Volume 36,Issue 3,2008 Table of Contents
2008, 36(3):257-261.
Abstract:
The importance of developing the shortwave canopy radiative transfer models in land surface process and airland interaction researches is described. A detailed review is made of advances in shortwave radiative transfer models. In combination with the current representative shortwave radiative transfer models in the land surface process research field, the problems needing further exploration are pointed out and the developmental tendencies of land surface process models are discussed.
The importance of developing the shortwave canopy radiative transfer models in land surface process and airland interaction researches is described. A detailed review is made of advances in shortwave radiative transfer models. In combination with the current representative shortwave radiative transfer models in the land surface process research field, the problems needing further exploration are pointed out and the developmental tendencies of land surface process models are discussed.
2008, 36(3):262-267.
Abstract:
Typhoon Talim is very similar to “Saomai,” but the influence that it caused differs greatly after typhoons landed. In combination with the objective analysis, conventional observation, surface radiosonde, mesoscale automatic weather station and numerical simulation data, the formation mechanisms of the differences in precipitation and wind fields of the two typhoons are studied. When Talim landed and moved northward, along with the westerly trough, a stabilized synoptic pattern, in which there was a deep tough in the middle troposphere in the north and a southwest vortex in the lower troposphere in the south, came into being, with weak cold air infiltrating southward in the boundary layer. When Saomai landed and moved northward, there was a highpressure “dam” in north without cold air activity. For Talim, the highenergy area was situated in the north of Zhejiang, and there was mesofrontogenesis and weak instability. For Saomai, the lowenergy area was in the north of Zhejiang, and the atmosphere was quite stable. It is concluded that similar typhoons may produce greatly different influences.
Typhoon Talim is very similar to “Saomai,” but the influence that it caused differs greatly after typhoons landed. In combination with the objective analysis, conventional observation, surface radiosonde, mesoscale automatic weather station and numerical simulation data, the formation mechanisms of the differences in precipitation and wind fields of the two typhoons are studied. When Talim landed and moved northward, along with the westerly trough, a stabilized synoptic pattern, in which there was a deep tough in the middle troposphere in the north and a southwest vortex in the lower troposphere in the south, came into being, with weak cold air infiltrating southward in the boundary layer. When Saomai landed and moved northward, there was a highpressure “dam” in north without cold air activity. For Talim, the highenergy area was situated in the north of Zhejiang, and there was mesofrontogenesis and weak instability. For Saomai, the lowenergy area was in the north of Zhejiang, and the atmosphere was quite stable. It is concluded that similar typhoons may produce greatly different influences.
2008, 36(3):268-272.
Abstract:
The algorithm for calculating unstable energy with high resolution is described. A applied program was designed with the algorithm. Accordingly, the unstable energy, surface pseudoequivalent potential temperature, and lifting condensation level of each surface meteorological station in the research area are calculated and displayed hourly on the Fujian map. A case study shows that convective echoes will develop if there occur convective echoes in three hours in the high unstable energy area or leeward area, the larger the unstable energy, the more intense the weather; and the pseudoequivalent potential temperature chart can reflect precisely the distribution of energy and cold air movement.
The algorithm for calculating unstable energy with high resolution is described. A applied program was designed with the algorithm. Accordingly, the unstable energy, surface pseudoequivalent potential temperature, and lifting condensation level of each surface meteorological station in the research area are calculated and displayed hourly on the Fujian map. A case study shows that convective echoes will develop if there occur convective echoes in three hours in the high unstable energy area or leeward area, the larger the unstable energy, the more intense the weather; and the pseudoequivalent potential temperature chart can reflect precisely the distribution of energy and cold air movement.
2008, 36(3):273-276.
Abstract:
The daybyday ridge line positions of the West Pacific subtropical high in the area of 110°to 130°E and 20°to 50 °N are analyzed by means of the NCEP/NCAR reanalysis 500 hPa data from 1958 to 2002. The results show that there is a large positive correlation area in North China, where the precipitation in midsummer (July and August) is related to the number of days with the West Pacific subtropical high intensity being over 5880 gpm and the ridge line being north of 30°N (the correlation coefficient at the center being 0.561 and the significant level being 0.001). In addition, the date of the first day of West Pacific subtropical high crossing 30°N, i.e., the first day of the subtropical high ridge line being north f 30°N in three successive days, is closely correlated with the midsummer precipitation over North China, with a correlation coefficient of －0.385. The midsummer precipitation in North China was heavier when the West Pacific subtropical high moved northward earlier, and vise versa. The results indicate that the number of the days of the subtropical high ridge line being north of 30°N and the date of the ridge line crossing 30°N for the first time in the area of 110° to 130°E can well describe the relationship between West Pacific subtropical high and midsummer precipitation in North China, even in the eastern China, which is important for heavy rainfall forecasting.
The daybyday ridge line positions of the West Pacific subtropical high in the area of 110°to 130°E and 20°to 50 °N are analyzed by means of the NCEP/NCAR reanalysis 500 hPa data from 1958 to 2002. The results show that there is a large positive correlation area in North China, where the precipitation in midsummer (July and August) is related to the number of days with the West Pacific subtropical high intensity being over 5880 gpm and the ridge line being north of 30°N (the correlation coefficient at the center being 0.561 and the significant level being 0.001). In addition, the date of the first day of West Pacific subtropical high crossing 30°N, i.e., the first day of the subtropical high ridge line being north f 30°N in three successive days, is closely correlated with the midsummer precipitation over North China, with a correlation coefficient of －0.385. The midsummer precipitation in North China was heavier when the West Pacific subtropical high moved northward earlier, and vise versa. The results indicate that the number of the days of the subtropical high ridge line being north of 30°N and the date of the ridge line crossing 30°N for the first time in the area of 110° to 130°E can well describe the relationship between West Pacific subtropical high and midsummer precipitation in North China, even in the eastern China, which is important for heavy rainfall forecasting.
2008, 36(3):277-280.
Abstract:
The precipitation anomaly percentage series and air temperature anomaly series in each month and season over the Changjiang River source region are established, and the interannual change of air temperature, precipitation, and runoff is analyzed, based on the precipitation and air temperature data at eight meteorological stations and runoff data at the Zhimenda hydrological station over the Changjiang river source region. The result shows that the climate over the Changjiang River source region has a very significant interannual change. The precipitation amount was normal or greafer than normal in the 1960s and 1980s, and less than normal in the 1970s and 1990s, which attributed mainly to precipitation variation in summer. Annual air temperature has a rising trend, with the coldest period in the 1960s, warm autumns in the 1990s, and warm winters in the 1980s; the warming began from the 1970s and became fast after the 1990s. Presently, the annual, summer, autumn and winter temperatures are the highest since 1960s. The annual runoff corresponded to the interannual change and abrupt change years, greater than normal in the 1960s and 1980s, less than normal in the 1970s and 1990s. Except in spring, the runoffs in summer, autumn and winter start to rise at present, and there were abrupt changes in 1965, 1979 and 1997.
The precipitation anomaly percentage series and air temperature anomaly series in each month and season over the Changjiang River source region are established, and the interannual change of air temperature, precipitation, and runoff is analyzed, based on the precipitation and air temperature data at eight meteorological stations and runoff data at the Zhimenda hydrological station over the Changjiang river source region. The result shows that the climate over the Changjiang River source region has a very significant interannual change. The precipitation amount was normal or greafer than normal in the 1960s and 1980s, and less than normal in the 1970s and 1990s, which attributed mainly to precipitation variation in summer. Annual air temperature has a rising trend, with the coldest period in the 1960s, warm autumns in the 1990s, and warm winters in the 1980s; the warming began from the 1970s and became fast after the 1990s. Presently, the annual, summer, autumn and winter temperatures are the highest since 1960s. The annual runoff corresponded to the interannual change and abrupt change years, greater than normal in the 1960s and 1980s, less than normal in the 1970s and 1990s. Except in spring, the runoffs in summer, autumn and winter start to rise at present, and there were abrupt changes in 1965, 1979 and 1997.
2008, 36(3):281-288.
Abstract:
A statistical analysis is made of the spatialtemporal distribution, weather circulation background and formation causes of radiation fogs in Yunnan Province by means of the radiosonde data in recent five years and the conventional meteorological data from 1976 to 2005 of 126 weather stations over Yunnan. The results show that the number of foggy days exhibited a yearbyyear undulatory variation trend and an overall dropping tendency, but the diurnal variation of fogs is relatively stable; the synoptic patterns favorable to fog formation include the westerly flow and the northerly flow patterns, with the northerly pattern accompanying heavier and longerduration fog process. The analysis of formation mechanisms of fogs indicates that the formation conditions for fogs include such weather situations as the good water vapor condition around the surface layer, calm or weak wind, clear sky or slight cloudiness, uniform pressure field behind the ground transformed cold anticyclone, weak ascending movement and warm advection at the lower levels, strong descending movement and cold advection at middle and upper levels, and an inversion layer in the boundary layer.
A statistical analysis is made of the spatialtemporal distribution, weather circulation background and formation causes of radiation fogs in Yunnan Province by means of the radiosonde data in recent five years and the conventional meteorological data from 1976 to 2005 of 126 weather stations over Yunnan. The results show that the number of foggy days exhibited a yearbyyear undulatory variation trend and an overall dropping tendency, but the diurnal variation of fogs is relatively stable; the synoptic patterns favorable to fog formation include the westerly flow and the northerly flow patterns, with the northerly pattern accompanying heavier and longerduration fog process. The analysis of formation mechanisms of fogs indicates that the formation conditions for fogs include such weather situations as the good water vapor condition around the surface layer, calm or weak wind, clear sky or slight cloudiness, uniform pressure field behind the ground transformed cold anticyclone, weak ascending movement and warm advection at the lower levels, strong descending movement and cold advection at middle and upper levels, and an inversion layer in the boundary layer.
2008, 36(3):289-292.
Abstract:
The seasonal and annual mean temperature and rainfall from 1953 to 2006 in Meizhou are calculated and analyzed by the means of the linear tendency equation, running mean and R/S (rescaled range analysis) methods. The results indicate that the seasonal and annual mean temperatures in the last 50 years assume increasing trends with the winter temperature having the greatest rate. The annual rainfall and the rainfall in spring, summer and winter also increased, with the summer rainfall having the biggest tendency rate. The R/S results show that temperature and rainfall, have obvious Hurst phenomenon; namely the climatic change in Meizhou has persistence. The H temperature index indicates that the annual and seasonal mean temperatures in Meizhou will continue to assume increasing trends. The temperature increase trend in summer will be more obvious. The H rainfall index indicates that the annul rainfall and rainfall in spring, summer and winter will show an upward tendency while the rainfall in autumn will keep a downward tendency. The increase tendency of spring rainfall will be more obvious.
The seasonal and annual mean temperature and rainfall from 1953 to 2006 in Meizhou are calculated and analyzed by the means of the linear tendency equation, running mean and R/S (rescaled range analysis) methods. The results indicate that the seasonal and annual mean temperatures in the last 50 years assume increasing trends with the winter temperature having the greatest rate. The annual rainfall and the rainfall in spring, summer and winter also increased, with the summer rainfall having the biggest tendency rate. The R/S results show that temperature and rainfall, have obvious Hurst phenomenon; namely the climatic change in Meizhou has persistence. The H temperature index indicates that the annual and seasonal mean temperatures in Meizhou will continue to assume increasing trends. The temperature increase trend in summer will be more obvious. The H rainfall index indicates that the annul rainfall and rainfall in spring, summer and winter will show an upward tendency while the rainfall in autumn will keep a downward tendency. The increase tendency of spring rainfall will be more obvious.
8 Analysis of Mesoscale Vortex Structure and HailFalling Area in a Severe Convective Weather Event
2008, 36(3):293-299.
Abstract:
A detailed analysis is conducted on a severe storm occurred on 18 June 2005, combined the new generation radar data of Linyi with mesoscale numerical model outputs. The result shows that the strong convection weather process took place under the condition of dry and cold at upper levels and warm and moisture at lower levels, and the main factor causing this event is an asymmetric mesoscale vortex at 700 hPa. The hailfalling area was located at the southeast part of the vortex. The analysis of radar echoes shows that the strong centers were almost distributed vertically. During the hail process, the echo intensity increased, and the echo top and VIL (Vertical Integrated Liquid water) decreased quickly.
A detailed analysis is conducted on a severe storm occurred on 18 June 2005, combined the new generation radar data of Linyi with mesoscale numerical model outputs. The result shows that the strong convection weather process took place under the condition of dry and cold at upper levels and warm and moisture at lower levels, and the main factor causing this event is an asymmetric mesoscale vortex at 700 hPa. The hailfalling area was located at the southeast part of the vortex. The analysis of radar echoes shows that the strong centers were almost distributed vertically. During the hail process, the echo intensity increased, and the echo top and VIL (Vertical Integrated Liquid water) decreased quickly.
9 Application of Airda3000 Boundary Wind Profile Radar in Analyzing Summer Heavy Rainfall in Beijing
2008, 36(3):300-304.
Abstract:
The heavy rainfall process occurred on 3 August 2005 in Beijing is analyzed in detail by means of the Airda3000 boundary wind profiler data from three stations in the Beijing urban and suburb areas. Results show that about 10 or more hours before the process started, there appeared doubled lowlevel jets, which had a complex structure with multiple centers. The wind profiler data show that the process had a complex vertical structure, the main mesoscale system of which was a vortex on the shear line induced by a highlevel trough and weak cold air; the surface wind convergence in the urban area started several hours before the heavy rainfall (nighttime); and the upward propagation of the convergence (shear) layer began at the beginning of rainfall, which was helpful to the development of the process.
The heavy rainfall process occurred on 3 August 2005 in Beijing is analyzed in detail by means of the Airda3000 boundary wind profiler data from three stations in the Beijing urban and suburb areas. Results show that about 10 or more hours before the process started, there appeared doubled lowlevel jets, which had a complex structure with multiple centers. The wind profiler data show that the process had a complex vertical structure, the main mesoscale system of which was a vortex on the shear line induced by a highlevel trough and weak cold air; the surface wind convergence in the urban area started several hours before the heavy rainfall (nighttime); and the upward propagation of the convergence (shear) layer began at the beginning of rainfall, which was helpful to the development of the process.
2008, 36(3):305-309.
Abstract:
A severe convective weather event occurred on 4 April 2007 is analyzed. Due to the persistent warming in previous days, a great deal of unstable energy was accumulated and vertical wind shear，dynamic，thermodynamic, and vapor conditions were all favorable to the formation of severe convective weather. The turbulence of temperature, humidity and kinetic energy on the ground and in upper air are analyzed. The results show that there was positive temperature turbulence before and during the convective weather and negative turbulence after. At the same time，the temperature turbulence on the ground was obviously bigger than that at upper levels, which means that the thermodynamic effect on the ground was larger than that in upper air； the humidity turbulence in the area of severe convective weather was smaller than that of the surrounding areas, which was likely one of reasons for thunderstorm and gale occurrence. The humidity turbulence at various levels was relatively great and the convection was strong consequently.The kinetic energy turbulence in the storm area was distinctly bigger during the storm than that before and afer. The kinetic energy turbulence on 850 hPa was the biggest and that on the ground was the second.
A severe convective weather event occurred on 4 April 2007 is analyzed. Due to the persistent warming in previous days, a great deal of unstable energy was accumulated and vertical wind shear，dynamic，thermodynamic, and vapor conditions were all favorable to the formation of severe convective weather. The turbulence of temperature, humidity and kinetic energy on the ground and in upper air are analyzed. The results show that there was positive temperature turbulence before and during the convective weather and negative turbulence after. At the same time，the temperature turbulence on the ground was obviously bigger than that at upper levels, which means that the thermodynamic effect on the ground was larger than that in upper air； the humidity turbulence in the area of severe convective weather was smaller than that of the surrounding areas, which was likely one of reasons for thunderstorm and gale occurrence. The humidity turbulence at various levels was relatively great and the convection was strong consequently.The kinetic energy turbulence in the storm area was distinctly bigger during the storm than that before and afer. The kinetic energy turbulence on 850 hPa was the biggest and that on the ground was the second.
2008, 36(3):310-317.
Abstract:
Various indexes of crop cold damage are introduced and compared on the basis of published research findings at home and abroad, and the advantages and disadvantages are analyzed. The progresses in the researches on relative cold damage risk assessment at home and abroad are introduced. The analysis shows that the researches on crop cold damage abroad are mainly concentrated on the mechanisms of crop cold damage, but the studies on cold damage index, as well as the monitoring, prediction, risk assessment of chilling damage, are comparatively less. Further research in future is necessary. The researches about damage risk assessment are mainly based on the probability of cold damage and temperature variance coefficient, so to establish a comprehensive risk index in China. The research findings in the risk assessment combined with crop production loss have not yet been reported.
Various indexes of crop cold damage are introduced and compared on the basis of published research findings at home and abroad, and the advantages and disadvantages are analyzed. The progresses in the researches on relative cold damage risk assessment at home and abroad are introduced. The analysis shows that the researches on crop cold damage abroad are mainly concentrated on the mechanisms of crop cold damage, but the studies on cold damage index, as well as the monitoring, prediction, risk assessment of chilling damage, are comparatively less. Further research in future is necessary. The researches about damage risk assessment are mainly based on the probability of cold damage and temperature variance coefficient, so to establish a comprehensive risk index in China. The research findings in the risk assessment combined with crop production loss have not yet been reported.
2008, 36(3):318-322.
Abstract:
To promote both accuracy and effectiveness of meteorological service for preventing fruit tree freezing injury at blooming stage and reduce economic loss, field experiments and investigations were conducted to decide the warning indexes of different grades for fruit tree freezing injury by means of the meteorological data from 1961 to 2000 from 30 stations and phenological data from 2001 to 2006 from 9 stations: serious low temperature and freezing injury (less than －2 ℃), low temperature and freezing injury （－2 ℃ to 0 ℃）, chilling injury (0 ℃ to 2 ℃).The characteristics of interannual variation and the temporal and spatial distribution of fruit tree freezing injuries at blooming stage in the major fruit planting areas are analyzed. The freeze injuries appeared most frequently in Yan’an and the western part of Weibei. Averagely, there are 4.1 to 6.3 low temperature and freezing injury days,and 3.2 to 6.0 serious low temperature and freezing injury days per year. The injures happened most likely in April. Some countermeasure for preventing damages are presented based on the experiments and analysis.
To promote both accuracy and effectiveness of meteorological service for preventing fruit tree freezing injury at blooming stage and reduce economic loss, field experiments and investigations were conducted to decide the warning indexes of different grades for fruit tree freezing injury by means of the meteorological data from 1961 to 2000 from 30 stations and phenological data from 2001 to 2006 from 9 stations: serious low temperature and freezing injury (less than －2 ℃), low temperature and freezing injury （－2 ℃ to 0 ℃）, chilling injury (0 ℃ to 2 ℃).The characteristics of interannual variation and the temporal and spatial distribution of fruit tree freezing injuries at blooming stage in the major fruit planting areas are analyzed. The freeze injuries appeared most frequently in Yan’an and the western part of Weibei. Averagely, there are 4.1 to 6.3 low temperature and freezing injury days,and 3.2 to 6.0 serious low temperature and freezing injury days per year. The injures happened most likely in April. Some countermeasure for preventing damages are presented based on the experiments and analysis.
2008, 36(3):323-326.
Abstract:
Weather condition is one of environmental factors influencing the sugar accumulation of wine grapes. Research shows that average air temperature, maximal air temperature, sunlight duration and temperaturehumidity ratio are four main weather factors affecting daily sugar accumulation from coloring stage to maturity stage. The daily sugar accumulation of grapes is optimal when average air temperature, maximal temperature, sunlight duration and temperaturehumidity ratio are 24.0 ℃, 29.3 ℃, 6.4 h and 0.35, respectively. At the range of less than these values，the daily sugar accumulation increases with these factors, and at the range of greater than theses values, the daily sugar accumulation decreases with these factors.
Weather condition is one of environmental factors influencing the sugar accumulation of wine grapes. Research shows that average air temperature, maximal air temperature, sunlight duration and temperaturehumidity ratio are four main weather factors affecting daily sugar accumulation from coloring stage to maturity stage. The daily sugar accumulation of grapes is optimal when average air temperature, maximal temperature, sunlight duration and temperaturehumidity ratio are 24.0 ℃, 29.3 ℃, 6.4 h and 0.35, respectively. At the range of less than these values，the daily sugar accumulation increases with these factors, and at the range of greater than theses values, the daily sugar accumulation decreases with these factors.
2008, 36(3):327-330.
Abstract:
The rocket rain enhancement effectiveness has been an issue of public concern. The rain enhancement with rockets has the characteristics of less investment, easy operation, and remarkable effect. The Longcheng district government began to invest in rocket rain enhancement from 2003, and since then rocket rain enhancement operations have been conducted successively in crop growing season. By means of precipitation variation analysis and contrast between affected and nonaffected areas, the rain enhancement operations in three years in the Longcheng district are analyzed and the assessment of rocket rain enhancement effectiveness is conducted. It is concluded that the effectiveness of rain enhancement with rockets is about 33%.
The rocket rain enhancement effectiveness has been an issue of public concern. The rain enhancement with rockets has the characteristics of less investment, easy operation, and remarkable effect. The Longcheng district government began to invest in rocket rain enhancement from 2003, and since then rocket rain enhancement operations have been conducted successively in crop growing season. By means of precipitation variation analysis and contrast between affected and nonaffected areas, the rain enhancement operations in three years in the Longcheng district are analyzed and the assessment of rocket rain enhancement effectiveness is conducted. It is concluded that the effectiveness of rain enhancement with rockets is about 33%.
2008, 36(3):331-334.
Abstract:
An analysis is made of the data from lightning position finders and radar echo data in 6 hail processes in Shandong Province. The results indicate that there was a regular variation in the 10min frequency distribution of lightning, with the peak (10 times) appearing 32 to 220 minutes before hailing; the positive lightning strikes increased rapidly two hour before hailing and then decreased rapidly. The positive lightning occupied basically above 50% of the total lightning before hailing, and lightning strikes distributed basically within the range of radar echoes. The lightningconcentrated areas did not completely correspond to the strong echo areas, but the movement of the lightningconcentrated areas can indicate the moving and developing track of hail clouds. The lightning frequency, the ratio of positive lightning to total, and the lightning time series can be used as references in hail warming.
An analysis is made of the data from lightning position finders and radar echo data in 6 hail processes in Shandong Province. The results indicate that there was a regular variation in the 10min frequency distribution of lightning, with the peak (10 times) appearing 32 to 220 minutes before hailing; the positive lightning strikes increased rapidly two hour before hailing and then decreased rapidly. The positive lightning occupied basically above 50% of the total lightning before hailing, and lightning strikes distributed basically within the range of radar echoes. The lightningconcentrated areas did not completely correspond to the strong echo areas, but the movement of the lightningconcentrated areas can indicate the moving and developing track of hail clouds. The lightning frequency, the ratio of positive lightning to total, and the lightning time series can be used as references in hail warming.
2008, 36(3):335-340.
Abstract:
An introduction is made to the principles, functions and dataprocessing procedures of the newly developed polarorbiting meteorological satellite realtime monitoring system of forest fires. This system can process the data of forest fires while a satellite is passing by. It has solved the problem of realtime monitoring that many other meteorological satellitemonitoring systems cannot handle. The realtime monitoring system is a parallel processing system composed of three computers. It divides the time sequence of recognizing a fire site from obscurity to confirmation into three steps, and the time sequences of datareceiving, firesite judging, firesite targeting, and displaying are distributed in three computers, which operate synchronously. This system has been put to operational use in the Guangzhou Meteorological Satellite Ground Station since 2005. Compared with the former satellite remote sensing monitoring system, it can monitor and report forest fires 30 minutes earlier.
An introduction is made to the principles, functions and dataprocessing procedures of the newly developed polarorbiting meteorological satellite realtime monitoring system of forest fires. This system can process the data of forest fires while a satellite is passing by. It has solved the problem of realtime monitoring that many other meteorological satellitemonitoring systems cannot handle. The realtime monitoring system is a parallel processing system composed of three computers. It divides the time sequence of recognizing a fire site from obscurity to confirmation into three steps, and the time sequences of datareceiving, firesite judging, firesite targeting, and displaying are distributed in three computers, which operate synchronously. This system has been put to operational use in the Guangzhou Meteorological Satellite Ground Station since 2005. Compared with the former satellite remote sensing monitoring system, it can monitor and report forest fires 30 minutes earlier.
2008, 36(3):341-344.
Abstract:
The first satellite of the National Polarorbiting Operational Environmental Satellite System (NPOESS) will be launched in 2010, and the Visible/Infrared Imager/Radiometer Suite (VIIRS) is the primary instrument in the NPOESS series. Its expected imagery is the first userrequirement product. A brief introduction is made to the characteristics of VIIRS instrument. By means of the imagery products in the similar channels of other sensors aboard in the satellite systems in existence, the concise analysis of VIIRS’s cloud imagery products is given on the basis of physical principles of cloud explanation. The application of VIIRS imagery will allow analysts to distinguish more readily the difference between clouds and cloudfree surfaces, and it will significantly improve the performance of cloud analysis and weather forecast.
The first satellite of the National Polarorbiting Operational Environmental Satellite System (NPOESS) will be launched in 2010, and the Visible/Infrared Imager/Radiometer Suite (VIIRS) is the primary instrument in the NPOESS series. Its expected imagery is the first userrequirement product. A brief introduction is made to the characteristics of VIIRS instrument. By means of the imagery products in the similar channels of other sensors aboard in the satellite systems in existence, the concise analysis of VIIRS’s cloud imagery products is given on the basis of physical principles of cloud explanation. The application of VIIRS imagery will allow analysts to distinguish more readily the difference between clouds and cloudfree surfaces, and it will significantly improve the performance of cloud analysis and weather forecast.
2008, 36(3):345-348.
Abstract:
The snow disaster is the most serious natural disaster for local animal husbandry in northern and southern border areas of Xizang. Using satellite remote sensing data to develop snow monitoring system and provide monitoring information has a practical significance. A method of snow monitoring based on the Tibet Plateau snow identification model using the MODIS data from Lhasa station is described. The result shows that it is feasible to develop the snow identification model through combining MODIS NDSI and NDVI with the data of channels 1, 2, 4, 6; and the model is useful for snow disaster monitoring in Tibet Plateau and can improve the accuracy of the model through considering the differences in land cover between forest and the nonforest areas in the eastern and southern Tibet Plateau especially.
The snow disaster is the most serious natural disaster for local animal husbandry in northern and southern border areas of Xizang. Using satellite remote sensing data to develop snow monitoring system and provide monitoring information has a practical significance. A method of snow monitoring based on the Tibet Plateau snow identification model using the MODIS data from Lhasa station is described. The result shows that it is feasible to develop the snow identification model through combining MODIS NDSI and NDVI with the data of channels 1, 2, 4, 6; and the model is useful for snow disaster monitoring in Tibet Plateau and can improve the accuracy of the model through considering the differences in land cover between forest and the nonforest areas in the eastern and southern Tibet Plateau especially.
2008, 36(3):349-354.
Abstract:
A systematical analysis is made of various possible alarm messages appeared during the calibration and check of CINRAD/SA, SB, CB RDA (radar data acquisition), in combination with CINRAD/SA, SB, CB RDA (radar data acquisition) alarm messages, technical specifications, capability parameters, adaptation data, and circuit block diagrams of the receiver and transmitter, and the corresponding countermeasures are presented. During the analysis, the opinions of experienced technicians and the source codes are considered, and even the parameters and working status of a certain least replaceable unit are modified temporarily. The alarm messages resulted from modifying the RDA capability parameters are used to check the analysis conclusions. The findings can be used as references for the technical maintenance personnel of RDA equipment.
A systematical analysis is made of various possible alarm messages appeared during the calibration and check of CINRAD/SA, SB, CB RDA (radar data acquisition), in combination with CINRAD/SA, SB, CB RDA (radar data acquisition) alarm messages, technical specifications, capability parameters, adaptation data, and circuit block diagrams of the receiver and transmitter, and the corresponding countermeasures are presented. During the analysis, the opinions of experienced technicians and the source codes are considered, and even the parameters and working status of a certain least replaceable unit are modified temporarily. The alarm messages resulted from modifying the RDA capability parameters are used to check the analysis conclusions. The findings can be used as references for the technical maintenance personnel of RDA equipment.
2008, 36(3):355-359.
Abstract:
The eddycovariance data from the heavy rainfall experiment at Feixi County in Anhui Province in 2002 is used to contrast two axisrotation method, aiming at the tilt errors of eddycovariance measurement. The results show that both triple axis rotation method and planar fit method can eliminate effectively the illusiveflux and sidestress errors caused by horizontal winds because of instrument tilt, so to improve flux precision. Both methods have its own strong points, but the planar fit method is better than triple axis rotation method relatively.
The eddycovariance data from the heavy rainfall experiment at Feixi County in Anhui Province in 2002 is used to contrast two axisrotation method, aiming at the tilt errors of eddycovariance measurement. The results show that both triple axis rotation method and planar fit method can eliminate effectively the illusiveflux and sidestress errors caused by horizontal winds because of instrument tilt, so to improve flux precision. Both methods have its own strong points, but the planar fit method is better than triple axis rotation method relatively.
2008, 36(3):360-363.
Abstract:
An analysis is made of various sorts of equipment breakdowns and damages induced by the electromagnetic pulses of thunders and lighting, thunders and lighting classification, and the invasion approaches of thunders and lightning into communication systems and computer networks. The types, components, and technical specifications of SPDs (Surge Protector Devices) are introduced. The emphases are put on the criterions for selecting SPDs for communication systems and computer networks. According to the detailed calculation of maximum continuous operating voltage and maximal discharge electric current of SPDs, the reasonable methods for selecting SPDs are presented based on the types of connection equipments and the demands of working voltage and frequency.
An analysis is made of various sorts of equipment breakdowns and damages induced by the electromagnetic pulses of thunders and lighting, thunders and lighting classification, and the invasion approaches of thunders and lightning into communication systems and computer networks. The types, components, and technical specifications of SPDs (Surge Protector Devices) are introduced. The emphases are put on the criterions for selecting SPDs for communication systems and computer networks. According to the detailed calculation of maximum continuous operating voltage and maximal discharge electric current of SPDs, the reasonable methods for selecting SPDs are presented based on the types of connection equipments and the demands of working voltage and frequency.
2008, 36(3):364-368.
Abstract:
A B/S (Browser/Server) mode weather modification information management system based on the .NET platform is developed. Subsystems include the basic information management, product release, press release and map release units. The system has the characteristics of: (1) the system is easy to use and has rich contents and friendly interface. (2) the threelevel (provincial, prefecture and county) users can administrate their own weather modification information by using one system and transfer data in real time and synchronously among the three levels. (3) Based on the .NET platform, the web sites have a strong extensibility and good maintainability. (4) Applying the WebGIS technology, weather modification map release can be realized by using ArcIMS. This system is developed by using C++ language and ASP.NET technology. The connection with and access to the database is realized with ADO.NET, and the administration of database is through Microsoft SQL Server 2000. The trial use proved that the system works stably, and can be carried out in high speed easily.
A B/S (Browser/Server) mode weather modification information management system based on the .NET platform is developed. Subsystems include the basic information management, product release, press release and map release units. The system has the characteristics of: (1) the system is easy to use and has rich contents and friendly interface. (2) the threelevel (provincial, prefecture and county) users can administrate their own weather modification information by using one system and transfer data in real time and synchronously among the three levels. (3) Based on the .NET platform, the web sites have a strong extensibility and good maintainability. (4) Applying the WebGIS technology, weather modification map release can be realized by using ArcIMS. This system is developed by using C++ language and ASP.NET technology. The connection with and access to the database is realized with ADO.NET, and the administration of database is through Microsoft SQL Server 2000. The trial use proved that the system works stably, and can be carried out in high speed easily.
2008, 36(3):369-371.
Abstract:
In order to guarantee basic meteorological service, enhance the frontlone staff’s management and maintenance capability, and improve observation data quality, a networkbased longdistance management and maintenance system for meteorological service is developed. The system adopts Windows Socket network technology and the customer/server mode and realizes the realtime communication and the longdistance screen sharing, document operation, system mode monitoring, and document automatic backup in P2P way. Through the wideband network, the system can carries out conveniently the longdistance management and maintenance of basic observation stations. The practice proved that the networkbased longdistant management and maintenance of meteorological services is an economical and feasible way, especially applicable to unattended observation stations.
In order to guarantee basic meteorological service, enhance the frontlone staff’s management and maintenance capability, and improve observation data quality, a networkbased longdistance management and maintenance system for meteorological service is developed. The system adopts Windows Socket network technology and the customer/server mode and realizes the realtime communication and the longdistance screen sharing, document operation, system mode monitoring, and document automatic backup in P2P way. Through the wideband network, the system can carries out conveniently the longdistance management and maintenance of basic observation stations. The practice proved that the networkbased longdistant management and maintenance of meteorological services is an economical and feasible way, especially applicable to unattended observation stations.
2008, 36(3):372-374.
Abstract:
The system queries the central SQL Server 2000 database of mesoscale automatic weather stations by VB Script. The automation function of Surfer 8 is used to analyze the gathered data in VB 6.0. The generated graphs are copied to the picture frame through the system clipboard. The queryinginformation input module and graph display module are compiled into Active X and linked into the Web page. The graphic service of any period to the users through the Internet is realized. The problem that most Web sites supply only the graphs of a specific period is resolved. Because the module and Active X technology are applied, the program editing workload is reduced, and the issuance is easier.
The system queries the central SQL Server 2000 database of mesoscale automatic weather stations by VB Script. The automation function of Surfer 8 is used to analyze the gathered data in VB 6.0. The generated graphs are copied to the picture frame through the system clipboard. The queryinginformation input module and graph display module are compiled into Active X and linked into the Web page. The graphic service of any period to the users through the Internet is realized. The problem that most Web sites supply only the graphs of a specific period is resolved. Because the module and Active X technology are applied, the program editing workload is reduced, and the issuance is easier.
2008, 36(3):375-377.
Abstract:
There occur frequently observation data errors induced by various causes, such as observation instrument breakdowns resulted from thunders and lightning, electromagnetism interruption from AMS sensor calibration and replacement, data missing from degraded sensor capability, etc. In order to ensure the complete and continuous records，based on twoyears experiences of data checking at the Jiaxing station， Aformat and Jformat data missing， wild values， errors in format, etc., are discussed, aiming to reduce the frequency of mistakes in data checking and to improve the data quality.
There occur frequently observation data errors induced by various causes, such as observation instrument breakdowns resulted from thunders and lightning, electromagnetism interruption from AMS sensor calibration and replacement, data missing from degraded sensor capability, etc. In order to ensure the complete and continuous records，based on twoyears experiences of data checking at the Jiaxing station， Aformat and Jformat data missing， wild values， errors in format, etc., are discussed, aiming to reduce the frequency of mistakes in data checking and to improve the data quality.
2008, 36(3):378-379.
Abstract:
2008, 36(3):380-382.
Abstract:
2008, 36(3):383-384.
Abstract:
External LinksChina Meteorological AdministrationCMA Meteorological Observation CentreChinese Academy of Meteorological SciencesBeijing Meteorological ServiceNational Satellite Meteorological Center
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Supported by:Beijing E-Tiller Technology Development Co., Ltd.
Supported by:Beijing E-Tiller Technology Development Co., Ltd.