Current Issue

• NUMERICAL SIMULATIONS STRATOSPHERIC STATIONARY CIRCULATION IN WINTER AND SUMMER
• Huang Ronghui
• 1984 Vol. 3 (3): 1-13. 
• Abstract ( ) PDF (806KB) ( )
• Numerical simulations of stratospheric stationary circulation in winter and summer are made by using a quasi-geostrophic, 34-level model with the Rayleigh friction, the effect of Newtonian cooling and the horizontal eddy thermal diffusivity included in a spherical coordinate system. The method proposed by Lindzen and Kuo is used to solve a complex two-order parial differential equation. The computed results show that the vertical distributions of amplitude and phase of stationary planetary waves and the stationary disturbance patterns in the stratosphere, responding to forcing by the northern hemispheric topography and heat sources, are in good agreement with the distributions obtained from the observed data. This can explain that the stratospheric stationary disturbance patterns are, mainly, due to propagation of the stationary disturbances responding to forcing by topography and heat sources from the troposphere into the stratosphere.

• NUMERICAL SIMULATIONS STRATOSPHERIC STATIONARY CIRCULATION IN WINTER AND SUMMER
• Zhou Yunhua
• 1984 Vol. 3 (3): 14-23. 
• Abstract ( ) PDF (726KB) ( )
• On cloudless days, atmospheric thermal radiation were measured by the Eppley precision infared radiometers at six stations in the period of the Qinghai-Xizang Plateau Meteorological Experiment(QXPMEX) during May and August, 1979. Based on observational data measured ten times a day, clear sky atmospheric apparent emissivities are calculated and compared with the isothermal emissivity of mixed layer of water vapour, carbon dioxide and ozone. The results show that the atmospheric apparent emissivities are greater than the isothermal emissivity of mixed layer. The deviation shows a diurnal variation with a maximum of 0.10, which appeares at noon in general, corresponding to the isothermal emissivity of mixed layer of 15% or 0.06 cal/cm ² ·min. The deviation can be related to the turbidity during daytime. The measured values of the atmospheric apparent emissivity are compared with the estimated values from the empirical formulae in which the screen air temperature is adopted as the variable. and it shows that the characteristics of the diural variaton for the deviations of the measured values to the estimated values are the same both over the Qinghai-Xizang Plateau and the plain.

• A COMPUTATION METHOD OF LONGWAVE RADIATION TRANSMISSIVITIES FOR WATER VAPOUR AND CO ₂
• Qian Yongfu
• 1984 Vol. 3 (3): 24-37. 
• Abstract ( ) PDF (972KB) ( )
• A method of computing longwave radiation transmissivities for water vapour and CO ₂ has been proposed in this paper.According to the experimental data of absorption bands of water vapour and CO ₂ we divide their spectra into 10 and 2 basic intervals, respectively, which we call basic wave bands. Some common formulas are derived and by the use of them we have calculated the transmissivities of water vapour and CO ₂ at the temperatures 220°,260° and 300°K.The comparison of the results with those computed by the so-called accurate formulas and by Kuo's method shows that the method in this paper is good enough to obtain the transmissivities and better than Kuo's.

• A STUDY OF THE EFFECT OF ATMOSPHERIC AND SURFACE PROPERTIES ON THE SOLAR RADIATION BUDGET
• Zhong Qiang
• 1984 Vol. 3 (3): 38-49. 
• Abstract ( ) PDF (796KB) ( )
• Based on the methodology of a two-stream approximation in vertically inhomogeneous atmosphere(Hense et al. 1982) the effects of water vapour, aerosol, surface albedo and surface elevation on the solar heating and the solar radiation budget of the earth-atmosphere system in cloudless model atmospheres were discussed.For the purposes of radiation-climate research and the application of satellite radiation measurements over the Tibetian plateau area, the solar heating and solar radiation budget for plateau's realistic atmospheres were calculated and compared with the results for midlatitude model atmospheres.

• THE STRUCTURE OF 500mb SHEAR LINE AND LARGE SCALE CIRCULATION OVER QINGZANG PLATEAU IN SUMMER
• Qiao Quanming;Tan Haiqing
• 1984 Vol. 3 (3): 50-57. 
• Abstract ( ) PDF (493KB) ( )
• It is found through analysis of the shear line over Qingzang Plateau from May to August in 1979 by the use of scientific experimental data that the plateau shear line can be generated respectively in the easterlies, in the westerlies and in the neighourhood of the zero line between easterlies and westerlies. Owing to the dissimilarities of the background of large scale circulations, the corresponding thermal and dynamical structures differs significantly, too. According to their properties, we may classify the shear lines into three kinds, namely, the warm, the baroclinic and the cold ones, in which the thickness of cold shear line may reach a level over 300mb.

• RESULTANT ANALYSIS OF LARGE-SCALE HEAVYRAIN STORM OVER SICHUAN BASIN
• Yu Shuhua
• 1984 Vol. 3 (3): 58-67. 
• Abstract ( ) PDF (658KB) ( )
• 23 cases of large-scale heavyrain storms over Sichuan Basin in 1959-1982 are selected and divided into three types. Resultant analysis are then made respectively for each type according to their middle and low-level tropospheric potential height field and wind field. It is shown that each type of heavyrain storm occurs respectively in different synoptic characteristic environment.These conclusions canbe applied to forecast the large-scale heavyrain storm over Sichuan Basin.

• THE INITIAL FRONTS OF FIRST RETURN STROKES
• Guo Changming
• 1984 Vol. 3 (3): 68-75. 
• Abstract ( ) PDF (496KB) ( )
• The wave form of F section in the first return stroke is analyzed in this paper. From the analysis, it seems impossible for F process occuring during the attachment process. The front process of the first return stroke(F)appears just after the attachment process and moves downward from the contact point to the strike point on the ground, and moves upward along the stepped leader channel, too.The front moves along the channel ionized by the stepped leader and connecting leader,while the generally accepted return stroke moves along the channel more deeply ionized by the front. Preliminary estimate shows that this front process could radiate enough peak electric or magnetic fields which are in good agreement with the data from the field observation. This front process could also explain the optical signal observed. Further simultaneous observation of optical and electric or magnetic signals radiated from the lightning would eventually prove whether there is really such a process or not.