Volume 41,Issue 5,2013 Table of Contents
2013, 41(5):791-795.
Abstract:
As the maintenance of large scale electronic equipment is very difficult for the higher joining threshold, longer repairing time, and lower efficiency,it is a practical problem that users encounter frequently. A set of theoretical bases and implementation methods of standardization maintenance for batch large scale equipment is put forward,and the maintenance processes for these electronic equipment are explained in detail. The construction methods of the hierarchical database and the fault case database for this electronic equipment are discussed,and the standardization maintenance procedures for large scale electronic equipment are introduced. The off line test maintenance platform for their fault components and component sets is designed, so to solve these problems.
As the maintenance of large scale electronic equipment is very difficult for the higher joining threshold, longer repairing time, and lower efficiency,it is a practical problem that users encounter frequently. A set of theoretical bases and implementation methods of standardization maintenance for batch large scale equipment is put forward,and the maintenance processes for these electronic equipment are explained in detail. The construction methods of the hierarchical database and the fault case database for this electronic equipment are discussed,and the standardization maintenance procedures for large scale electronic equipment are introduced. The off line test maintenance platform for their fault components and component sets is designed, so to solve these problems.
2013, 41(5):796-802.
Abstract:
The Multi Axis Differential Absorption Spectroscopy (MAX DOAS) technique is introduced and the field experimental results of a mini MAX DOAS instrument are presented, which was designed on the basis of the MAX DOAS principle.The zenith scattered light observation spectrum measured at noon are used as reference spectrum (called Fraunhofer reference spectrum), and the measured spectra are processed by eliminating noise, calibrating wavelength, and subtracting Fraunhofer structure.The atmospheric NO2 differential slant column densities (DSCD) are derived with the least square fitting method, by using the measurement spectra and Ring effect optical density and molecule absorption optical densities.The inversion results of NO2 DSCDs in Wuqing, Tianjin are analyzed and then changed into tropospheric vertical column densities （VCD） with geometric approximation.It is shown that MAX DOAS is suitable for monitoring tropospheric NO2 vertical column densities over polluted areas.
The Multi Axis Differential Absorption Spectroscopy (MAX DOAS) technique is introduced and the field experimental results of a mini MAX DOAS instrument are presented, which was designed on the basis of the MAX DOAS principle.The zenith scattered light observation spectrum measured at noon are used as reference spectrum (called Fraunhofer reference spectrum), and the measured spectra are processed by eliminating noise, calibrating wavelength, and subtracting Fraunhofer structure.The atmospheric NO2 differential slant column densities (DSCD) are derived with the least square fitting method, by using the measurement spectra and Ring effect optical density and molecule absorption optical densities.The inversion results of NO2 DSCDs in Wuqing, Tianjin are analyzed and then changed into tropospheric vertical column densities （VCD） with geometric approximation.It is shown that MAX DOAS is suitable for monitoring tropospheric NO2 vertical column densities over polluted areas.
2013, 41(5):803-808.
Abstract:
In the traditional cloud type recognition method, a set of features describing the color, texture and shape features of clouds are extracted, in which there are some irrelevance and redundancy features leading to the reduced recognition rate of cloud type. Based on the criteria of the max relevance and min redundancy (mRMR), symmetrical uncertainty is employed to overcome the inherent defect of mutual information, which tends to have more value attributes. The improved mRMR feature selection method is putted forward, and the best feature subsets are selected by this method, and then the support vector machine is used to the recognition of cloud type. Experimental results show that the correct recognition rate of altocumulus, cirrus, clear, cumulus, and stratus are improved significantly, with the total recognition rate being 86.96%; after feature selection, the total recognition rate can increase to 89.04%, and the recognition rate increases by 2%. For cloud type classification research, the texture feature is better than the shape feature; the shape features based on Zernike moment is better than HU moment invariants; the texture feature based on the gray level co occurrence matrix is the optimum feature extraction method.
In the traditional cloud type recognition method, a set of features describing the color, texture and shape features of clouds are extracted, in which there are some irrelevance and redundancy features leading to the reduced recognition rate of cloud type. Based on the criteria of the max relevance and min redundancy (mRMR), symmetrical uncertainty is employed to overcome the inherent defect of mutual information, which tends to have more value attributes. The improved mRMR feature selection method is putted forward, and the best feature subsets are selected by this method, and then the support vector machine is used to the recognition of cloud type. Experimental results show that the correct recognition rate of altocumulus, cirrus, clear, cumulus, and stratus are improved significantly, with the total recognition rate being 86.96%; after feature selection, the total recognition rate can increase to 89.04%, and the recognition rate increases by 2%. For cloud type classification research, the texture feature is better than the shape feature; the shape features based on Zernike moment is better than HU moment invariants; the texture feature based on the gray level co occurrence matrix is the optimum feature extraction method.
2013, 41(5):809-817.
Abstract:
The reflectivity quality control algorithm in SWAN is described, including data preprocessing,isolating noise echo filtering, and AP echo suppression. Data preprocessing converts raw radar data to RD20 format and checks data quality. Isolating noise echo filtering includes bi directional searching and echo feature filtering. AP echo suppression uses the fuzzy logic method.The parameters of the algorithm are described. As the probability distributions of AP features from Wuhan, Suizhou, Xian radar are similar, it is concluded that the default parameters can be applied in more than one radar site.The evaluation of the algorithm shows that the most AP echoes can be suppressed; meanwhile some AP far away from radar cannot be suppressed; and some rainfall echoes are wrongly identified as AP.
The reflectivity quality control algorithm in SWAN is described, including data preprocessing,isolating noise echo filtering, and AP echo suppression. Data preprocessing converts raw radar data to RD20 format and checks data quality. Isolating noise echo filtering includes bi directional searching and echo feature filtering. AP echo suppression uses the fuzzy logic method.The parameters of the algorithm are described. As the probability distributions of AP features from Wuhan, Suizhou, Xian radar are similar, it is concluded that the default parameters can be applied in more than one radar site.The evaluation of the algorithm shows that the most AP echoes can be suppressed; meanwhile some AP far away from radar cannot be suppressed; and some rainfall echoes are wrongly identified as AP.
2013, 41(5):818-824.
Abstract:
Wind profiler is a kind of clear air remote sense device. The Doppler radar information obtained under rain conditions is mainly results of moving precipitation particles, which causes great wind field calculation errors. It is of importance to distinguish whether echo signals are contaminated by precipitation. An ensemble analysis algorithm,based on the K Means clustering, is applied to acquire the vertical radial velocity threshold for SNR variation, which is further used to decide whether the radar data is interfered by rain drops.The method is tested with the observational data from August to December 2011 and March to April 2012 of the Nanjing CLC 11 wind profiler. The results show that this method can be used for distinguishing precipitation and clear air data at different heights, as well as decide properly whether echo signals are contaminated.
Wind profiler is a kind of clear air remote sense device. The Doppler radar information obtained under rain conditions is mainly results of moving precipitation particles, which causes great wind field calculation errors. It is of importance to distinguish whether echo signals are contaminated by precipitation. An ensemble analysis algorithm,based on the K Means clustering, is applied to acquire the vertical radial velocity threshold for SNR variation, which is further used to decide whether the radar data is interfered by rain drops.The method is tested with the observational data from August to December 2011 and March to April 2012 of the Nanjing CLC 11 wind profiler. The results show that this method can be used for distinguishing precipitation and clear air data at different heights, as well as decide properly whether echo signals are contaminated.
2013, 41(5):825-831.
Abstract:
The technical features of the AC variable frequency CINRAD/SA Digital Servo System are summarized, and the main channel signal process, monitoring signal process, and frequency converter signal process are described.According to the monitoring information,alarm information,and key points parameter, from the three aspects of position loop,velocity loop, and acceleration loop, a detailed discussion is made on the fault diagnosis methods of AC variable frequency CINRAD/SA digital AC servo system, as well as uncontrolled antenna, abnormal antenna running, jump code or corner code, and inconsistent antenna location. Two typical fault cases, as examples, are discussed and summarized in terms of theoretical analysis and processing steps, and some suggestions for the maintenance of AC variable frequency digital servo systems and CINRAD technology support are given for reference.
The technical features of the AC variable frequency CINRAD/SA Digital Servo System are summarized, and the main channel signal process, monitoring signal process, and frequency converter signal process are described.According to the monitoring information,alarm information,and key points parameter, from the three aspects of position loop,velocity loop, and acceleration loop, a detailed discussion is made on the fault diagnosis methods of AC variable frequency CINRAD/SA digital AC servo system, as well as uncontrolled antenna, abnormal antenna running, jump code or corner code, and inconsistent antenna location. Two typical fault cases, as examples, are discussed and summarized in terms of theoretical analysis and processing steps, and some suggestions for the maintenance of AC variable frequency digital servo systems and CINRAD technology support are given for reference.
2013, 41(5):837-842.
Abstract:
Since the fault diagnosis of wind direction sensors is extremely concealed owning to its Gray code encoding, traditional fault detection methods need to disassemble the wind direction sensor, which destroys the integrity of meteorological observation data. A measurement model for wind direction sensors based on probability distribution is built, based on which, a fault detection algorithm in terms of distribution law rules is proposed. A graphic wind direction sensor fault detection program is developed though VB/SQL/MATLAB hybrid programming technology. Finally, the fault detection test is carried out, and the results show that the fault detection algorithm can recognize the single or mixed faults exactly without disassembling the wind direction sensor.
Since the fault diagnosis of wind direction sensors is extremely concealed owning to its Gray code encoding, traditional fault detection methods need to disassemble the wind direction sensor, which destroys the integrity of meteorological observation data. A measurement model for wind direction sensors based on probability distribution is built, based on which, a fault detection algorithm in terms of distribution law rules is proposed. A graphic wind direction sensor fault detection program is developed though VB/SQL/MATLAB hybrid programming technology. Finally, the fault detection test is carried out, and the results show that the fault detection algorithm can recognize the single or mixed faults exactly without disassembling the wind direction sensor.
2013, 41(5):843-846.
Abstract:
The Pitot tube is the main standard device of the wind calibration facility, whose measurement accuracy is important for calibration quality. From the measurement principles of Pitot tube, the factors influencing the measurement errors of Pitot tubes are introduced in detail. The measurement deviation causing by these influence factors is simulated. The main influencing factors of measurement errors of Pitot tubes are analyzed.The results show that the temperature and obstruction coefficients are the main factors to produce measurement errors for second class Pitot tubes.When the deviation of environment temperature reaches ±8℃, the wind error of the Pitot tube is 044 m/s (〖WTBX〗v〖WTBZ〗=30 m/s).When the deviation of obstruction coefficient reaches ±002, the wind error of the Pitot tube is ±06 m/s (〖WTBX〗v〖WTBZ〗=30 m/s). The effects of the Pitot tube coefficient, pressure, and humidity are smaller.
The Pitot tube is the main standard device of the wind calibration facility, whose measurement accuracy is important for calibration quality. From the measurement principles of Pitot tube, the factors influencing the measurement errors of Pitot tubes are introduced in detail. The measurement deviation causing by these influence factors is simulated. The main influencing factors of measurement errors of Pitot tubes are analyzed.The results show that the temperature and obstruction coefficients are the main factors to produce measurement errors for second class Pitot tubes.When the deviation of environment temperature reaches ±8℃, the wind error of the Pitot tube is 044 m/s (〖WTBX〗v〖WTBZ〗=30 m/s).When the deviation of obstruction coefficient reaches ±002, the wind error of the Pitot tube is ±06 m/s (〖WTBX〗v〖WTBZ〗=30 m/s). The effects of the Pitot tube coefficient, pressure, and humidity are smaller.
2013, 41(5):847-851.
Abstract:
While calculating vapor pressure using relative humidity and temperature of L band radar sounding,the water saturation vapor pressure formula must be used,since the relative humidity is based on water surface.There may be an error in using the ice saturation vapor pressure formula.The comparison of vapor pressure bias between water and ice saturation vapor pressure formulas is discussed.Taking -45 ℃ and 0 ℃ as a threshold，vapor pressure values are analyzed when using the ice and water saturation vapor pressure formulas,respectively.Results show that the absolute deviation produced by ice and water saturation vapor pressure formulas is not very great, but the relative deviation may be up to 50%,which has climatic effects on upper troposphere for actual water vapor pressure.
While calculating vapor pressure using relative humidity and temperature of L band radar sounding,the water saturation vapor pressure formula must be used,since the relative humidity is based on water surface.There may be an error in using the ice saturation vapor pressure formula.The comparison of vapor pressure bias between water and ice saturation vapor pressure formulas is discussed.Taking -45 ℃ and 0 ℃ as a threshold，vapor pressure values are analyzed when using the ice and water saturation vapor pressure formulas,respectively.Results show that the absolute deviation produced by ice and water saturation vapor pressure formulas is not very great, but the relative deviation may be up to 50%,which has climatic effects on upper troposphere for actual water vapor pressure.
2013, 41(5):852-856.
Abstract:
By means of the contrast observation evaporation data from E 601B and the small sized evaporator data from 1985 to 2001 during the unfrozen period (April to October) at Tacheng National Standard Climatic Station and the contrast observation evaporation data from 2009 to 2011 during the frozen period (November to March) from the Tacheng Hydrological Station, the conversion coefficient is acquired by the ratio method and the multiple linear regression analysis method. Results show that the data arrays from contrast observation evaporation appear linearly correlated.The correlation coefficient is 0877 in the unfrozen period and 0924 in the frozen period. The conversion coefficient is 0596 in the unfrozen period and 0349 in the frozen period. It provides important basis for using long sequence single observation data of small sized evaporation pans.
By means of the contrast observation evaporation data from E 601B and the small sized evaporator data from 1985 to 2001 during the unfrozen period (April to October) at Tacheng National Standard Climatic Station and the contrast observation evaporation data from 2009 to 2011 during the frozen period (November to March) from the Tacheng Hydrological Station, the conversion coefficient is acquired by the ratio method and the multiple linear regression analysis method. Results show that the data arrays from contrast observation evaporation appear linearly correlated.The correlation coefficient is 0877 in the unfrozen period and 0924 in the frozen period. The conversion coefficient is 0596 in the unfrozen period and 0349 in the frozen period. It provides important basis for using long sequence single observation data of small sized evaporation pans.
2013, 41(5):857-860.
Abstract:
In order to meet the requirements for establishing the pilot emergency communication system by means of Beidou satellites, the Nanping Meteorological Service selected three representative stations as Beidou satellite communication terminals. The Beidou satellite communication receiving systems were built in Nanping Meteorological Service and the Fujian Provincial Meteorological Information Center, and both the software of Beidou communication center and the terminal software were deployed. By using the Beidou satellite communication system, the transmission of text messages and observation data of national automatic stations and system time correction are released.The trail application indicates that the transmission rate, error rate, delay, and stability all meet the requirements for operational running. Under the emergency condition such as the interruption of the public network, the automatic station observation data and text messages can still be transmitted properly.
In order to meet the requirements for establishing the pilot emergency communication system by means of Beidou satellites, the Nanping Meteorological Service selected three representative stations as Beidou satellite communication terminals. The Beidou satellite communication receiving systems were built in Nanping Meteorological Service and the Fujian Provincial Meteorological Information Center, and both the software of Beidou communication center and the terminal software were deployed. By using the Beidou satellite communication system, the transmission of text messages and observation data of national automatic stations and system time correction are released.The trail application indicates that the transmission rate, error rate, delay, and stability all meet the requirements for operational running. Under the emergency condition such as the interruption of the public network, the automatic station observation data and text messages can still be transmitted properly.
2013, 41(5):861-863.
Abstract:
Life cycle concepts and theories,which are widely used in electronic products,machinery equipment,and especially military products,are introduced into the field of meteorological equipment technical support. Several concepts of meteorological equipment life, such as design life,physical life,economical life, technical life, and remaining useful life, are defined.The application of each life concept is preliminarily studied.Fully understanding of the different concepts of meteorological equipment life will help improve the maintenance, repair, renewal, and abandonment more scientifically.The concept of remaining useful life is especially important, and the prediction and application of it will promote the construction of modern maintenance and repair ideas.
Life cycle concepts and theories,which are widely used in electronic products,machinery equipment,and especially military products,are introduced into the field of meteorological equipment technical support. Several concepts of meteorological equipment life, such as design life,physical life,economical life, technical life, and remaining useful life, are defined.The application of each life concept is preliminarily studied.Fully understanding of the different concepts of meteorological equipment life will help improve the maintenance, repair, renewal, and abandonment more scientifically.The concept of remaining useful life is especially important, and the prediction and application of it will promote the construction of modern maintenance and repair ideas.
2013, 41(5):864-869.
Abstract:
Gravity waves (GWs) play a role in exciting and enhancing typhoons,rainstorms and hail storms, and have myriad effects and major contributions to the circulation, structure, and variability of the atmospheric.The main advancements in tropospheric GWs researches in last 50 years are summarized,which include the sources, dynamical mechanisms, and observation of GWs. Results show that GWs are mainly excited by jet streams, followed by deep convection, mountain terrain, and water vapor. Normally,the strength of GWs is proportional to the vertical wind shear, absolute vorticity, buoyancy frequency, and the frequency of GWs. GWs propagation velocity is proportional to the amplitude and pulse width of GWs. GWs is strengthened in the stability atmosphere. Latent heating is favorable to the formation of GWs, and thermal heating is not. The means of GWs detection include micro pressure devices, satellites,radar, etc. The basic activity regularity of GWs has been founded out through detection in recent years.
Gravity waves (GWs) play a role in exciting and enhancing typhoons,rainstorms and hail storms, and have myriad effects and major contributions to the circulation, structure, and variability of the atmospheric.The main advancements in tropospheric GWs researches in last 50 years are summarized,which include the sources, dynamical mechanisms, and observation of GWs. Results show that GWs are mainly excited by jet streams, followed by deep convection, mountain terrain, and water vapor. Normally,the strength of GWs is proportional to the vertical wind shear, absolute vorticity, buoyancy frequency, and the frequency of GWs. GWs propagation velocity is proportional to the amplitude and pulse width of GWs. GWs is strengthened in the stability atmosphere. Latent heating is favorable to the formation of GWs, and thermal heating is not. The means of GWs detection include micro pressure devices, satellites,radar, etc. The basic activity regularity of GWs has been founded out through detection in recent years.
2013, 41(5):870-877.
Abstract:
The wind forecasting results of the mesoscale meteorological model are closely related to the adaptability of the parameterization schemes. Two pilot wind farms with typical underlying surface are selected as simulation regions, which are the undulating hilly terrain of Inner Mongolia and the flat land sea border terrain of Jiangsu respectively. Six kinds of physical process parameterizations of WRFV32 (Weather Research and Forecast Model) are adopted in forecasting the wind speed and direction of the two wind farms in January 2010 and July 2010, and the impacts of parameterizations difference on wind forecasting are analyzed. The results show that: (1) In the experimental area of Inner Mongolia,the MRF boundary Layer parameterization scheme is more reasonable than MYJ does in describing the structure of the boundary layer; the microphysical scheme WSM3 forecasts the wind speed better than WSM6 in summer and vice versa in winter; the land surface process scheme increases the influence on the boundary layer structure of complicated terrain, especially after summer rainfall, and the Noah scheme is better than that without any land surface process. (2) In the experimental area of Jiangsu, the MRF boundary Layer parameterization schemes describes the structure of the boundary layer more reasonable than MYJ; the land surface process RUC is superior to the heat diffusion and Noah schemes in January; the heat diffusion scheme is superior to the RUC and Noah in July. (3) The forecasting wind direction statistics of the six parameterization combination schemes and the actual recorded wind direction statistics are in good agreement, and the wind direction probability distribution is similar, and the prevailing wind direction is consistent and stable.
The wind forecasting results of the mesoscale meteorological model are closely related to the adaptability of the parameterization schemes. Two pilot wind farms with typical underlying surface are selected as simulation regions, which are the undulating hilly terrain of Inner Mongolia and the flat land sea border terrain of Jiangsu respectively. Six kinds of physical process parameterizations of WRFV32 (Weather Research and Forecast Model) are adopted in forecasting the wind speed and direction of the two wind farms in January 2010 and July 2010, and the impacts of parameterizations difference on wind forecasting are analyzed. The results show that: (1) In the experimental area of Inner Mongolia,the MRF boundary Layer parameterization scheme is more reasonable than MYJ does in describing the structure of the boundary layer; the microphysical scheme WSM3 forecasts the wind speed better than WSM6 in summer and vice versa in winter; the land surface process scheme increases the influence on the boundary layer structure of complicated terrain, especially after summer rainfall, and the Noah scheme is better than that without any land surface process. (2) In the experimental area of Jiangsu, the MRF boundary Layer parameterization schemes describes the structure of the boundary layer more reasonable than MYJ; the land surface process RUC is superior to the heat diffusion and Noah schemes in January; the heat diffusion scheme is superior to the RUC and Noah in July. (3) The forecasting wind direction statistics of the six parameterization combination schemes and the actual recorded wind direction statistics are in good agreement, and the wind direction probability distribution is similar, and the prevailing wind direction is consistent and stable.
2013, 41(5):878-882.
Abstract:
The meteorological data from five meteorological stations in Shenyang from 2005 to 2009 are used, and the spatial and temporal distribution regularities of fogs in Shenyang are summarized. The results show that there appears mist weather in nearly half a year in Shenyang, 164 heavy fog days per a year averagely.The frequency of mist and fog weather is relatively high in summer and autumn, and low in spring. Heavy fogs tend to appear in the morning. On the basis of the numerical forecasting, using the UPS forecasting method to make correction forecasting further for fog weather, the fog forecasting procedure for the Shenyang area is established.When the numerical forecast for fog weather shows 〖WTBX〗T-T〖WTBZ〗xover≤5 ℃,then there will appear fog weather; if -4 ℃＜〖WTBX〗T-T〖WTBZ〗xover≤5 ℃, there will be fog with visibility ≤500 m; and if 〖WTBX〗T-T〖WTBZ〗xover≤-4 ℃, there will be strong fog with visibility ≤200 m. When T-Txover＞5 ℃, if there is warm and moist advection, there will be fog weather, and if there is no warm and moist advection, there will no fog weather appear.
The meteorological data from five meteorological stations in Shenyang from 2005 to 2009 are used, and the spatial and temporal distribution regularities of fogs in Shenyang are summarized. The results show that there appears mist weather in nearly half a year in Shenyang, 164 heavy fog days per a year averagely.The frequency of mist and fog weather is relatively high in summer and autumn, and low in spring. Heavy fogs tend to appear in the morning. On the basis of the numerical forecasting, using the UPS forecasting method to make correction forecasting further for fog weather, the fog forecasting procedure for the Shenyang area is established.When the numerical forecast for fog weather shows 〖WTBX〗T-T〖WTBZ〗xover≤5 ℃,then there will appear fog weather; if -4 ℃＜〖WTBX〗T-T〖WTBZ〗xover≤5 ℃, there will be fog with visibility ≤500 m; and if 〖WTBX〗T-T〖WTBZ〗xover≤-4 ℃, there will be strong fog with visibility ≤200 m. When T-Txover＞5 ℃, if there is warm and moist advection, there will be fog weather, and if there is no warm and moist advection, there will no fog weather appear.
2013, 41(5):883-888.
Abstract:
By using the data of precipitation and sunshine duration in Sichuan,Chongqing,Yunnan and Guizhou over Southwest China,the monitoring indexes of autumn rainfall over Southwest China for extreme weather and climate events are discussed. An autumn rain event is defined as: with the number of successive rainy days greater than 5; the amounts of precipitation more than 01 mm; and the sunshine duration less than 01 hour. This index can describe the disaster characteristics of continuity and less sunshine of autumn rain events over Southwest China.The results indicate that autumn rain events in Southwest China happen mainly in the middle and south of the Sichuan basin,western Chongqing,northeastern Yunnan and northern Guizhou, with the occurrence frequency being more than 16 times per year in the central area of the region and the average number of rainy days being over 11 The intensity of autumn rainfall over Southwest China exhibits a downtrend with fluctuation.Combining with the simultaneous NCEP/NCAR data of the geopotential height fields, water vapor field and wind data, the causes of autumn rainfall over Southwest China are systematically analyzed. The results indicate that in severe autumn rain years, the pressure at 500 hPa in the polar zone is quite high, and the subtropical ridge line is northward and the Indian and Burma trough is deeper. In the area where the autumn rain is severe,there is an obvious water vapor convergence at 850 hPa over Southwest China. There is an upward motion working along with the vertical latitudinal and longitudinal circulation.
By using the data of precipitation and sunshine duration in Sichuan,Chongqing,Yunnan and Guizhou over Southwest China,the monitoring indexes of autumn rainfall over Southwest China for extreme weather and climate events are discussed. An autumn rain event is defined as: with the number of successive rainy days greater than 5; the amounts of precipitation more than 01 mm; and the sunshine duration less than 01 hour. This index can describe the disaster characteristics of continuity and less sunshine of autumn rain events over Southwest China.The results indicate that autumn rain events in Southwest China happen mainly in the middle and south of the Sichuan basin,western Chongqing,northeastern Yunnan and northern Guizhou, with the occurrence frequency being more than 16 times per year in the central area of the region and the average number of rainy days being over 11 The intensity of autumn rainfall over Southwest China exhibits a downtrend with fluctuation.Combining with the simultaneous NCEP/NCAR data of the geopotential height fields, water vapor field and wind data, the causes of autumn rainfall over Southwest China are systematically analyzed. The results indicate that in severe autumn rain years, the pressure at 500 hPa in the polar zone is quite high, and the subtropical ridge line is northward and the Indian and Burma trough is deeper. In the area where the autumn rain is severe,there is an obvious water vapor convergence at 850 hPa over Southwest China. There is an upward motion working along with the vertical latitudinal and longitudinal circulation.
2013, 41(5):889-894.
Abstract:
The spatial and temporal distributive characteristics and variation trends of precipitable water in the southwest area are analyzed by using NCEP monthly precipitable water data from 1980 to 2009 The results show that influenced by geographical environment and climate,the distribution of annual and seasonal precipitable water in Southwest China has obvious regional difference, greater in the southeast and less in the northwest.Precipitable water varies with season obviously, with the value in summer being visibly higher than that in winter, and that in autumn slightly higher than that in spring.The annual distribution of precipitable water is uneven: the greatest precipitable water appearing in July, the secondary in August, and the least in January. Around the recent 30 years, the annual precipitable water in the southwest fluctuates alternately. There is an upward trend in annual precipitable water, as well as in spring and winter. The spatial distribution of annual precipitable water exhibits not only consistency in the whole area, but also reverse patterns.
The spatial and temporal distributive characteristics and variation trends of precipitable water in the southwest area are analyzed by using NCEP monthly precipitable water data from 1980 to 2009 The results show that influenced by geographical environment and climate,the distribution of annual and seasonal precipitable water in Southwest China has obvious regional difference, greater in the southeast and less in the northwest.Precipitable water varies with season obviously, with the value in summer being visibly higher than that in winter, and that in autumn slightly higher than that in spring.The annual distribution of precipitable water is uneven: the greatest precipitable water appearing in July, the secondary in August, and the least in January. Around the recent 30 years, the annual precipitable water in the southwest fluctuates alternately. There is an upward trend in annual precipitable water, as well as in spring and winter. The spatial distribution of annual precipitable water exhibits not only consistency in the whole area, but also reverse patterns.
2013, 41(5):895-905.
Abstract:
By using the conventional observation, FY 2E satellite, radar detection, and automatic weather station rainfall data, the extreme severe rainstorm on 28 June 2010 in Guangxi is analyzed. The results show: (1) The rainstorm disaster has the features of small influencing area, concentrated in time, large process rainfall, short duration, and serious secondary disaster. (2) The rainstorm occurred in the circulation pattern of “two ridges and one trough” over the high latitude Eurasia at 500 hPa, with the ridge line of South Asia High throughout Guangxi at 200 hPa accompanying with active southwest monsoon. Configuration of the upper vortex and surface dry line indicates a vortex type storm. (3) The main physical quantity characteristics included the presence of strong instability energy and stratification, low level convergence at 850 hPa and below, obvious vortex near 700 hPa, upward motion in the whole atmosphere, and high humidity and strong convergence of water vapor at 850 hPa and below. (4) Mesoscale low, vortex, convergence of airflow, etc., triggered the mesoscale convection. Formation and mergence of convective cloud clusters on the FY 2E satellite cloud picture has implications for heavy rainfall. The rainstorm occurring in the development stage of clouds and TBB value being less than 200 K could be used as an indicator of short term heavy rainfall. The train effect produced by the low centroid radar echoes and the effect of topography are important factors in causing heavy rainfall. Strong vertical motion induced by the low level convergence and upper level divergence is conducive to the development and maintenance of strong convection.
By using the conventional observation, FY 2E satellite, radar detection, and automatic weather station rainfall data, the extreme severe rainstorm on 28 June 2010 in Guangxi is analyzed. The results show: (1) The rainstorm disaster has the features of small influencing area, concentrated in time, large process rainfall, short duration, and serious secondary disaster. (2) The rainstorm occurred in the circulation pattern of “two ridges and one trough” over the high latitude Eurasia at 500 hPa, with the ridge line of South Asia High throughout Guangxi at 200 hPa accompanying with active southwest monsoon. Configuration of the upper vortex and surface dry line indicates a vortex type storm. (3) The main physical quantity characteristics included the presence of strong instability energy and stratification, low level convergence at 850 hPa and below, obvious vortex near 700 hPa, upward motion in the whole atmosphere, and high humidity and strong convergence of water vapor at 850 hPa and below. (4) Mesoscale low, vortex, convergence of airflow, etc., triggered the mesoscale convection. Formation and mergence of convective cloud clusters on the FY 2E satellite cloud picture has implications for heavy rainfall. The rainstorm occurring in the development stage of clouds and TBB value being less than 200 K could be used as an indicator of short term heavy rainfall. The train effect produced by the low centroid radar echoes and the effect of topography are important factors in causing heavy rainfall. Strong vertical motion induced by the low level convergence and upper level divergence is conducive to the development and maintenance of strong convection.
2013, 41(5):906-914.
Abstract:
Based on the TBB grid data from the FY 2E satellite and NCEP\\NCAR reanalysis data and the data of the heavy rainfall from 31 May to 2 June 2010, the features of mean TBB field distribution and evolution are analyzed to reveal the internal relationship between strong rainfall cloud dissipation and heavy rainfall development. The results show that the development of these Mesoscale Convective Complexes (MCCs) was associated with the formation and evolution of several cloud clusters in South China．There were obvious corresponding relationships between low TBB area and precipitation location. The rapid TBB decrease and rainfall enhancement were quite coherent. The evolution of strong rainfall and the changes of TBB gradient had apparent correspondent relationship; the sudden decrease was followed by the strengthening of rainfall, and vice verse. When TBB decreased to the lowest, rainfall reached the strongest. The transported water vapor from the South China Sea along the west side of the subtropical high and the constant flow from Upper trough met in South China, which played an important part in the generation, development, and maintenance of the strong convective cloud cluster in Guangxi. The lower TBB band along the central Guangxi and warm shear was less dynamically stable with a small north to south swing, which resulted in the torrential rainfall.
Based on the TBB grid data from the FY 2E satellite and NCEP\\NCAR reanalysis data and the data of the heavy rainfall from 31 May to 2 June 2010, the features of mean TBB field distribution and evolution are analyzed to reveal the internal relationship between strong rainfall cloud dissipation and heavy rainfall development. The results show that the development of these Mesoscale Convective Complexes (MCCs) was associated with the formation and evolution of several cloud clusters in South China．There were obvious corresponding relationships between low TBB area and precipitation location. The rapid TBB decrease and rainfall enhancement were quite coherent. The evolution of strong rainfall and the changes of TBB gradient had apparent correspondent relationship; the sudden decrease was followed by the strengthening of rainfall, and vice verse. When TBB decreased to the lowest, rainfall reached the strongest. The transported water vapor from the South China Sea along the west side of the subtropical high and the constant flow from Upper trough met in South China, which played an important part in the generation, development, and maintenance of the strong convective cloud cluster in Guangxi. The lower TBB band along the central Guangxi and warm shear was less dynamically stable with a small north to south swing, which resulted in the torrential rainfall.
2013, 41(5):915-922.
Abstract:
The TOA narrow to broadband conversion model,bidirectional reflectance model,and atmospheric correction model are the necessary models for retrieving surface albedos with reflectance from NOAA AVHRR. Based on the models and NOAA 18 AVHRR 1B data, the clear sky surface albedos in the area of 10°to 60°N and 65°to 145°E with a resolution of 001°×001°lat/lon from January 2006 to December 2010 are calculated. A 15 day data combination technology is used to produce the albedo products in a 15 day cycle. Comparison is conducted between the two year products and MODIS measurements. The RMSs are 0028 to 0074, correlation coefficients are 076 to 093 The larger errors occurred in winter are caused by the different combination technologies adopted by the two products. The daily mean surface albedos from 21 first class surface meteorological radiation stations over China are selected and compared with the produced data.The results show: RMS is 0053, and the correlation coefficient is 08808 The impacts of Clouds and aerosols are the main error sources of surface albedo retrieval from satellite.
The TOA narrow to broadband conversion model,bidirectional reflectance model,and atmospheric correction model are the necessary models for retrieving surface albedos with reflectance from NOAA AVHRR. Based on the models and NOAA 18 AVHRR 1B data, the clear sky surface albedos in the area of 10°to 60°N and 65°to 145°E with a resolution of 001°×001°lat/lon from January 2006 to December 2010 are calculated. A 15 day data combination technology is used to produce the albedo products in a 15 day cycle. Comparison is conducted between the two year products and MODIS measurements. The RMSs are 0028 to 0074, correlation coefficients are 076 to 093 The larger errors occurred in winter are caused by the different combination technologies adopted by the two products. The daily mean surface albedos from 21 first class surface meteorological radiation stations over China are selected and compared with the produced data.The results show: RMS is 0053, and the correlation coefficient is 08808 The impacts of Clouds and aerosols are the main error sources of surface albedo retrieval from satellite.
2013, 41(5):923-928.
Abstract:
The Sichuan Lightning Protection Center developed the multi factor lightning nowcasting system, which has been put into operational use.Cooperated with the Chinese Academy of Meteorological Sciences, the CAMS_LNWS lightning nowcasting system was manufactured and localized in Sichuan. A brief introduction is made to the two systems and the trial use in lightning forecasting.The results by forecasting 19 lightning activities show that they both have strong lightning warning capability, and their TS score are greater than 075 The CAMS_LNWS system has well warning capability for new appearing lightning activities, and the multi factor lightning nowcasting system is better in the prediction of lightning moving path and development.Combination of two systems can provide well technical support for lightning nowcasting service in Sichuan.
The Sichuan Lightning Protection Center developed the multi factor lightning nowcasting system, which has been put into operational use.Cooperated with the Chinese Academy of Meteorological Sciences, the CAMS_LNWS lightning nowcasting system was manufactured and localized in Sichuan. A brief introduction is made to the two systems and the trial use in lightning forecasting.The results by forecasting 19 lightning activities show that they both have strong lightning warning capability, and their TS score are greater than 075 The CAMS_LNWS system has well warning capability for new appearing lightning activities, and the multi factor lightning nowcasting system is better in the prediction of lightning moving path and development.Combination of two systems can provide well technical support for lightning nowcasting service in Sichuan.
2013, 41(5):929-933.
Abstract:
In terms of the present situation and business needs, a command system for airplane artificial precipitation enhancement is developed based on GPS/Beidou satellite and GIS technology. The system has such functions as data acquisition, information display, route design, decision analysis, real time monitoring, operation command, and data management, so it can optimize the operation flow of airplane artificial precipitation enhancement, and provide a decision making basis for operation command and dispatch. Using satellite communication technology, the system has also realized the point to multi point air ground real time communication, which is fit for the construction of cross regional operation command systems for airplane artificial precipitation enhancement and has a certain promotion and application value.
In terms of the present situation and business needs, a command system for airplane artificial precipitation enhancement is developed based on GPS/Beidou satellite and GIS technology. The system has such functions as data acquisition, information display, route design, decision analysis, real time monitoring, operation command, and data management, so it can optimize the operation flow of airplane artificial precipitation enhancement, and provide a decision making basis for operation command and dispatch. Using satellite communication technology, the system has also realized the point to multi point air ground real time communication, which is fit for the construction of cross regional operation command systems for airplane artificial precipitation enhancement and has a certain promotion and application value.
2013, 41(5):934-939.
Abstract:
Using weather， physical geographic and socio economic data of Nanning, four indexes of natural disaster making factors are constituted: susceptibility, disaster hitting environment sensitivity, disaster bearing object vulnerability, and disaster prevention and reduction capability. With GIS technology, the rainstorm and flooding risk assessment index system is established, and the rainstorm and flooding risk of Nanning was zoned in 1000 m×1000 m cells. Results show that the area with the highest risk of storms and flooding disasters is Binyang.Thereinto, the most seismic risk area is in the north and east of Binyang, and the most fragility area is in the middle of Binyang, as well as southeast of Hengxian. The zoning result reveals the distribution of potential risk of rainstorms and flooding disasters in Nanning. Key disaster prevention measures for rainstorms and flooding disasters should focus on the high risk area.
Using weather， physical geographic and socio economic data of Nanning, four indexes of natural disaster making factors are constituted: susceptibility, disaster hitting environment sensitivity, disaster bearing object vulnerability, and disaster prevention and reduction capability. With GIS technology, the rainstorm and flooding risk assessment index system is established, and the rainstorm and flooding risk of Nanning was zoned in 1000 m×1000 m cells. Results show that the area with the highest risk of storms and flooding disasters is Binyang.Thereinto, the most seismic risk area is in the north and east of Binyang, and the most fragility area is in the middle of Binyang, as well as southeast of Hengxian. The zoning result reveals the distribution of potential risk of rainstorms and flooding disasters in Nanning. Key disaster prevention measures for rainstorms and flooding disasters should focus on the high risk area.
2013, 41(5):940-944.
Abstract:
An evaluation method of meteorological service satisfaction based on AHP is proposed.A meteorological service satisfaction measurement model is constructed by such steps as establishing the evaluation index, building the judgment matrix, testing the consistency of matrix, and calculating the level weights. In combination with the measurement model and the weather service satisfaction quantization formula, a quantitative evaluation method of the meteorological service satisfaction is achieved. According to the data obtained by meteorological service questionnaire instances, the method proved to be widely practicable and applicable, and has certain guiding significance for meteorological services.
An evaluation method of meteorological service satisfaction based on AHP is proposed.A meteorological service satisfaction measurement model is constructed by such steps as establishing the evaluation index, building the judgment matrix, testing the consistency of matrix, and calculating the level weights. In combination with the measurement model and the weather service satisfaction quantization formula, a quantitative evaluation method of the meteorological service satisfaction is achieved. According to the data obtained by meteorological service questionnaire instances, the method proved to be widely practicable and applicable, and has certain guiding significance for meteorological services.
2013, 41(5):945-948.
Abstract:
By using the daily maximum electric power load data from the the Southern Hebei Electric Power Company from 2007 to 2009, the variation regularity of the daily maximum power load in summer (May to August) over the southern Hebei Province is studied. By means of the standardized and correlation analysis, the correlation between maximum power load and month by month meteorological factors is analyzed, and the weekly variation characteristics of maximum power load, as well as the variation of maximum power load during holidays,are discussed.In addition,in combination with the growth characteristics of crops in the southern Hebei Province, the variation characteristics of maximum power load of the Southern Hebei Electric Power Network are studied, which are useful to the forecasting of maximum electric power load.
By using the daily maximum electric power load data from the the Southern Hebei Electric Power Company from 2007 to 2009, the variation regularity of the daily maximum power load in summer (May to August) over the southern Hebei Province is studied. By means of the standardized and correlation analysis, the correlation between maximum power load and month by month meteorological factors is analyzed, and the weekly variation characteristics of maximum power load, as well as the variation of maximum power load during holidays,are discussed.In addition,in combination with the growth characteristics of crops in the southern Hebei Province, the variation characteristics of maximum power load of the Southern Hebei Electric Power Network are studied, which are useful to the forecasting of maximum electric power load.
2013, 41(5):949-954.
Abstract:
According to Observation and Forecasting Levels of Haze ( QX/T113 2010 ) issued by the China Meteorological Administration, the Xinjiang meteorological Service developed the Operational Automatic Identification System of Fog/Haze for Xinjiang, which has the capabilities of automatically identifying fog, haze, and sunny weather phenomenon and displaying such parameters of atmospheric status as PM25 and aerosol absorption properties of automatic meteorological stations in real time on line over 24 hours.The system provides an auxiliary fog/haze identification tool for meteorological observers and an on line verification tool of fog/haze weather forecast quality for weather forecasters,which has been put to use in weather stations in Urumqi and performs satisfactorily.
According to Observation and Forecasting Levels of Haze ( QX/T113 2010 ) issued by the China Meteorological Administration, the Xinjiang meteorological Service developed the Operational Automatic Identification System of Fog/Haze for Xinjiang, which has the capabilities of automatically identifying fog, haze, and sunny weather phenomenon and displaying such parameters of atmospheric status as PM25 and aerosol absorption properties of automatic meteorological stations in real time on line over 24 hours.The system provides an auxiliary fog/haze identification tool for meteorological observers and an on line verification tool of fog/haze weather forecast quality for weather forecasters,which has been put to use in weather stations in Urumqi and performs satisfactorily.
2013, 41(5):955-959.
Abstract:
A weather service system for self driving is proposed, in order to meet the needs of precision and individuation of public weather services. The system uses the Magento system as portals, using JMS to realize the communication between the servers and GMAP API to obtain the route information, storage service, and meteorological information in Mysql database storage and the NC file repository. To realize the functions of user customized weather service products, a method integrating the SSL security certification, Alipay, GMAP API, JMS, and portal technology is proposed.At present, the system has put into trial operation. The results show that the system can meet the requirements of individuation and differentiation of public meteorological services, and is beneficial to the development of meteorological service.
A weather service system for self driving is proposed, in order to meet the needs of precision and individuation of public weather services. The system uses the Magento system as portals, using JMS to realize the communication between the servers and GMAP API to obtain the route information, storage service, and meteorological information in Mysql database storage and the NC file repository. To realize the functions of user customized weather service products, a method integrating the SSL security certification, Alipay, GMAP API, JMS, and portal technology is proposed.At present, the system has put into trial operation. The results show that the system can meet the requirements of individuation and differentiation of public meteorological services, and is beneficial to the development of meteorological service.
2013, 41(5):960-964.
Abstract:
The comfortability measurement system has six components: acquisition, sensor, bracket part, water supply system, communication module, and data acquisition. Except the communication module, the other five parts are design newly. The acquisition unit is the core part of the system, which is responsible for data collection, processing and transmission. The data acquisition software installed on the central server is responsible for data collection, processing, display and storage, remote monitoring and remote detection of the site equipment. The related theories about comfortability are analyzed and the grading standards of comfortability index for the Guangzhou region are proposed. The measurements are also analyzed. The trial operation of nearly one year shows that the system is stable, and the data are reliable, which meets the operational requirements.
The comfortability measurement system has six components: acquisition, sensor, bracket part, water supply system, communication module, and data acquisition. Except the communication module, the other five parts are design newly. The acquisition unit is the core part of the system, which is responsible for data collection, processing and transmission. The data acquisition software installed on the central server is responsible for data collection, processing, display and storage, remote monitoring and remote detection of the site equipment. The related theories about comfortability are analyzed and the grading standards of comfortability index for the Guangzhou region are proposed. The measurements are also analyzed. The trial operation of nearly one year shows that the system is stable, and the data are reliable, which meets the operational requirements.
2013, 41(5):965-969.
Abstract:
In order to improve the quality of radiosonde observation and reduce the abnormal balloon tracing, an analysis is made of the phenomenon of balloon loss and side lobe echoes caused by the radar performance, frequency drifting, electromagnetic interference, low elevation angles, and so on. Combined with the actual working experiences, a new method for using the saturated signal principle is presented.Some suggestions, such as the radar precision setting check and battery soak time control, are given. The application indicates that these methods work well.
In order to improve the quality of radiosonde observation and reduce the abnormal balloon tracing, an analysis is made of the phenomenon of balloon loss and side lobe echoes caused by the radar performance, frequency drifting, electromagnetic interference, low elevation angles, and so on. Combined with the actual working experiences, a new method for using the saturated signal principle is presented.Some suggestions, such as the radar precision setting check and battery soak time control, are given. The application indicates that these methods work well.
2013, 41(5):970-973.
Abstract:
A typical dynamic range abnormal event of the CINRAD / SA radar digitized receiver is described and the main influencing factors on receiver dynamic range and the expansion of dynamic performance limitations are analyzed, focusing on the dynamic range abnormalities. Through the step by step sub module troubleshooting, the causes of the malfunction of the receiver dynamic range abnormality are diagnosed in detail, and the rapid and accurate positioning procedure of the faulty is discussed to provide references for the troubleshooting of radar digital receiver dynamic range abnormalities.
A typical dynamic range abnormal event of the CINRAD / SA radar digitized receiver is described and the main influencing factors on receiver dynamic range and the expansion of dynamic performance limitations are analyzed, focusing on the dynamic range abnormalities. Through the step by step sub module troubleshooting, the causes of the malfunction of the receiver dynamic range abnormality are diagnosed in detail, and the rapid and accurate positioning procedure of the faulty is discussed to provide references for the troubleshooting of radar digital receiver dynamic range abnormalities.
2013, 41(5):974-976.
Abstract:
Lead acid batteries are used widely in regional automatic weather stations, affected by weather factors, prone to such faults as the leakage corrosion of the electrode, unable to charge, and power supply power failure, which directly affects the meteorological data collection and transmission. In view of the characteristics of lead acid battery maintenance in regional automatic weather stations, the maintenance techniques such as the replenishment, plate vulcanizing, and electrode corrosion processing, as well as operation procedures, precautions, suggestions for field emergency charging, etc., are described in detail, which can be used as references for automatic weather station maintenance personnel.
Lead acid batteries are used widely in regional automatic weather stations, affected by weather factors, prone to such faults as the leakage corrosion of the electrode, unable to charge, and power supply power failure, which directly affects the meteorological data collection and transmission. In view of the characteristics of lead acid battery maintenance in regional automatic weather stations, the maintenance techniques such as the replenishment, plate vulcanizing, and electrode corrosion processing, as well as operation procedures, precautions, suggestions for field emergency charging, etc., are described in detail, which can be used as references for automatic weather station maintenance personnel.
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.