ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 34,Issue 12,2008 Table of Contents
2008, 34(12):3-10.
DOI: 10.7519/j.issn.1000-0526.2008.12.001
Abstract:
For understanding the influences of solar radiation to convection of northeaster n cold vortex, a case of severe storm in a cold vortex over northeastern on 12 July 2002 over Liaoning Province was simulated by MM5. The contrasting examinat ions of solar radiation affecting severe storm showed that atmospheric solar rad iation can trigger severe convection by inspiring mesoscale circulation but not by accumulating instable energy in the background of synopticscale system of c old vortex. It is an important condition to trigger this severe convection in co ld vortex that surface shortwave radiation heats up lower layer of troposphere a tmosphere, and produces strong mesoscale convergence and convective instable l ayer onset and maintenance of convection.
For understanding the influences of solar radiation to convection of northeaster n cold vortex, a case of severe storm in a cold vortex over northeastern on 12 July 2002 over Liaoning Province was simulated by MM5. The contrasting examinat ions of solar radiation affecting severe storm showed that atmospheric solar rad iation can trigger severe convection by inspiring mesoscale circulation but not by accumulating instable energy in the background of synopticscale system of c old vortex. It is an important condition to trigger this severe convection in co ld vortex that surface shortwave radiation heats up lower layer of troposphere a tmosphere, and produces strong mesoscale convergence and convective instable l ayer onset and maintenance of convection.
2008, 34(12):11-20.
DOI: 10.7519/j.issn.1000-0526.2008.12.002
Abstract:
By using the NCEP/NCAR reanalysis data and the diagnosis analysis meth od of wave packet propagation (WPD), wave packet propagation and accumulation du ring the extreme lowtemperature, heavy snowstorm and frost disasters occurred i n South China were analyzed. Results show that the characteristic of wave packe t propagation at 500 hPa and 700 hPa can better display four processes of rainst orm weather.Accumulated perturbation energy has been maintaining high value when these four processes occur. Frozen weather appears in the high value region of wave packet. The characteristic of wave packet propagation shows that the pe rsistent processes of severe weathers with cold surge, icesnow and frozen rain on January 2008 are influenced by the Indian and Burma trough (IBT) in the south side of the QinghaiXizang Plateau. Because it is quite active, it also favors to the moisture transportation to China along the YunnanGuizhou Plateau from th e Indian Ocean and Bay of Bengal. Perturbation energies of cold air in the north ward path and in the eastward side of western Pacific subtropical high (WPSTH) a re certainly reflected on the wavepacket map. It indicates that the diagnosis a nalysis of wave packet propagation (WPD) is meaningful to predict the weather pr ocess.
By using the NCEP/NCAR reanalysis data and the diagnosis analysis meth od of wave packet propagation (WPD), wave packet propagation and accumulation du ring the extreme lowtemperature, heavy snowstorm and frost disasters occurred i n South China were analyzed. Results show that the characteristic of wave packe t propagation at 500 hPa and 700 hPa can better display four processes of rainst orm weather.Accumulated perturbation energy has been maintaining high value when these four processes occur. Frozen weather appears in the high value region of wave packet. The characteristic of wave packet propagation shows that the pe rsistent processes of severe weathers with cold surge, icesnow and frozen rain on January 2008 are influenced by the Indian and Burma trough (IBT) in the south side of the QinghaiXizang Plateau. Because it is quite active, it also favors to the moisture transportation to China along the YunnanGuizhou Plateau from th e Indian Ocean and Bay of Bengal. Perturbation energies of cold air in the north ward path and in the eastward side of western Pacific subtropical high (WPSTH) a re certainly reflected on the wavepacket map. It indicates that the diagnosis a nalysis of wave packet propagation (WPD) is meaningful to predict the weather pr ocess.
2008, 34(12):21-26.
DOI: 10.7519/j.issn.1000-0526.2008.12.003
Abstract:
Doppler radar products of damage wind process in Linyi，Shandong on 28 April 20 06 were analyzed. The echo was a typical bow echo, in the front of the bow echo a supercell developed with “VNOTCH”, BWER, then mesocyclone and heavy ra in occurred. After heavy rain, the top of the storm, the height of storm centroi d and maximum reflectivity fell rapidly. The damage wind occurred at this time. Investigated data shows that the path of damage wind go along with the path that the right edge of the mesocyclone passed. It suggests that the horizontal mom entum of the mesocyclone was brought down to the surface by heavy rain. At the right edge of mesocyclone the momentum and RIF have the same direction, the t wo airflows overlay togetherand make the wind increase, so damage wind occurred.
Doppler radar products of damage wind process in Linyi，Shandong on 28 April 20 06 were analyzed. The echo was a typical bow echo, in the front of the bow echo a supercell developed with “VNOTCH”, BWER, then mesocyclone and heavy ra in occurred. After heavy rain, the top of the storm, the height of storm centroi d and maximum reflectivity fell rapidly. The damage wind occurred at this time. Investigated data shows that the path of damage wind go along with the path that the right edge of the mesocyclone passed. It suggests that the horizontal mom entum of the mesocyclone was brought down to the surface by heavy rain. At the right edge of mesocyclone the momentum and RIF have the same direction, the t wo airflows overlay togetherand make the wind increase, so damage wind occurred.
Zhou Yuquan
,
Chen Yingying
,
Li Juan
,
Huang Yimei
,
He Xiaodong
,
Zhou Feifei
,
Wu Menxin
,
Hu Bo
,
Mao Jietai
2008, 34(12):27-35.
DOI: 10.7519/j.issn.1000-0526.2008.12.004
Abstract:
Cloud macro and micro physical characteristic parameters play an important role not only in the field of the analysis and forecast of the weather and climate, but also in the field of weather modification to identify the seeding c ondition. Based on the data from FY-2C/D stationary satellite and SBDART radiati on transfer model, associated with the sounding data and surface information, a method retrieving cloud macro and micro physical parameters is established in th is research. These parameters include cloud top height, cloud top temperature, d epth of super-cooled layer, depth of warm layer, cloud bottom height, depth of c loud, cloud optical thickness, cloud effective particle radius and cloud liquid water content. It has been run operationally. In this paper, the correlated info rmation such as physical meaning, retrieving method and technology, retrieving p rocess and data format are simply introduced. Furthermore, comparing with the ob servation of Cloudsat up to the minute, the retrieving results of main cloud par ameters are proved to be reasonable and usable. By contrast with same kind produ cts of MODIS, it also shows good corresponding relationship.
Cloud macro and micro physical characteristic parameters play an important role not only in the field of the analysis and forecast of the weather and climate, but also in the field of weather modification to identify the seeding c ondition. Based on the data from FY-2C/D stationary satellite and SBDART radiati on transfer model, associated with the sounding data and surface information, a method retrieving cloud macro and micro physical parameters is established in th is research. These parameters include cloud top height, cloud top temperature, d epth of super-cooled layer, depth of warm layer, cloud bottom height, depth of c loud, cloud optical thickness, cloud effective particle radius and cloud liquid water content. It has been run operationally. In this paper, the correlated info rmation such as physical meaning, retrieving method and technology, retrieving p rocess and data format are simply introduced. Furthermore, comparing with the ob servation of Cloudsat up to the minute, the retrieving results of main cloud par ameters are proved to be reasonable and usable. By contrast with same kind produ cts of MODIS, it also shows good corresponding relationship.
5 Application Analysis of Direct Assimilation of Satellite Radiation Data on Hea vy Rain Forecasting
2008, 34(12):36-43.
DOI: 10.7519/j.issn.1000-0526.2008.12.005
Abstract:
To examine the ability of T213-SSI system on heavy rain forecasting, a nd to evaluate the application of satellite data on numerical prediction of heav y rain, this study used T213-SSI system to numerically simulate the heavy rai n fall in Sichuan Basin during July 16-19, 2007. This process was transition pr ocess of precipitation under adjusting of westerlies system and caused severe da mage. It is very difficult to be predicted and is very deserved to be researched . Three experiments are completed in this study using different data during diff erent period. The first experiment only uses conventional observations; the seco nd uses conventional observations and satellite microwave data during continuous 10 days. The last experiment uses conventional observation and satellite microw ave data during 6 hours. The results show that the second experiment is better t han the third. It means that satellite data need to be used for a long time to a chieve a good effect. In addition, employing of long time satellite data can imp rove largescale environmental flow. Thus, the heavy rain process will be close r to the truth. In the end, AMSU-A and AMSU-B data are very influential to the temperature and moisture fields respectively.
To examine the ability of T213-SSI system on heavy rain forecasting, a nd to evaluate the application of satellite data on numerical prediction of heav y rain, this study used T213-SSI system to numerically simulate the heavy rai n fall in Sichuan Basin during July 16-19, 2007. This process was transition pr ocess of precipitation under adjusting of westerlies system and caused severe da mage. It is very difficult to be predicted and is very deserved to be researched . Three experiments are completed in this study using different data during diff erent period. The first experiment only uses conventional observations; the seco nd uses conventional observations and satellite microwave data during continuous 10 days. The last experiment uses conventional observation and satellite microw ave data during 6 hours. The results show that the second experiment is better t han the third. It means that satellite data need to be used for a long time to a chieve a good effect. In addition, employing of long time satellite data can imp rove largescale environmental flow. Thus, the heavy rain process will be close r to the truth. In the end, AMSU-A and AMSU-B data are very influential to the temperature and moisture fields respectively.
2008, 34(12):44-53.
DOI: 10.7519/j.issn.1000-0526.2008.12.006
Abstract:
The characters and effects of sealand breeze in Yangjiang were studied. The ba sic data were taken from weather stations, automatic weather stations in Yangjia ng and two towers of 80metrehigh gradient observation on the seaside. The re sult shows that the western coast sea breeze formed earlier than the eastern coa st one. In surface layer, the sealand breeze increases with height. Sometimes in May, the sealand breeze is too weak to reach the height of 80m. The change from land breeze to sea breeze occurs mostly during 11:00-12:00. On th e contrary the change from sea breeze to land breeze happens at about 23:00, both dur ing the period of daily peak of pressure fluctuation. The sealand breeze can r each 70-75 km far from the coastline when it superimposes valley wind, but it ca nnot pass over the Mist Hill. During the period of sealand conversion, a conve rgent zone formed near the bay, which made the urban district of Yangjiang at it s northern side to be a rainy center from April to July. The sea breeze converse d in the pipe socket area near Yangchun and made this region become another rain y center. All above are important factors making Yangjiang to be the rainy cente r of Guangdong. In addition, if the sea-land breeze circulation was not broken down, Yangjiang coastal areas would not have high temperature weather.
The characters and effects of sealand breeze in Yangjiang were studied. The ba sic data were taken from weather stations, automatic weather stations in Yangjia ng and two towers of 80metrehigh gradient observation on the seaside. The re sult shows that the western coast sea breeze formed earlier than the eastern coa st one. In surface layer, the sealand breeze increases with height. Sometimes in May, the sealand breeze is too weak to reach the height of 80m. The change from land breeze to sea breeze occurs mostly during 11:00-12:00. On th e contrary the change from sea breeze to land breeze happens at about 23:00, both dur ing the period of daily peak of pressure fluctuation. The sealand breeze can r each 70-75 km far from the coastline when it superimposes valley wind, but it ca nnot pass over the Mist Hill. During the period of sealand conversion, a conve rgent zone formed near the bay, which made the urban district of Yangjiang at it s northern side to be a rainy center from April to July. The sea breeze converse d in the pipe socket area near Yangchun and made this region become another rain y center. All above are important factors making Yangjiang to be the rainy cente r of Guangdong. In addition, if the sea-land breeze circulation was not broken down, Yangjiang coastal areas would not have high temperature weather.
2008, 34(12):54-62.
DOI: 10.7519/j.issn.1000-0526.2008.12.007
Abstract:
The two cold vortex processes occurred on July 5, 2006 and June 16, 2006 are inv estigated. The positions of the two cold vortices are similar, but weather pheno mena are different. With the conventional meteorological data, satellite images, automatic weather station(AWS) data and NCEP reanalysis data (horizontal resolu tion 1°×1°), two processes are analyzed in aspects of largescale circulatio n, the evolution of the satellite image, the energetic and dynamical field. The results show that (1) in the two cases, the T distribution at the low and middle level, the strength of systems in the upstream and downstream area is differen t. (2)The cloud cluster located the end of cold vortex band propagates forward. (3) The strong convective storms have a good relationship with the region of hig h θse gradient value, SI<0, high value of CAPE, as well as SW flow lo cated south of surface convergent line.
The two cold vortex processes occurred on July 5, 2006 and June 16, 2006 are inv estigated. The positions of the two cold vortices are similar, but weather pheno mena are different. With the conventional meteorological data, satellite images, automatic weather station(AWS) data and NCEP reanalysis data (horizontal resolu tion 1°×1°), two processes are analyzed in aspects of largescale circulatio n, the evolution of the satellite image, the energetic and dynamical field. The results show that (1) in the two cases, the T distribution at the low and middle level, the strength of systems in the upstream and downstream area is differen t. (2)The cloud cluster located the end of cold vortex band propagates forward. (3) The strong convective storms have a good relationship with the region of hig h θse gradient value, SI<0, high value of CAPE, as well as SW flow lo cated south of surface convergent line.
2008, 34(12):63-71.
DOI: 10.7519/j.issn.1000-0526.2008.12.008
Abstract:
Based on the reanalysis data with 1.0°×1.0° resolution from NCEP/NCAR, the ci rculation background and the main influencing systems of “07.17” torrential ra instorm in the west of Chongqing in 2007 are analyzed. The results indicate that under advantageous largescale circulation background coordination, the main i nfluence systems were the southwest vortex and lowlevel jet stream. The west P acific subtropical high provided the advantageous condition for transport ation of water vapor by its west stretch and north lift. The strong raining processes began at the peak of the development of southwest vortex. The high center and i ntensity of vertical helicity had a corresponding connection with the position a nd intensity of heavy rainfall. Although without surface cold air intrusion, in the upper troposphere the dry air intrusion provided triggering power of rainsto rm. The strong convection weather was affected directly by the dry and cold lid at high level caused by strong cold advection and the warm and wet air at low le vel when they interacted with strong ascending. The different influences of dry intrusion at different levels over the southwest vortex made high potential vort icity in upper troposphere go down and increase in lower troposphere, which stre ngthened southwest vortex and the intensity of precipitation.
Based on the reanalysis data with 1.0°×1.0° resolution from NCEP/NCAR, the ci rculation background and the main influencing systems of “07.17” torrential ra instorm in the west of Chongqing in 2007 are analyzed. The results indicate that under advantageous largescale circulation background coordination, the main i nfluence systems were the southwest vortex and lowlevel jet stream. The west P acific subtropical high provided the advantageous condition for transport ation of water vapor by its west stretch and north lift. The strong raining processes began at the peak of the development of southwest vortex. The high center and i ntensity of vertical helicity had a corresponding connection with the position a nd intensity of heavy rainfall. Although without surface cold air intrusion, in the upper troposphere the dry air intrusion provided triggering power of rainsto rm. The strong convection weather was affected directly by the dry and cold lid at high level caused by strong cold advection and the warm and wet air at low le vel when they interacted with strong ascending. The different influences of dry intrusion at different levels over the southwest vortex made high potential vort icity in upper troposphere go down and increase in lower troposphere, which stre ngthened southwest vortex and the intensity of precipitation.
2008, 34(12):72-78.
DOI: 10.7519/j.issn.1000-0526.2008.12.009
Abstract:
By use of AWS and other upper data, NCEP reanalysis, satellite and rad ar data, the reasons of heavy rain and strong wind in Shanghai caused by Typhoon Krosa (0716) during Oct. 7-8, 2007 are analyzed. Results show that the precipit ation in Shanghai can be divided into two phases: the first is strong precipitat ion caused by the mesoscale cloud evolved from the periphery of typhoon; the se cond is the steady precipitation caused by combination of cold air and typhoon. The time of cold air invasion coincides closely with that of precipitation in Sh anghai. The invasion of cold air is the main reason of heavy rain in Shanghai. I n addition to the rich water vapor of typhoon itself, the subtropical high weake ns on the northern side of typhoon and wind direction turns to southerly on th e midhigh level of troposphere, the heat and vapor are providedfor the developme nt and maintenance of strong precipitation on the periphery of typhoon. Southwar ds cold and dry air together with warm and waterish current on the periphery of typhoon lead to stronger convergence, which provides the dynamic elevation mech anism for mesoscale convective cloud on the periphery of typhoon. Due to the f limsy cold air, the warm core of typhoon on the high levels is not destroyed. It leads to the cold air hovering near Shanghai, which slows down the moving vel ocity of typhoon and helps to durative heavy rain in Shanghai.
By use of AWS and other upper data, NCEP reanalysis, satellite and rad ar data, the reasons of heavy rain and strong wind in Shanghai caused by Typhoon Krosa (0716) during Oct. 7-8, 2007 are analyzed. Results show that the precipit ation in Shanghai can be divided into two phases: the first is strong precipitat ion caused by the mesoscale cloud evolved from the periphery of typhoon; the se cond is the steady precipitation caused by combination of cold air and typhoon. The time of cold air invasion coincides closely with that of precipitation in Sh anghai. The invasion of cold air is the main reason of heavy rain in Shanghai. I n addition to the rich water vapor of typhoon itself, the subtropical high weake ns on the northern side of typhoon and wind direction turns to southerly on th e midhigh level of troposphere, the heat and vapor are providedfor the developme nt and maintenance of strong precipitation on the periphery of typhoon. Southwar ds cold and dry air together with warm and waterish current on the periphery of typhoon lead to stronger convergence, which provides the dynamic elevation mech anism for mesoscale convective cloud on the periphery of typhoon. Due to the f limsy cold air, the warm core of typhoon on the high levels is not destroyed. It leads to the cold air hovering near Shanghai, which slows down the moving vel ocity of typhoon and helps to durative heavy rain in Shanghai.
2008, 34(12):79-83.
DOI: 10.7519/j.issn.1000-0526.2008.12.010
Abstract:
By using the information of high impact weather events and dialing num bers of weather service phone (named 12121)，the distribution of estimated meteo rological attention degrees of general public was calculated. Further more, the social benefit values of public weather service through willingness to pay (WTP ) are also estimated. Taking Xi’an city as an example, it chooses occurring d ays of ten high impact weather events closely related to general public from 200 4 to 2007，which are granted as potential meteorological risk resources, i.e. hi gh temperature,heat wave，sultry weather,scattered precipitation, moderate sho wer,heavy rain,thunderstorm,snow, fog or haze and consecutively rainy day. Accor ding to demography information and average local phone charge, the total WTP values were calculated respectively. The results show that there were approximat ely 1174.854 ten thousand Yuan/year on temperature weather events, about 4973.39 4 ten thousand Yuan/year on precipitation events, roughly 311.269 ten thousand Y uan/year on thunderstorm and probably 471.637 ten thousand Yuan/year on fog or h aze weather. The result is helpful for quantitative judgments about societal inf luence of publicmeteorological services.
By using the information of high impact weather events and dialing num bers of weather service phone (named 12121)，the distribution of estimated meteo rological attention degrees of general public was calculated. Further more, the social benefit values of public weather service through willingness to pay (WTP ) are also estimated. Taking Xi’an city as an example, it chooses occurring d ays of ten high impact weather events closely related to general public from 200 4 to 2007，which are granted as potential meteorological risk resources, i.e. hi gh temperature,heat wave，sultry weather,scattered precipitation, moderate sho wer,heavy rain,thunderstorm,snow, fog or haze and consecutively rainy day. Accor ding to demography information and average local phone charge, the total WTP values were calculated respectively. The results show that there were approximat ely 1174.854 ten thousand Yuan/year on temperature weather events, about 4973.39 4 ten thousand Yuan/year on precipitation events, roughly 311.269 ten thousand Y uan/year on thunderstorm and probably 471.637 ten thousand Yuan/year on fog or h aze weather. The result is helpful for quantitative judgments about societal inf luence of publicmeteorological services.
2008, 34(12):90-95.
DOI: 10.7519/j.issn.1000-0526.2008.12.012
Abstract:
Based on T213 NWP(Numerical Weather Prediction）model outputs and prec ipitation observations, crossvalidation is performed with random samples to fi n d the samples with best predictors and optimal parameters. The forecast models o f precipitation are established at 72 meteorological stations in China by the SV M (Support Vector Machine) statistical method. The models are verified with inde pendent samples. The predictors are selected and the precipitation forecast mode ls are improved by pressing close degree. Forecast experiments show that the imp roved models are better. The precipitation forecasted by SVM models is superi or to the precipitation of T213 DMO (direct model output) in real-time experimen ts.
Based on T213 NWP(Numerical Weather Prediction）model outputs and prec ipitation observations, crossvalidation is performed with random samples to fi n d the samples with best predictors and optimal parameters. The forecast models o f precipitation are established at 72 meteorological stations in China by the SV M (Support Vector Machine) statistical method. The models are verified with inde pendent samples. The predictors are selected and the precipitation forecast mode ls are improved by pressing close degree. Forecast experiments show that the imp roved models are better. The precipitation forecasted by SVM models is superi or to the precipitation of T213 DMO (direct model output) in real-time experimen ts.
2008, 34(12):96-102.
DOI: 10.7519/j.issn.1000-0526.2008.12.013
Abstract:
Relative humidity is one of the most important variables. So the list register w ith correct humidity observations can dispose the effect to trend of long climat e observations. From 2000 on, the manmade observation which was used in past several decades was replaced by auto weather station (AWS). About 17 obs ervation stations were selected and analyzed by means of computing the annual a verage difference, standard deviation and the difference of diurnal variation. A ccording to each disadvantage of auto weather station and manmade observationsystems, relative humidity was sorted to 9 species in terms of the diversity wit h temperature and relative humidity, and compared and analyzed. It is indicated that there is systemic bias between manmade and auto weather observation in m ost stations. The magnitude of manmade observation is usually about 3.5% larger than auto weather station. This phenomenon is more obvious in humid area. The bi as is comparatively large in humid area in the same temperature, and there is si milar result when the high temperature in the same relative humidity.
Relative humidity is one of the most important variables. So the list register w ith correct humidity observations can dispose the effect to trend of long climat e observations. From 2000 on, the manmade observation which was used in past several decades was replaced by auto weather station (AWS). About 17 obs ervation stations were selected and analyzed by means of computing the annual a verage difference, standard deviation and the difference of diurnal variation. A ccording to each disadvantage of auto weather station and manmade observationsystems, relative humidity was sorted to 9 species in terms of the diversity wit h temperature and relative humidity, and compared and analyzed. It is indicated that there is systemic bias between manmade and auto weather observation in m ost stations. The magnitude of manmade observation is usually about 3.5% larger than auto weather station. This phenomenon is more obvious in humid area. The bi as is comparatively large in humid area in the same temperature, and there is si milar result when the high temperature in the same relative humidity.
2008, 34(12):103-109.
DOI: 10.7519/j.issn.1000-0526.2008.12.014
Abstract:
According to the gas poisoning data provided by Prophylaxis and the Control Cent er of Hebei province and the meteorological data in winter from 2006 to 2007 yea r in Shijiazhuang, the relationship between carbon monoxide poisoning events and the meteorological condition was analyzed. The results indicated that:(1) the g as poisoning event mainly occurs in the night to the morning, specially in the coldest December and January; (2) Small wind velocity (grade 1 to 2), surface layer with inversion temperature gradient, small temperature change (within ±3 .0℃), fog and haze are the meteorological conditions favorable to the gas poiso ning; (3) 500 hPa upper air situations such as the west air current, westerly tr ough and upperlevel trough, and the ground synoptic situations such as weak high pressure, low pressure and equal pressure, are favorable to the poisoning event occurrence. In the forecast service these weather situat ions should be paid more consideration.
According to the gas poisoning data provided by Prophylaxis and the Control Cent er of Hebei province and the meteorological data in winter from 2006 to 2007 yea r in Shijiazhuang, the relationship between carbon monoxide poisoning events and the meteorological condition was analyzed. The results indicated that:(1) the g as poisoning event mainly occurs in the night to the morning, specially in the coldest December and January; (2) Small wind velocity (grade 1 to 2), surface layer with inversion temperature gradient, small temperature change (within ±3 .0℃), fog and haze are the meteorological conditions favorable to the gas poiso ning; (3) 500 hPa upper air situations such as the west air current, westerly tr ough and upperlevel trough, and the ground synoptic situations such as weak high pressure, low pressure and equal pressure, are favorable to the poisoning event occurrence. In the forecast service these weather situat ions should be paid more consideration.
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ISSN:1000-0526 CN:11-2282/P