Volume 38,Issue 3,2010 Table of Contents
2010, 38(3):275-280.
Abstract:
A synoptic analysis and numerical simulation are conducted on an explosive cyclone happened on the East China Sea on 1 June 2006, in order to further understand the physical mechanisms of the cyclone explosive development. The results show that: the main influencing system on the surface is an inverse trough from the sea area around Taiwan Islands, which encountered a strong upperlevel trough over the northern coastal area of Zhejiang. The largescale upperlevel trough provided a conducive environment for cyclone development and maintenance by positive vorticity transport before the trough and the strengthening role of cold and warm advection on baroclinic instability. At the same time, a highaltitude jet provided a favorable environment for the development and maintenance of the cyclone through divergence and warm advection around its exit. The uplifting role of strong vorticity advection in middle and lower levels induced precipitation, and the latent heat release produced by water vapor condensation strengthened the development of the ground cyclone system, during which cyclone and precipitation constituted a positive feedback mechanism. The latent heat release was excited by the uplifting movement caused by the baroclinic instability before the highaltitude trough and divergence around the exit of the jet on the right side, which played an important role in the cyclone development.
A synoptic analysis and numerical simulation are conducted on an explosive cyclone happened on the East China Sea on 1 June 2006, in order to further understand the physical mechanisms of the cyclone explosive development. The results show that: the main influencing system on the surface is an inverse trough from the sea area around Taiwan Islands, which encountered a strong upperlevel trough over the northern coastal area of Zhejiang. The largescale upperlevel trough provided a conducive environment for cyclone development and maintenance by positive vorticity transport before the trough and the strengthening role of cold and warm advection on baroclinic instability. At the same time, a highaltitude jet provided a favorable environment for the development and maintenance of the cyclone through divergence and warm advection around its exit. The uplifting role of strong vorticity advection in middle and lower levels induced precipitation, and the latent heat release produced by water vapor condensation strengthened the development of the ground cyclone system, during which cyclone and precipitation constituted a positive feedback mechanism. The latent heat release was excited by the uplifting movement caused by the baroclinic instability before the highaltitude trough and divergence around the exit of the jet on the right side, which played an important role in the cyclone development.
2010, 38(3):281-288.
Abstract:
In order to reveal the development mechanisms of heavy snowfall in Hebei Province,two heave snow processes on 14 to 16 March 2003 and 20 to 21 February 2004 are selected. A contrast analysis of their meteorological characteristics is made from aspect of synoptic situation and physical mechanism by means of numerical diagnosis with the NCEP reanalysis data and conventional observation data. The results show that the combination of south and north troughs with identical phase around 110°E at 500 hPa, the allocation of the surface pressure field with high in north and low in south, and the appearance of the ground inverted trough in the Hetao area of NW China, as well as the thermodynamic conditions with warm temperature tongue and warm advection in the lower troposphere, are the favorable largescale background for the formation of heavy snowfall. There are three important paths of water vapor in the two snow events: from southwest in front of the 500 hPa trough, from east at low level, and from lowlevel jet. From the cross sections of vorticity, divergence, vertical velocity and vertical helicity, it is found that the vertical distribution of convergence at low level but divergence at upper level and ascending motion in the whole troposphere benefit the forming and maintaining of heavy snowfall, and the distribution of positive vorticity (vertical helicity) in the whole troposphere is most favorable. It is also suggested the temperature descending to below 0 ℃ at both 850 hPa and 925 hPa, meanwhile below 1 ℃ in the surface, is favorable to snowing. The results can be used as reference in the forecasting heavy snowfall.
In order to reveal the development mechanisms of heavy snowfall in Hebei Province,two heave snow processes on 14 to 16 March 2003 and 20 to 21 February 2004 are selected. A contrast analysis of their meteorological characteristics is made from aspect of synoptic situation and physical mechanism by means of numerical diagnosis with the NCEP reanalysis data and conventional observation data. The results show that the combination of south and north troughs with identical phase around 110°E at 500 hPa, the allocation of the surface pressure field with high in north and low in south, and the appearance of the ground inverted trough in the Hetao area of NW China, as well as the thermodynamic conditions with warm temperature tongue and warm advection in the lower troposphere, are the favorable largescale background for the formation of heavy snowfall. There are three important paths of water vapor in the two snow events: from southwest in front of the 500 hPa trough, from east at low level, and from lowlevel jet. From the cross sections of vorticity, divergence, vertical velocity and vertical helicity, it is found that the vertical distribution of convergence at low level but divergence at upper level and ascending motion in the whole troposphere benefit the forming and maintaining of heavy snowfall, and the distribution of positive vorticity (vertical helicity) in the whole troposphere is most favorable. It is also suggested the temperature descending to below 0 ℃ at both 850 hPa and 925 hPa, meanwhile below 1 ℃ in the surface, is favorable to snowing. The results can be used as reference in the forecasting heavy snowfall.
2010, 38(3):289-294.
Abstract:
With the intensive observation data and NCEP/NCAR reanalyzed data, an unusual heavy fog process occurred over the eastcentral China from 25 to 27 December in 2006 is analyzed in aspects of the largescale synoptic condition and dynamic and thermodynamic mechanisms. It was shown that the fog occurred while the nearground wind velocity varied from 0.3 to 2.9 m/s and the dense fog occurred while the wind velocity varied from 0.3 to 2.4 m/s and the visibility was within 15 meters when velocity was from 0.8 to 1.1 m/s. Although vapor condition was bad and rainfall didn’t occur within a few days before the heavy fog, the continuous vapor transportation of the southwestern air current before a trough offered plentiful vapor for the fog. The results also show that the stable stratification gradually established before the fog.At first, the instable stratification built at higher levels after sunrise, subsequently passed downward to lower levels, and then the inversion layer destroyed and the fog dispersed and cleared off. The results indicate that the visibility changed rapidly and violently before the first stage of the severe heavy fog but it did not before the second stage.
With the intensive observation data and NCEP/NCAR reanalyzed data, an unusual heavy fog process occurred over the eastcentral China from 25 to 27 December in 2006 is analyzed in aspects of the largescale synoptic condition and dynamic and thermodynamic mechanisms. It was shown that the fog occurred while the nearground wind velocity varied from 0.3 to 2.9 m/s and the dense fog occurred while the wind velocity varied from 0.3 to 2.4 m/s and the visibility was within 15 meters when velocity was from 0.8 to 1.1 m/s. Although vapor condition was bad and rainfall didn’t occur within a few days before the heavy fog, the continuous vapor transportation of the southwestern air current before a trough offered plentiful vapor for the fog. The results also show that the stable stratification gradually established before the fog.At first, the instable stratification built at higher levels after sunrise, subsequently passed downward to lower levels, and then the inversion layer destroyed and the fog dispersed and cleared off. The results indicate that the visibility changed rapidly and violently before the first stage of the severe heavy fog but it did not before the second stage.
2010, 38(3):295-299.
Abstract:
The advances in tornado researches are reviewed in three aspects: (1) general description, from simple cases to weather and climatic analysis of tornadoes, the structure and the formation causes of tornadoes; (2) methods for studying tornadoes, with data only from meteorological stations in the last century, but presently data not only from stations but also from satellite, Doppler radar and numerical models (WRF，ARPS); (3) problems encountered in tornado researches and prospects.
The advances in tornado researches are reviewed in three aspects: (1) general description, from simple cases to weather and climatic analysis of tornadoes, the structure and the formation causes of tornadoes; (2) methods for studying tornadoes, with data only from meteorological stations in the last century, but presently data not only from stations but also from satellite, Doppler radar and numerical models (WRF，ARPS); (3) problems encountered in tornado researches and prospects.
2010, 38(3):300-305.
Abstract:
The relationship between previous winter and springtime soil moisture and summer climate in the eastern China is investigated with the retrieved monthly soil moisture data of 139 stations and the precipitation and temperature observations of 160 stations over China from 1951 to 1999. The results show that there exists one or twoseason lagged positive correlation between soil moisture in spring or previous winter and summer rainfall in the regions south of the Huanghe River valley, and negative correlation in the regions north of the Huanghe River valley. The relationship is quite different in different regions. The significant twoseason lagged correlation exists in the YunnanGuizhou Plateau, Central China and North China. The oneseason lagged correlation is not significant, except over the YunnanGuizhou Plateau, where summer climate is sensitive to spring soil moisture.
The relationship between previous winter and springtime soil moisture and summer climate in the eastern China is investigated with the retrieved monthly soil moisture data of 139 stations and the precipitation and temperature observations of 160 stations over China from 1951 to 1999. The results show that there exists one or twoseason lagged positive correlation between soil moisture in spring or previous winter and summer rainfall in the regions south of the Huanghe River valley, and negative correlation in the regions north of the Huanghe River valley. The relationship is quite different in different regions. The significant twoseason lagged correlation exists in the YunnanGuizhou Plateau, Central China and North China. The oneseason lagged correlation is not significant, except over the YunnanGuizhou Plateau, where summer climate is sensitive to spring soil moisture.
2010, 38(3):306-310.
Abstract:
The rainstorm data of 1960 to 2008 from 66 weather observations in Fujian province are used to analyze the spatial and temporal distribution and main influencing synoptic systems of winter rainstorms. The results show that winter rainstorms appear mainly in the western Fujian. The main influencing systems include the eastward moving south westerly trough, steady shear line, and southward moving cold air; the physical conditions for winter rainstorm formation are correlated with abundant vapor, atmospheric instability, and convergent upward movement, but the stratification of the atmosphere is more stable in winter than those in flood season; the atmosphere circulation at 500 hPa is closely related to seasurface temperature anomalies around the equatorial middleeastern Pacific, which may induced the abnormity of winter rainstorms over Fujian through influencing the atmosphere circulation.
The rainstorm data of 1960 to 2008 from 66 weather observations in Fujian province are used to analyze the spatial and temporal distribution and main influencing synoptic systems of winter rainstorms. The results show that winter rainstorms appear mainly in the western Fujian. The main influencing systems include the eastward moving south westerly trough, steady shear line, and southward moving cold air; the physical conditions for winter rainstorm formation are correlated with abundant vapor, atmospheric instability, and convergent upward movement, but the stratification of the atmosphere is more stable in winter than those in flood season; the atmosphere circulation at 500 hPa is closely related to seasurface temperature anomalies around the equatorial middleeastern Pacific, which may induced the abnormity of winter rainstorms over Fujian through influencing the atmosphere circulation.
2010, 38(3):311-315.
Abstract:
The interannual and interdecadal changes of air temperature and the correlation with totaland lowcloud covers are analyzed, by means of the observed data of surface air temperature from 24 stations over the Loess Plateau region of Shaanxi in recent 50 years. The results indicate that mean temperature increased in a wavy way, especially after the 1987s; the interannual changes of air temperature in the northern sanddrifting areas were obvious, with the warming amplitudes decreasing from north to south; since 1957, the annual mean total cloud cover gradually decreased, and the decreasing tendency of low cloud cover was more obvious than that of the total, but the total cloud cover increased after 2000. The correlation analysis indicates that there was negative relation between annual mean air temperature and total and low cloud covers in the Loess Plateau region of Shaanxi, both passed the test with the significant level being 0.001 and the low cloud cover had more significant relation with temperature; there was obvious positive relation between precipitation and total and low cloud covers; meanwhile, the correlation coefficients between air temperature and totaland lowcloud covers were different greatly in different regions and seasons, but there was significant correlation between cloud cover and precipitation.
The interannual and interdecadal changes of air temperature and the correlation with totaland lowcloud covers are analyzed, by means of the observed data of surface air temperature from 24 stations over the Loess Plateau region of Shaanxi in recent 50 years. The results indicate that mean temperature increased in a wavy way, especially after the 1987s; the interannual changes of air temperature in the northern sanddrifting areas were obvious, with the warming amplitudes decreasing from north to south; since 1957, the annual mean total cloud cover gradually decreased, and the decreasing tendency of low cloud cover was more obvious than that of the total, but the total cloud cover increased after 2000. The correlation analysis indicates that there was negative relation between annual mean air temperature and total and low cloud covers in the Loess Plateau region of Shaanxi, both passed the test with the significant level being 0.001 and the low cloud cover had more significant relation with temperature; there was obvious positive relation between precipitation and total and low cloud covers; meanwhile, the correlation coefficients between air temperature and totaland lowcloud covers were different greatly in different regions and seasons, but there was significant correlation between cloud cover and precipitation.
2010, 38(3):316-320.
Abstract:
The variation trend，abrupt changes and anomalous years of annual and seasonal mean soil temperature at shallow layers from 1961 to 2005 in Xishuangbanna, Yunnan Province are investigated by using the statistical diagnostic methods such as linear trend analysis，accumulated variance and signalnoise ratio. The results indicate：(1) In terms of linear trend，the seasonal mean soil temperature in the shallow layers displayed a significant increasing trend in Xishuangbanna in past 45 years with an increase rate of 0.14 to 0.40 ℃/10a, maximum in winter，minimum in spring. The interdecadal variations of the annual and seasonal mean soil temperature in the shallow layers had an obvious increasing tendency, especially in winter and spring. (2) The abrupt changes of mean soil temperature in various layers occurred in autumn of 1980，and the abrupt changes in winter appeared in 1978; the period before the abrupt change is colder and the period after is warmer. Before the abrupt change, only annual mean soil temperature at 20 cm kept the same increasing trend, but a significant increasing trend after the abrupt changes, which shows that the annual mean soil temperature at 20 cm response to climate warming more sensitively since the 1980s. (3) Except that the annual mean soil temperature at 10 cm was anomalously lower in 1971，anomalously higher temperature occurred in 2003 at the other shallow levels. The results proved that the significant increase of air temperature is the main cause of the increase of soil temperature.
The variation trend，abrupt changes and anomalous years of annual and seasonal mean soil temperature at shallow layers from 1961 to 2005 in Xishuangbanna, Yunnan Province are investigated by using the statistical diagnostic methods such as linear trend analysis，accumulated variance and signalnoise ratio. The results indicate：(1) In terms of linear trend，the seasonal mean soil temperature in the shallow layers displayed a significant increasing trend in Xishuangbanna in past 45 years with an increase rate of 0.14 to 0.40 ℃/10a, maximum in winter，minimum in spring. The interdecadal variations of the annual and seasonal mean soil temperature in the shallow layers had an obvious increasing tendency, especially in winter and spring. (2) The abrupt changes of mean soil temperature in various layers occurred in autumn of 1980，and the abrupt changes in winter appeared in 1978; the period before the abrupt change is colder and the period after is warmer. Before the abrupt change, only annual mean soil temperature at 20 cm kept the same increasing trend, but a significant increasing trend after the abrupt changes, which shows that the annual mean soil temperature at 20 cm response to climate warming more sensitively since the 1980s. (3) Except that the annual mean soil temperature at 10 cm was anomalously lower in 1971，anomalously higher temperature occurred in 2003 at the other shallow levels. The results proved that the significant increase of air temperature is the main cause of the increase of soil temperature.
2010, 38(3):321-324.
Abstract:
With the daily fog data of 16 weather stations in Southeast Guizhou from 1961 to 2007, a detailed analysis is made of the daily, seasonal, annual, and interdecade variation characteristics and longterm trends of fog distribution over Southeast Guizhou. It is concluded that the maximum number of foggy days averagely occurred in the 1960s, and minimum in the 1980s, with an increasing trend after 2000; the greatest number of foggy days are found in autumn and the least in spring, the greatest in November and the least in February; there is a quasi40 year period and a quasi5 year period in the variation of the number of heavy fog days; heavy fog weather occurred most frequently around the central part of Southeast Guizhou and relatively less in the southeast and northwest parts of Southeast Guizhou.
With the daily fog data of 16 weather stations in Southeast Guizhou from 1961 to 2007, a detailed analysis is made of the daily, seasonal, annual, and interdecade variation characteristics and longterm trends of fog distribution over Southeast Guizhou. It is concluded that the maximum number of foggy days averagely occurred in the 1960s, and minimum in the 1980s, with an increasing trend after 2000; the greatest number of foggy days are found in autumn and the least in spring, the greatest in November and the least in February; there is a quasi40 year period and a quasi5 year period in the variation of the number of heavy fog days; heavy fog weather occurred most frequently around the central part of Southeast Guizhou and relatively less in the southeast and northwest parts of Southeast Guizhou.
2010, 38(3):325-331.
Abstract:
By means of the radiosonde data and the threeyear data of the microwave radiometer in Beijing in recent 3 years, from the aspects of total average, daily change, annual mean change, and different sky status, etc, the evaluation and analysis of the retrieval products are made The results indicate: (1) The rootmeansquare error of temperature increased from surface to 5000 meters and decreased above 5000 meters gradually The overall average relative error was less than 02 ℃ with a positive value, which shows that the retrieved temperature was higher than that from the radiosondes (2) The rootmeansquare error of humidity increased from surface to 3000 meters and decreased above 3000 meters, and the overall average relative error was positive, which shows that the retrieved humidity was also higher than that from the radiosondes (3) The error at 20:00 was smaller than that at 08:00 (4) The temperature error was relatively small while it was clear and clear to cloudy, and bigger while overcast or cloudy to overcast The humidity error in overcast and cloudy to overcast weather was small (5) There was a small annual change range in the rootmeansquare error of temperature under 1500 m, but big above 1500 m, smallest in August, biggest in March and April; the rootmeansquare error of relative humidity had a similar change pattern as above under 1500 m, and changed more obviously above 1500 m
By means of the radiosonde data and the threeyear data of the microwave radiometer in Beijing in recent 3 years, from the aspects of total average, daily change, annual mean change, and different sky status, etc, the evaluation and analysis of the retrieval products are made The results indicate: (1) The rootmeansquare error of temperature increased from surface to 5000 meters and decreased above 5000 meters gradually The overall average relative error was less than 02 ℃ with a positive value, which shows that the retrieved temperature was higher than that from the radiosondes (2) The rootmeansquare error of humidity increased from surface to 3000 meters and decreased above 3000 meters, and the overall average relative error was positive, which shows that the retrieved humidity was also higher than that from the radiosondes (3) The error at 20:00 was smaller than that at 08:00 (4) The temperature error was relatively small while it was clear and clear to cloudy, and bigger while overcast or cloudy to overcast The humidity error in overcast and cloudy to overcast weather was small (5) There was a small annual change range in the rootmeansquare error of temperature under 1500 m, but big above 1500 m, smallest in August, biggest in March and April; the rootmeansquare error of relative humidity had a similar change pattern as above under 1500 m, and changed more obviously above 1500 m
2010, 38(3):332-335.
Abstract:
Considering problems from the operation of new generation Doppler weather radar, three subsystems are developed: the raw data management system, the secondaryproduct display system, and the remote terminalmonitoring system, respectively, which run on different radar terminals to achieve the compression management of radar raw data, the sharing of secondary products, and the remote monitoring of the terminals. The task of each subsystem is designed specially, targeted to resolve specific problems in the related field. The system uses a number of mature software development technology and relates to many aspects of software development. The application of the core technologies, such as multithreaded, directory monitoring, remote control, image cache, and memory, file transfer, can ensure the system stability and efficient operation.
Considering problems from the operation of new generation Doppler weather radar, three subsystems are developed: the raw data management system, the secondaryproduct display system, and the remote terminalmonitoring system, respectively, which run on different radar terminals to achieve the compression management of radar raw data, the sharing of secondary products, and the remote monitoring of the terminals. The task of each subsystem is designed specially, targeted to resolve specific problems in the related field. The system uses a number of mature software development technology and relates to many aspects of software development. The application of the core technologies, such as multithreaded, directory monitoring, remote control, image cache, and memory, file transfer, can ensure the system stability and efficient operation.
2010, 38(3):336-339.
Abstract:
A special fault in the receiving system of the CINRAD/CC radar at Puer of Yunnan Province is discussed. The calibration and analysis are conducted of the main performance indexes of the radar system. The fault location and elimination was performed through testing and analyzing the spectrum signals from the spectrum analyzer, according to the working principles and signal flow. It proved that a spectrum analyzer is useful in the troubleshooting of CINRAD/CC radar receiving systems.
A special fault in the receiving system of the CINRAD/CC radar at Puer of Yunnan Province is discussed. The calibration and analysis are conducted of the main performance indexes of the radar system. The fault location and elimination was performed through testing and analyzing the spectrum signals from the spectrum analyzer, according to the working principles and signal flow. It proved that a spectrum analyzer is useful in the troubleshooting of CINRAD/CC radar receiving systems.
2010, 38(3):340-343.
Abstract:
Through analyzing the principles and methods for measuring the transmitting power of the pulse Doppler Weather Radar, the key elements and their effects, as well as the measurement reference, are summarized. Combining with the application of the Sband Pulse Doppler Weather Radar, the scientific and normative methods, skills, and key technologies for measuring the radar transmitting power are studied. The results show that the accuracy of the measuring results is affected by many factors, and can be vastly distorted by nonstandard measuring methods. Therefore, in order to ensure the accuracy of radar examining, testing and calibration, it is important to study the scientific and normative technologies and methods for measuring the radar transmitting power.
Through analyzing the principles and methods for measuring the transmitting power of the pulse Doppler Weather Radar, the key elements and their effects, as well as the measurement reference, are summarized. Combining with the application of the Sband Pulse Doppler Weather Radar, the scientific and normative methods, skills, and key technologies for measuring the radar transmitting power are studied. The results show that the accuracy of the measuring results is affected by many factors, and can be vastly distorted by nonstandard measuring methods. Therefore, in order to ensure the accuracy of radar examining, testing and calibration, it is important to study the scientific and normative technologies and methods for measuring the radar transmitting power.
2010, 38(3):344-346.
Abstract:
2010, 38(3):347-352.
Abstract:
On the basis of the analysis of WLAN (Wireless Local Area Network) security authentication based on 802.1x/EAP (Extensible Authentication Protocol), the EAP/TLS (Transport Layer Security) is selected through comparing several common authentication solutions. The principles of EAP/TLS authentication, the mechanisms of session key derivation, the detailed procedures of authentication, and the validation lab to test the EAPTLS deployment in the meteorological network are described. The EAPTLS authentication technology proved feasible and practical. In combination with the current status of the system, two problems are discussed, i.e., reliability and applicability of the authentication and DHCP servers, encountered in the application of EAP/TLSbased WLAN in the meteorological network system in China.
On the basis of the analysis of WLAN (Wireless Local Area Network) security authentication based on 802.1x/EAP (Extensible Authentication Protocol), the EAP/TLS (Transport Layer Security) is selected through comparing several common authentication solutions. The principles of EAP/TLS authentication, the mechanisms of session key derivation, the detailed procedures of authentication, and the validation lab to test the EAPTLS deployment in the meteorological network are described. The EAPTLS authentication technology proved feasible and practical. In combination with the current status of the system, two problems are discussed, i.e., reliability and applicability of the authentication and DHCP servers, encountered in the application of EAP/TLSbased WLAN in the meteorological network system in China.
2010, 38(3):353-356.
Abstract:
The multicast technology is applied to the establishment of the realtime radar data sharing network by means of the function of newgeneration weather radar system CINRAD/SC in support of multicast transmission. Based on the existing broadband network, the realtime radar data sharing from citylevel to countylevel could be achieved, which allows county stations to select, except the mode control of radar operation, the functions of the radar system, such as image display and map information setting and resolved the problem of time delay in the previous radar data sharing due to body sweep, data storage, data upload and download. The establishment of the realtime sharing network can help provide guarantee for weather modification operation timely.
The multicast technology is applied to the establishment of the realtime radar data sharing network by means of the function of newgeneration weather radar system CINRAD/SC in support of multicast transmission. Based on the existing broadband network, the realtime radar data sharing from citylevel to countylevel could be achieved, which allows county stations to select, except the mode control of radar operation, the functions of the radar system, such as image display and map information setting and resolved the problem of time delay in the previous radar data sharing due to body sweep, data storage, data upload and download. The establishment of the realtime sharing network can help provide guarantee for weather modification operation timely.
2010, 38(3):357-362.
Abstract:
A meteorological information sharing platform is designed for Lishui with the Div+CSS layout, developed by using JavaScript，C++，VB，ASP and other computer programming language, based on database technology. The platform, standardizing the meteorological information content and release process, can meet well the needs of the current operational meteorological service and make document sharing possible for meteorological decisionmaking service. The automatic display and sharing of meteorological information are realized successfully on the platform through the Web with high efficiency in a manner of graphics and characters. The platform also has alarming and reminding functions.
A meteorological information sharing platform is designed for Lishui with the Div+CSS layout, developed by using JavaScript，C++，VB，ASP and other computer programming language, based on database technology. The platform, standardizing the meteorological information content and release process, can meet well the needs of the current operational meteorological service and make document sharing possible for meteorological decisionmaking service. The automatic display and sharing of meteorological information are realized successfully on the platform through the Web with high efficiency in a manner of graphics and characters. The platform also has alarming and reminding functions.
2010, 38(3):363-367.
Abstract:
Based on the principles of soilmoisture balance, the core of the model takes full account of the exchange relations of soil, atmosphere, and plant, with the forecast period being ten days. The cornfield soil relative humidity for every 10 days from 34 moisture measurement stations in Heilongjiang Province were used to represent that of the corresponding county. The soil relative humidity at the end of the last 10 days and the forecasted precipitation of the next ten days were used to forecast the soil relative humidity at the end of the next 10 days. According to soil drought indicators，the level of soil droughts/floods was determined, and a test was made with the observed soil humidity in the cornfields from March to November in 2007. The results show that the forecasts were more accurate in spring and autumn, with absolute errors being less than 5 percent; errors in summer were slightly higher than those in spring and autumn, with absolute errors being under 6 percents, even zero in some places. To use the determined levels of soil droughts/floods to test the forecasting accuracy of soil droughts/floods, the results proved satisfactory.
Based on the principles of soilmoisture balance, the core of the model takes full account of the exchange relations of soil, atmosphere, and plant, with the forecast period being ten days. The cornfield soil relative humidity for every 10 days from 34 moisture measurement stations in Heilongjiang Province were used to represent that of the corresponding county. The soil relative humidity at the end of the last 10 days and the forecasted precipitation of the next ten days were used to forecast the soil relative humidity at the end of the next 10 days. According to soil drought indicators，the level of soil droughts/floods was determined, and a test was made with the observed soil humidity in the cornfields from March to November in 2007. The results show that the forecasts were more accurate in spring and autumn, with absolute errors being less than 5 percent; errors in summer were slightly higher than those in spring and autumn, with absolute errors being under 6 percents, even zero in some places. To use the determined levels of soil droughts/floods to test the forecasting accuracy of soil droughts/floods, the results proved satisfactory.
Zhu Haixia
,
Ji Yanghui
,
Yan Ping
,
Wang Qiujing
,
Gong Lijuan
,
Wang Liangliang
,
Wang Ping
,
Jiang Lixia
2010, 38(3):368-372.
Abstract:
Using the data of daily temperature, corn development phases, and corn chilling damage during the growing periods from 1961 to 2003 from 69 counties over Heilongjiang Province, based on the principles of the accumulated temperature theory, established and analyzed are the index system, risk degree, and forecast model of chilling damage occurrence of corn during different development periods. The trends of corn chilling injury risks during the 43 years are analyzed and tested with the MannKendall method. The results show that the period of 1961 to 1983 is a highrisk period of lowtemperature/chilling risk with the highest risk years in 1964, 1969, 1972, and 1983; 1983 to 2003 is the lowrisk period, especially obviously increased relative accumulated temperature (lowrisk period) being found in the later years. The risk forecast model of corn chilling damage can forecast and assess the risk and area of chilling damage. The outcome verification indicates that the model has good objectivity and usability.
Using the data of daily temperature, corn development phases, and corn chilling damage during the growing periods from 1961 to 2003 from 69 counties over Heilongjiang Province, based on the principles of the accumulated temperature theory, established and analyzed are the index system, risk degree, and forecast model of chilling damage occurrence of corn during different development periods. The trends of corn chilling injury risks during the 43 years are analyzed and tested with the MannKendall method. The results show that the period of 1961 to 1983 is a highrisk period of lowtemperature/chilling risk with the highest risk years in 1964, 1969, 1972, and 1983; 1983 to 2003 is the lowrisk period, especially obviously increased relative accumulated temperature (lowrisk period) being found in the later years. The risk forecast model of corn chilling damage can forecast and assess the risk and area of chilling damage. The outcome verification indicates that the model has good objectivity and usability.
2010, 38(3):373-376.
Abstract:
According to the formula recommended by the Grain and Agricultural Organization of UN for calculating the quantity of heat radiation of crops, the quantity of water needed by the vegetable crops in the flatland area of Zhangjiakou is calculated. The results from the demonstration fields show that drip irrigation under mulch is the best way for saving water,spraying irrigation the second, then piping irrigation. The meteological service for mediating and controlling watersaving irrigation, giving the quantities of average waterneeding irrigation and irrigation in different watersaving patterns, is described. The results show that the irrigation, according to the water needing of crops and meteological conditions, can save water by 40% without investment, while engineering watersaving, combined with meteological service, can save water by 40% to 70%, which is the most economical way for saving water.
According to the formula recommended by the Grain and Agricultural Organization of UN for calculating the quantity of heat radiation of crops, the quantity of water needed by the vegetable crops in the flatland area of Zhangjiakou is calculated. The results from the demonstration fields show that drip irrigation under mulch is the best way for saving water,spraying irrigation the second, then piping irrigation. The meteological service for mediating and controlling watersaving irrigation, giving the quantities of average waterneeding irrigation and irrigation in different watersaving patterns, is described. The results show that the irrigation, according to the water needing of crops and meteological conditions, can save water by 40% without investment, while engineering watersaving, combined with meteological service, can save water by 40% to 70%, which is the most economical way for saving water.
2010, 38(3):377-382.
Abstract:
A contrastive analysis is made of the frog and cricket phenological phases from 1989 to 2007 and meteorological data from 1975 to 2007 in the northern Guangxi. The results indicate that the dates of beginning chirps of frogs and crickets exhibited an advancing trend; those of ending chirps kept unchanged, and the beginningending intervals had an obvious extending trend. The mean annual temperature presented a markedly increasing trend in the last 34 years in the Yanshan Mountains, especially in the last 10 years, mainly in spring. The FebruarytoApril mean temperature and March mean maximum temperature are the main climatic factors that impact the dates of beginning and ending chirps of frogs and crickets and the intervals. The changes of animal phenology are the responses of animals to climate warming.
A contrastive analysis is made of the frog and cricket phenological phases from 1989 to 2007 and meteorological data from 1975 to 2007 in the northern Guangxi. The results indicate that the dates of beginning chirps of frogs and crickets exhibited an advancing trend; those of ending chirps kept unchanged, and the beginningending intervals had an obvious extending trend. The mean annual temperature presented a markedly increasing trend in the last 34 years in the Yanshan Mountains, especially in the last 10 years, mainly in spring. The FebruarytoApril mean temperature and March mean maximum temperature are the main climatic factors that impact the dates of beginning and ending chirps of frogs and crickets and the intervals. The changes of animal phenology are the responses of animals to climate warming.
2010, 38(3):383-388.
Abstract:
To optimize the allocation of the resources in a trilevel (provincemunicipalitycounty) operation command system for weather modification, a new operation command scheme is proposed according to the responsibility scope and the mission characteristics of weather modification offices at various levels. The provincial level is mainly responsible for plane precipitation enhancement operations, groundbased early warning for weather modification, operating information collection, and monitoring in the whole province. The municipal level is mainly responsible for the direct command of operational sites within the region. The main task at the county level is to carry out monitoring. The system embodies the peculiar advantage of the mode, i.e.， the direct commanding of operating sites by municipal centers, which gives full play to the technological advantages of the provincial plane operation and groundbased operational early warning and solves the problem which is caused by the less staff and weak technological force of countylevel weather modification offices. Also it realized the trilevel resource sharing, solved the problem of time delay while receiving operation instructions，and improved operational timeliness and performance.
To optimize the allocation of the resources in a trilevel (provincemunicipalitycounty) operation command system for weather modification, a new operation command scheme is proposed according to the responsibility scope and the mission characteristics of weather modification offices at various levels. The provincial level is mainly responsible for plane precipitation enhancement operations, groundbased early warning for weather modification, operating information collection, and monitoring in the whole province. The municipal level is mainly responsible for the direct command of operational sites within the region. The main task at the county level is to carry out monitoring. The system embodies the peculiar advantage of the mode, i.e.， the direct commanding of operating sites by municipal centers, which gives full play to the technological advantages of the provincial plane operation and groundbased operational early warning and solves the problem which is caused by the less staff and weak technological force of countylevel weather modification offices. Also it realized the trilevel resource sharing, solved the problem of time delay while receiving operation instructions，and improved operational timeliness and performance.
2010, 38(3):389-393.
Abstract:
Based on the history meteorological data in Dalian, the hailsuppression operation warning, decisionmaking and discriminant index system is established and analyzed. The hailsuppression conception model is devised. Based on the uptodate hailsuppression technology, research findings, and experiences from local practices, the technical operation scheme is designed and analyzed scientifically. On the basis of the MICAPS system and Doppler radar, the advanced technologies such as artificial hailsuppression, radar detection, satellite remote sensing, upperair meteorological detection, geographical information, lightning location, etc., are integrated. The artificial hailsuppression decisionmaking and command system, adapting to Dalian, is developed, which has such functions as hailsuppression operation warning, hail cloud identifying, operational decisionmaking, operational scheme determination, realtime effectiveness analyses, etc. It is highly automatic and practical, and easy to use and spread. The system is planned to put into hailsuppression operation use.
Based on the history meteorological data in Dalian, the hailsuppression operation warning, decisionmaking and discriminant index system is established and analyzed. The hailsuppression conception model is devised. Based on the uptodate hailsuppression technology, research findings, and experiences from local practices, the technical operation scheme is designed and analyzed scientifically. On the basis of the MICAPS system and Doppler radar, the advanced technologies such as artificial hailsuppression, radar detection, satellite remote sensing, upperair meteorological detection, geographical information, lightning location, etc., are integrated. The artificial hailsuppression decisionmaking and command system, adapting to Dalian, is developed, which has such functions as hailsuppression operation warning, hail cloud identifying, operational decisionmaking, operational scheme determination, realtime effectiveness analyses, etc. It is highly automatic and practical, and easy to use and spread. The system is planned to put into hailsuppression operation use.
2010, 38(3):394-398.
Abstract:
The characteristics of benefit assessment of major meteorological disaster service are analyzed. The benefit assessment models, indexes, and working flow are constructed, and a comprehensive assessment is conducted in aspects of weather forecast accuracy, forecasting service coverage, feedback from government decisionmaking departments, and overall assessment of service benefits, and so on. The system is based on the Asp.Net platform and B/S (Browser/Server) structure of. Taking the low temperature and snow/freeze disaster of 2008 as an example, an operation application assessment is carried out with the system, which proved a useful tool for evaluating the benefits of major meteorological disaster service.
The characteristics of benefit assessment of major meteorological disaster service are analyzed. The benefit assessment models, indexes, and working flow are constructed, and a comprehensive assessment is conducted in aspects of weather forecast accuracy, forecasting service coverage, feedback from government decisionmaking departments, and overall assessment of service benefits, and so on. The system is based on the Asp.Net platform and B/S (Browser/Server) structure of. Taking the low temperature and snow/freeze disaster of 2008 as an example, an operation application assessment is carried out with the system, which proved a useful tool for evaluating the benefits of major meteorological disaster service.
25 Characteristics of Maximum Wind Velocity and Estimation of Extreme Maximum Velocity in Return Period
2010, 38(3):399-402.
Abstract:
Based on the 10minute maximum wind velocity data of Zaozhuang from 1971 to 2008, the characteristics of maximum wind velocity are analyzed. The results show that the annual maximum wind velocity displayed a decreasing trend in spring, summer, autumn, and winter in the past 40 years. The annual maximum wind velocity had a downward trend of 1.47 m/s per 10 years, decreased most quickly in winter, with the decreasing rate being 1.67 m/s per 10 years. The decreasing rates of maximum wind velocity in summer and autumn are lower than that of annual maximum wind velocity. The spring maximum wind velocity descended most slowly, and the extreme maximum wind velocity was mainly appearing in spring. The monthly maximum wind velocity shows a decreasing trend with a twopeaktwovalley pattern. By using the method of Gumbel distribution, the extreme maximum wind velocity for occurring once every 10, 20, 30, 50, 100, 200, 500, and 1000 years are estimated. It can satisfy the needs of users.
Based on the 10minute maximum wind velocity data of Zaozhuang from 1971 to 2008, the characteristics of maximum wind velocity are analyzed. The results show that the annual maximum wind velocity displayed a decreasing trend in spring, summer, autumn, and winter in the past 40 years. The annual maximum wind velocity had a downward trend of 1.47 m/s per 10 years, decreased most quickly in winter, with the decreasing rate being 1.67 m/s per 10 years. The decreasing rates of maximum wind velocity in summer and autumn are lower than that of annual maximum wind velocity. The spring maximum wind velocity descended most slowly, and the extreme maximum wind velocity was mainly appearing in spring. The monthly maximum wind velocity shows a decreasing trend with a twopeaktwovalley pattern. By using the method of Gumbel distribution, the extreme maximum wind velocity for occurring once every 10, 20, 30, 50, 100, 200, 500, and 1000 years are estimated. It can satisfy the needs of users.
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.