ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 36,Issue 10,2010 Table of Contents
2010, 36(10):1-7.
DOI: 10.7519/j.issn.1000-0526.2010.10.001
Abstract:
Seasonal operational forecast dataset of summer precipitation (1978-2008) was used to investigate the forecast ability and forecast skill. Compared with 160 stations’ observations (1951-2008), the high forecast skill years and the low forecast skill years were distinguished. The highest forecast skill appeared in the years when dry domain controls the Yangtze-Huaihe River Basin; however, the lowest score appeared in the years when the mid-low Yangtze River Basin was wet. Two signals from inter-decadal and interannual timescales should be utilized in the operational forecast. For the interdecadal timescale, the monsoon region in East China should be divided into several sub-regions first, and then actual inter-decadal signals at individual sub-region can be used in the operational forecast. Inter-annual precursory signals could be the biennial oscillation and seasonal forcing such as the sea temperature, snow cover and soil moisture anomalies.
Seasonal operational forecast dataset of summer precipitation (1978-2008) was used to investigate the forecast ability and forecast skill. Compared with 160 stations’ observations (1951-2008), the high forecast skill years and the low forecast skill years were distinguished. The highest forecast skill appeared in the years when dry domain controls the Yangtze-Huaihe River Basin; however, the lowest score appeared in the years when the mid-low Yangtze River Basin was wet. Two signals from inter-decadal and interannual timescales should be utilized in the operational forecast. For the interdecadal timescale, the monsoon region in East China should be divided into several sub-regions first, and then actual inter-decadal signals at individual sub-region can be used in the operational forecast. Inter-annual precursory signals could be the biennial oscillation and seasonal forcing such as the sea temperature, snow cover and soil moisture anomalies.
2010, 36(10):8-13.
DOI: 10.7519/j.issn.1000-0526.2010.10.002
Abstract:
Using conventional and unconventional observation data, with NCEP reanlysis data, a largescale continuous high temperature process occurring in North China Plain was studied.Some results were shown as follows: Highpressure (ridge) in the upperlevel, stable hightemperature zone on 850 hPa and the low pressure generated in Northwest China with surface stretching or moving eastward are the causes for the formation and maintenance of the sustained high temperatures process. Meanwhile, the quantitative values of the advection term, perpendicular term and nonadiabatic term leading to local temperature variations are estimated. The advection term varies complicatedly, but it plays a very weak role. The perpendicular term leads to temperature increase by 30% in this process. The local temperature increment is mainly from the nonadiabatic term, and it plays a significant role (about 41% in this process) in local temperature increment. Therefore, in the operational forecast, the role played by advection can be ignored, the perpendicular term and nonadiabatic term should be focused and considered.
Using conventional and unconventional observation data, with NCEP reanlysis data, a largescale continuous high temperature process occurring in North China Plain was studied.Some results were shown as follows: Highpressure (ridge) in the upperlevel, stable hightemperature zone on 850 hPa and the low pressure generated in Northwest China with surface stretching or moving eastward are the causes for the formation and maintenance of the sustained high temperatures process. Meanwhile, the quantitative values of the advection term, perpendicular term and nonadiabatic term leading to local temperature variations are estimated. The advection term varies complicatedly, but it plays a very weak role. The perpendicular term leads to temperature increase by 30% in this process. The local temperature increment is mainly from the nonadiabatic term, and it plays a significant role (about 41% in this process) in local temperature increment. Therefore, in the operational forecast, the role played by advection can be ignored, the perpendicular term and nonadiabatic term should be focused and considered.
2010, 36(10):14-20.
DOI: 10.7519/j.issn.1000-0526.2010.10.003
Abstract:
During January 12 to February 20 of 2008, the low temperature, sleet and frost weather process occurred in Guangxi, whose duration has been the longest and the average temperature has been the lowest since 1951, and the accumulative temperature of the process reached the standard level of abnormal low. Circulation features and indices of six remarkable low temperature and sleet processes at the corresponding period in Guangxi were analyzed, then EMD (empirical mode decomposition) research was carried out for four kinds of circulation indices which are obviously correlated, results showed that major circulation characteristics of abnormal low temperature of Guangxi are of dipole type at 500 hPa circulation in the Northern Hemisphere, therefore, there are stable high ridges over high and midlatitudes of Asia and North Pacific, and it also has the stable trough over the QinghaiTibetan Plateau and the Bay of Bengal at the same time. These are the major circulations for abnormal low temperature weather in Guangxi. The stronger trough over Mongolia and the Bay of Bengal, the stronger blockinghigh, and more days for the westward extension of the subtropicalhigh ridge from the South China Sea to Philippines, all these are the main influence factors for the low temperature, sleet and frost weather process, so that the low temperature, sleet and frost synoptic process happened in Guangxi at the beginning of 2008 when these conditions are satisfied.
During January 12 to February 20 of 2008, the low temperature, sleet and frost weather process occurred in Guangxi, whose duration has been the longest and the average temperature has been the lowest since 1951, and the accumulative temperature of the process reached the standard level of abnormal low. Circulation features and indices of six remarkable low temperature and sleet processes at the corresponding period in Guangxi were analyzed, then EMD (empirical mode decomposition) research was carried out for four kinds of circulation indices which are obviously correlated, results showed that major circulation characteristics of abnormal low temperature of Guangxi are of dipole type at 500 hPa circulation in the Northern Hemisphere, therefore, there are stable high ridges over high and midlatitudes of Asia and North Pacific, and it also has the stable trough over the QinghaiTibetan Plateau and the Bay of Bengal at the same time. These are the major circulations for abnormal low temperature weather in Guangxi. The stronger trough over Mongolia and the Bay of Bengal, the stronger blockinghigh, and more days for the westward extension of the subtropicalhigh ridge from the South China Sea to Philippines, all these are the main influence factors for the low temperature, sleet and frost weather process, so that the low temperature, sleet and frost synoptic process happened in Guangxi at the beginning of 2008 when these conditions are satisfied.
2010, 36(10):21-28.
DOI: 10.7519/j.issn.1000-0526.2010.10.004
Abstract:
Predicted rainfall in the area of the Tian’anmen Square, the site for the firstround grand National Day celebration rehearsal, had prompted Chinese authorities to postpone the date for the second round from 5 September. 2009 to the next day. By utilizing the monitoring data of FY 2C, the new generation weather radar network, automatic weather stations, wind profile, and microwave radiometer etc., with the combination of the products of BJRUC model, the very shortrange forecast for the rainfall event in the area of the Tian’anmen Square was produced, and the tailored meteorological service was provided, then the good service effect had achieved. Through the forecasting service, it is proved that comprehensive monitoring data are very useful for the explanation and application to the status of atmospheric physics and making up the lack of temporal and spatial distribution of conventional data. The data are helpful for the determination of the position and variation of the synoptic system, even the extrapolation beyond 2 hours.
Predicted rainfall in the area of the Tian’anmen Square, the site for the firstround grand National Day celebration rehearsal, had prompted Chinese authorities to postpone the date for the second round from 5 September. 2009 to the next day. By utilizing the monitoring data of FY 2C, the new generation weather radar network, automatic weather stations, wind profile, and microwave radiometer etc., with the combination of the products of BJRUC model, the very shortrange forecast for the rainfall event in the area of the Tian’anmen Square was produced, and the tailored meteorological service was provided, then the good service effect had achieved. Through the forecasting service, it is proved that comprehensive monitoring data are very useful for the explanation and application to the status of atmospheric physics and making up the lack of temporal and spatial distribution of conventional data. The data are helpful for the determination of the position and variation of the synoptic system, even the extrapolation beyond 2 hours.
2010, 36(10):29-36.
DOI: 10.7519/j.issn.1000-0526.2010.10.005
Abstract:
In order to study the physical and chemical processes of Nanjing winter fog, reveal the relationship between air pollution and the chemical structure of fog water and establish fog forecasting methods， a comprehensive observation of fog during the winter of 2006 and 2007 was made in NUIST (Nanjing University of Information Science and Technology). Based on the obtained fog data and conventional meteorological observation data during 2006 to 2008 at Nanjing Meteorological Observatory, the synoptic situations and macromicrostructure characteristics of precipitation fog were analyzed. Results show that: The weather situation when precipitation fog happened can be divided into 3 kinds: frontal surface pattern, pattern under high pressure, and low pressure pattern with inverted trough; Invasion of weak cold air is an important condition for the formation of precipitation fog; Another important condition is that a strong inversion layer exists, namely the temperature is higher in upper of the boundary layer than it near the surface; Rain enhancement or increasing surface wind speed, intrusion of the durative dry cold air are likely to result in dissipation of precipitation fog, the nature of which is evaporation fog. Compared with other types of fog, the number density, water content and average diameter of precipitation fog are smaller. Fog droplet spectrum is very narrow, and its curve exponentially rapidly decreases.
In order to study the physical and chemical processes of Nanjing winter fog, reveal the relationship between air pollution and the chemical structure of fog water and establish fog forecasting methods， a comprehensive observation of fog during the winter of 2006 and 2007 was made in NUIST (Nanjing University of Information Science and Technology). Based on the obtained fog data and conventional meteorological observation data during 2006 to 2008 at Nanjing Meteorological Observatory, the synoptic situations and macromicrostructure characteristics of precipitation fog were analyzed. Results show that: The weather situation when precipitation fog happened can be divided into 3 kinds: frontal surface pattern, pattern under high pressure, and low pressure pattern with inverted trough; Invasion of weak cold air is an important condition for the formation of precipitation fog; Another important condition is that a strong inversion layer exists, namely the temperature is higher in upper of the boundary layer than it near the surface; Rain enhancement or increasing surface wind speed, intrusion of the durative dry cold air are likely to result in dissipation of precipitation fog, the nature of which is evaporation fog. Compared with other types of fog, the number density, water content and average diameter of precipitation fog are smaller. Fog droplet spectrum is very narrow, and its curve exponentially rapidly decreases.
2010, 36(10):37-45.
DOI: 10.7519/j.issn.1000-0526.2010.10.006
Abstract:
For the purpose of applying the surface cloud observation data, satellite images and Doppler radar reflectivity to the GRAPESMeso (Mesoscale of the Global and Regional Assimilation and Prediction System) model， the GRAPES cloud analysis system has been developed for the first time which is based on the LAPS (Local Analysis and Prediction System) cloud analysis program and referring to ARPS Data Analysis System (ADAS). The adjustments of the 3D cloud cover and initial field and cloud water and hydrometeors have been analyzed when the surface cloud observation data, satellite images and Doppler radar reflectivity are assimilated in the GRAPESMeso. A heavy precipitation lasting from June 28 to July 4, 2009 in Hunan is simulated, and the results show： (a) the distribution of 3D cloud cover has been retrieved from the cloud analysis system; (b) the cloud water and hydrometeors have been produced quickly based on the 3D cloud cover and the heights of cloud top and bottom, and also the initial relative humidity field has been adjusted; and (c) the duration of spinup time has been remarkably decreased, and the forecast precipitation has been significantly increased in the early hours, the performance of 24 h precipitation forecast has been also improved obviously.
For the purpose of applying the surface cloud observation data, satellite images and Doppler radar reflectivity to the GRAPESMeso (Mesoscale of the Global and Regional Assimilation and Prediction System) model， the GRAPES cloud analysis system has been developed for the first time which is based on the LAPS (Local Analysis and Prediction System) cloud analysis program and referring to ARPS Data Analysis System (ADAS). The adjustments of the 3D cloud cover and initial field and cloud water and hydrometeors have been analyzed when the surface cloud observation data, satellite images and Doppler radar reflectivity are assimilated in the GRAPESMeso. A heavy precipitation lasting from June 28 to July 4, 2009 in Hunan is simulated, and the results show： (a) the distribution of 3D cloud cover has been retrieved from the cloud analysis system; (b) the cloud water and hydrometeors have been produced quickly based on the 3D cloud cover and the heights of cloud top and bottom, and also the initial relative humidity field has been adjusted; and (c) the duration of spinup time has been remarkably decreased, and the forecast precipitation has been significantly increased in the early hours, the performance of 24 h precipitation forecast has been also improved obviously.
2010, 36(10):46-51.
DOI: 10.7519/j.issn.1000-0526.2010.10.007
Abstract:
Based on econometrics and meteorology, the meteorological factors have been introduced into the renowned economic CobbDouglas production function, yielding an integrated model using real data from 1978-2006. The concepts of elasticity and range rate are presented in this paper to evaluate the effects of weather conditions on agriculture economic output over China. The results show that, the rationality and scientificalness of the model have been verified as the inclusion of meteorological factors improves the overall fit of the traditional CD production function and the interannual variability of agriculture economic output can be simulated accurately. Compared with precipitation, temperature has greater and more significant impacts on agriculture economic output over China. The magnitudes of range rate are from 5% to 85% for 31 administrative regions and a range from 3.4% to 19.5% for eight geographical regions of China. Econometric model can quantitatively assess the socioeconomic impacts of weather and climate variability, provide a new approach for weather and climate change research and there will be a bright prospect for its application.
Based on econometrics and meteorology, the meteorological factors have been introduced into the renowned economic CobbDouglas production function, yielding an integrated model using real data from 1978-2006. The concepts of elasticity and range rate are presented in this paper to evaluate the effects of weather conditions on agriculture economic output over China. The results show that, the rationality and scientificalness of the model have been verified as the inclusion of meteorological factors improves the overall fit of the traditional CD production function and the interannual variability of agriculture economic output can be simulated accurately. Compared with precipitation, temperature has greater and more significant impacts on agriculture economic output over China. The magnitudes of range rate are from 5% to 85% for 31 administrative regions and a range from 3.4% to 19.5% for eight geographical regions of China. Econometric model can quantitatively assess the socioeconomic impacts of weather and climate variability, provide a new approach for weather and climate change research and there will be a bright prospect for its application.
2010, 36(10):52-56.
DOI: 10.7519/j.issn.1000-0526.2010.10.008
Abstract:
The annual mean wind speed data of 701 meteorological observation stations have been detected by using Penalized Maximal F Test （PMFT） and the detailed metadata archive. The results show that the homogeneity detection method works well for the annual mean wind speed data over China. The number of change points of the annual mean wind speed may be one or two. The annual mean wind speed series of 61.3 percent are homogeneous among the detected 701 stations, showing that the homogeneity of the annual mean wind speed is good in most areas of China. The changes of instrument and location are the two main causes for the nonhomogeneity, and the changes in the type of the observation instrument are the most important causes for the nonhomogeneity of the annual mean wind speed over China.
The annual mean wind speed data of 701 meteorological observation stations have been detected by using Penalized Maximal F Test （PMFT） and the detailed metadata archive. The results show that the homogeneity detection method works well for the annual mean wind speed data over China. The number of change points of the annual mean wind speed may be one or two. The annual mean wind speed series of 61.3 percent are homogeneous among the detected 701 stations, showing that the homogeneity of the annual mean wind speed is good in most areas of China. The changes of instrument and location are the two main causes for the nonhomogeneity, and the changes in the type of the observation instrument are the most important causes for the nonhomogeneity of the annual mean wind speed over China.
9 Detecting and Adjusting on Temporal Inhomogeneities
of Air Pressure Datasets in Three Gorges Areas
2010, 36(10):57-61.
DOI: 10.7519/j.issn.1000-0526.2010.10.009
Abstract:
Using an RHtestV2 software package, this paper tested the inhomogeneities of monthly air pressure series in Three Gorges areas and then the discontinuities were adjusted. The results show that for most stations, the inhomogeneities or change points can be detected and are almost consistent with the station relocation time in metadata. At the same time, the air pressure series were adjusted. This adjusted dataset is more reliable in climate change research or local climate impact analysis after Three Gorges sluice. At Zigui Station, there were 7year parallel observations and we also use the difference method to adjust the air pressure series. The results show that the two methods both gave reasonably adjusted air pressure series.
Using an RHtestV2 software package, this paper tested the inhomogeneities of monthly air pressure series in Three Gorges areas and then the discontinuities were adjusted. The results show that for most stations, the inhomogeneities or change points can be detected and are almost consistent with the station relocation time in metadata. At the same time, the air pressure series were adjusted. This adjusted dataset is more reliable in climate change research or local climate impact analysis after Three Gorges sluice. At Zigui Station, there were 7year parallel observations and we also use the difference method to adjust the air pressure series. The results show that the two methods both gave reasonably adjusted air pressure series.
2010, 36(10):62-66.
DOI: 10.7519/j.issn.1000-0526.2010.10.010
Abstract:
Based on the data of automatic observation stations, the characteristics of the air humidity, temperature and comfort index of urban microclimate zone, marine microclimate zone, mountain microclimate zone, hilly microclimate zone on typical clear days in Shenzhen were analyzed. And the results show that: the characteristics of the air humidity, temperature and comfort index of the four microclimate zones are obviously different. The minimum, maximum, average and diurnal variations of the air humidity, temperature and comfort index of the four microclimate zones are significantly different. In the daytime, the highest temperature occurs in the hilly microclimate zone, the second highest in the urban microclimate zone, and the lowest in the marine microclimate zone. In the nighttime, the lowest temperatures of the marine, urban, hilly and mountain microclimate zones rank from high to low in correct order. In the daytime, the hilly microclimate zone is the hottest, the urban microclimate zone is the second, and the marine microclimate zone is the most comfortable. While in the nighttime, the marine microclimate zone is the most uncomfortable, and the urban microclimate zone is the second, the mountain microclimate zone is the most comfortable.
Based on the data of automatic observation stations, the characteristics of the air humidity, temperature and comfort index of urban microclimate zone, marine microclimate zone, mountain microclimate zone, hilly microclimate zone on typical clear days in Shenzhen were analyzed. And the results show that: the characteristics of the air humidity, temperature and comfort index of the four microclimate zones are obviously different. The minimum, maximum, average and diurnal variations of the air humidity, temperature and comfort index of the four microclimate zones are significantly different. In the daytime, the highest temperature occurs in the hilly microclimate zone, the second highest in the urban microclimate zone, and the lowest in the marine microclimate zone. In the nighttime, the lowest temperatures of the marine, urban, hilly and mountain microclimate zones rank from high to low in correct order. In the daytime, the hilly microclimate zone is the hottest, the urban microclimate zone is the second, and the marine microclimate zone is the most comfortable. While in the nighttime, the marine microclimate zone is the most uncomfortable, and the urban microclimate zone is the second, the mountain microclimate zone is the most comfortable.
2010, 36(10):67-71.
DOI: 10.7519/j.issn.1000-0526.2010.10.011
Abstract:
Based on the surface wind speed, and the area of arable land data from 1961 to 2004 in Heilongjiang Province, the spatial distribution and seasonal variation of the characteristics of wind speed variation in Heilongjiang Province are analyzed. The results show that in the past 44 years, over most parts of Heilongjiang Province, the wind speed has been reduced significantly. In Heilongjiang Province the annual mean wind speed is reduced by 1.35 m·s-1. In different seasons, the mean wind speed is decreased differently.The largest decrease of mean wind speed is 1.74 m·s-1 in spring, followed by 1.40 m·s-1 in winter, and then 1.33 m·s-1 in autunm, finally the smallest 0.99 m·s-1 in summer. Wind speeds at national weather stations decrease more than agricultural weather stations in the Sanjiang Plain. These differences in wind speed changes may be caused by different land use patterns. On the other hand, the increasing temperature, artificial largearea surface property changes in the atmospheric environment in Heilongjiang Province are the reasons for reduced surface wind speeds.
Based on the surface wind speed, and the area of arable land data from 1961 to 2004 in Heilongjiang Province, the spatial distribution and seasonal variation of the characteristics of wind speed variation in Heilongjiang Province are analyzed. The results show that in the past 44 years, over most parts of Heilongjiang Province, the wind speed has been reduced significantly. In Heilongjiang Province the annual mean wind speed is reduced by 1.35 m·s-1. In different seasons, the mean wind speed is decreased differently.The largest decrease of mean wind speed is 1.74 m·s-1 in spring, followed by 1.40 m·s-1 in winter, and then 1.33 m·s-1 in autunm, finally the smallest 0.99 m·s-1 in summer. Wind speeds at national weather stations decrease more than agricultural weather stations in the Sanjiang Plain. These differences in wind speed changes may be caused by different land use patterns. On the other hand, the increasing temperature, artificial largearea surface property changes in the atmospheric environment in Heilongjiang Province are the reasons for reduced surface wind speeds.
2010, 36(10):72-77.
DOI: 10.7519/j.issn.1000-0526.2010.10.012
Abstract:
Based on the data of 48 stations in eastern Yunnan during 1959-2006 and year 2008, we assessed the temperature, precipitation and other disastercausing factors of the freezing disaster in Yunnan from January 14 to February 28, 2008, which caused significant economic losses and casualties. According to the number of freezing days and the supplemental data of the average minimum temperature in the process, we have constructed a frost freezing disaster estimation composite index. A comprehensive assessment is conducted on the frost freezing disaster on the basis of the fuzzy information distribution theory and the method of return period of right probability extremum. The results show that comparing with the same period in many years, the maximum temperature of eastern Yunnan in 2008 is 4.7 ℃ lower, breaking the lowest historical record; the average temperature, 2.5 ℃ lower—the second lowest historical record; the number of cloudyday, 10.3 days more—a 90% increase and breaking the maximum historical record; the days of precipitation, 8.7 days more—a 78% increase which also breaks the maximum historical record; the figure of intensity index of the frost freezing disaster breaks the maximum historical record as well. The frost freezing disaster in Yunnan from January 14 to Feburary 28 in 2008 is the extraordinarily serious frost freezing disaster compared to the same period within 100 years；the figure of intensity index of the disaster is also the maximum historical record in winter in Yunnan. The disaster is the extraordinarily serious frost freezing disaster in winter within 50 years.
Based on the data of 48 stations in eastern Yunnan during 1959-2006 and year 2008, we assessed the temperature, precipitation and other disastercausing factors of the freezing disaster in Yunnan from January 14 to February 28, 2008, which caused significant economic losses and casualties. According to the number of freezing days and the supplemental data of the average minimum temperature in the process, we have constructed a frost freezing disaster estimation composite index. A comprehensive assessment is conducted on the frost freezing disaster on the basis of the fuzzy information distribution theory and the method of return period of right probability extremum. The results show that comparing with the same period in many years, the maximum temperature of eastern Yunnan in 2008 is 4.7 ℃ lower, breaking the lowest historical record; the average temperature, 2.5 ℃ lower—the second lowest historical record; the number of cloudyday, 10.3 days more—a 90% increase and breaking the maximum historical record; the days of precipitation, 8.7 days more—a 78% increase which also breaks the maximum historical record; the figure of intensity index of the frost freezing disaster breaks the maximum historical record as well. The frost freezing disaster in Yunnan from January 14 to Feburary 28 in 2008 is the extraordinarily serious frost freezing disaster compared to the same period within 100 years；the figure of intensity index of the disaster is also the maximum historical record in winter in Yunnan. The disaster is the extraordinarily serious frost freezing disaster in winter within 50 years.
2010, 36(10):78-83.
DOI: 10.7519/j.issn.1000-0526.2010.10.013
Abstract:
In the temperaturevegetationdrought index (TVDI)， the impacts of the land surface temperature and the vegetation index on the remote drought monitoring are simultaneously taken into account, and also both merits are combined. Therefore, the effect of vegetation coverage fraction is effectively reduced and the accuracy in remote sensing of drought is obviously improved. Land surface temperature is retrieved based on the Planck radiation function，in which the surface emissivity is used to be a gray body emission. Highest and lowest land temperatures corresponding to each vegetation index are extracted to make up NDVI-Ts space. In this paper, the remote sensing data of the Earth Observing Satellite (EOS) MODIS are used to analyze and reveal the particular morphological characteristics of NDVI-Ts space over Guizhou complex mountains. Soil surface dry conditions on July 25, 2006 and August 19, 2007 are inversed and simultaneously verified with the soil moisture information from local weather stations. The results show that TVDI is significantly related to soil moisture. Because of high temporal and spectral resolution as well as moderate spatial resolution of EOS/MODIS remote sensing data, the method is suitable for the detection and early warning of soil drought in largescale and complex terrains.
In the temperaturevegetationdrought index (TVDI)， the impacts of the land surface temperature and the vegetation index on the remote drought monitoring are simultaneously taken into account, and also both merits are combined. Therefore, the effect of vegetation coverage fraction is effectively reduced and the accuracy in remote sensing of drought is obviously improved. Land surface temperature is retrieved based on the Planck radiation function，in which the surface emissivity is used to be a gray body emission. Highest and lowest land temperatures corresponding to each vegetation index are extracted to make up NDVI-Ts space. In this paper, the remote sensing data of the Earth Observing Satellite (EOS) MODIS are used to analyze and reveal the particular morphological characteristics of NDVI-Ts space over Guizhou complex mountains. Soil surface dry conditions on July 25, 2006 and August 19, 2007 are inversed and simultaneously verified with the soil moisture information from local weather stations. The results show that TVDI is significantly related to soil moisture. Because of high temporal and spectral resolution as well as moderate spatial resolution of EOS/MODIS remote sensing data, the method is suitable for the detection and early warning of soil drought in largescale and complex terrains.
2010, 36(10):84-90.
DOI: 10.7519/j.issn.1000-0526.2010.10.014
Abstract:
The Doppler radar data of 37 hail and thunderstorm cases in Dalian during 2003-2008 were calculated and processed by PUP softwares, several radar main parameters including echo intensity, echo top height, 30 dBz echo center height, top height of strong echo intensity VIL etc. and their temporal variations were obtained. Technique index models of hailcloud identification were summarized. Based on hail characteristics in Dalian, the hailclouds were divided into three types: cell, multicell and supercell, and types of hailcloud radar indexes were summarized (namely hailsuppression decision indexes). By integrating the latest hailsuppression catalytic techniques and practical experience, the Dalian artificial hailsuppression operation models (operation technique projects) were studied and designed. The research did some basic work on hailcloud identification, hailsuppression scientific decision and operation, and greatly improved the scientific level and economic benefit on Dalian artificial hailsuppression operation.
The Doppler radar data of 37 hail and thunderstorm cases in Dalian during 2003-2008 were calculated and processed by PUP softwares, several radar main parameters including echo intensity, echo top height, 30 dBz echo center height, top height of strong echo intensity VIL etc. and their temporal variations were obtained. Technique index models of hailcloud identification were summarized. Based on hail characteristics in Dalian, the hailclouds were divided into three types: cell, multicell and supercell, and types of hailcloud radar indexes were summarized (namely hailsuppression decision indexes). By integrating the latest hailsuppression catalytic techniques and practical experience, the Dalian artificial hailsuppression operation models (operation technique projects) were studied and designed. The research did some basic work on hailcloud identification, hailsuppression scientific decision and operation, and greatly improved the scientific level and economic benefit on Dalian artificial hailsuppression operation.
2010, 36(10):91-96.
DOI: 10.7519/j.issn.1000-0526.2010.10.015
Abstract:
This paper revealed spatial and temporal distribution characteristics and rules of lightning activity in Hubei Area. The results can be used in lightning protection and lightning risk assessment. The research is based on the cloudground lightning data from Mar.2006 to Feb.2009 collected by the lightning detection and location system which is composed of 13 lightning detectors. The daily and monthly lightning variation, lightning intensity, polarity and density, and the time and space distribution features of cloudground lightning in Hubei area are analyzed. The results are showed as follows: the ratio of negative lightning is 96.2%, and the ratio of positive lightning is 3.8%; Daily variation of lightning frequency shows obviously single peak and single valley, its maximum value appears at 15:00—16:00 LT(local time), the minimum value appears at 9:00—10:00 LT. The number of the lightning appearing from April to August in one year accounts to 96.7% of the annual total; the lightning appears most frequently in July and August; The intensity of positive and negative lightning is mainly concentrated in 10-50 kA. The number of the lightning whose intensity more than 30 kA accounts to 50% of the total, more than 60 kA accounts to 8.1%, more than 100 kA accounts to 1.6%. A probability equation is set up according to the lightning intensity and its corresponding cumulative frequency. Through statistical analysis, the correlation coefficient between the measured values and the calculated is as high as 0.99998. Lightning density distribution has obvious regional difference, the high density areas of lightning are cities of Jiayu，Xianning，Huangshi，Ezhou in Southeast Hubei．And the second highdensity areas are Yuanan,Dangyang nearby in western Hubei. Mountains and hills, plain transition zone, that is, the situation of the surface changed significantly zone is a lightningprone area. Thunderstorm days in mountain counties and cities in Southwest Hubei are more, but lightning density does not necessarily increase as the thunderstorm days. The reason possibly is a result of the combined effect of two factors: the mountain county soil resistivity is larger and these places belong to the local microclimate environment.
This paper revealed spatial and temporal distribution characteristics and rules of lightning activity in Hubei Area. The results can be used in lightning protection and lightning risk assessment. The research is based on the cloudground lightning data from Mar.2006 to Feb.2009 collected by the lightning detection and location system which is composed of 13 lightning detectors. The daily and monthly lightning variation, lightning intensity, polarity and density, and the time and space distribution features of cloudground lightning in Hubei area are analyzed. The results are showed as follows: the ratio of negative lightning is 96.2%, and the ratio of positive lightning is 3.8%; Daily variation of lightning frequency shows obviously single peak and single valley, its maximum value appears at 15:00—16:00 LT(local time), the minimum value appears at 9:00—10:00 LT. The number of the lightning appearing from April to August in one year accounts to 96.7% of the annual total; the lightning appears most frequently in July and August; The intensity of positive and negative lightning is mainly concentrated in 10-50 kA. The number of the lightning whose intensity more than 30 kA accounts to 50% of the total, more than 60 kA accounts to 8.1%, more than 100 kA accounts to 1.6%. A probability equation is set up according to the lightning intensity and its corresponding cumulative frequency. Through statistical analysis, the correlation coefficient between the measured values and the calculated is as high as 0.99998. Lightning density distribution has obvious regional difference, the high density areas of lightning are cities of Jiayu，Xianning，Huangshi，Ezhou in Southeast Hubei．And the second highdensity areas are Yuanan,Dangyang nearby in western Hubei. Mountains and hills, plain transition zone, that is, the situation of the surface changed significantly zone is a lightningprone area. Thunderstorm days in mountain counties and cities in Southwest Hubei are more, but lightning density does not necessarily increase as the thunderstorm days. The reason possibly is a result of the combined effect of two factors: the mountain county soil resistivity is larger and these places belong to the local microclimate environment.
2010, 36(10):97-101.
DOI: 10.7519/j.issn.1000-0526.2010.10.016
Abstract:
Because the current situation of manual observations of electric wire with ice accretion is a body of work, inefficient and low accurately, moreover the recorded data are discontinuous and realtime poorly, it is proposed that the monitoring system of the electric wire with ice accretion is built on the frame of electric wire used in the meteorological technical standards. The system not only measures in real time and displays the weight of ice accretion, but also has the ability of waterproofing, freezeproofing, easytoassemble and so on. After the performance test in Weining County of Guizhou Province, the system is able to monitor the continuous data of ice accretion weight, and achieves the expected objective. This is helpful for reducing labor intensity and increasing the observation efficiency.
Because the current situation of manual observations of electric wire with ice accretion is a body of work, inefficient and low accurately, moreover the recorded data are discontinuous and realtime poorly, it is proposed that the monitoring system of the electric wire with ice accretion is built on the frame of electric wire used in the meteorological technical standards. The system not only measures in real time and displays the weight of ice accretion, but also has the ability of waterproofing, freezeproofing, easytoassemble and so on. After the performance test in Weining County of Guizhou Province, the system is able to monitor the continuous data of ice accretion weight, and achieves the expected objective. This is helpful for reducing labor intensity and increasing the observation efficiency.
2010, 36(10):102-105.
DOI: 10.7519/j.issn.1000-0526.2010.10.017
Abstract:
By using the meteorological monitoring data, the meteorological causes for the massive mudslide in Zhouqu which occurred on 8 August 2010 are analyzed. Results demonstrate that the severe convective weather process with heavy precipitation is the main cause for this massive mudslide. The characteristics of this heavy precipitation are local, large intensity in short time and paroxysmal. The data of radar and satellites suggest that the weather system has obviously mesoscale characteristics. This kind of mesoscale weather system is produced by the forcing of the shear line in the low level, when the cold air in the high level is moving eastward and southward.
By using the meteorological monitoring data, the meteorological causes for the massive mudslide in Zhouqu which occurred on 8 August 2010 are analyzed. Results demonstrate that the severe convective weather process with heavy precipitation is the main cause for this massive mudslide. The characteristics of this heavy precipitation are local, large intensity in short time and paroxysmal. The data of radar and satellites suggest that the weather system has obviously mesoscale characteristics. This kind of mesoscale weather system is produced by the forcing of the shear line in the low level, when the cold air in the high level is moving eastward and southward.
2010, 36(10):106-109.
DOI: 10.7519/j.issn.1000-0526.2010.10.018
Abstract:
Based on the pentadbypentad data of systematic investigation of riceplanthopper population per 100 crowds from 2005 to 2007 at Tongcheng, the main meteorological factors affecting the occurrence grade of riceplanthopper have been analyzed. The results show that: there are significant negative correlations between dekad average temperature, pentad average temperature and the data of riceplanthopper population per 100 crowds, high temperatures have inhibition effects on riceplanthopper population, and the optimum pentad average temperatures for occurrence of riceplanthoppers are 20.5 ℃. The model of forecasting riceplanthopper occurrence by use of Kalman filter has been established, which can forecast the meteorological conditions of riceplanthopper occurrence and provide a basis for pest control. The historical data fitting and test application in 2008 show that the accuracy, reliability and stability of the model are good, therefore it can be applied to agrometeorological operations.
Based on the pentadbypentad data of systematic investigation of riceplanthopper population per 100 crowds from 2005 to 2007 at Tongcheng, the main meteorological factors affecting the occurrence grade of riceplanthopper have been analyzed. The results show that: there are significant negative correlations between dekad average temperature, pentad average temperature and the data of riceplanthopper population per 100 crowds, high temperatures have inhibition effects on riceplanthopper population, and the optimum pentad average temperatures for occurrence of riceplanthoppers are 20.5 ℃. The model of forecasting riceplanthopper occurrence by use of Kalman filter has been established, which can forecast the meteorological conditions of riceplanthopper occurrence and provide a basis for pest control. The historical data fitting and test application in 2008 show that the accuracy, reliability and stability of the model are good, therefore it can be applied to agrometeorological operations.
2010, 36(10):110-113.
DOI: 10.7519/j.issn.1000-0526.2010.10.019
Abstract:
With the floodseason precipitation data at 3 sampling meteorological stations in Jianghuai Watershed area of Anhui Province from 1957 to 2008, the Z-index method was applied to judge the flood/drought grades in Jianghuai Watershed area, and it is found that the theoretical Z-index is not suited to Jianghuai Watershed area. In this case the theoretical boundary of Z-index should be adjusted, and there are two principles of adjustment: the first is slightly adjustment, and the second is that years of drought and flood are nearly equal. The new boundaries of Z-index for the grades of flood/drought are more suitable for the Jianghuai Watershed area. Therefore the modified Z-index can be well applied to Jianghuai Watershed area.
With the floodseason precipitation data at 3 sampling meteorological stations in Jianghuai Watershed area of Anhui Province from 1957 to 2008, the Z-index method was applied to judge the flood/drought grades in Jianghuai Watershed area, and it is found that the theoretical Z-index is not suited to Jianghuai Watershed area. In this case the theoretical boundary of Z-index should be adjusted, and there are two principles of adjustment: the first is slightly adjustment, and the second is that years of drought and flood are nearly equal. The new boundaries of Z-index for the grades of flood/drought are more suitable for the Jianghuai Watershed area. Therefore the modified Z-index can be well applied to Jianghuai Watershed area.
20 Precision of the Tropical Cyclone Positioning and
Forecasts over the Western North Pacific in 2009
2010, 36(10):114-121.
DOI: 10.7519/j.issn.1000-0526.2010.10.020
Abstract:
Operational positioning and forecast errors of tropical cyclones (TC) over the western North Pacific in 2009 are evaluated according to “Regulations on Typhoon Operation and Service”. The evaluations are performed on the positioning of six methods, the track forecasts from twelve integrated, three objective and six numerical weather prediction (NWP) methods, and the intensity forecasts from four methods. The results show that the TC positioning is better than that in 2008, with an average error in all methods 17.1 km and each less than 21 km. The average errors of domestic integrated track forecast in 24 h, 48 h, and 72 h are 115.8 km, 217.5 km and 357.1 km, respectively, which are worse than those in 2008. The objective forecasts are better than the integrated forecasts with the average errors 113.0 km in 24 h and 211.4 km in 48 h. The comparison of the track forecast errors from four official integrated methods shows that National Meteorological Center (NMC) has good performance in TC track forecast in China Seas. The intensity forecasts still rely mainly on statistical methods with the average errors of 4.90 m·s-1 in 24 h and 7.43 m·s-1 in 48 h. Comparing to the average performance in recent 10 years, the intensity forecast has not made obvious improvement.
Operational positioning and forecast errors of tropical cyclones (TC) over the western North Pacific in 2009 are evaluated according to “Regulations on Typhoon Operation and Service”. The evaluations are performed on the positioning of six methods, the track forecasts from twelve integrated, three objective and six numerical weather prediction (NWP) methods, and the intensity forecasts from four methods. The results show that the TC positioning is better than that in 2008, with an average error in all methods 17.1 km and each less than 21 km. The average errors of domestic integrated track forecast in 24 h, 48 h, and 72 h are 115.8 km, 217.5 km and 357.1 km, respectively, which are worse than those in 2008. The objective forecasts are better than the integrated forecasts with the average errors 113.0 km in 24 h and 211.4 km in 48 h. The comparison of the track forecast errors from four official integrated methods shows that National Meteorological Center (NMC) has good performance in TC track forecast in China Seas. The intensity forecasts still rely mainly on statistical methods with the average errors of 4.90 m·s-1 in 24 h and 7.43 m·s-1 in 48 h. Comparing to the average performance in recent 10 years, the intensity forecast has not made obvious improvement.
2010, 36(10):122-127.
DOI: 10.7519/j.issn.1000-0526.2010.10.021
Abstract:
The following are the main characteristics of the general circulation of atmosphere in July 2010.There is one polar vortex center in the Northern Hemisphere. The circulation presents a fivewave pattern in middlehigh latitudes. The intensity of five main deep troughs are stronger than or equivalent to that of trough in average conditions. The subtropical high shows an eastwest belt figure and it is stronger than the corresponding time of normal years. Mean precipitation in China is 121.2 mm in July 2010, and 5.3 mm higher than the averaged over many years. Meanwhile, the mean temperature in China is 22.8 ℃, and 1.4 ℃ higher than the averaged over many years (21.4 ℃). The main weather events in July were rainstorm and flooding occurring at the middle and lower reaches of the Changjiang River, Sichuan Basin, southeast of Northwest China, parts of HuangheHuaihe Plain and parts of Northeast China. Typhoons “Conson” and “Chanthu” made landfall in China. The hailstorm disasters happened in Jilin Province, Jiangxi Province, Inner Mongolia Autonomous Region and other parts of China, etc. Sustained high temperature weather occurred in South China, south of the lower reaches of the Changjiang River, ChangjiangHanjiang Plain, HuangheHuaihe Plain， North China, Northwest China and other parts of China, etc.
The following are the main characteristics of the general circulation of atmosphere in July 2010.There is one polar vortex center in the Northern Hemisphere. The circulation presents a fivewave pattern in middlehigh latitudes. The intensity of five main deep troughs are stronger than or equivalent to that of trough in average conditions. The subtropical high shows an eastwest belt figure and it is stronger than the corresponding time of normal years. Mean precipitation in China is 121.2 mm in July 2010, and 5.3 mm higher than the averaged over many years. Meanwhile, the mean temperature in China is 22.8 ℃, and 1.4 ℃ higher than the averaged over many years (21.4 ℃). The main weather events in July were rainstorm and flooding occurring at the middle and lower reaches of the Changjiang River, Sichuan Basin, southeast of Northwest China, parts of HuangheHuaihe Plain and parts of Northeast China. Typhoons “Conson” and “Chanthu” made landfall in China. The hailstorm disasters happened in Jilin Province, Jiangxi Province, Inner Mongolia Autonomous Region and other parts of China, etc. Sustained high temperature weather occurred in South China, south of the lower reaches of the Changjiang River, ChangjiangHanjiang Plain, HuangheHuaihe Plain， North China, Northwest China and other parts of China, etc.
2010, 36(10):128-133.
DOI: 10.7519/j.issn.1000-0526.2010.10.022
Abstract:
The differences of circuit design between CINRAD/SB alternating frequencyconversion numerical servo system and those of CINRAD/SA are summarized herein. Based on the signal procedure of servo system and principle of power protection, the fault diagnosis methods of numerical servo system are detailedly described through analyzing the condition monitoring information, file FC information, alarm, key point parameter measurements and key signal transmission paths. Meanwhile, two different typical fault examples are analyzed theoretically. And then some suggestions are given on maintaining the servo system, which are providing useful references to CINRAD techniques.
The differences of circuit design between CINRAD/SB alternating frequencyconversion numerical servo system and those of CINRAD/SA are summarized herein. Based on the signal procedure of servo system and principle of power protection, the fault diagnosis methods of numerical servo system are detailedly described through analyzing the condition monitoring information, file FC information, alarm, key point parameter measurements and key signal transmission paths. Meanwhile, two different typical fault examples are analyzed theoretically. And then some suggestions are given on maintaining the servo system, which are providing useful references to CINRAD techniques.
Mobile website
® 2024 All Rights Reserved
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
ISSN:1000-0526 CN:11-2282/P