Current Issue

• A ANALYSIS OF CHARACTERISTICS OF THUNDERSTORM AND ARTIFICIALLY TRIGGERED LIGHTNING IN THE NORTH AND SOUTH OF CHINA
• Zhang Yijun;Liu Xinsheng;Xiao Qingfu
• 1997 Vol. 16 (2): 113-121. 
• Abstract ( ) PDF (314KB) ( )
• In this paper,characteristics of thunderstorm and artificially triggered lightning in the north and south of China were analysed The results indicate characteristics of thunderstorm and triggered lightning appear to be significant different in the north and south of China In the north triggered lightning was usually associated with positive charge overhead,which produces positive ground field by convention The discharge contained only upward moving negative leader followed by continuous current process and dipole current pulse without return strokes The maximum peak current of discharge was 1 kA and the charge transferred was several Coulomb In contrast to triggered lightning in the northern China,triggered lightning in the south of China were all with negative ground field(negative charge overhead) They appear to be more energetic than that in the northern China and usually contained several return strokes The peak current was more than 10 kA The electric field values at ground just before rocket launching were little different in the north and south of China The minimum triggered altitude of lightning discharge was 260 m in the north and maximum altitude was 300 m in the south of China And the differences of these characteristics were discussed in theory.

• THE CHEMICAL COMPOSITION AND CONCENTRATION OF ATMOSPHERIC AEROSOL AT WUDAOLIANG AND ITS SEASONAL VARIATION
• Liu Haiyan;Zhang Xiaoye;Shen Zhibao
• 1997 Vol. 16 (2): 122-129. 
• Abstract ( ) PDF (357KB) ( )
• The chemical composition as well as concentration and its seasonal variation of aerosol were analysed by use of the data of the concentrations of the chemical elements in the aerosol sampled at Wudaoliang during the periods September~October 1993,April~May and July~August 1994 The composition of aerosol in the lower atmosphere at Wudaoliang is basically same as the natural atmosphere, this means that the chemical elements of the soil are the main components of the aerosol, and the pollution materials caused by human activities is not at all serious The mean total concentration of aerosol in spring is about 1 75 times larger than that in autumn, but is nearly the same in summer,autumn and spring The elements of aerosol composition can be divided to three types according to their seasonal variation of the concentration; the typical crustal elements, the seasonal variations of their concentration are the same as that of the totals; the second is Na, its concentration in autumn is about 1 15 times larger than that in spring, the ratios of it to Al or Fe are as same as that of crustal mean in spring, but about 2 times larger in autumn;the third is some rare earth elements, their concentrations are nearly the same in the year.

• EXPERIMENTAL STUDY OF REGIONAL AIR QUALITY MODEL OVER COMPLEX MOUNTAIN-VALLEY TERRAIN
• Yan Yuping;Chen Changhe;Tian Wenshou
• 1997 Vol. 16 (2): 130-139. 
• Abstract ( ) PDF (364KB) ( )
• Simulation of regional air quality over complex terrain is difficult because of the changeable flow With the need of total air pollution control and environmental programing, an air quality model which is suitable to mountain-valley city is developed in this essay:(1) a three-dimensional boundary-layer model over complex terrain is used for offering the boundary-layer meteorological elements which are need for the diffusion model (2) The three-dimensional advcution diffusion model and Gauss model over complex terrain are respectively used to simulate the surface SO ₂ concentrations that are made by low sources(including area sources) and elevated point sources, two of the simulated concentrations are added on the corresponding grids The verification of the model indicates that the simulated results are well compatible with the available observations So this model can be used in the work of regional air quality control and management over complex terrain.

• THE PRELIMINARY NUMERICAL EXPERIMENTS OF EFFECT OF ANOMALOUS SNOW COVER OVER PLATEAU IN WINTER ON EAST AND SOUTH ASIAN SUMMER MONSOON
• Fan Guangzhou;Luo Siwei;Lü Shihua
• 1997 Vol. 16 (2): 140-152. 
• Abstract ( ) PDF (522KB) ( )
• A general circulation model, which has been coupled with the simple biosphere model,was used to assess the influence of anomalous Plateau snow cover in winter on the east and south Asian summer monsoon circulation and rainfall The results point out that the summer monsoon in the east and south Asia would be weakened when the winter snow cover over Plateau is increased The main features are that the precipitation is reduced in the east and south Asian summer monsoon region and the Somali jet,the Indian monsoon trough and the Indian southwest air flow are weakened In addition,we have also examined the sensitivity of the effects of the snow cover over the Eurasia and the east Plateau on the Asian monsoon It is found that the Plateau snow cover was more sensitive than that over Eurasia If only the east Plateau snow cover was increased,the precipitation in the east region of the Plateau, such as in east Asia,would be more reduced,but it might be increased in the area of the east and south India and the bay of Bengal.

• NUMERICAL EXPERIMENTS OF THE INFLUENCE OF QINGHAI-XIZANG PLATEAU ON THE MEAN CIRCULATION OF ASIAN MONSOON
• Wu Aiming;Ni Yunqi
• 1997 Vol. 16 (2): 153-164. 
• Abstract ( ) PDF (584KB) ( )
• An atmospheric general circulation model with 9 sigma levels in the vertical and rhomboidal trunction at wave number 15 in the horizonal is run for 10 years with and without Qinghai-Xizang Plateau respectively(called TP and NTP experiments hereafter) Comparing the results of TP and NTP experiment,the influence of Qinghai-Xizang Plateau on the mean circulation of Asian monsoon is investigated It is found that obvious differences between the mean circulations of Asian monsoon with and without Qinghai-Xizang Plateau exist either in summer or in winter Were Qinghai-Xizang Plateau moved away,both position and strength of the South Asian low in the lower layer and the anti-cyclonic circulation in the upper layer as well as the subtropical high in summer would change greatly,so does the continental cold high in winter The East Asian trough in winter and the cross-equatorial flow near Somali in summer are stronger with Qinghai-Xizang Plateau than those without it The intensity and distribution of precipitation are also affected by Qinghai-Xizang Plateau Furthermore,the seasonal variation of the subtropic high and rain belt have a close relation with Qinghai-Xizang Plateau.

• NUMERICAL MODELING FOR EFFECT OF VEGETATIVE DISTRIBUTION ON HEAVY RAIN PROCESSES OCCURRED IN EAST SIDE OF QINGHAI-XIZANG PLATEAU
• Chen Wanlong;Wang Geli;Zhou Suoquan
• 1997 Vol. 16 (2): 165-173. 
• Abstract ( ) PDF (330KB) ( )
• In this paper,the vegetative parameterization developed by Deardorff was introduced into the limited area fine mesh model developed by Yan Hong et al and was used to simulate two heavy rain processes occurred in the Qinghai-Xizang Plateau downstream areas It is shown that the model run is still stable and the prediction for precipitation intensity is certainly improved.

• SINGULAR VALUE DECOMPOSITION AND ITS APPLICATION TO TELECONNECTION BETWEEN LAND AIR TEMPERATURE IN NORTH AMERICA AND RAINFALL IN CHINA
• Wei Fengying;Cao Hongxing
• 1997 Vol. 16 (2): 174-182. 
• Abstract ( ) PDF (328KB) ( )
• In this paper,some mathematical computational methods on singular value decomposition(SVD) are described in detail in matrix theory SVD is a technique in analyzing teleconnection between two fields As an example,the SVD modes based on two fields between summer rainfall in China and land air temperature in North America are computed and credibility of teleconnection analyzed by SVD and the implication for forecasting are also discussed The results show that winter land air temperature over North America has premonition for forecasting summer rainfall over both the middle and lower reaches of Changjiang River and the northwestern part of China.

• THE REAL-TIME PRECIPITATION PREDICTION FROM MAY TO SEPTEMBER 1995 WITH A η-COORDINATE MODEL
• He Guangbi;Teng Jiamo;Xiao Yuhua
• 1997 Vol. 16 (2): 183-190. 
• Abstract ( ) PDF (289KB) ( )
• In this paper,the precipitation predictions in 1995's summer by the operational η-coordinate model with step mountain representation are displaied,and several important precipitation processes are also given The results reveal that the model is of better abilities on the presage of weather conversion,and the area,intensity and duration of precipitation Of course,there are some defects in the model,which are just what we are going to improve next.

• STUDY ON CALCULATION OF FIELD EVAPOTRANSPIRATION FOR DIFFERENT CROPS BY MEANS OF THE PRIESTLEY-TAYLOR FORMULA
• Liu Shaomin;Liu Zhihui
• 1997 Vol. 16 (2): 191-196. 
• Abstract ( ) PDF (215KB) ( )
• In the paper,based on the measured data in field, comprehensively considering the meteorological conditions,crop and soil state,we established the calculation model of field evapotranspiration for different crops (cotton,maize and winter wheat) by means of the Priestley-Taylor formula The model is convenient to calculation,using only routine meteorological and agrometeorological data,it is valuable in utilization.

• THE RELATIONSHIP BETWEEN MESO-β SCALE TOPOGRAPHY WITH HAIL AND HEAVY RAIN OVER GUIZHOU PROVINCE
• Yang Yang;Liu Yilan
• 1997 Vol. 16 (2): 197-203. 
• Abstract ( ) PDF (281KB) ( )
• The topography height fields of Guizhou mid-west areas were separated into meso-β scale and larger scale topography fields by using low pass filter method It is found that the special wave pattern and larger longitudinal gradient of meso-β scale topography are related with the frequent occurrence of hail and heavy rain The latitudinal and longitudinal gradients of larger scale topography are also related with the occurrence of hail and heavy rain From case analyses of hail and heavy rain,the larger up-motion velocity of meso-β scale topography is close related with the occurrence of hail and the strength variation of precipitation in especially heavy rain area.

• COMPARING CHARACTERISTICS OF BUDGET FOR DIVERGENT AND ROTATIONAL COMPONENTS OF KINETIC ENERGY IN HEAVY RAIN AND NO-HEAVY RAIN PROCESSES
• Duan Xu;Sun Jihua;Wang Zhongxing
• 1997 Vol. 16 (2): 204-209. 
• Abstract ( ) PDF (214KB) ( )
• By using budget equations for rotational and divergent components of kinetic energy,the area-time averages of each term are computed for 200~400,400~600,600~800 hPa layers to describe energetics of the lower,middle and upper troposphere for heavy rain and no-heavy rain processes The results show that the generation,conversion and transport for divergent components of kinetic energy are different and the signs of the major energy budget are opposite in heavy rain and no-heavy rain processes.

• A MULTI-CHANNEL REAL-TIME DATA COLLECTION AND ROLLING DISPLAY SYSTEM FOR SYNCHRONOUSLY MEASURING ATMOSPHERIC ELECTRIC FIELD AND CURRENT
• Zhang Guangshu;Qie Xiushu
• 1997 Vol. 16 (2): 210-215. 
• Abstract ( ) PDF (217KB) ( )
• This paper describes the principle, method and programming of a long duration, multi-channel PC recording and real-time display system for measuring atmospheric electric field and Maxwell current density Through field experiment, the synchronous digital data of field and current density were recorded automatically The measured signal is continuously displayed on VGA monitor with analog form Digital signal is stored on hard disk in real-time for later processing or display.

• THE MEASUREMENTS OF LIGHTNING PEAK CURRENT WITH MAGNETIC TAPE DETECTOR
• Xiao Qingfu;Wang Caiwei
• 1997 Vol. 16 (2): 216-219. 
• Abstract ( ) PDF (157KB) ( )
• The method for measurement of lightning current by use of the demagnetization of ordinary audio tape is a simple with the advantage of low cost and easy to set up,and very effective in field work The peak currents of triggered lightning were successfully obtained with this method in 1994 and 1995.

• A RAINFALL RECORDER BY MEANS OF TECHNOLOGY OF SINGLE CHIP PROCESSOR
• Song Xinmin;Qiu Chuantao;Wang Zhijun
• 1997 Vol. 16 (2): 220-224. 
• Abstract ( ) PDF (189KB) ( )
• In this paper,we developed a tipping-bucket raingauge by means of technology of single chip processor,in comparison with the conventional rainguage,because it uses EEPROM storage of the technology of single chip processor in method of recording data,it has characteristics of real-time recording rainfall,high accuracy,little human effects and free-maintain etc This system has extensive and potential application in field experiments of meteorology,hydrology,ocean and agriculture.