Current Issue

• AN ECONOMIC METHOD FOR CALCULATWN Of? LONG WAVE RADIATION COOLING RATE IN THE ATMOSPHERE
• Qian Yongfu
• 1985 Vol. 4 (2): 101-108. 
• Abstract ( ) PDF (488KB) ( )
• An economic method for calculating the long wave radiation cooling rate in the atmosphere is developed. It can be called recurrence method, because the upward and downward long wave radiation fluxes at the atmospheric levels are computed one by one recurrently. Computation shows that the method has enough accuracy and is time-saving. A tabulation method for calculation of long wave transmissivities is also developed.

• THE EFFECTS OF THE QINGHAI-XIZANG PLATEAU ON THE MEAN GENERAL CIRCULATION IN EAST ASIA IN WINTER
• Wang Anyu;Wang Qianqian
• 1985 Vol. 4 (2): 109-120. 
• Abstract ( ) PDF (856KB) ( )
• The effects of the Qinghai-Xizang Plateau orography on East Asian atmospheric circulation in Winter is investigated by using the P-σ incorporated coordinate 5-layer primitive equation numerical model(1) and the January heating fields in 1979 computed by Yiao et al.The initial geopoten-tial heights used in the model are taken from mean January zonal average. We have done 2 experiments of Simulation(HH scheme and HN scheme)(5). Some numerical simulations show that the heating fields in East Asia in Winter has a secondary importance in comparison with the dynamic effect of the Plateau.The synoptic patterns in Winter in East Asia mainly depend on the dynamic effect of the topography while the intensities of the atmospheric systems are enhanced by the thermal effect of the heating fields.

• THE DISTRIBUTION AND STRUCTURE OF WATER VAPOUR FLUX FIELD OVER EAST ASIA IN SUMMER
• Qu Yanlu;Zhang Chengdao
• 1985 Vol. 4 (2): 121-128. 
• Abstract ( ) PDF (534KB) ( )
• Using total water vapour flux expression(1/g)( )=(1/g)( )+(1/g)( ) the water vapour flux fields over East Asia in July for the period of 1980-1982 are calculated and analysed, the distribution and structure of water vapour flux field over East Asia in Summer are further known.

• THE CLIMATIC FEATURES AND THE CHARACTERISTICS OF GENERAL CIRCULATION ABOUT THE BREAK STAGES AND ACTIVE STAGES OVER THE QINGZANG PLATEAU'S RAINY SEASON DURING 1979
• Qu Zhang
• 1985 Vol. 4 (2): 129-138. 
• Abstract ( ) PDF (671KB) ( )
• In this paper we firstly base upon the pattern of curves showing the daily mean precipitation during June-August for years and stations in the Qingzang Plateau and, then, differentiate the precipitation area into three portions, namely, the eastern, middle and western ones.As shown Jrom the above data, the rainy season starts and develops from east to west.The corresponding data in 1979 shows a consistency with the so said features. According to a certain standard, the plateau's rainy season from June to August of 1979 is divided into a break stage and an active stage.Then, the characteristics of circulation in these two stages are studied respectively.For the active period,it may be summarized into two essential points:in the subtropical westerlies at the upper layer of troposphere, both the latitudes and intensities of pressure(ridge) in European district are much higher than those in Asia; at 300mb and 500mb, besides an air flow by north in the north, there is also a flow by south over the Qingzang Plateau and its southern area. While for the break stage, the positioning of both European and Asian pressure(ridge) are quite the reverse, and there is only an air flow by south over the plateau and its southern side. The European and plateau regional mean values for 200mb and 500mb show that, in the active rainy season, the height field value in Europe is higher than that in Asia; while in the break of the rainy season, the case is reverse. Throughout the processes within the period of June to August of 1979, the height field values vary alternately in this manner, and the values in the Plateau region itself oscillates synchronously, too.

• A NEW METHOD FOR ANALYSING THE MEAN MONTHLY SEA LEVEL PRESSURE MAPS IN THE TIBETAN PLATEAU AREA AND ITS PRIMARY RESULTS
• Tang Maocang;An Lin
• 1985 Vol. 4 (2): 139-148. 
• Abstract ( ) PDF (690KB) ( )
• Another fundamental rule for analysing the sea level pressure maps in the high plateau area is proposed in this paper, that is the equalization of geostrophic winds between the sea level maps and the ground surface. According to this rule, the monthly mean sea level pressure maps from January to December are analysed.The geostrophic wind accounted by these maps are in agreement with the surface prevailing wind over the Tibe-ton Plateau quite well, It means that the rule mentioned in this paper is much better than the "linear interpolation" rule by the pressure data surrounding the Tibetan Plateau.

• A TEST OF CALCULATING TURBULENT HEAT FLUX NEAR THE GROUND OVER THE QINGHAI-XIZANG PLATEAU
• Ma Yutang;Xu Zhaosheng;Zhou Shuxiu
• 1985 Vol. 4 (2): 149-156. 
• Abstract ( ) PDF (502KB) ( )
• In view of the fact that the nqrmal diffusion method of calculating turbulent heat flux near the ground does not suitable for the Plateau region.In this paper, proceeding from the turbulent similarity theory and ac cording to the certain special data of Geermu during the period of the QXPMEX, the authors established a semi-empirical formula to calculate the turbulent heat flux near the ground over the Q-X Plateau. Using this formula the turbulent heat fluxes of all the stations of QXPMEX have been calculated.The tests of all these calculations show that the results were reasonable.

• AN ANALYSIS OF VERTICAL TRAJECTORY OF HAILSTONE GROWTH BY USING CRYSTAL SIZE AND BUBBLE CONCENTRATION
• Yang Songxi;Ren Dongsheng;Chen Yushan;He Dade;Hu Zhaoquan;Xu Yangchun
• 1985 Vol. 4 (2): 157-166. 
• Abstract ( ) PDF (4781KB) ( )
• Some thin slice photographs of 6 hailstones(2.6-5.9cm dia.) collected on the ground in the area of the Liu-Pan mount are given in this paper, and their vertical growth trajectories have been calculated b.y Macklin scheme[13]. The average growth duration of 6 embryoes(3-6mm dia.) of the hailstones is 165 sec. the formation height of frozen droplets is about 1200m lower than that of the graupel. The average growth duration from diameters 0 to 3cm of the 6 hailstones is 1073 sec. The growth duration of the largest hailstone is 2302 sec.(0-5.9cm dia). The growing level of these hailstones is from 5700 to 8440m(a, s. 1) and the temperature is from-9.2 to-24.2℃.The credibility and some disadvantages of Macklin scheme are also discussed in this paper.

• THE JUSTIFICATION OF POINT CHARGE MODEL TO GROUND FLASHES AND THE PIECE-WISE STREAMER MODEL OF CLOUD FLASHES
• Liu Xinsheng
• 1985 Vol. 4 (2): 165-175. 
• Abstract ( ) PDF (750KB) ( )
• This paper discusses the justification and possible error when using single point charge model to calculate the charge parameters neutralized by a ground flash from multi-station measurements of electric-field changes. Assuming the charge neutralized by a ground flash is distributed uniformly on a disc, to simulate the observation facts that the horizontal extent of negative charge distribution within thundercloud is much greater than its vertical extent, the single charge model is a good approximation if the disc dimension is small in compare with its height above ground; conversely it will overestimate the charge height and charge value. The second part of the paper proposes a piecewise-linear streamer model for intracloud discharge. The polarity,propagating direction and speed of initial streamer can be determined by using the model and ground multistation measurements of field changes. The data analysis to a few cases of intraclod flashes indicates that the discharges were initiated by an upward-propagating negative streamer. The initial streamer propagated upward at speeds of the order of 10 ⁵m/s, similar to that of step leader of ground flashes, and reached the maximum extension in 10-30 milliseconds after initiation. These results are not consistent with the earlier qualitative estimation by other investigators that the streamer extends continuo-sly for half the duration of the flash or more and its propagting speed is slow in nature.