ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 37,Issue 2,2011 Table of Contents
2011, 37(2):129-135.
DOI: 10.7519/j.issn.1000-0526.2011.2.001
Abstract:
The teaching work in the forecaster training starting from the autumn of 2009 is summarized. The importance of basic meteorological knowledge, synoptic practices, and longterm accumulation is emphasized. The applications of Tlogp diagram, geostationary satellite imagery, and quasigeostrophic theory are discussed detailedly. It is also discussed how to make complicated things simple based on the example of heavyrain forecasting. Finally, the issues induced by Q vector, helicity, and isoentropic potential vorticity are presented to demonstrate the problems caused by making simple things complicated.
The teaching work in the forecaster training starting from the autumn of 2009 is summarized. The importance of basic meteorological knowledge, synoptic practices, and longterm accumulation is emphasized. The applications of Tlogp diagram, geostationary satellite imagery, and quasigeostrophic theory are discussed detailedly. It is also discussed how to make complicated things simple based on the example of heavyrain forecasting. Finally, the issues induced by Q vector, helicity, and isoentropic potential vorticity are presented to demonstrate the problems caused by making simple things complicated.
2011, 37(2):136-141.
DOI: 10.7519/j.issn.1000-0526.2011.2.002
Abstract:
This paper calculated 18 physical parameters and their 6h, 12h, and 24h variations by the sounding data from Beijing Nanjiao Observatory, and then analyzed the physical parameter differences of hailstone, thunderstorm gale, and storm rainfall from May to September in 2007 and 2008. The results show that, as the physical parameters, the 0 ℃ height, the -20 ℃ height, the difference of temperature between 500 hPa and 850 hPa, the inversion height and the lowlevel wind shear could distinguish the category of the rainstorm and hailstorm. Besides, the depression of dew point of 850 hPa and the difference of θse between 500 hPa and 850 hPa are also the important 〖HJ〗conditions. On the other hand, for the 6h variations of the CAPE, DCAPE， K index, the difference of θse between 500 hPa and 850 hPa, PW， and the vertical wind shear of the lower troposphere could also be better to distinguish the hailstorm and the storm rainfall. The results indicate that it is possible to distinguish the summer convective weather by better using of sounding data.
This paper calculated 18 physical parameters and their 6h, 12h, and 24h variations by the sounding data from Beijing Nanjiao Observatory, and then analyzed the physical parameter differences of hailstone, thunderstorm gale, and storm rainfall from May to September in 2007 and 2008. The results show that, as the physical parameters, the 0 ℃ height, the -20 ℃ height, the difference of temperature between 500 hPa and 850 hPa, the inversion height and the lowlevel wind shear could distinguish the category of the rainstorm and hailstorm. Besides, the depression of dew point of 850 hPa and the difference of θse between 500 hPa and 850 hPa are also the important 〖HJ〗conditions. On the other hand, for the 6h variations of the CAPE, DCAPE， K index, the difference of θse between 500 hPa and 850 hPa, PW， and the vertical wind shear of the lower troposphere could also be better to distinguish the hailstorm and the storm rainfall. The results indicate that it is possible to distinguish the summer convective weather by better using of sounding data.
2011, 37(2):142-155.
DOI: 10.7519/j.issn.1000-0526.2011.2.003
Abstract:
Using the Variational Doppler Radar Analysis System (VDRAS) combined with local unconventional observation data, a more indepth contrastive analysis is carried on the initiation mechanism of two storm cases in Beijing, one is 814 (August 14, 2008) case with strong rainfall that we call it as moiststorm and the other is 824 (August 24, 2008) case with little rainfall that we call it as drystorm. The results show: (1) The synopticscale systems of 814 storm were stable Northeast cold vortexlow trough at 500 hPa and shear line at 850 hPa, the specific humidity that more than 12 g·kg-1 below 850 hPa and the relative humidity that more than 90% in the surface indicated that the atmosphere was very moist. It had convective instability caused by humidity advection in lower levels. The 824 storm had a prevailing straight west wind in high levels, an anticyclone in lower levels, and a surface cold front moving fast.The specific humidity that less than 6 g·kg-1, and the relative humidity that less than 30% below 850 hPa indicated that the atmosphere was very dry. It had convective instability caused by temperature advection. (2) There was much strong vertical wind shear in the whole vertical layer for 814 storm case, the clockwise wind direction with height within 500-1500 m intensified the warm and humidity inflow of lower layer advantageous to storm initiation and development. While there was weak vertical wind shear and unobvious warm and humidity inflow of lower layer for 824 case, which was not conducive to storm initiation and development. In addition, composited wind of the whole troposphere and storm movement speed were very low for 814 case, but they were very high for 824 case. (3) The 814 storm was formed by the collision and mergence of multicell storms, a convergence line was formed by the cold pool outflow produced by the precipitation of the upstream of thunderstorm cell and the east wind in low levels which forced the lowlevel warm and moist air to uplift, additionally the strong convective instability and vertical wind shear supported the formation and development of new storm. The interactions (collisions) of gust fronts in the leading edge of cold pool of multicell thunderstorm group, further exacerbating the lowlevel instability, leading to the regeneration and mergence of new convective thunderstorms. The 824 storm was a line convective system accompanied with cold front that rapid moved eastward and lasted for short time, there was no east wind with warm and moisture air accompanying the cold pool outflow produced by the downdrafts of thunderstorm. The absence of mesoscale lifting mechanism and moisture inflow couldn’t support the formation and development of new storm.
Using the Variational Doppler Radar Analysis System (VDRAS) combined with local unconventional observation data, a more indepth contrastive analysis is carried on the initiation mechanism of two storm cases in Beijing, one is 814 (August 14, 2008) case with strong rainfall that we call it as moiststorm and the other is 824 (August 24, 2008) case with little rainfall that we call it as drystorm. The results show: (1) The synopticscale systems of 814 storm were stable Northeast cold vortexlow trough at 500 hPa and shear line at 850 hPa, the specific humidity that more than 12 g·kg-1 below 850 hPa and the relative humidity that more than 90% in the surface indicated that the atmosphere was very moist. It had convective instability caused by humidity advection in lower levels. The 824 storm had a prevailing straight west wind in high levels, an anticyclone in lower levels, and a surface cold front moving fast.The specific humidity that less than 6 g·kg-1, and the relative humidity that less than 30% below 850 hPa indicated that the atmosphere was very dry. It had convective instability caused by temperature advection. (2) There was much strong vertical wind shear in the whole vertical layer for 814 storm case, the clockwise wind direction with height within 500-1500 m intensified the warm and humidity inflow of lower layer advantageous to storm initiation and development. While there was weak vertical wind shear and unobvious warm and humidity inflow of lower layer for 824 case, which was not conducive to storm initiation and development. In addition, composited wind of the whole troposphere and storm movement speed were very low for 814 case, but they were very high for 824 case. (3) The 814 storm was formed by the collision and mergence of multicell storms, a convergence line was formed by the cold pool outflow produced by the precipitation of the upstream of thunderstorm cell and the east wind in low levels which forced the lowlevel warm and moist air to uplift, additionally the strong convective instability and vertical wind shear supported the formation and development of new storm. The interactions (collisions) of gust fronts in the leading edge of cold pool of multicell thunderstorm group, further exacerbating the lowlevel instability, leading to the regeneration and mergence of new convective thunderstorms. The 824 storm was a line convective system accompanied with cold front that rapid moved eastward and lasted for short time, there was no east wind with warm and moisture air accompanying the cold pool outflow produced by the downdrafts of thunderstorm. The absence of mesoscale lifting mechanism and moisture inflow couldn’t support the formation and development of new storm.
2011, 37(2):156-160.
DOI: 10.7519/j.issn.1000-0526.2011.2.004
Abstract:
Using the NCEP/NCAR reanalysis data and observation data (8 times daily) from the Central Meteorological Observatory from January 10 to February 2, 2008, we analyzed the characters of spatialtemporal structure about temperature inversion layers, the variability of intensity of the four freezing rain processes happening in southern China and the relationship between them. The results show that the third out of the four main freezing rain processes is the strongest, then is followed by the second, and the first is the weakest process. Meanwhile, there is a close relationship between the strength variability of freezing rain and reversion layers, which could be revealed either from the regional average value or from the horizontal distribution. Furthermore, the thicknesses and altitudes of the cold layer, the warm layer and the whole inversion layer are able to affect the formation of the freezing rain, but the influence on the strength of the freezing rain is not significant. The results provide a good idea for forecasting the variability of the freezing rain, which is of reference value.
Using the NCEP/NCAR reanalysis data and observation data (8 times daily) from the Central Meteorological Observatory from January 10 to February 2, 2008, we analyzed the characters of spatialtemporal structure about temperature inversion layers, the variability of intensity of the four freezing rain processes happening in southern China and the relationship between them. The results show that the third out of the four main freezing rain processes is the strongest, then is followed by the second, and the first is the weakest process. Meanwhile, there is a close relationship between the strength variability of freezing rain and reversion layers, which could be revealed either from the regional average value or from the horizontal distribution. Furthermore, the thicknesses and altitudes of the cold layer, the warm layer and the whole inversion layer are able to affect the formation of the freezing rain, but the influence on the strength of the freezing rain is not significant. The results provide a good idea for forecasting the variability of the freezing rain, which is of reference value.
2011, 37(2):161-169.
DOI: 10.7519/j.issn.1000-0526.2011.2.005
Abstract:
Using the NCEP/NCAR reanalysis data and observation data (8 times daily) from the Central Meteorological Observatory from January 10 to February 2, 2008, we analyzed the characters of spatialtemporal structure about temperature inversion layers, the variability of intensity of the four freezing rain processes happening in southern China and the relationship between them. The results show that the third out of the four main freezing rain processes is the strongest, then is followed by the second, and the first is the weakest process. Meanwhile, there is a close relationship between the strength variability of freezing rain and reversion layers, which could be revealed either from the regional average value or from the horizontal distribution. Furthermore, the thicknesses and altitudes of the cold layer, the warm layer and the whole inversion layer are able to affect the formation of the freezing rain, but the influence on the strength of the freezing rain is not significant. The results provide a good idea for forecasting the variability of the freezing rain, which is of reference value.
Using the NCEP/NCAR reanalysis data and observation data (8 times daily) from the Central Meteorological Observatory from January 10 to February 2, 2008, we analyzed the characters of spatialtemporal structure about temperature inversion layers, the variability of intensity of the four freezing rain processes happening in southern China and the relationship between them. The results show that the third out of the four main freezing rain processes is the strongest, then is followed by the second, and the first is the weakest process. Meanwhile, there is a close relationship between the strength variability of freezing rain and reversion layers, which could be revealed either from the regional average value or from the horizontal distribution. Furthermore, the thicknesses and altitudes of the cold layer, the warm layer and the whole inversion layer are able to affect the formation of the freezing rain, but the influence on the strength of the freezing rain is not significant. The results provide a good idea for forecasting the variability of the freezing rain, which is of reference value.
2011, 37(2):170-176.
DOI: 10.7519/j.issn.1000-0526.2011.2.006
Abstract:
This paper describes a kind of mesoscale analysis field by use of LAPS （Local Analysis and Prediction System） ingesting surface observation, radiosonde observation, radar reflectivity, and analyzes the LAPS field compared with observed precipitation, radar echo, and TBB. The results indicate that LAPS analysis field has more detailed description of mesoscale system. Various kinds of experiments are designed to ingest various observed data and investigate the effect of these data in LAPS, then the RMS errors of these experiments are calculated. It is shown that the LAPS analysis field which ingested all of the observed data is the best. The model AREM is used to forecast precipitation respectively by two kinds of initial fields, and the TS scores of two forecast fields show that LAPS has good ability to improve the initial field, and then improve the forecast ability of model.
This paper describes a kind of mesoscale analysis field by use of LAPS （Local Analysis and Prediction System） ingesting surface observation, radiosonde observation, radar reflectivity, and analyzes the LAPS field compared with observed precipitation, radar echo, and TBB. The results indicate that LAPS analysis field has more detailed description of mesoscale system. Various kinds of experiments are designed to ingest various observed data and investigate the effect of these data in LAPS, then the RMS errors of these experiments are calculated. It is shown that the LAPS analysis field which ingested all of the observed data is the best. The model AREM is used to forecast precipitation respectively by two kinds of initial fields, and the TS scores of two forecast fields show that LAPS has good ability to improve the initial field, and then improve the forecast ability of model.
2011, 37(2):177-184.
DOI: 10.7519/j.issn.1000-0526.2011.2.007
Abstract:
Based on the hazardous weather report, disaster telegraph data and NCEP 1°×1° reanalysis data from 175 stations in Beijing, Tianjin and Hebei from May to September during 2001-2008， the statistical analyses are used to explore the temporalspatial distribution and synoptic characteristics of severe convective weather there. The analysis results indicate that：(1) In this period， the wind force always reaches 7-8 scales with prevailing northerly and westerly winds， the southcentral and northwest of Hebei area, and Beijing and Tianjin have strong winds； Larger hails often occur in Beijing, Tianjin and the northwest and north of Hebei； Within 10-60 minutes， the precipitation easily reaches 20-25 mm， while during 130-180 minutes， the precipitation can reach 50-100 mm. (2) During 2001-2008， the winds often occur in May and June， the hails occur in June， but the shorttime rainstorms occur in July and August； (3) Except for shorttime rainstorms， winds and hails approach to the Taihang and Yinshan Mountains and reduce gradually from northwest to southeast. The severe convective weather has the obvious characteristics of daily variation， a majority of severe convective weathers (62%) occur in the afternoon and early evening (14:00-20:00 BT). (4) There are three main weather circulations： the cold vortex pattern in which mainly appear hails accompanied by gales or shorttime rainstorms， the cold trough pattern in which mainly appear strong winds with shorttime rainstorm， and the trough and subtropical anticyclone pattern which always brings shorttime rainstorms. A weather conceptual model which is established through the typical case has a good significance for weather forecasting.
Based on the hazardous weather report, disaster telegraph data and NCEP 1°×1° reanalysis data from 175 stations in Beijing, Tianjin and Hebei from May to September during 2001-2008， the statistical analyses are used to explore the temporalspatial distribution and synoptic characteristics of severe convective weather there. The analysis results indicate that：(1) In this period， the wind force always reaches 7-8 scales with prevailing northerly and westerly winds， the southcentral and northwest of Hebei area, and Beijing and Tianjin have strong winds； Larger hails often occur in Beijing, Tianjin and the northwest and north of Hebei； Within 10-60 minutes， the precipitation easily reaches 20-25 mm， while during 130-180 minutes， the precipitation can reach 50-100 mm. (2) During 2001-2008， the winds often occur in May and June， the hails occur in June， but the shorttime rainstorms occur in July and August； (3) Except for shorttime rainstorms， winds and hails approach to the Taihang and Yinshan Mountains and reduce gradually from northwest to southeast. The severe convective weather has the obvious characteristics of daily variation， a majority of severe convective weathers (62%) occur in the afternoon and early evening (14:00-20:00 BT). (4) There are three main weather circulations： the cold vortex pattern in which mainly appear hails accompanied by gales or shorttime rainstorms， the cold trough pattern in which mainly appear strong winds with shorttime rainstorm， and the trough and subtropical anticyclone pattern which always brings shorttime rainstorms. A weather conceptual model which is established through the typical case has a good significance for weather forecasting.
2011, 37(2):185-193.
DOI: 10.7519/j.issn.1000-0526.2011.2.008
Abstract:
The highdensity precipitation data from both meteorological and hydrological observations in China are interpolated to finemesh grid at a resolution of 0.15° by combining the Barnes scheme with precipitation frequency, then 0-24 h quantitative precipitation forecast (QPF) from GRAPES_Meso is interpolated to the station spot. The QPF has been verified against two datasets using BIA, ETS and TSS. Moreover, an objectbased verification developed recently is carried out to verify the raincluster more than 5 mm. The results are as follows: (1) For all thresholds, the QPF exhibits a higher performance in the east part of China than that in the west, as well as more skillful in plain areas than in mountainous ones. The model forecasts more events above the threshold than observed in the upwind side of mountains (overforecasting) while the model forecasts less events than observations for interior Tibet and the north of Xinjiang (underforecasting). (2) As a whole, the scores calculated for the verifications against gridded observations have shown that the model performs better than could be anticipated from local observations, thus gridded observations better represent the gridbox behavior described by the model. (3) For the threshold more than 5 mm, the distribution of number against the cluster size of the QPF is similar to observations. Especially, the best forecast is to the cluster size of 60 km. As for spatial distributions, in the east of Inner Mongolia, the Northeast China, North China, the region between the Yangtze River and Huaihe River, Shaanxi Province as well as the south of Gansu Province, numbers of QPF are almost the same as observed ones, but more to the south of Yangtze River, especially in the east part of Southwest China.
The highdensity precipitation data from both meteorological and hydrological observations in China are interpolated to finemesh grid at a resolution of 0.15° by combining the Barnes scheme with precipitation frequency, then 0-24 h quantitative precipitation forecast (QPF) from GRAPES_Meso is interpolated to the station spot. The QPF has been verified against two datasets using BIA, ETS and TSS. Moreover, an objectbased verification developed recently is carried out to verify the raincluster more than 5 mm. The results are as follows: (1) For all thresholds, the QPF exhibits a higher performance in the east part of China than that in the west, as well as more skillful in plain areas than in mountainous ones. The model forecasts more events above the threshold than observed in the upwind side of mountains (overforecasting) while the model forecasts less events than observations for interior Tibet and the north of Xinjiang (underforecasting). (2) As a whole, the scores calculated for the verifications against gridded observations have shown that the model performs better than could be anticipated from local observations, thus gridded observations better represent the gridbox behavior described by the model. (3) For the threshold more than 5 mm, the distribution of number against the cluster size of the QPF is similar to observations. Especially, the best forecast is to the cluster size of 60 km. As for spatial distributions, in the east of Inner Mongolia, the Northeast China, North China, the region between the Yangtze River and Huaihe River, Shaanxi Province as well as the south of Gansu Province, numbers of QPF are almost the same as observed ones, but more to the south of Yangtze River, especially in the east part of Southwest China.
2011, 37(2):194-202.
DOI: 10.7519/j.issn.1000-0526.2011.2.009
Abstract:
Seeding effect evaluation is focused on whether the clouds and precipitation produced the expected significant changes after the cloud seeding, which is manifested in the process of macro and micro changes, thus it is necessary to learn something about cloud microphysical characteristics after cloud seeding. Based on the PMS data of an artificial precipitation in a convective line with trailing stratiform cloud system in Hebei Province on April 18, 2009, the cloud microphysical characteristics are studied. The results indicate that: accompanied by a significant reduction of the liquid water content after seeding, the average particle diameter increases from 20.4 μm to 23.9 μm; the spectrums of cloud particles have also undergone great changes in the structure. Simultaneously, the number of ice crystals reduces, but the size of precipitation particles increases significantly; in the cloudseeding affected zone on the ground an hour later, the accumulated rainfall reaches the maximum.
Seeding effect evaluation is focused on whether the clouds and precipitation produced the expected significant changes after the cloud seeding, which is manifested in the process of macro and micro changes, thus it is necessary to learn something about cloud microphysical characteristics after cloud seeding. Based on the PMS data of an artificial precipitation in a convective line with trailing stratiform cloud system in Hebei Province on April 18, 2009, the cloud microphysical characteristics are studied. The results indicate that: accompanied by a significant reduction of the liquid water content after seeding, the average particle diameter increases from 20.4 μm to 23.9 μm; the spectrums of cloud particles have also undergone great changes in the structure. Simultaneously, the number of ice crystals reduces, but the size of precipitation particles increases significantly; in the cloudseeding affected zone on the ground an hour later, the accumulated rainfall reaches the maximum.
2011, 37(2):203-212.
DOI: 10.7519/j.issn.1000-0526.2011.2.010
Abstract:
An operational challenge in using Doppler radar velocity field is that velocity measurements are often aliased. The experiments of velocity dealiasing are developed by introducing an Automated 2D MultiPass Doppler Radar Velocity Dealiasing Scheme from Zhang Jian (NSSL in USA) into typhoon data and severe convective storm data from Doppler radar (SA and CB) in China. This paper analyzed the characteristics of the new algorithm in detail, and proposed the schemes of data preprocessing. The results showed that the new algorithm from Zhang Jian could not only perform continuous velocity fields, but also possess improvements in regions near data voids and range folded observations. However, it has also disadvantages for isolated echo. At the same time, it is found that AP (anomalous propagation) clutters may affect the effect of the dealiasing.
An operational challenge in using Doppler radar velocity field is that velocity measurements are often aliased. The experiments of velocity dealiasing are developed by introducing an Automated 2D MultiPass Doppler Radar Velocity Dealiasing Scheme from Zhang Jian (NSSL in USA) into typhoon data and severe convective storm data from Doppler radar (SA and CB) in China. This paper analyzed the characteristics of the new algorithm in detail, and proposed the schemes of data preprocessing. The results showed that the new algorithm from Zhang Jian could not only perform continuous velocity fields, but also possess improvements in regions near data voids and range folded observations. However, it has also disadvantages for isolated echo. At the same time, it is found that AP (anomalous propagation) clutters may affect the effect of the dealiasing.
2011, 37(2):213-218.
DOI: 10.7519/j.issn.1000-0526.2011.2.011
Abstract:
The integrated meteorological observation system is the foundation of weather forecast service, and guaranteeing the integrated meteorological observation system operation steady and reliable has become the key point of the development of meteorological service in China. This paper expounded the construction structure, the technical route, the key technical methods, the characteristics and the functions of the Atmospheric Observing System Operations and Monitoring (ASOM) in China. Besides, combining with the current situations of China’s meteorological equipment monitoring and maintenance, it explored the potential benefits and the future improving direction of the ASOM system.
The integrated meteorological observation system is the foundation of weather forecast service, and guaranteeing the integrated meteorological observation system operation steady and reliable has become the key point of the development of meteorological service in China. This paper expounded the construction structure, the technical route, the key technical methods, the characteristics and the functions of the Atmospheric Observing System Operations and Monitoring (ASOM) in China. Besides, combining with the current situations of China’s meteorological equipment monitoring and maintenance, it explored the potential benefits and the future improving direction of the ASOM system.
2011, 37(2):219-225.
DOI: 10.7519/j.issn.1000-0526.2011.2.012
Abstract:
The integrated observation network operational monitoring system is the realtime professional platform for the meteorological observation equipment operational supporting in China. This paper gave the synthesis evaluation index system of meteorological facilities’ operation, maintenance and supporting in the integrated meteorological observation network in China, based on the equipment technique supporting engineering theory. The evaluation index system contained reliability, maintainability, supportability, daily job and economic categories, and then evaluated the integrated meteorological observation network from the facilities’ operational status, parameters, the observation data’s quality, the information transmission, the supply guarantee and the maintenance. Synthesis evaluation index system can not only make the integrated observation system operation stable and reliable, but also can provide information for decision makers and equipment manufacturers to select and to improve equipments in China.
The integrated observation network operational monitoring system is the realtime professional platform for the meteorological observation equipment operational supporting in China. This paper gave the synthesis evaluation index system of meteorological facilities’ operation, maintenance and supporting in the integrated meteorological observation network in China, based on the equipment technique supporting engineering theory. The evaluation index system contained reliability, maintainability, supportability, daily job and economic categories, and then evaluated the integrated meteorological observation network from the facilities’ operational status, parameters, the observation data’s quality, the information transmission, the supply guarantee and the maintenance. Synthesis evaluation index system can not only make the integrated observation system operation stable and reliable, but also can provide information for decision makers and equipment manufacturers to select and to improve equipments in China.
2011, 37(2):226-231.
DOI: 10.7519/j.issn.1000-0526.2011.2.013
Abstract:
The cumulative probability of lightning current amplitudes is one of the most significant parameters of lightning flash. Here presented are the statistical data of the firststroke current of lightning flash， collected by LLS (Lightning Location System) of ADTD type. Negative first strokes have traditionally been considered to produce the worst stress on the earth. The positive strokes have about the same median current value as the negative first strokes and longer fronts, thus producing less stress. However, their duration is longer than that of the negative strokes. Therefore, we estimate the firststroke current distribution in Chongqing using the empirical equations from the IEEE standards and the DL/T standards， respectively. It is found that the firststroke current distribution is changed with the polarity and the density of lightning stroke is different with the intensity of lightning current. Ｔhe LLSinferred peak current distribution estimate equation according to the Task Force recommendations into IEEE standards is effective, because the results according to the Task Force recommendations into IEEE standards fit more suitably to the statistical data than those according to the power team recommendations into DL/T standards.
The cumulative probability of lightning current amplitudes is one of the most significant parameters of lightning flash. Here presented are the statistical data of the firststroke current of lightning flash， collected by LLS (Lightning Location System) of ADTD type. Negative first strokes have traditionally been considered to produce the worst stress on the earth. The positive strokes have about the same median current value as the negative first strokes and longer fronts, thus producing less stress. However, their duration is longer than that of the negative strokes. Therefore, we estimate the firststroke current distribution in Chongqing using the empirical equations from the IEEE standards and the DL/T standards， respectively. It is found that the firststroke current distribution is changed with the polarity and the density of lightning stroke is different with the intensity of lightning current. Ｔhe LLSinferred peak current distribution estimate equation according to the Task Force recommendations into IEEE standards is effective, because the results according to the Task Force recommendations into IEEE standards fit more suitably to the statistical data than those according to the power team recommendations into DL/T standards.
2011, 37(2):232-236.
DOI: 10.7519/j.issn.1000-0526.2011.2.014
Abstract:
Using Kappa value and taking out the impact of chance and random this paper measures the interagreement of predictive results of three different air quality forecasting methods. The result shows that, the predicting results of both numerical model forecasting and synthesis experience forecasting are of medium identities, and they are not casual. The results measured are clear, and the differences from subjective assessment can be avoided. Furthermore, this research would promote the understanding of different forecasting models and be important to the improvement of forecasting accuracy.
Using Kappa value and taking out the impact of chance and random this paper measures the interagreement of predictive results of three different air quality forecasting methods. The result shows that, the predicting results of both numerical model forecasting and synthesis experience forecasting are of medium identities, and they are not casual. The results measured are clear, and the differences from subjective assessment can be avoided. Furthermore, this research would promote the understanding of different forecasting models and be important to the improvement of forecasting accuracy.
2011, 37(2):237-241.
DOI: 10.7519/j.issn.1000-0526.2011.2.015
Abstract:
In order to improve the ability of T639 model, the synoptic verification on its mediumrange forecasting in autumn is made in comparison with ECMWF and Japan models. The results show that the three models have good performances in the aspect of predicting the largescale circulation evolution and adjustment in the middle and high latitudes of Asian areas， but the T639 model shows a relative weak performance advanced 144 hours. The T639 model failed in forecasting the track and the JP model underestimated the intensity of FANAPI (No.1011). Compared with the T639 model and Japan model, the ECMWF model is better in forecasting most weather systems and gets the most similar to the observation.
In order to improve the ability of T639 model, the synoptic verification on its mediumrange forecasting in autumn is made in comparison with ECMWF and Japan models. The results show that the three models have good performances in the aspect of predicting the largescale circulation evolution and adjustment in the middle and high latitudes of Asian areas， but the T639 model shows a relative weak performance advanced 144 hours. The T639 model failed in forecasting the track and the JP model underestimated the intensity of FANAPI (No.1011). Compared with the T639 model and Japan model, the ECMWF model is better in forecasting most weather systems and gets the most similar to the observation.
2011, 37(2):242-248.
DOI: 10.7519/j.issn.1000-0526.2011.2.016
Abstract:
The following are the main characteristics of the general circulation of atmosphere in November 2010: there is a single polar vortex center in the Northern Hemisphere. The circulation presents a threewave pattern in middlehigh latitudes, where the European trough is stronger than the same period of normal years, and the East Asian trough closer to the same period; the polar vortex in the Novaya Zemlya and Siberia is negative anomalies, which show that the cold air is weaker than the same period of normal years; Northwest Pacific subtropical high area is close to the same period of normal years, with slightly weaker intensity, ridge line is located further south and western ridge point more eastward. The monthly mean temperature (3.5 ℃) is 1.4 ℃ higher than and the mean precipitation (11.8 mm) is 34.4% less than the same period of normal years. In this month, cold air was frequent and part of the Northeast China and inner Mongolia suffered from snow disasters; HuangheHuaihe regions and North China had drought increased; Hunan, Hubei, Sichuan, Chongqing, Guizhou etc. had heavy fog weather; there were sandstorms in central and western Inner Mongolia; Shandong and Chongqing etc. suffered from wind and hail damages.
The following are the main characteristics of the general circulation of atmosphere in November 2010: there is a single polar vortex center in the Northern Hemisphere. The circulation presents a threewave pattern in middlehigh latitudes, where the European trough is stronger than the same period of normal years, and the East Asian trough closer to the same period; the polar vortex in the Novaya Zemlya and Siberia is negative anomalies, which show that the cold air is weaker than the same period of normal years; Northwest Pacific subtropical high area is close to the same period of normal years, with slightly weaker intensity, ridge line is located further south and western ridge point more eastward. The monthly mean temperature (3.5 ℃) is 1.4 ℃ higher than and the mean precipitation (11.8 mm) is 34.4% less than the same period of normal years. In this month, cold air was frequent and part of the Northeast China and inner Mongolia suffered from snow disasters; HuangheHuaihe regions and North China had drought increased; Hunan, Hubei, Sichuan, Chongqing, Guizhou etc. had heavy fog weather; there were sandstorms in central and western Inner Mongolia; Shandong and Chongqing etc. suffered from wind and hail damages.
2011, 37(2):249-253.
DOI: 10.7519/j.issn.1000-0526.2011.2.017
Abstract:
The use of the color graph digitizing processing technology of the precipitation recording paper， is an effective exploration for rescuing the archives of climate history. The technology applying graph scanning and data processing, can scan pictures of precipitation recording paper, and can extract dropdown curve and convert precipitation recording papers into digitizing data of precipitation per minute, by the use of digitizing processing system of the precipitation recording paper.Then we can achieve a series of data set, including precipitation graph and precipitation curve, which based on minuteindex or hourindex .Finally we can get the standard file of precipitation intensity per minute or hour, so as to achieve the goals of saving data of precipitation autographic records wholly, actually and safely. The technology is the only way to change the current situation, and it makes full use of the implications of the information and reflects the value fully. By the use of the color graph digitizing technologic processing of the precipitation recording paper, and in the light of practical work experiences, we can analyze in detail the technologic problems during the course of digitizing processing and find their solutions.
The use of the color graph digitizing processing technology of the precipitation recording paper， is an effective exploration for rescuing the archives of climate history. The technology applying graph scanning and data processing, can scan pictures of precipitation recording paper, and can extract dropdown curve and convert precipitation recording papers into digitizing data of precipitation per minute, by the use of digitizing processing system of the precipitation recording paper.Then we can achieve a series of data set, including precipitation graph and precipitation curve, which based on minuteindex or hourindex .Finally we can get the standard file of precipitation intensity per minute or hour, so as to achieve the goals of saving data of precipitation autographic records wholly, actually and safely. The technology is the only way to change the current situation, and it makes full use of the implications of the information and reflects the value fully. By the use of the color graph digitizing technologic processing of the precipitation recording paper, and in the light of practical work experiences, we can analyze in detail the technologic problems during the course of digitizing processing and find their solutions.
2011, 37(2):254-256.
DOI: 10.7519/j.issn.1000-0526.2011.2.018
Abstract:
n recent years, the new automatic weather station (AWS) observation on the ground has played an increasing role in groundbased meteorological stations， and the data precheck is an important task to ensure the accuracy of meteorological data. With the applications of computer processing to the AWS report precheck, lots of logic errors between the data can be resolved. However, because the existing groundbased meteorological observation and forecasting business softwares on the function of precheck statements are not very well, and also by equipment failure of collection data and the impact of mistakes in operation, it is easy to make the record data of meteorological factors having the abnormal extremum. Analysis is conducted on the causes of such problems and the related treatment methods are proposed.
n recent years, the new automatic weather station (AWS) observation on the ground has played an increasing role in groundbased meteorological stations， and the data precheck is an important task to ensure the accuracy of meteorological data. With the applications of computer processing to the AWS report precheck, lots of logic errors between the data can be resolved. However, because the existing groundbased meteorological observation and forecasting business softwares on the function of precheck statements are not very well, and also by equipment failure of collection data and the impact of mistakes in operation, it is easy to make the record data of meteorological factors having the abnormal extremum. Analysis is conducted on the causes of such problems and the related treatment methods are proposed.
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ISSN:1000-0526 CN:11-2282/P