloud seeding effectiveness evaluation result is poor when using traditional statistical test method because of larger spatial and temporal variation. The floating target area method, a new method proposed by Woodley, is introduced, which is based on radar echoes. Some modifications are made in this scheme in combination with Tianjin geography and weather modification operation characteristics. The radar base data are used to determine the floating target cell recognition and tracking methods, then determine the catalytic units and control units in the floating target cells; the physical parameters and the retrieved precipitation of each unit are recorded, and the precipitation enhancement effect is calculated to provide physical evidences of artificial rainfall. The method is used to evaluate the effectiveness of convective cloud seeding on 24 July 2011 in Tianjin, for example, and the objective evaluation results are obtained, which shows that: the value of the maximum echo intensity and echo top height increased as the catalyst got into the clouds. It is proved that artificial catalysis takes effect in precipitation enhancement. The effectiveness of precipitation enhancement is 7.69% at a significance of 0.043.
The reliability of convective cloud seeding effectiveness evaluation result is poor when using traditional statistical test method because of larger spatial and temporal variation. The floating target area method, a new method proposed by Woodley, is introduced, which is based on radar echoes. Some modifications are made in this scheme in combination with Tianjin geography and weather modification operation characteristics. The radar base data are used to determine the floating target cell recognition and tracking methods, then determine the catalytic units and control units in the floating target cells; the physical parameters and the retrieved precipitation of each unit are recorded, and the precipitation enhancement effect is calculated to provide physical evidences of artificial rainfall. The method is used to evaluate the effectiveness of convective cloud seeding on 24 July 2011 in Tianjin, for example, and the objective evaluation results are obtained, which shows that: the value of the maximum echo intensity and echo top height increased as the catalyst got into the clouds. It is proved that artificial catalysis takes effect in precipitation enhancement. The effectiveness of precipitation enhancement is 7.69% at a significance of 0.043.
2014, 42(6):1137-1142.
Abstract:
In order to improve the level and efficiency, based on a variety of observation data in Xuzhou from 2010 to 2012, by means of a new effectiveness evaluation method for rainfall enhancement operations, considering the topographic features and working habits of Xuzhou, the rainfall enhancement potential analysis models for 12 hour forecast and nowcasting are established. The potential areas are classified into two categories: ClassⅠ(smaller) and class Ⅱ (larger), and rainfall enhancement operation advices are provided by the two categories. Results of rainfall operations in Xuzhou in 2013 show that the rainfall enhancement potential analysis models for 12 hour forecasting and nowcasting have a satisfactory accuracy. Based on the models, the operation procedures of rainfall enhancement Xuzhou are revised to improve the efficiency of the command staff and the effectiveness of rainfall enhancement operations.
In order to improve the level and efficiency, based on a variety of observation data in Xuzhou from 2010 to 2012, by means of a new effectiveness evaluation method for rainfall enhancement operations, considering the topographic features and working habits of Xuzhou, the rainfall enhancement potential analysis models for 12 hour forecast and nowcasting are established. The potential areas are classified into two categories: ClassⅠ(smaller) and class Ⅱ (larger), and rainfall enhancement operation advices are provided by the two categories. Results of rainfall operations in Xuzhou in 2013 show that the rainfall enhancement potential analysis models for 12 hour forecasting and nowcasting have a satisfactory accuracy. Based on the models, the operation procedures of rainfall enhancement Xuzhou are revised to improve the efficiency of the command staff and the effectiveness of rainfall enhancement operations.
2014, 42(6):1143-1146.
Abstract:
The Anhui Weather Modification Office applies IOT technology to the management of weather modification operations for the first time, and developed the Anhui Weather Modification Intelligent Management System based on IOT technology. The system takes advantage of RFID (Radio Frequency IDentification) technology, brings GPRS, GPS and GIS technology together, and has achieved the automatical and intelligent collection, transmission, data management of weather information (the personnel, equipment, ammunition, weather, etc.), and service management by the real time interaction between operation site and commanding center, through the construction of weather modification operation management and service platform. The system improved the safety, efficiency and information management level of weather modification operations, and plays an important role in the practical weather modification service.
The Anhui Weather Modification Office applies IOT technology to the management of weather modification operations for the first time, and developed the Anhui Weather Modification Intelligent Management System based on IOT technology. The system takes advantage of RFID (Radio Frequency IDentification) technology, brings GPRS, GPS and GIS technology together, and has achieved the automatical and intelligent collection, transmission, data management of weather information (the personnel, equipment, ammunition, weather, etc.), and service management by the real time interaction between operation site and commanding center, through the construction of weather modification operation management and service platform. The system improved the safety, efficiency and information management level of weather modification operations, and plays an important role in the practical weather modification service.
2014, 42(6):1147-1153.
Abstract:
Based on remote sensing and Geographic Information System (GIS) technology, the gridded meteorological elements calculated by the ground based DEM and meteorological station monitor data, including maximum temperature, minimum relative humidity, and maximum wind speed, the daily precipitation products from the FY2 geostationary meteorological satellite, and AVHRR snow inversion products, are integrated to compute the gridded forest fire danger Weather Index (FWI). The vegetation type, NDVI, terrain features, highways, settlements, population, and other elements are used to assess the risk of Forest fire danger Risk Index (FRI). Both FWI and FRI are computed to get the gridded Tibet forest fire danger index prediction. The software application is built based on MeteoInfo components to achieve fully automatic forecasting. The comparison analysis of forest fire events shows that the gridded Tibet forest fire danger index is better. The method provides an effective reference for Tibet forest fire prevention.
Based on remote sensing and Geographic Information System (GIS) technology, the gridded meteorological elements calculated by the ground based DEM and meteorological station monitor data, including maximum temperature, minimum relative humidity, and maximum wind speed, the daily precipitation products from the FY2 geostationary meteorological satellite, and AVHRR snow inversion products, are integrated to compute the gridded forest fire danger Weather Index (FWI). The vegetation type, NDVI, terrain features, highways, settlements, population, and other elements are used to assess the risk of Forest fire danger Risk Index (FRI). Both FWI and FRI are computed to get the gridded Tibet forest fire danger index prediction. The software application is built based on MeteoInfo components to achieve fully automatic forecasting. The comparison analysis of forest fire events shows that the gridded Tibet forest fire danger index is better. The method provides an effective reference for Tibet forest fire prevention.
2014, 42(6):1154-1158.
Abstract:
Using the daily gas load data and corresponding meteorological observational datasets in Hangzhou from 2008 to 2011, the variation characteristics of daily gas load and the impacts of meteorological conditions on gas loads are analyzed. Based on this, the daily gas load is predicted with the Elman network. The results show that the gas load increased significantly from 2008 to 2011 in Hangzhou. The peak point appeared usually one month before the Spring Festival, and the variation of the gas load decreased obviously during Spring Festival holidays. Temperature and pressure were the main factors responsible for the variation of gas load, with the correlation being most significant in winter. The gas load was significantly correlated to temperature negatively and pressure positively, most sensitive to the average air temperature from 6 ℃ to 15 ℃. According to the influence of meteorological factors and the Spring Festival, the daily gas load forecasting model in the wintertime is established with the Elman network. Based on the indexes such as mean relative error and correlation coefficient, it is illustrated that the Elman network has a satisfactory precision. While there appears noticeable fluctuations in the gas load, the result of simulation lags behind the observation.
Using the daily gas load data and corresponding meteorological observational datasets in Hangzhou from 2008 to 2011, the variation characteristics of daily gas load and the impacts of meteorological conditions on gas loads are analyzed. Based on this, the daily gas load is predicted with the Elman network. The results show that the gas load increased significantly from 2008 to 2011 in Hangzhou. The peak point appeared usually one month before the Spring Festival, and the variation of the gas load decreased obviously during Spring Festival holidays. Temperature and pressure were the main factors responsible for the variation of gas load, with the correlation being most significant in winter. The gas load was significantly correlated to temperature negatively and pressure positively, most sensitive to the average air temperature from 6 ℃ to 15 ℃. According to the influence of meteorological factors and the Spring Festival, the daily gas load forecasting model in the wintertime is established with the Elman network. Based on the indexes such as mean relative error and correlation coefficient, it is illustrated that the Elman network has a satisfactory precision. While there appears noticeable fluctuations in the gas load, the result of simulation lags behind the observation.
2014, 42(6):1159-1162.
Abstract:
Weather conditions have a great impact on highway safety. GIS data and meteorological data needed for highway meteorological services are analyzed and processed. Using the interpolation algorithm and meteorological elements, including visibility, precipitation, temperature, and wind velocity, are processed spatially, and the whole data processing flow are sorted. The techniques of projecting meteorological factors on the high speed sections are studied by means of the GIS based spatial analysis. The results of the operation are stored in a database in JSON for traffic meteorological services. The application of the meteorological service technology is discussed, and traffic weather forecast guidance products are produced. The application to meteorological navigation in transportation is also attempted, which improves the effectiveness of traffic meteorological services.
Weather conditions have a great impact on highway safety. GIS data and meteorological data needed for highway meteorological services are analyzed and processed. Using the interpolation algorithm and meteorological elements, including visibility, precipitation, temperature, and wind velocity, are processed spatially, and the whole data processing flow are sorted. The techniques of projecting meteorological factors on the high speed sections are studied by means of the GIS based spatial analysis. The results of the operation are stored in a database in JSON for traffic meteorological services. The application of the meteorological service technology is discussed, and traffic weather forecast guidance products are produced. The application to meteorological navigation in transportation is also attempted, which improves the effectiveness of traffic meteorological services.
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.