Current Issue

• THE INTER-HEMISPHERES MONSOONS-AN IMPORTANT MECHANISM OF THE INTERA-CTION BETWEEN NORTHERN AND SOUTERN HEMISPHERIC ATMOSPHERE
• Gao Youxi;Li Ci
• 1982 Vol. 1 (1): 1-13. 
• Abstract ( ) PDF (860KB) ( )
• In this paper the formation and the role of the inter-hemispheres' monsoon has been discussed.It is pointed out that the monsoon phenomenon of inter-hemisphere over eastern hemisphere play an important role in the global general circulation of atmosphere.The cross equator flow in troposphere over equator region are nearly opposite in winter and summer in eastern hemisphere. The seasonal variation of monsoon trough and mean meridional circulations are also very marked. The formation of the inter hemisphere monaoon are not only caused by seasonal variation of sun's altitude but also caused by the difference of land sea distribution. However, the inter-hemisphere monsoon of western hemisphere is not obvious or even not able to be feeled. The most part of the cross equator trans-fer of various physical quantities of inter-hemisphere are carried out by the meridional wind over the monsoon region. It is clear that the inter-hemispheres' monsoon is an important mechanism of the interaction, balance and modulation between northern and southern hemisphere atmosphere.

• THE ENERGY BUDGETS OF SEVERE RAINFALLS IN THE MIDDLE YELLOW RIVER REGIONS
• Hou Yiru;Bai Zhaoye
• 1982 Vol. 1 (1): 14-23. 
• Abstract ( ) PDF (1761KB) ( )
• In this paper average structure and large scale heat, moisture and momentum budgets of heavy rainfalls for two typical cases are examined. An important result is that the height of nondivergent level is about 500mb. There exists a convergence below it and a divergence above. Large-scale upward motions dominate the whole troposphere with a maximum value at nondivergent level. The structure is different from that of the severe convections. Total heat energy (heat and moisture) transports upward due to sub-grid-scale convections. Therefore there exists a net decrease in the lower part of the troposphere and a net increase in the upper part of it. There is a horizontal moisture convergence below 500mb and a horizontal moisture divergence above. The moisture of upper troposphere is originated from the lower part. Over heavy rainfall areas there are apparent sinks of moisture in deep layer due to condensation. Momentum is transported downward in the middle-upper troposphere and the maximum flux is about 3-5 dyne/cm ². Subgrid-scale kinetic enery contributes a great part to the energy budgets.

• THE ENERGY VARIATION OF THE UNDERLYING SURFACE AND THE CHANGES OF THE WEA-THER AND CLIMATE
• Tang Maocang;Sun Shuhua;Zhong Qiang;Wu Shijie
• 1982 Vol. 1 (1): 24-34. 
• Abstract ( ) PDF (1927KB) ( )
• Firstly, we have analysed relationships between some cases of the ground temperature departure and the following distribution of precipitation departure. According to these instances, it may be concluded that the ground temperature is one of the important factors for the weather and climatic changes. Secondly, we have discussed the result of the summer half-year fore-casting from 1975 to 1979, by using the point of view of this paper. It is emphasized that this method can be applied to the qualitative forecasting. Finally, according to some simplified postulations, we have obtained a simple formula for the atmospheric oscillation: E _m=λT _mo/√τ(τ: the period of the oscillation; T _mo: the amplitude of the earths surface temper-ature;E _m: the amplitude of the energy flux for the same oscillation; constant).It may be pointed out from the above formula that: E _m∝1/τ(E _m·τ≈5×10 ²cal/cm ²) for the long range weather changes.E _m is an order smaller than that has been supposed by Sawyer ^[5](1/10 of the long wave radiation).

• THE MONTHLY MEAN ATMOSPHERIC HEATING FIELDS AND VARIATIONS OF CIRCULATION IN MAY-JULY OVER EAST ASIA
• Zhang Ningdan;Qian Zhengan;Luo Siwei
• 1982 Vol. 1 (1): 35-42. 
• Abstract ( ) PDF (1632KB) ( )
• In this paper the monthly mean variations of circulation are analyzed and the atmospheric heating fields are calculated in May-July over East Asia. The appearing of the atmospheric heating field over the plateau is earlier in lower layer than in the upper layer and is earlier in the western region of the Plateau than in its eastern region. The distribution of the atmospheric heating field over the ocean and continent indicates opposite signs. It is found that the change of the monthly mean zonal west wind on 500mb surface over the plateau and its surrounaings is slow from May to June and is sudden from June to July. But the variation of the zonal wi-nd on 200mb surface shows a sudden change from May to June.The former change (on 500 mb) may be due to that the heating effect of the Plateau is the strongest in July and the later variation (on 200 mb) is owing to the seasonal circulation change in the more large scale.

• A NUMERICAL STUDY ON THE RELATION BETWEEN CONVECTIVE MOTIONS AND HORIZO-NTAL VORTICITY IN SHEAR FLOW
• Xu Wenjun
• 1982 Vol. 1 (1): 43-52. 
• Abstract ( ) PDF (850KB) ( )
• A two-dimensional model has been developed. It contains cumulus dynamic equations and a vorticity equation.According to these equations, numerical experiments have been done, the results are as follows; 1 In a vertical wind shear flow,the mechanisms of horizontal vorticity generation of convection motion are convergence and tilting effects. 2 The intensity of vorticity is proportional to the intensity of wind shear. 3 The effect of tilting term is mainly in forming a pair of antisymmetric vorticity distribution to north and south sides of the convection cell, the effect of convergence term makes horizontal distribution of the pair vorticities more practical. 4 The reason for maximum strength vorticity which could situa ted sta-bly at the lower part of convection motion is mainly due to the effect of atmospheric density decreasing with heights. 5 The duration of maintaining maximum vorticity is nearly corresponding to developing time of convection motion but with a phase being later about three minutes than the later. It is found that the calculated results are roughly similar to the observed data.

• HAILFALL IN THE PING LIANG REGION AND ITS RELATION WITH THE ENVIRONMENT FIELD ELEMENTS
• Liu Quangen;Ma Jide
• 1982 Vol. 1 (1): 53-62. 
• Abstract ( ) PDF (696KB) ( )
• In this paper,basing on the hail damage data of May-Sept, of 1973-1979 in the Ping Liang region, we have analysed the characteristics of hailfall and its relation with the environment meteorological elements. The results shows: l.The average hail damage days over Ping-Liang area are 18.3 days in a year.The geographical distribution of occurrence of hail appears in the wave feature with a wavelength about 42 km.The lee effects of Liu-pan mountain behave obviously. 2.The thermodynamic instability of stratification in the atmosphere is an important factor for hail fall in Ping-Liang region. 3.The effect of the vertical shear of horizontal wind on the development of thunderstorm differs with its various heights of intensive shear.The intensive shears of thunderstorm days appear in the upper troposphere (7-9 km M.S.L.), which is above the centrum of intensity echo(4. 6km). The intensive shear of large-hail days is located at the middle troposphere (5-7km M.S.L.), which is delow the centrum of intensity echo(8. 6-10.1km). The intensive shear of morderate and small hail days are corresponded with the centrum height of intensity echo(abont 7km). 4.The intensity of hailfall bears a close relation to the thickness of the negative temperature zone, the greater is the thickness of the negative temperature zone, the more the hailfall is intensive. 5.The water vapour in the morninng of hail days requires much moist-ure in lower troposphere but less and drier in the middle and upper ones. The thunderstorm is possible to develop when more moisture content exis-ts in all tropospheres, but it will be of no benefit to hailfall.

• A PRELIMINARY STUDY ON THE ELECTRIC FIELD OF THUNDERSTORM
• Chen Qian;Guo Changming;Ye zongxiu
• 1982 Vol. 1 (1): 63-67. 
• Abstract ( ) PDF (383KB) ( )
• The ground electric field produced by thunderstorm was studied by using field mill, lightning counter and weather radar.It was found that the charge distribution of thunderstorms in Pingliang,Gansu, is generally with a upper positive charge zone extending upward in the upper layer and a lower negative charge zone of which the horizontal dimension may reach tens of hilometers.In addition there is a minor positive charge area expanding horizontally over 10 km near cloud base. The ground electric field within precipitation area appears to be positive. The change of electric moment of thundercloud due to a lightning discharge ranges from 40 to 300 ckm and is 120 ckm on the average. With the growing of clouds,i.e.with the rising of intensive radar echo height, the number of lightning discharges having the electric moment changes more than 180 ckm increases.The initial recorery rate of electric field after a lightning discharge is l/7sec-1 on the average. A possible mechanism responsible for explaining the characteristics of electric field of thunderstorm i.s djscussid briefly.

• ANALOG REFLECTIVITY FACTOR-HEIGHT SCOPE FOR RADAR
• Liao Shimin;Chen Shuhui
• 1982 Vol. 1 (1): 68-75. 
• Abstract ( ) PDF (529KB) ( )
• This paper illustrates briefly, with a block diagram of the instrument the operational principle of analog reflectivity factor-height scope for radar.A brief description to the special demand of circuits is also. Presented.Lastly, the identification method of this instrument and its operation are described.

• THE DOUBLE CHANNEL LIGHTNING COUNTER(DB-TYPE)
• Xu Longjia;Lu Kunliang
• 1982 Vol. 1 (1): 76-80. 
• Abstract ( ) PDF (333KB) ( )
• There are some defects in various kinds of lightning couters,for example, the function of anti-interference isn't good and the range finding is too far or its price is much expensive.While the Double Channel Lightning counter has the advantage to overcome the defects as stated above. It is suitable for the identification between hailstorm and thunderstorm. Through the tests for several years,the accuracy in identification is higher than eighty per cent.In this paper the principles of circuit and the adjusting method of the lightning counter, etc, are discussed.