[Objective] The research aimed to understand role of the forecast data about physical quantity field in precipitation forecast.[Method] By contrasting forecast and actual situation of the precipitation in Yantai durin...[Objective] The research aimed to understand role of the forecast data about physical quantity field in precipitation forecast.[Method] By contrasting forecast and actual situation of the precipitation in Yantai during 2-3 July and 12-15 September,2011,advantages and disadvantages of the different numerical forecast models (Japan fax chart,European center,MM5,Grapes and T639) were analyzed.[Result] MICAPS system could provide live situation of the physical quantity field,but couldn't provide the future evolution situation.Japan fax chart,European center,MM5,Grapes and T639 could provide future evolution situation of the physical quantity field.[Conclusion] The contrasts and analyses on forecast situations of the physical quantity fields in many precipitation processes showed that evolutions of the vertical velocity,temperature dew point difference,relative humidity and wind field at the different heights could improve forecast accuracy of the precipitation in Yantai.展开更多
[ Objective] The research aimed to contrast physical quantity diagnosis and wind profile radar data of two heavy rainfalls. [ Method ] From circulation background, physical quantity field and wind profile radar data, ...[ Objective] The research aimed to contrast physical quantity diagnosis and wind profile radar data of two heavy rainfalls. [ Method ] From circulation background, physical quantity field and wind profile radar data, we analyzed two big rainstorm weather processes （8 -9 July and August 10） in Lianyungang City in 2012. [ Result] Rainstorm generation was related to favorable large-scale circulation situation. The first-stage precipitation during 8 -9 July was warm-zone precipitation, and the precipitation at the second stage was triggered by shear line. Precipitation on August 10 was generated by typhoon low-pressure inverted trough and cold air. Sufficient water vapor content and strong water vapor transportation were favorable for generation of the heavy precipitation. Suction effect by divergence at high layer and convergence at middle and low layers was favorable for maintenance of the strong ascending motion. Occurrence of the heavy precipitation must have ascending motion condition. But it was not that the stronger the ascending motion, the stronger the rainfall intensity. Kindex and θse500 -θse 850 were closely related to rainstorm occurrence. Horizontal wind data of the wind profile radar provided fine structure of the atmospheric horizontal motion at vertical direction, could clearly display vertical structure of the wind field in rainstorm process, and directly reflected change characteristics of the wind field in precipitation process. [ Conclusion] The research could provide reference for future forecast work.展开更多
This paper presents an analogical study between electromagnetic and elastic wave fields,with a one-to-one correspondence principle established regarding the basic wave equations,the physical quantities and the differe...This paper presents an analogical study between electromagnetic and elastic wave fields,with a one-to-one correspondence principle established regarding the basic wave equations,the physical quantities and the differential operations.Using the electromagnetic-to-elastic substitution,the analogous relations of the conservation laws of energy and momentum are investigated between these two physical fields.Moreover,the energy-based and momentum-based reciprocity theorems for an elastic wave are also derived in the time-harmonic state,which describe the interaction between two elastic wave systems from the perspectives of energy and momentum,respectively.The theoretical results obtained in this analysis can not only improve our understanding of the similarities of these two linear systems,but also find potential applications in relevant fields such as medical imaging,non-destructive evaluation,acoustic microscopy,seismology and exploratory geophysics.展开更多
Based on the high-altitude and ground observation data,as well as physical quantity field data,a cold wave weather process in Northeast China,North China and Inner Mongolia during January 1-6,2010 was comprehensively ...Based on the high-altitude and ground observation data,as well as physical quantity field data,a cold wave weather process in Northeast China,North China and Inner Mongolia during January 1-6,2010 was comprehensively analyzed from the aspects of circulation background,circulation situation,influence system,dynamic conditions,water vapor conditions,etc.The results show that the cold wave weather process appeared during the transition of circulation pattern from zonal to meridional type in middle and high latitudes in the northern Hemisphere.Due to the development of the European trough,the strong warm advection was transported to the Ural Ridge,making it strongly developed.The strong northerly wind belt in front of the ridge moved southwards.The warm advection at the rear of the transverse trough and the cold advection in the southeast in front of the transverse trough on the northwest side of Lake Baikal caused the transverse trough to turn upright and moved southwards,and the longitude of the circulation increased continuously to guide cold air to move southwards,resulting in this strong cold air process.The large ground pressure gradient caused by strong cold air and the frontogenesis of strong surface cyclone led to the gale in North China.展开更多
Based on conventional observation data,NCEP reanalysis data and observation data of automatic stations,a rainstorm weather process occurring in Shaoguan City during December 14-17,2013 was analyzed.The results show th...Based on conventional observation data,NCEP reanalysis data and observation data of automatic stations,a rainstorm weather process occurring in Shaoguan City during December 14-17,2013 was analyzed.The results show that the main causes of the winter rainstorm in Shaoguan City were the strong southwest airflow at 500 and 700 hPa,high humidity,the influence of a low-pressure trough at 850 hPa,and the southward movement of cold air on the ground.展开更多
Optically detected magnetic resonance(ODMR)has emerged as a powerful technique for quantum sensing,enabling high-sensitivity detection of physical quantities even at room temperature.Solid-state defects,such as nitrog...Optically detected magnetic resonance(ODMR)has emerged as a powerful technique for quantum sensing,enabling high-sensitivity detection of physical quantities even at room temperature.Solid-state defects,such as nitrogen-vacancy(NV)centers in diamond,have demonstrated remarkable capabilities in this domain[1–4].However,these systems are limited by their rigid lattice structures and lack tunability.展开更多
Using physical quantities calculated by 16 radiosonde stations of Southwest China during 2010-2015,nine kinds of physical quantities with certain representational significance in water vapor,thermal and dynamic condit...Using physical quantities calculated by 16 radiosonde stations of Southwest China during 2010-2015,nine kinds of physical quantities with certain representational significance in water vapor,thermal and dynamic conditions were selected.Via box-plot,statistical analysis was conducted,and thresholds of sounding physical quantities of rainstorm in Southwest China were obtained,which could provide certain reference for further improving the rainstorm forecast in Southwest China.展开更多
In the present paper, using the method of separating coupled physic quantity bypotential operator, we derive two special minmum principles in coupled thermoelastodynamics.
As an early philosopher who paid attention to the aesthetic value of natural scenery,Kant’s aesthetic thought of natural scenery mainly focused on the analysis of the sense of sublimity.Through the comparative interp...As an early philosopher who paid attention to the aesthetic value of natural scenery,Kant’s aesthetic thought of natural scenery mainly focused on the analysis of the sense of sublimity.Through the comparative interpretation of the two concepts of“sublime beauty”and“natural beauty”,the author expounded that the aesthetic object of natural beauty was mainly the individual form of“organic matters”,and the aesthetic object of sublime beauty was the natural environment composed of organic matters and inorganic matters.Through the analysis of different forms and categories of sense of sublimity,this paper summarized the characteristics of Kant’s natural landscape aesthetics:paying attention to the quantitative characteristics of space and time,preferring the original nature and wild nature and the original energy contained therein,and then revealed that the essence of Kant’s natural landscape aesthetics was the recognition of human moral emotion and their own value in the natural landscape.展开更多
By using the synoptic chart,the physical quantity field,the satellite cloud image and the meteorological elements in the single station,a typical heavy rain to rainstorm weather process which occurred in Liaoning duri...By using the synoptic chart,the physical quantity field,the satellite cloud image and the meteorological elements in the single station,a typical heavy rain to rainstorm weather process which occurred in Liaoning during August 18-20 in 2009 was comprehensively analyzed.The results showed that this process was a weather process which was affected by the upper trough and the subtropical high.Baikal Lake split cold air and Hetao cold air shifted eastward and formed the vortex.The subtropical high extended westward,lifted northward,and the warm wet airflow in the edge cut in.The low-altitude jet stream accelerated the transportation of water vapor,and several active meso-scale convective cloud clusters which appeared in 588 line periphery in the right side of high-altitude jet stream outlet gradually merged with the westerlies system.It caused that the strong mixed precipitation process occurred.展开更多
Conventional observation data,precipitation data from regional automatic stations,1°×1° NCEP reanalysis data and TBB pictures of FY-2C geostationary meteorological satellite as well as Doppler radar,etc...Conventional observation data,precipitation data from regional automatic stations,1°×1° NCEP reanalysis data and TBB pictures of FY-2C geostationary meteorological satellite as well as Doppler radar,etc.were utilized to analyzing the heavy precipitation process in Hunan Province from June 8 to 10.The results indicated that this heavy precipitation process was caused under the condition of western Pacific subtropical high jumped northward and fell southward rapidly,maintained and swung the shear line of low and middle-level atmosphere over long periods,and configurated temperature-moisture energy.Through analysis we found that precipitation period and precipitation area had a good corresponding to radar product and satellite TBB image,the high potential pseudo-equivalent temperature(θse) of low level and high convergence available potential energy(CAPE) area as well as ascending area of strong convergence.With the extension of effective forecasted period,the forecast location of T639 and EC on the western ridge points of western Pacific subtropical high became more and more easterly and the intensity became weaker and weaker,which had some deviations for forecasting heavy precipitation area.展开更多
[ Objective] The study aimed to discuss the temporal-spatial distribution and short-range prediction indicators of hail weather in east central Haixi Prefecture of Qinghai Province. [Method] Using hail data of six sta...[ Objective] The study aimed to discuss the temporal-spatial distribution and short-range prediction indicators of hail weather in east central Haixi Prefecture of Qinghai Province. [Method] Using hail data of six stations in east central Haixi Prefecture from 1960 to 2010, the temporal and spatial distribution of hail weather was analyzed firstly. Afterwards, based on the high-altitude factual data of 30 case studies of hail during 2006 -2010, its high-altitude and ground weather situation and physical quantity field were studied to summarize short-term circulation pattern and shod- range prediction characteristics of hail weather. [ Result] In east central Haixi, hail appeared from April to September, and it was most frequently from May to August. Meanwhile, hail was frequent from 14：00 to 20：00. Among the six stations, hail was most frequent in Tianjun but least frequent in Wulan. Moreover, hail disaster mainly occurred in Wulan and Tianjun. In addition, there were three typos of circulation pattern of hail weather at 500 hPa. Hail mainly occurred under the effect of northwest airflow, and it had shortwave trough, cold center or trough, jet stream core or one of the three. Hail appeared frequently under the situation of upper-level divergence and low-level convergence, and abundant water vapor and water vapor flux convergence at low levels were important conditions for hailing. [ Conclusion] The research could provide scientific references for improving the accuracy of hail forecast.展开更多
[Objective] The aim was to study the formation and development of a heavy snow in Benxi area. [Method] Based on conventional meteorological data, the formation and development of a heavy snow in Benxi area from Decemb...[Objective] The aim was to study the formation and development of a heavy snow in Benxi area. [Method] Based on conventional meteorological data, the formation and development of a heavy snow in Benxi area from December 4th to 5th in 2009 were analyzed from the aspects of weather situation evolution and physical quantity field feature. [Result] The heavy snow was caused by upper trough and North China cyclone. In this process, there was upper level divergence and lower level convergence over Benxi area, and it was warm at low attitude and cold at high attitude; southwest jet at low attitude transported water vapor from Bohai Sea to eastern Liaoning, which provided good water vapor condition for snow, but it didn’t reach heavy snow due to inadequate ascending force. The development of Ural Mountains high ridge played an important role in the snow process and the strengthened high ridge moving northward was beneficial to the southward movement of cold air and deepening of upper trough. Analysis on physical quantity field could provide reference for predicting beginning and ending time and strength of heavy snow. [Conclusion] The study could provide basis for the forecast of heavy snow.展开更多
[Objective] The research aimed to analyze a rare low temperature and rainy weather process which happened in Anhui Province from July 22 to August 14,2009.[Method] Based on the data of conventional observation,NCEP an...[Objective] The research aimed to analyze a rare low temperature and rainy weather process which happened in Anhui Province from July 22 to August 14,2009.[Method] Based on the data of conventional observation,NCEP analysis field and automatic station,a rare low temperature and rainy weather process which occurred in Anhui Province from July 22 to August 14,2009 was analyzed.The formation reason of continuous rainy process in midsummer was discussed.The circulation characteristics and influence systems of continuous rainy process were revealed.On the base,the influences of configuration of circulation fields and difference of physical quantity fields at high and low layers on range and intensity of precipitation were analyzed.[Result] According to the circulation situation and influence system,the continuous rainy process could be divided into four stages:July 22-24,from July 27 to August 1,August 4-8 and August 9-14.Moreover,it was respectively affected by northeast low vortex,cold and warm air,high-level low trough,typhoon and periphery of subtropical high at four stages.The maintenance of big specific humidity zone provided sufficient water vapor condition for the continuous rainy weather.The rainstorm appeared in dense zone of specific humidity line,where the specific humidity >13 g/kg in the humidity front zone.A temperature trough maintained at 850 hPa.The cold air which continued to diffuse and go south was main reason of the abnormally low temperature during the continuous rainy period.Moreover,it provided ascending motion condition for precipitation maintenance.[Conclusion] The research provided references for actual forecast of continuous rainy weather.展开更多
The large-range heavy precipitation occurred in the central-southern coast of Fujian on October 6,2008.By using the conventional meteorological data and NCEP 1°×1° 6 h one time analysis data,we analyzed...The large-range heavy precipitation occurred in the central-southern coast of Fujian on October 6,2008.By using the conventional meteorological data and NCEP 1°×1° 6 h one time analysis data,we analyzed,diagnosed and discussed the reasons of this heavy rainstorm occurrence and maintenance.The results showed that this heavy rainstorm weather process was mainly formed by the low-pressure system which was remained after ' Higos' weakened.The low-pressure system was excited by the weak cold air in the low layer which was brought by 500 hPa westerly trough.The common effect of southwest jet stream in the low altitude in the southeast of low pressure and the northerly airflow in the northwest made that the low-pressure circulation strengthened and maintained.The calculation gained the physical quantity field configuration which was favorable for the appearance of heavy precipitation.The analysis on the relative helicity of windstorm showed that the distribution and the time evolution of helicity had the good corresponding relationship with the distribution and the time evolution of heavy precipitation.The intensity variation of helicity had the certain instruction significance on the rainstorm evolution.展开更多
By using the observation data,routine data and NCEP reanalysis data in the automatic station,5 times heavy fog weather processes in Zhangjiajie City in December,2009 were contrasted and analyzed.The results showed tha...By using the observation data,routine data and NCEP reanalysis data in the automatic station,5 times heavy fog weather processes in Zhangjiajie City in December,2009 were contrasted and analyzed.The results showed that 3 conditions were the essential conditions of heavy fog occurrence in Zhangjiajie area.3 conditions were that the wind speed was during 0.1-3.0 m/s,the relative humidity ≥90% and the depression of dew point ΔT ≤1.5 ℃.The fog concentration had no positive correlation relationship with the above conditions.The accumulation of humidity condition in the previous period was also the main reason which affected the generation of heavy fog.The physical quantity field which related to the stability and the relative humidity field which related to the water vapor condition had the certain directive significance for forecasting the heavy fog weather.The fog concentration presented the positive correlation relationship with the inversion intensity.展开更多
[ Objective] The research aimed to analyze a local snowstorm weather process which happened in Beijing, Tianjin and Hebei during I - 4 January, 2010. [ Method] Based on routine meteorological observation data and NCEP...[ Objective] The research aimed to analyze a local snowstorm weather process which happened in Beijing, Tianjin and Hebei during I - 4 January, 2010. [ Method] Based on routine meteorological observation data and NCEP/NCAR 2.5° ×2.5° grid data （four times every day）, a lo- cal snowstorm weather process which happened in Beijing, Tianjin and Hebei during 1 -4 January, 2010 was carried out diagnostic analysis by using composite analysis method. [Result] Circumfluence on the ground and strong cold advection in the rear of upper trough were the main weath- er system of the snowfall. The deep thick wet layer and strong water vapor convergence provided sufficient water vapor for snowfall. The divergence field of low-level convergence and high^level divergence, dynamic coupling effect of vorticity provided favorable dynamic condition upwardly for the occurrence of strong snowfall. The steep dense area of Oso, low temperature at the ground layer and inversion temperature at the high layer provided certain energy condition for the development of snowfall weather. [ Conclusion] The research provided theoretical basis for snowfall forecast in future.展开更多
This paper suggests a principle to find a unitary operator U which transforms non-physical quantity, zero-potential Hamiltonian H<SUB>0</SUB>, into true physical quantity UH<SUB>0</SUB>U<SUP...This paper suggests a principle to find a unitary operator U which transforms non-physical quantity, zero-potential Hamiltonian H<SUB>0</SUB>, into true physical quantity UH<SUB>0</SUB>U<SUP>?</SUP> for a charged particle in classical electromagnetic field, and puts forward a unified form of constructing gauge-independent transition probabilities in this case. Different methods correspond to different unitary operators which satisfy the above-mentioned principle.展开更多
[Objective] The research aimed to study the influence of typhoon Usagi on Shaoyang in 2013. [Method] By using synoptic analysis, physical quantity diagnosis and Doppler radar, a rainstorm process caused by typhoon Usa...[Objective] The research aimed to study the influence of typhoon Usagi on Shaoyang in 2013. [Method] By using synoptic analysis, physical quantity diagnosis and Doppler radar, a rainstorm process caused by typhoon Usagi was analyzed. [ Result] Sufficient water vaper and strong ascending motion caused by high-altitude divergence were favorable conditions for rainstorm generation in Shaoyang. Uplifting effect of the terrain in Shaoyang was also one of favorable conditions for rainstorm generation in Shaoyang. [Conclusion] The research could provide reference for flood prevention and disaster reduction in Shaoyang area.展开更多
文摘[Objective] The research aimed to understand role of the forecast data about physical quantity field in precipitation forecast.[Method] By contrasting forecast and actual situation of the precipitation in Yantai during 2-3 July and 12-15 September,2011,advantages and disadvantages of the different numerical forecast models (Japan fax chart,European center,MM5,Grapes and T639) were analyzed.[Result] MICAPS system could provide live situation of the physical quantity field,but couldn't provide the future evolution situation.Japan fax chart,European center,MM5,Grapes and T639 could provide future evolution situation of the physical quantity field.[Conclusion] The contrasts and analyses on forecast situations of the physical quantity fields in many precipitation processes showed that evolutions of the vertical velocity,temperature dew point difference,relative humidity and wind field at the different heights could improve forecast accuracy of the precipitation in Yantai.
基金Supported by Social Development Fund Project of the Science and Technology Bureau in Lianyungang City,China ( SH1207)
文摘[ Objective] The research aimed to contrast physical quantity diagnosis and wind profile radar data of two heavy rainfalls. [ Method ] From circulation background, physical quantity field and wind profile radar data, we analyzed two big rainstorm weather processes （8 -9 July and August 10） in Lianyungang City in 2012. [ Result] Rainstorm generation was related to favorable large-scale circulation situation. The first-stage precipitation during 8 -9 July was warm-zone precipitation, and the precipitation at the second stage was triggered by shear line. Precipitation on August 10 was generated by typhoon low-pressure inverted trough and cold air. Sufficient water vapor content and strong water vapor transportation were favorable for generation of the heavy precipitation. Suction effect by divergence at high layer and convergence at middle and low layers was favorable for maintenance of the strong ascending motion. Occurrence of the heavy precipitation must have ascending motion condition. But it was not that the stronger the ascending motion, the stronger the rainfall intensity. Kindex and θse500 -θse 850 were closely related to rainstorm occurrence. Horizontal wind data of the wind profile radar provided fine structure of the atmospheric horizontal motion at vertical direction, could clearly display vertical structure of the wind field in rainstorm process, and directly reflected change characteristics of the wind field in precipitation process. [ Conclusion] The research could provide reference for future forecast work.
基金funded by the National Natural Science Foundation of China(Grant No.12404507)the Natural Science Research of Jiangsu Higher Education Institutions of China(Grant No.24KJB140013)the Scientific Startup Foundation of Nanjing Normal University(Grant No.184080H201B49).
文摘This paper presents an analogical study between electromagnetic and elastic wave fields,with a one-to-one correspondence principle established regarding the basic wave equations,the physical quantities and the differential operations.Using the electromagnetic-to-elastic substitution,the analogous relations of the conservation laws of energy and momentum are investigated between these two physical fields.Moreover,the energy-based and momentum-based reciprocity theorems for an elastic wave are also derived in the time-harmonic state,which describe the interaction between two elastic wave systems from the perspectives of energy and momentum,respectively.The theoretical results obtained in this analysis can not only improve our understanding of the similarities of these two linear systems,but also find potential applications in relevant fields such as medical imaging,non-destructive evaluation,acoustic microscopy,seismology and exploratory geophysics.
文摘Based on the high-altitude and ground observation data,as well as physical quantity field data,a cold wave weather process in Northeast China,North China and Inner Mongolia during January 1-6,2010 was comprehensively analyzed from the aspects of circulation background,circulation situation,influence system,dynamic conditions,water vapor conditions,etc.The results show that the cold wave weather process appeared during the transition of circulation pattern from zonal to meridional type in middle and high latitudes in the northern Hemisphere.Due to the development of the European trough,the strong warm advection was transported to the Ural Ridge,making it strongly developed.The strong northerly wind belt in front of the ridge moved southwards.The warm advection at the rear of the transverse trough and the cold advection in the southeast in front of the transverse trough on the northwest side of Lake Baikal caused the transverse trough to turn upright and moved southwards,and the longitude of the circulation increased continuously to guide cold air to move southwards,resulting in this strong cold air process.The large ground pressure gradient caused by strong cold air and the frontogenesis of strong surface cyclone led to the gale in North China.
文摘Based on conventional observation data,NCEP reanalysis data and observation data of automatic stations,a rainstorm weather process occurring in Shaoguan City during December 14-17,2013 was analyzed.The results show that the main causes of the winter rainstorm in Shaoguan City were the strong southwest airflow at 500 and 700 hPa,high humidity,the influence of a low-pressure trough at 850 hPa,and the southward movement of cold air on the ground.
文摘Optically detected magnetic resonance(ODMR)has emerged as a powerful technique for quantum sensing,enabling high-sensitivity detection of physical quantities even at room temperature.Solid-state defects,such as nitrogen-vacancy(NV)centers in diamond,have demonstrated remarkable capabilities in this domain[1–4].However,these systems are limited by their rigid lattice structures and lack tunability.
文摘Using physical quantities calculated by 16 radiosonde stations of Southwest China during 2010-2015,nine kinds of physical quantities with certain representational significance in water vapor,thermal and dynamic conditions were selected.Via box-plot,statistical analysis was conducted,and thresholds of sounding physical quantities of rainstorm in Southwest China were obtained,which could provide certain reference for further improving the rainstorm forecast in Southwest China.
文摘In the present paper, using the method of separating coupled physic quantity bypotential operator, we derive two special minmum principles in coupled thermoelastodynamics.
基金Sponsored by 2025 Humanities and Social Sciences Project of Henan Universities(2025ZZJH379).
文摘As an early philosopher who paid attention to the aesthetic value of natural scenery,Kant’s aesthetic thought of natural scenery mainly focused on the analysis of the sense of sublimity.Through the comparative interpretation of the two concepts of“sublime beauty”and“natural beauty”,the author expounded that the aesthetic object of natural beauty was mainly the individual form of“organic matters”,and the aesthetic object of sublime beauty was the natural environment composed of organic matters and inorganic matters.Through the analysis of different forms and categories of sense of sublimity,this paper summarized the characteristics of Kant’s natural landscape aesthetics:paying attention to the quantitative characteristics of space and time,preferring the original nature and wild nature and the original energy contained therein,and then revealed that the essence of Kant’s natural landscape aesthetics was the recognition of human moral emotion and their own value in the natural landscape.
文摘By using the synoptic chart,the physical quantity field,the satellite cloud image and the meteorological elements in the single station,a typical heavy rain to rainstorm weather process which occurred in Liaoning during August 18-20 in 2009 was comprehensively analyzed.The results showed that this process was a weather process which was affected by the upper trough and the subtropical high.Baikal Lake split cold air and Hetao cold air shifted eastward and formed the vortex.The subtropical high extended westward,lifted northward,and the warm wet airflow in the edge cut in.The low-altitude jet stream accelerated the transportation of water vapor,and several active meso-scale convective cloud clusters which appeared in 588 line periphery in the right side of high-altitude jet stream outlet gradually merged with the westerlies system.It caused that the strong mixed precipitation process occurred.
文摘Conventional observation data,precipitation data from regional automatic stations,1°×1° NCEP reanalysis data and TBB pictures of FY-2C geostationary meteorological satellite as well as Doppler radar,etc.were utilized to analyzing the heavy precipitation process in Hunan Province from June 8 to 10.The results indicated that this heavy precipitation process was caused under the condition of western Pacific subtropical high jumped northward and fell southward rapidly,maintained and swung the shear line of low and middle-level atmosphere over long periods,and configurated temperature-moisture energy.Through analysis we found that precipitation period and precipitation area had a good corresponding to radar product and satellite TBB image,the high potential pseudo-equivalent temperature(θse) of low level and high convergence available potential energy(CAPE) area as well as ascending area of strong convergence.With the extension of effective forecasted period,the forecast location of T639 and EC on the western ridge points of western Pacific subtropical high became more and more easterly and the intensity became weaker and weaker,which had some deviations for forecasting heavy precipitation area.
文摘[ Objective] The study aimed to discuss the temporal-spatial distribution and short-range prediction indicators of hail weather in east central Haixi Prefecture of Qinghai Province. [Method] Using hail data of six stations in east central Haixi Prefecture from 1960 to 2010, the temporal and spatial distribution of hail weather was analyzed firstly. Afterwards, based on the high-altitude factual data of 30 case studies of hail during 2006 -2010, its high-altitude and ground weather situation and physical quantity field were studied to summarize short-term circulation pattern and shod- range prediction characteristics of hail weather. [ Result] In east central Haixi, hail appeared from April to September, and it was most frequently from May to August. Meanwhile, hail was frequent from 14：00 to 20：00. Among the six stations, hail was most frequent in Tianjun but least frequent in Wulan. Moreover, hail disaster mainly occurred in Wulan and Tianjun. In addition, there were three typos of circulation pattern of hail weather at 500 hPa. Hail mainly occurred under the effect of northwest airflow, and it had shortwave trough, cold center or trough, jet stream core or one of the three. Hail appeared frequently under the situation of upper-level divergence and low-level convergence, and abundant water vapor and water vapor flux convergence at low levels were important conditions for hailing. [ Conclusion] The research could provide scientific references for improving the accuracy of hail forecast.
文摘[Objective] The aim was to study the formation and development of a heavy snow in Benxi area. [Method] Based on conventional meteorological data, the formation and development of a heavy snow in Benxi area from December 4th to 5th in 2009 were analyzed from the aspects of weather situation evolution and physical quantity field feature. [Result] The heavy snow was caused by upper trough and North China cyclone. In this process, there was upper level divergence and lower level convergence over Benxi area, and it was warm at low attitude and cold at high attitude; southwest jet at low attitude transported water vapor from Bohai Sea to eastern Liaoning, which provided good water vapor condition for snow, but it didn’t reach heavy snow due to inadequate ascending force. The development of Ural Mountains high ridge played an important role in the snow process and the strengthened high ridge moving northward was beneficial to the southward movement of cold air and deepening of upper trough. Analysis on physical quantity field could provide reference for predicting beginning and ending time and strength of heavy snow. [Conclusion] The study could provide basis for the forecast of heavy snow.
文摘[Objective] The research aimed to analyze a rare low temperature and rainy weather process which happened in Anhui Province from July 22 to August 14,2009.[Method] Based on the data of conventional observation,NCEP analysis field and automatic station,a rare low temperature and rainy weather process which occurred in Anhui Province from July 22 to August 14,2009 was analyzed.The formation reason of continuous rainy process in midsummer was discussed.The circulation characteristics and influence systems of continuous rainy process were revealed.On the base,the influences of configuration of circulation fields and difference of physical quantity fields at high and low layers on range and intensity of precipitation were analyzed.[Result] According to the circulation situation and influence system,the continuous rainy process could be divided into four stages:July 22-24,from July 27 to August 1,August 4-8 and August 9-14.Moreover,it was respectively affected by northeast low vortex,cold and warm air,high-level low trough,typhoon and periphery of subtropical high at four stages.The maintenance of big specific humidity zone provided sufficient water vapor condition for the continuous rainy weather.The rainstorm appeared in dense zone of specific humidity line,where the specific humidity >13 g/kg in the humidity front zone.A temperature trough maintained at 850 hPa.The cold air which continued to diffuse and go south was main reason of the abnormally low temperature during the continuous rainy period.Moreover,it provided ascending motion condition for precipitation maintenance.[Conclusion] The research provided references for actual forecast of continuous rainy weather.
文摘The large-range heavy precipitation occurred in the central-southern coast of Fujian on October 6,2008.By using the conventional meteorological data and NCEP 1°×1° 6 h one time analysis data,we analyzed,diagnosed and discussed the reasons of this heavy rainstorm occurrence and maintenance.The results showed that this heavy rainstorm weather process was mainly formed by the low-pressure system which was remained after ' Higos' weakened.The low-pressure system was excited by the weak cold air in the low layer which was brought by 500 hPa westerly trough.The common effect of southwest jet stream in the low altitude in the southeast of low pressure and the northerly airflow in the northwest made that the low-pressure circulation strengthened and maintained.The calculation gained the physical quantity field configuration which was favorable for the appearance of heavy precipitation.The analysis on the relative helicity of windstorm showed that the distribution and the time evolution of helicity had the good corresponding relationship with the distribution and the time evolution of heavy precipitation.The intensity variation of helicity had the certain instruction significance on the rainstorm evolution.
文摘By using the observation data,routine data and NCEP reanalysis data in the automatic station,5 times heavy fog weather processes in Zhangjiajie City in December,2009 were contrasted and analyzed.The results showed that 3 conditions were the essential conditions of heavy fog occurrence in Zhangjiajie area.3 conditions were that the wind speed was during 0.1-3.0 m/s,the relative humidity ≥90% and the depression of dew point ΔT ≤1.5 ℃.The fog concentration had no positive correlation relationship with the above conditions.The accumulation of humidity condition in the previous period was also the main reason which affected the generation of heavy fog.The physical quantity field which related to the stability and the relative humidity field which related to the water vapor condition had the certain directive significance for forecasting the heavy fog weather.The fog concentration presented the positive correlation relationship with the inversion intensity.
文摘[ Objective] The research aimed to analyze a local snowstorm weather process which happened in Beijing, Tianjin and Hebei during I - 4 January, 2010. [ Method] Based on routine meteorological observation data and NCEP/NCAR 2.5° ×2.5° grid data （four times every day）, a lo- cal snowstorm weather process which happened in Beijing, Tianjin and Hebei during 1 -4 January, 2010 was carried out diagnostic analysis by using composite analysis method. [Result] Circumfluence on the ground and strong cold advection in the rear of upper trough were the main weath- er system of the snowfall. The deep thick wet layer and strong water vapor convergence provided sufficient water vapor for snowfall. The divergence field of low-level convergence and high^level divergence, dynamic coupling effect of vorticity provided favorable dynamic condition upwardly for the occurrence of strong snowfall. The steep dense area of Oso, low temperature at the ground layer and inversion temperature at the high layer provided certain energy condition for the development of snowfall weather. [ Conclusion] The research provided theoretical basis for snowfall forecast in future.
文摘This paper suggests a principle to find a unitary operator U which transforms non-physical quantity, zero-potential Hamiltonian H<SUB>0</SUB>, into true physical quantity UH<SUB>0</SUB>U<SUP>?</SUP> for a charged particle in classical electromagnetic field, and puts forward a unified form of constructing gauge-independent transition probabilities in this case. Different methods correspond to different unitary operators which satisfy the above-mentioned principle.
文摘[Objective] The research aimed to study the influence of typhoon Usagi on Shaoyang in 2013. [Method] By using synoptic analysis, physical quantity diagnosis and Doppler radar, a rainstorm process caused by typhoon Usagi was analyzed. [ Result] Sufficient water vaper and strong ascending motion caused by high-altitude divergence were favorable conditions for rainstorm generation in Shaoyang. Uplifting effect of the terrain in Shaoyang was also one of favorable conditions for rainstorm generation in Shaoyang. [Conclusion] The research could provide reference for flood prevention and disaster reduction in Shaoyang area.
