Volume 38,Issue 1,2010 Table of Contents
2010, 38(1):1-8.
Abstract:
An introduction of the main reanalysis data of NCEP, ECMWF, JMA and the preliminary comparison among them are given from the following aspects: (1) assimilation systems, including the assimilation module and method; (2) the data used in the reanalysis; and (3) the methods of quality control and bias correction. The main assimilation methods of all reanalysis datasets include the 3D variational method, 4D variational method, and optimum interpolation. The dominating differences of these reanalysis datasets are data types and the resolution of modules. In addition, the advantages and deficiencies of these reanalysis datasets are given by empirical analysis. It is helpful for selecting the correct reanalysis dataset. The advances in reanalysis in China ars introduced simply and some problems on the improvement of the reanalysis in China are discussed.
An introduction of the main reanalysis data of NCEP, ECMWF, JMA and the preliminary comparison among them are given from the following aspects: (1) assimilation systems, including the assimilation module and method; (2) the data used in the reanalysis; and (3) the methods of quality control and bias correction. The main assimilation methods of all reanalysis datasets include the 3D variational method, 4D variational method, and optimum interpolation. The dominating differences of these reanalysis datasets are data types and the resolution of modules. In addition, the advantages and deficiencies of these reanalysis datasets are given by empirical analysis. It is helpful for selecting the correct reanalysis dataset. The advances in reanalysis in China ars introduced simply and some problems on the improvement of the reanalysis in China are discussed.
2010, 38(1):9-14.
Abstract:
Taking the monthly mean precipitation of Wenzhou (90 stations) from 1991 to 2001 as an example, with the aid of GIS, a comparison is conducted of three interpolation methods: the spline, Kriging, and inverse distance square methods. The different station densities are used to determine the minimum number of the stations that can make the results stable, and the effect of spatial resolution on interpolation results is considered. After a great deal of calculation and statistic analysis, the results are as following: (1) the inverse distance square and spline methods are better for calculating monthly mean precipitation; (2) compared the interpolation results for the two methods applied to different station density cases with different spatial resolutions, it is shown that when selecting 50 stations, the inverse distance square method is most stable with the minimum error, and the effect of spatial resolution is very little, can be neglected. The inverse distance square method and 50 stations are selected finally to calculate the precipitation of the 1km×1km area. This method offers a good areal precipitation estimating method for hydrology prediction service.
Taking the monthly mean precipitation of Wenzhou (90 stations) from 1991 to 2001 as an example, with the aid of GIS, a comparison is conducted of three interpolation methods: the spline, Kriging, and inverse distance square methods. The different station densities are used to determine the minimum number of the stations that can make the results stable, and the effect of spatial resolution on interpolation results is considered. After a great deal of calculation and statistic analysis, the results are as following: (1) the inverse distance square and spline methods are better for calculating monthly mean precipitation; (2) compared the interpolation results for the two methods applied to different station density cases with different spatial resolutions, it is shown that when selecting 50 stations, the inverse distance square method is most stable with the minimum error, and the effect of spatial resolution is very little, can be neglected. The inverse distance square method and 50 stations are selected finally to calculate the precipitation of the 1km×1km area. This method offers a good areal precipitation estimating method for hydrology prediction service.
2010, 38(1):15-20.
Abstract:
The conventional observation, weather satellite, and NCEP/NCAR reanalysis data are used to perform the dynamic and mesoscale analyses of the rare mountain flood in history in Lushi County in the western Henna Province from 28 to 30 July in 2007. The results show that the subtropic high over the West Pacific enhanced and overlapped on the Begal high and thus resulted in a blocking pattern; the lowlevel jet with a large amount of water vapor converged around the strong frontogenesis field in the west of Henna, which led to the occurrence of the extreme rainstorm. In the strong inclined ascending motion area, there was a conditional symmetric unstable mechanism at lower levels, which caused the occurrence and development of the mesoβ clouds, and consequently induced the rainstorm.
The conventional observation, weather satellite, and NCEP/NCAR reanalysis data are used to perform the dynamic and mesoscale analyses of the rare mountain flood in history in Lushi County in the western Henna Province from 28 to 30 July in 2007. The results show that the subtropic high over the West Pacific enhanced and overlapped on the Begal high and thus resulted in a blocking pattern; the lowlevel jet with a large amount of water vapor converged around the strong frontogenesis field in the west of Henna, which led to the occurrence of the extreme rainstorm. In the strong inclined ascending motion area, there was a conditional symmetric unstable mechanism at lower levels, which caused the occurrence and development of the mesoβ clouds, and consequently induced the rainstorm.
2010, 38(1):21-25.
Abstract:
By using the conventional observation and NCEP reanalysis data， a study is made to discuss the heavy rain took place in the central Fujian Province on 21 May 2008. The results indicate that the heavy rain took place in the area where the convergence of the divergence term and the advection term of the moisture flux divergence disposed well; the stronger vorticity advection at upper levels promoted the ascending movement; the stronger vertically differential thermal advection of pseudoequivalent potential temperature resulted in the development of instability， in favor of the updraft; and the central position and the strength of the lowerlevel horizontal movement frontogenesis were in good agreement with the location and strength 6 hours in future of the heavy rainfall.
By using the conventional observation and NCEP reanalysis data， a study is made to discuss the heavy rain took place in the central Fujian Province on 21 May 2008. The results indicate that the heavy rain took place in the area where the convergence of the divergence term and the advection term of the moisture flux divergence disposed well; the stronger vorticity advection at upper levels promoted the ascending movement; the stronger vertically differential thermal advection of pseudoequivalent potential temperature resulted in the development of instability， in favor of the updraft; and the central position and the strength of the lowerlevel horizontal movement frontogenesis were in good agreement with the location and strength 6 hours in future of the heavy rainfall.
2010, 38(1):26-31.
Abstract:
A total of 31 precipitation cases in July and August 2007 over the Qilian Mountains are classified on the basis of the dominant air currents at 500 hPa and the cloud pattern of FY2D satellite images，taking the difference between 110°E and 90°E of the mean 500 hPa geopotential height of the grid points in 30° to 45°N as the classification standard.The precipitation cases can be classified as three main patterns: southwest current，northwest current， and flat west current.The southwest current pattern is divided into two subtypes: moving and blocking; the northwest current: cold advection and Hetao cold vortex.On the basis of data of the mesoscale automatic weather station network over the experimental region， the relation of precipitation with altitude and slope direction is discussed.The circulation characteristics and precipitation intensity of each circulation pattern that generated precipitation are analyzed. It is found that different largescale circulation patterns will result in different topographically forced mesoscale systems due to topographic dynamic and thermodynamic effects.
A total of 31 precipitation cases in July and August 2007 over the Qilian Mountains are classified on the basis of the dominant air currents at 500 hPa and the cloud pattern of FY2D satellite images，taking the difference between 110°E and 90°E of the mean 500 hPa geopotential height of the grid points in 30° to 45°N as the classification standard.The precipitation cases can be classified as three main patterns: southwest current，northwest current， and flat west current.The southwest current pattern is divided into two subtypes: moving and blocking; the northwest current: cold advection and Hetao cold vortex.On the basis of data of the mesoscale automatic weather station network over the experimental region， the relation of precipitation with altitude and slope direction is discussed.The circulation characteristics and precipitation intensity of each circulation pattern that generated precipitation are analyzed. It is found that different largescale circulation patterns will result in different topographically forced mesoscale systems due to topographic dynamic and thermodynamic effects.
6 Analysis of Typhoons “FungWong” and “Norris” with Similar Tracks and Different Rainfall Patterns
2010, 38(1):32-36.
Abstract:
The Tropical Cyclones （TC）with similar tracks generally have similar rainstorm patterns， but Typhoons FungWong （0808） and Norris （8012） are exceptions， which have similar tracks but different precipitation distribution. The rainstorms of FungWong distributed in two sides of the track， but those of Norris distributed in the left side of its track. The typhoon rainstorms are diagnosed and analyzed by means of moist potential vorticity （MPV） and vertical wind shear analysis. It is found that， regardless of FungWong or Norris， MPV and vertical wind shear of both have the consistent corresponding relationship with typhoon rainstorms. The strong precipitation occurred on the vertical wind shear left side， and when vertical wind shear vectors and TC track angled differently， there occurred different heavy rainfall distributions along the TC track. The overlapped areas of negative MPV1 and positive MPV2 are usually severe rainfall areas， and the greater the positive value of MPV2 in the overlapped area， the stronger the intensity of rainstorm. Therefore， in the typhoon forecasting practice， the accuracy of rainfall location forecast can be improved by using the comprehensive analysis of MPV and vertical wind shear.
The Tropical Cyclones （TC）with similar tracks generally have similar rainstorm patterns， but Typhoons FungWong （0808） and Norris （8012） are exceptions， which have similar tracks but different precipitation distribution. The rainstorms of FungWong distributed in two sides of the track， but those of Norris distributed in the left side of its track. The typhoon rainstorms are diagnosed and analyzed by means of moist potential vorticity （MPV） and vertical wind shear analysis. It is found that， regardless of FungWong or Norris， MPV and vertical wind shear of both have the consistent corresponding relationship with typhoon rainstorms. The strong precipitation occurred on the vertical wind shear left side， and when vertical wind shear vectors and TC track angled differently， there occurred different heavy rainfall distributions along the TC track. The overlapped areas of negative MPV1 and positive MPV2 are usually severe rainfall areas， and the greater the positive value of MPV2 in the overlapped area， the stronger the intensity of rainstorm. Therefore， in the typhoon forecasting practice， the accuracy of rainfall location forecast can be improved by using the comprehensive analysis of MPV and vertical wind shear.
7 Application of Doppler Radar Radial Velocity Assimilation to Numerical Simulation of Heavy Rainfall
2010, 38(1):37-43.
Abstract:
In order to study the influence of Doppler radar radial velocity assimilation on the numerical simulation of heavy rainfall， the roles played by WRF and WRF3DVAR in improving the initial fields and simulation results are analyzed.A investigation is conducted on a heavy rainfall event occurred in Guangdong Province on 6 June 2008， and the results indicate that radial velocity， which can be assimilated effectively by WRF3DVAR， affected the initial dynamical field. By adjusting horizontal wind and vertical velocity around the radar station，the mesoscale characteristics of the initial wind field are improved.Moreover， for rainfall simulation， the radial velocity assimilation experiment is better than those without assimilation.
In order to study the influence of Doppler radar radial velocity assimilation on the numerical simulation of heavy rainfall， the roles played by WRF and WRF3DVAR in improving the initial fields and simulation results are analyzed.A investigation is conducted on a heavy rainfall event occurred in Guangdong Province on 6 June 2008， and the results indicate that radial velocity， which can be assimilated effectively by WRF3DVAR， affected the initial dynamical field. By adjusting horizontal wind and vertical velocity around the radar station，the mesoscale characteristics of the initial wind field are improved.Moreover， for rainfall simulation， the radial velocity assimilation experiment is better than those without assimilation.
2010, 38(1):44-48.
Abstract:
By means of the numerical prediction data， wind profile and Doppler radar data， and automatic meteorological observation data from the main landing site， an analysis is made of a hail storms process on 14 September 2008.The results indicate that during the hailstorm， the essential meteorological factors changed fiercely， and the cold front of the invasive Mongolia low along with a mesoscale convergence line， moving close to the main landing site， triggered the rapid development of strong convection； in the earlier period vertical wind shear increased obviously； the main formation causes include deep wet convective instability stratification， intense vorticity advection， and vertical ascent movement.TBB decreased rapidly in the earlier period， and the nonecho dome area on the RHI chart is the hail source area.The hailstorm occurred on the north side of the axis of 〖WTBX〗θ〖WTBZ〗se tongue and the south side of the upper front zone.
By means of the numerical prediction data， wind profile and Doppler radar data， and automatic meteorological observation data from the main landing site， an analysis is made of a hail storms process on 14 September 2008.The results indicate that during the hailstorm， the essential meteorological factors changed fiercely， and the cold front of the invasive Mongolia low along with a mesoscale convergence line， moving close to the main landing site， triggered the rapid development of strong convection； in the earlier period vertical wind shear increased obviously； the main formation causes include deep wet convective instability stratification， intense vorticity advection， and vertical ascent movement.TBB decreased rapidly in the earlier period， and the nonecho dome area on the RHI chart is the hail source area.The hailstorm occurred on the north side of the axis of 〖WTBX〗θ〖WTBZ〗se tongue and the south side of the upper front zone.
2010, 38(1):49-52.
Abstract:
A largescale haze process happened on 12 to 13 December 2008 over Jiangxi Province is analyzed comprehensively based on the air pollution index, conventional observation, and radiosonde data. The results show that the joint influence of the southward moving cold air induced by the vertically turning horizontal trough and the dry warm tongue in the middlelevel layer is the background cause of the haze process. The cold air could not invade the highlevel layer above 700 hPa rapidly because of the restraining effect of the dry warm tongue, and then there appeared a “temperature inversion” structure, which facilitated the formation and maintenance of the largescale haze process. Affected jointly by the diurnal temperature difference and the cold air, with a relative low humidity, the weather changed frequently between haze and light fogs. A lower height of mixing layer made the pollutants move horizontally and spread along the mountains, and consequently turned the haze area into a eastwest pattern from a northsouth pattern.
A largescale haze process happened on 12 to 13 December 2008 over Jiangxi Province is analyzed comprehensively based on the air pollution index, conventional observation, and radiosonde data. The results show that the joint influence of the southward moving cold air induced by the vertically turning horizontal trough and the dry warm tongue in the middlelevel layer is the background cause of the haze process. The cold air could not invade the highlevel layer above 700 hPa rapidly because of the restraining effect of the dry warm tongue, and then there appeared a “temperature inversion” structure, which facilitated the formation and maintenance of the largescale haze process. Affected jointly by the diurnal temperature difference and the cold air, with a relative low humidity, the weather changed frequently between haze and light fogs. A lower height of mixing layer made the pollutants move horizontally and spread along the mountains, and consequently turned the haze area into a eastwest pattern from a northsouth pattern.
2010, 38(1):53-57.
Abstract:
A heavy rainstorm occurred in autumn in Nan’an is analyzed by means of the regular observation， intensive observation from the automatic station， synoptic map， physical parameters， and cloud pictures to study the influencing weather systems and water vapor conditions of this heavy rainstorm. The atmospheric instability and its dynamic mechanisms are also studied.By analyzing the evolution of the weather systems in combination with the related physical parameters， it is found that the tropical depression and cold air are important factors for this heavy rainstorm， and the application of the sounding data plays an important part in quantitatively analyzing the evolution of the weather systems.
A heavy rainstorm occurred in autumn in Nan’an is analyzed by means of the regular observation， intensive observation from the automatic station， synoptic map， physical parameters， and cloud pictures to study the influencing weather systems and water vapor conditions of this heavy rainstorm. The atmospheric instability and its dynamic mechanisms are also studied.By analyzing the evolution of the weather systems in combination with the related physical parameters， it is found that the tropical depression and cold air are important factors for this heavy rainstorm， and the application of the sounding data plays an important part in quantitatively analyzing the evolution of the weather systems.
2010, 38(1):58-65.
Abstract:
On the basis of the 30year ground observational cloud and precipitation data from 77 meteorological stations as well as NCEP reanalysis data， addressed are the distribution and variation of clouds and water resources in clouds in Sichuan.The analysis results indicate that annually， there were 1935 overcast days， 154.0 precipitation days， 147.1 small/moderate precipitation days （0.1 to 25 mm）， with the annual precipitable water being 181.30 kg〖DK〗·m-2， the total cloud cover being 7.2/10， and the lowlevel cloud cover being 4.7/10 over Sichuan. Cloud cover varied obviously with season: the greatest total cloud cover appearing in summer， the secondary in spring， and the least in winter; the greatest lowlevel cloud cover appearing in summer， the secondary in autumn， and the least in winter. Precipitable water varied also with season obviously， being the greatest in summer， secondary in autumn， and least in winter.The spatial distribution of clouds and small/moderate precipitation days differ obviously over the different parts of Sichuan， while the spatial distribution in summer was different obviously with the annual spatial distribution. In the recent 30 years， total cloud cover fluctuated around the average level with a slightly downward tendency over the plateau， while lowlevel cloud cover， small/moderate precipitation days， and precipitation days fluctuated around the average level with a slightly upward tendency.However， in the basin， total cloud cover， lowlevel cloud cover， precipitation days， and small/moderate precipitation days varied with a downward tendency.The precipitable water had an upward tendency in the 30 years.
On the basis of the 30year ground observational cloud and precipitation data from 77 meteorological stations as well as NCEP reanalysis data， addressed are the distribution and variation of clouds and water resources in clouds in Sichuan.The analysis results indicate that annually， there were 1935 overcast days， 154.0 precipitation days， 147.1 small/moderate precipitation days （0.1 to 25 mm）， with the annual precipitable water being 181.30 kg〖DK〗·m-2， the total cloud cover being 7.2/10， and the lowlevel cloud cover being 4.7/10 over Sichuan. Cloud cover varied obviously with season: the greatest total cloud cover appearing in summer， the secondary in spring， and the least in winter; the greatest lowlevel cloud cover appearing in summer， the secondary in autumn， and the least in winter. Precipitable water varied also with season obviously， being the greatest in summer， secondary in autumn， and least in winter.The spatial distribution of clouds and small/moderate precipitation days differ obviously over the different parts of Sichuan， while the spatial distribution in summer was different obviously with the annual spatial distribution. In the recent 30 years， total cloud cover fluctuated around the average level with a slightly downward tendency over the plateau， while lowlevel cloud cover， small/moderate precipitation days， and precipitation days fluctuated around the average level with a slightly upward tendency.However， in the basin， total cloud cover， lowlevel cloud cover， precipitation days， and small/moderate precipitation days varied with a downward tendency.The precipitable water had an upward tendency in the 30 years.
12 SpatialTemporal Characteristic of Droughts Based on Standard Precipitation Index in Shijiazhuang
2010, 38(1):66-70.
Abstract:
Drought is one of important natural hazards in Shijiazhuang，Hebei Province.Based on the standard precipitation index，the spatialtemporal characteristics of droughts from 1972 to 2006 in Shijiazhuang are studied by means of the principal component analysis method.The results show that the drought intensity varied with time in total，more severe in the 1970s and 1990s.The spring droughs were relatively serious in the 1970s，and summer and autumn droughts were more serious in the 1990s.The spatial distribution of droughts was significantly consistent，but there existed regional difference.The droughts had an increased tendency in the east and south parts of Shijiazhuang， but a decreased tendency in the north part of Shijiazhuang since the 1990s.
Drought is one of important natural hazards in Shijiazhuang，Hebei Province.Based on the standard precipitation index，the spatialtemporal characteristics of droughts from 1972 to 2006 in Shijiazhuang are studied by means of the principal component analysis method.The results show that the drought intensity varied with time in total，more severe in the 1970s and 1990s.The spring droughs were relatively serious in the 1970s，and summer and autumn droughts were more serious in the 1990s.The spatial distribution of droughts was significantly consistent，but there existed regional difference.The droughts had an increased tendency in the east and south parts of Shijiazhuang， but a decreased tendency in the north part of Shijiazhuang since the 1990s.
2010, 38(1):71-74.
Abstract:
Through parallel observation, the temperature data from both conventional stations and automatic weather stations (AWS) in winter with snow cover at three stations of Dezhou Meteorological Bureau (Lingxian, 2003 to 2004; Wu Yi, 2004 to 2005; Dezhou, 2006 to 2007) are analyzed statistically. The ratio of conventionally measured snow surface temperature to the AWS measured under the condition of snow cover is gained. Since ground temperature can be better representative of the actual situation on the ground, the ratio can be used as a useful and better parameter in surface temperature measurement for scientists in the related fields such as hydrological and agricultural departments.
Through parallel observation, the temperature data from both conventional stations and automatic weather stations (AWS) in winter with snow cover at three stations of Dezhou Meteorological Bureau (Lingxian, 2003 to 2004; Wu Yi, 2004 to 2005; Dezhou, 2006 to 2007) are analyzed statistically. The ratio of conventionally measured snow surface temperature to the AWS measured under the condition of snow cover is gained. Since ground temperature can be better representative of the actual situation on the ground, the ratio can be used as a useful and better parameter in surface temperature measurement for scientists in the related fields such as hydrological and agricultural departments.
2010, 38(1):75-77.
Abstract:
Using the rainfall data of 11 counties over the Nansi Lake basin from 1971 to 2007, analyzed are the starting and ending times of the first and the last heavy rainfall over the Nansi Lake basin, as well as the temporal and spatial distributional characteristics of heavy rainfall. It is found out that there are different temporal and spatial distributions in heavy rainfall over the Nansi Lake basin. The probability of daily maximum possible precipitation exhibited a 〖WTBX〗Λ〖WTBZ〗(x)typed progressive distribution. The daily maximum precipitation that happened once in certain years is estimated by using the Gumbel distribution. Estimation results show that the return periods of the estimated daily maximum precipitation of the next 10 years, 20 years, 40 years are basically the same as those in history, which is a good reference for the estimates of next 50 to 200 years.
Using the rainfall data of 11 counties over the Nansi Lake basin from 1971 to 2007, analyzed are the starting and ending times of the first and the last heavy rainfall over the Nansi Lake basin, as well as the temporal and spatial distributional characteristics of heavy rainfall. It is found out that there are different temporal and spatial distributions in heavy rainfall over the Nansi Lake basin. The probability of daily maximum possible precipitation exhibited a 〖WTBX〗Λ〖WTBZ〗(x)typed progressive distribution. The daily maximum precipitation that happened once in certain years is estimated by using the Gumbel distribution. Estimation results show that the return periods of the estimated daily maximum precipitation of the next 10 years, 20 years, 40 years are basically the same as those in history, which is a good reference for the estimates of next 50 to 200 years.
2010, 38(1):78-85.
Abstract:
The changing trend of surface air temperature is a critical issue in studies of climate change detection and attribution. Due to the large urbanization effect， however， the current dataset of surface air temperature of many national meteorological stations can hardly meet the demands of climate change researches. Based on the station information from all the meteorological stations of China， the quality of the surface air temperature data is evaluated， and the reference surface stations are selected for the studies of urbanization effect and regional climate change detection.The principles and methodology for selecting the reference stations are discussed. A total of 138 stations across the country have been finally chosen as the reference surface air temperature stations.The data from these stations can represent best the baseline change in surface air temperature in China，and can be used for evaluating the urbanization effects on surface air temperature change of national stations. They can also be used directly for detecting the surface air temperature change in China.
The changing trend of surface air temperature is a critical issue in studies of climate change detection and attribution. Due to the large urbanization effect， however， the current dataset of surface air temperature of many national meteorological stations can hardly meet the demands of climate change researches. Based on the station information from all the meteorological stations of China， the quality of the surface air temperature data is evaluated， and the reference surface stations are selected for the studies of urbanization effect and regional climate change detection.The principles and methodology for selecting the reference stations are discussed. A total of 138 stations across the country have been finally chosen as the reference surface air temperature stations.The data from these stations can represent best the baseline change in surface air temperature in China，and can be used for evaluating the urbanization effects on surface air temperature change of national stations. They can also be used directly for detecting the surface air temperature change in China.
2010, 38(1):86-95.
Abstract:
For the effective application and better understanding of correlation between NDVI (Normalized Difference Vegetation Index) and ST (Surface Temperature) and the conversion process between them to better monitor and evaluate the land cover change, especially for explaining the situation with NDVI being saturated based on the parameters of the land cover and soil moisture inversion, the relation of NDVI to ST and the application of different characteristicspace NDVIST models in drought monitoring are analyzed. The results indicate that the arbitrariness in the simulation of the NDVIST characteristic space increased when the land cover was high, which influences the accuracy of drought monitoring. The uncertainty of the effects of multifactors on ST and NDVI also affected the accuracy of drought monitoring. Suggestions are given: the analysis of the variation regularities of the NDVIST space under different land cover and different moisture conditions should be based on the multitemporal remote sensing and different resolution images and focused on the modification of the models of the NDVIST characteristic space and the characteristic changes of drywet edges applied in drought monitoring, especially in the higher land cover situation, so to best facilitate the application of the NDVITs characteristic space method in drought monitoring.
For the effective application and better understanding of correlation between NDVI (Normalized Difference Vegetation Index) and ST (Surface Temperature) and the conversion process between them to better monitor and evaluate the land cover change, especially for explaining the situation with NDVI being saturated based on the parameters of the land cover and soil moisture inversion, the relation of NDVI to ST and the application of different characteristicspace NDVIST models in drought monitoring are analyzed. The results indicate that the arbitrariness in the simulation of the NDVIST characteristic space increased when the land cover was high, which influences the accuracy of drought monitoring. The uncertainty of the effects of multifactors on ST and NDVI also affected the accuracy of drought monitoring. Suggestions are given: the analysis of the variation regularities of the NDVIST space under different land cover and different moisture conditions should be based on the multitemporal remote sensing and different resolution images and focused on the modification of the models of the NDVIST characteristic space and the characteristic changes of drywet edges applied in drought monitoring, especially in the higher land cover situation, so to best facilitate the application of the NDVITs characteristic space method in drought monitoring.
2010, 38(1):96-101.
Abstract:
The dataprocessing center of the meteorological satellite ground application system manages a huge amount of data each day， so high timeefficiency and reliability is required.In view of the high requirement and load balance in the cluster system， in use of the experiences of the Ants algorithm， Reserving Resource， Dynamic Priority strategy, and virtual server application concepts， a parallelscheduling algorithm (a dynamic pheromone weighting algorithm based on performance forecast and link weight calculation) is presented, which can be applied in the dynamical load balance of HPC, help the cluster find the optimum server to deal with the requirements of application rapidly and exactly， thus realize the high dateprocessing capability of the data processing center.
The dataprocessing center of the meteorological satellite ground application system manages a huge amount of data each day， so high timeefficiency and reliability is required.In view of the high requirement and load balance in the cluster system， in use of the experiences of the Ants algorithm， Reserving Resource， Dynamic Priority strategy, and virtual server application concepts， a parallelscheduling algorithm (a dynamic pheromone weighting algorithm based on performance forecast and link weight calculation) is presented, which can be applied in the dynamical load balance of HPC, help the cluster find the optimum server to deal with the requirements of application rapidly and exactly， thus realize the high dateprocessing capability of the data processing center.
2010, 38(1):102-106.
Abstract:
The frequentlyoccurred problems for CE318 sunphotometers are discussed based on the operation of CE318 sunphotometers， and their reasons are analyzed. A set of routine maintenance rules is established， including daily check and weekly and monthly maintenance. These rules can provide references for technicians at stations in the maintenance of sunphotometers， and provide the basic technical assurance for the operation stability and data quality of sunphotometers.
The frequentlyoccurred problems for CE318 sunphotometers are discussed based on the operation of CE318 sunphotometers， and their reasons are analyzed. A set of routine maintenance rules is established， including daily check and weekly and monthly maintenance. These rules can provide references for technicians at stations in the maintenance of sunphotometers， and provide the basic technical assurance for the operation stability and data quality of sunphotometers.
2010, 38(1):107-110.
Abstract:
In meteorological and hydrological services，the evaporation of water surface is measured by ultrasonic sensors，whose precision is only 15 mm and measurement is easily disturbed by environmental factors.In order to solve these problems，a new evaporation measurement unit based on magnetostriction technology whose precision is up to 01 mm is presented.The related schematic circuit is given.The unit is tested for 6 months in an automatic weather station.Through comparing the results of manual and automatic methods，the feasibility of the automatic evaporation measurement unit with this technology is verified.The results indicate that this unit can be used instead of ultrasonic sensors to achieve the goal of high precision and better stability in meteorological and hydrological services.
In meteorological and hydrological services，the evaporation of water surface is measured by ultrasonic sensors，whose precision is only 15 mm and measurement is easily disturbed by environmental factors.In order to solve these problems，a new evaporation measurement unit based on magnetostriction technology whose precision is up to 01 mm is presented.The related schematic circuit is given.The unit is tested for 6 months in an automatic weather station.Through comparing the results of manual and automatic methods，the feasibility of the automatic evaporation measurement unit with this technology is verified.The results indicate that this unit can be used instead of ultrasonic sensors to achieve the goal of high precision and better stability in meteorological and hydrological services.
2010, 38(1):111-113.
Abstract:
An Introduction is made of the working principles and technical specifications of digitalE601B evaporation sensors (AG11type ultrasonic，AG20type ultrasonic，FFZ01type digital，ZQZDV).Through comparing comprehensively the evaporation test data，the programming of total evaporation calculation，and the failure rate，the performances of the apparatus are discussed.The analysis results indicate that through improving the measuring environment and processing programs and reducing manual interventi〖JP2〗on， the antijamming capability of these new evaporation sensors under severe weather are improved，which makes allweather automatic precise evaporation observation possible and provides technical support for conducting automation evaporation observation in substitution for manual observation.
An Introduction is made of the working principles and technical specifications of digitalE601B evaporation sensors (AG11type ultrasonic，AG20type ultrasonic，FFZ01type digital，ZQZDV).Through comparing comprehensively the evaporation test data，the programming of total evaporation calculation，and the failure rate，the performances of the apparatus are discussed.The analysis results indicate that through improving the measuring environment and processing programs and reducing manual interventi〖JP2〗on， the antijamming capability of these new evaporation sensors under severe weather are improved，which makes allweather automatic precise evaporation observation possible and provides technical support for conducting automation evaporation observation in substitution for manual observation.
2010, 38(1):114-119.
Abstract:
Photosynthetic measurements were taken in the water controllable field at Gucheng，Hebei Prvince when winter wheat was in the early milk stage， and different water controls were designed for no water stress（CK）， low water stress （soil moisture 50% to 70%） and high water stress （soil moisture under 50%）. Diurnal changes of photosynthetic parameters of flag leaves in winter wheat were measured by Licor6400 under CK and different water stress conditions in shining days.The main results are:（1） Diurnal change of the net photosynthetic rate of flag leaves showed a singlepeak type and there occurred no “noonbreak” under CK conditions. Contrarily， all the diurnal changes of the net photosynthetic rate of flag leaves under different water stress conditions showed the doublepeak type，and the noon break in winter wheat under the high water stress condition shortened for 2 hours compared with that under low water stress condition.（2） Diurnal changes of transpiration rate all showed the doublepeak type under three water controls，and there was obviously positive correlation between transpiration rate and stomatal conductance.The feedback sensitivity of flag leaves kept at a lowlevel when winter wheat was in the appropriate soil moisture （CK） and soil drought （soil moisture under 50%） conditions.（3） The net photosynthetic rate of flag leaves and the wateruse efficiency （WUE） under low water stress condition were over 2.8% to 9.0% and 10.6% to 12.9% higher than that under the CK condition respectively，which may explain the phenomena that the high yield of winter wheat can be gained at a water stress condition.
Photosynthetic measurements were taken in the water controllable field at Gucheng，Hebei Prvince when winter wheat was in the early milk stage， and different water controls were designed for no water stress（CK）， low water stress （soil moisture 50% to 70%） and high water stress （soil moisture under 50%）. Diurnal changes of photosynthetic parameters of flag leaves in winter wheat were measured by Licor6400 under CK and different water stress conditions in shining days.The main results are:（1） Diurnal change of the net photosynthetic rate of flag leaves showed a singlepeak type and there occurred no “noonbreak” under CK conditions. Contrarily， all the diurnal changes of the net photosynthetic rate of flag leaves under different water stress conditions showed the doublepeak type，and the noon break in winter wheat under the high water stress condition shortened for 2 hours compared with that under low water stress condition.（2） Diurnal changes of transpiration rate all showed the doublepeak type under three water controls，and there was obviously positive correlation between transpiration rate and stomatal conductance.The feedback sensitivity of flag leaves kept at a lowlevel when winter wheat was in the appropriate soil moisture （CK） and soil drought （soil moisture under 50%） conditions.（3） The net photosynthetic rate of flag leaves and the wateruse efficiency （WUE） under low water stress condition were over 2.8% to 9.0% and 10.6% to 12.9% higher than that under the CK condition respectively，which may explain the phenomena that the high yield of winter wheat can be gained at a water stress condition.
2010, 38(1):120-124.
Abstract:
The late rice drought index is constructed from the aspect of crop moisture demands.The drought level index of late rice in Hunan is brought forward through analyzing contradistinctively the drought index and drought data of the typical year.The validation with the drought data of late rice in growing season shows that droughts can be reflected by the late rice drought index and drought level index. The results show: as for growing seasons，the probabilityes of extreme drought in the fast growing，midgrowing，and maturity stages are greater than that in the prime growing season obviously， generally greater than 40%; as for regions， the probabilities of severe drought in the middle and northern parts of Hunan are greater than those in the western and southern parts.This model can be used to analyze the drought situation of late rice in different parts of Hunan Province at different times， providing useful references for drought resisting of late rice.
The late rice drought index is constructed from the aspect of crop moisture demands.The drought level index of late rice in Hunan is brought forward through analyzing contradistinctively the drought index and drought data of the typical year.The validation with the drought data of late rice in growing season shows that droughts can be reflected by the late rice drought index and drought level index. The results show: as for growing seasons，the probabilityes of extreme drought in the fast growing，midgrowing，and maturity stages are greater than that in the prime growing season obviously， generally greater than 40%; as for regions， the probabilities of severe drought in the middle and northern parts of Hunan are greater than those in the western and southern parts.This model can be used to analyze the drought situation of late rice in different parts of Hunan Province at different times， providing useful references for drought resisting of late rice.
23 Meteorological Conditions and Countermeasures for Premature Senescence of InsectResistant Cotton
2010, 38(1):125-128.
Abstract:
An analysis is made of the effects of temperature and precipitation on premature senescence of cotton based on the observation data of Huimin from 1988 to 2007 (the data on regular cotton is from 1988 to 1997， and those on insectresistant cotton is from 1998 to 2007).The results show that the number of autumn bells was negatively correlated to the mean temperature from April to July，the higher the mean temperature from May to July， the less the autumn bells， the more serious the premature senescence. If precipitation was less than normal from midJune to midJuly，there occurred seedling weak and premature senescence; while if precipitation was less than normal from midAugust to midSeptember， there occurred less autumn bells and premature senescence. Countermeasures are presented in the aspect of meteorological conditions.
An analysis is made of the effects of temperature and precipitation on premature senescence of cotton based on the observation data of Huimin from 1988 to 2007 (the data on regular cotton is from 1988 to 1997， and those on insectresistant cotton is from 1998 to 2007).The results show that the number of autumn bells was negatively correlated to the mean temperature from April to July，the higher the mean temperature from May to July， the less the autumn bells， the more serious the premature senescence. If precipitation was less than normal from midJune to midJuly，there occurred seedling weak and premature senescence; while if precipitation was less than normal from midAugust to midSeptember， there occurred less autumn bells and premature senescence. Countermeasures are presented in the aspect of meteorological conditions.
2010, 38(1):129-132.
Abstract:
Based on climate characteristics of light, temperature, water, diseases, and climate, the adaptability and superiority of Pinggu peach are analyzed from the aspects of geographic features, soil and water resources, winter freeze injury, spring frost, blossom pollination, fruit bearing periods, diurnal temperature ranges, disease conditions, etc. The results show that peach planting in Pinggu has superiority geographically and climatically, without winter freeze injury and almost without spring frost. Compared with Daxing, Pinggu has obvious superiority in peach blossom pollination, favorable days during the fruitbearing period and unfavorable high temperature days, diurnal temperature ranges, and diseases. Pinggu’s climate is most favorable for planting peach than other areas in Beijing.
Based on climate characteristics of light, temperature, water, diseases, and climate, the adaptability and superiority of Pinggu peach are analyzed from the aspects of geographic features, soil and water resources, winter freeze injury, spring frost, blossom pollination, fruit bearing periods, diurnal temperature ranges, disease conditions, etc. The results show that peach planting in Pinggu has superiority geographically and climatically, without winter freeze injury and almost without spring frost. Compared with Daxing, Pinggu has obvious superiority in peach blossom pollination, favorable days during the fruitbearing period and unfavorable high temperature days, diurnal temperature ranges, and diseases. Pinggu’s climate is most favorable for planting peach than other areas in Beijing.
2010, 38(1):133-135.
Abstract:
The phenological observations of mango grafting survival were conducted in phases over the years, and the statistical analysis is made of the meteorological observation data in the same period. The results show that the survival rate of mango grafting is positively correlated with the temperature during the healing period of grafting interfaces, and no obvious correlation is found with the light, rainfall, and relative humidity. The regression equation of the grafting survival rate and the sixday average temperature and maximum temperature after grafting is established. The main factor impacting grafting survival is the daily average temperature. In the critical period of mango grafting survival, that is, the physically vulnerable period of graft interface healing, morethannormal low or unusual high temperature has tremendous negative impact on grafting survival. Some suggestions are discussed about the increase of the grafting survival rate according to meteorological conditions.
The phenological observations of mango grafting survival were conducted in phases over the years, and the statistical analysis is made of the meteorological observation data in the same period. The results show that the survival rate of mango grafting is positively correlated with the temperature during the healing period of grafting interfaces, and no obvious correlation is found with the light, rainfall, and relative humidity. The regression equation of the grafting survival rate and the sixday average temperature and maximum temperature after grafting is established. The main factor impacting grafting survival is the daily average temperature. In the critical period of mango grafting survival, that is, the physically vulnerable period of graft interface healing, morethannormal low or unusual high temperature has tremendous negative impact on grafting survival. Some suggestions are discussed about the increase of the grafting survival rate according to meteorological conditions.
2010, 38(1):136-140.
Abstract:
A continuous severe rain occurred on 2 November 2008 in Chuxiong，Yunnan Province，which initiated an exceptional big geological disaster and created a huge loss of life and property. By means of the data of MICAPS 3， conventional meteorological rainfall， intensive unattended station rainfall， and satellite cloud pictures， the meteorological causes of the event are analyzed.The results indicate that besides natural causes such as geological condition and landform，the historically rarely seen severe rainfall is a major trigger.The direct factors of the event include the mesoscale convergence weather system， abundant watervapor transport and convergence， upperlevel and lowerlevel jets， and lowermid level shear.
A continuous severe rain occurred on 2 November 2008 in Chuxiong，Yunnan Province，which initiated an exceptional big geological disaster and created a huge loss of life and property. By means of the data of MICAPS 3， conventional meteorological rainfall， intensive unattended station rainfall， and satellite cloud pictures， the meteorological causes of the event are analyzed.The results indicate that besides natural causes such as geological condition and landform，the historically rarely seen severe rainfall is a major trigger.The direct factors of the event include the mesoscale convergence weather system， abundant watervapor transport and convergence， upperlevel and lowerlevel jets， and lowermid level shear.
2010, 38(1):141-144.
Abstract:
By means of the advanced information technology， in combination with weather forecast and climate analysis，based the small and mediumscale network of automatic weather stations， a GISbased realtime weather information service system for natural rubber planting is established. The system， based on the physiological characteristics of rubber at the cutting and nocutting stages， can be applied to the supervision and management of rubber trees in Xishuangbanna according to the realtime weather conditions （precipitation， temperature）， by which inquiring， monitoring， and forecasting can be conducted in a timely manner， so to minimize the adverse effect of weather on rubber tree and to reduce production losses as much as possible.
By means of the advanced information technology， in combination with weather forecast and climate analysis，based the small and mediumscale network of automatic weather stations， a GISbased realtime weather information service system for natural rubber planting is established. The system， based on the physiological characteristics of rubber at the cutting and nocutting stages， can be applied to the supervision and management of rubber trees in Xishuangbanna according to the realtime weather conditions （precipitation， temperature）， by which inquiring， monitoring， and forecasting can be conducted in a timely manner， so to minimize the adverse effect of weather on rubber tree and to reduce production losses as much as possible.
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.