Current Issue

• ESTIMATION OF THE PLANETARY ALBEDO AND EMISSION OVER THE TIBETAN PLATEAU FROM AVHRR-DATA
• Zhong Qiang
• 1984 Vol. 3 (2): 1-9. 
• Abstract ( ) PDF (1516KB) ( )
• A method of estimating the planetary albedo and outgoing longwave flux from AVHRR-data is described. the two-stream approximation radiation models (Heuse et al., 1982 and schmetz et al., 1981) were used to establish the relation between the total planetary albedo and filtered albedos (for 0.58-0.68μm and 0.725-11.1μm)and the relation between the total outgoing lorgwave flux and spectral flux (for 10.55-11.46 μm) respectively. The algorithm developed is applied to the Tibetan plateau area. A case on Feb. 15, 1982 has been analysed over this area.

• THE DIAGNOSTIC ANALYSIS FOR POTENTIAL VORTICITY AND EQUIVALENT POTENTIAL VORTICITY DURING THE "81.7" HEAVY RAIN
• Sheng Hua
• 1984 Vol. 3 (2): 10-18. 
• Abstract ( ) PDF (598KB) ( )
• The diagnostic analysis is made of potential vorticity and equivalent potential vorticity for the "81.7" heavy rain. The potential vorticity or equivalent potential vorticity is a physical variable combined dynamic effect with thermodynamic effect. Therefore, it is more available to show the characters of synoptic systems. This diagnostic study demonstrates: the centres of potential vorticity and equivalent potential vorticity remove from the northeast of Qinghai-Xizang plateau to the Si Chuan basin. The areas of the heavy rain are primarily in accordance with the centres of potential vorticity or equivalent potential vorticity.

• THE NUMERICAL EXPERIMENTS FOR THE OROGRAPHIC EFFECT OF TIBETAN PLATEAU UPON ITS NEIGHBOURING FLOW FIELDS IN SUMMER
• Luo Siwei;Wang Anyu;Zhang Jungen
• 1984 Vol. 3 (2): 19-30. 
• Abstract ( ) PDF (820KB) ( )
• In this paper the numerical experiments have been performed by using the simple two-layer p-σ primitive equation model in which we take the Tibetan Plateau as a ellipsoid and the zonal wind and the stationary heat sources as the initial fields. In these experiments we have discussed the thermal and dynamical effect of the orography on the circulation systems over and nearby the Tibetan Plateau and have got the following qualitative results: 1. In summer the formation and development of the shearlines over the Tibetan Plateau on 500 mb surface are mainly determined by the dynamical effect of orography and the thermal effect has the contribution to its intensification, too. The formation of the south-west vorte is determined perfectly by the dynamical effect of orography under specific condition and the thermal effect has no contribution. The existence of the-low pressure over the Bay of Bengal is also perhaps related with the dynamical effect of the Tibetan Plateau. 2. If the zonal wind velocity is very weak, the thermal effect of the Tibetan Plateau on the formation and maintenance of the Tibetan High on 100 mb surface is very large, while that over the south side of Tibetan Plateau has little effect on its formation, even though the strength of the later is many times larger than that of the former. The dynamical effect of the Tibetan Plateau on Tibetan High on 100mb surface is negative and serves a weakening function.

• A REPORT ON THE ANALYSIS OF DAILY SURFACE WEATHER MAP OF THE TIBET PLATEAU IN JUNE-AUG.1979.
• Li Rpngqing;Luo Linjie;Ge Huiyan
• 1984 Vol. 3 (2): 31-41. 
• Abstract ( ) PDF (761KB) ( )
• The daily surface weather maps of the Tibet plateau are analysed from 1 June to 31 Aug.1979 with 2 times per day (00 and 12 GMT) by the method called "Conservative geostrophic wind" ^[1] (which means that the geostr ophic wind on the sea surface map will be equal to the real geostrophic wind on the ground of the same point).It is shown that the pressure systems in the maps are much more detailed and exact than in the "historic maps", which are analysed by the National Meteorologic Bureau of China. The Tibet heat low as a manifestation of the plaetau summer monsoon and the Indian heat low as a manifestation of SW monsoon are always mutually exclusive in strength each other on the daily maps. It seems to say that the active center of the East Asia is only a single center, which is sometimes over India and sometimes over the Tibet Plateau.

• THE LOW CIRCULATION OVER THE URBAN AREA OF LANZHOU GANSU IN WINTER
• Ji Guoliang;Shen Zhibao;Wang Yaoqi;Chen Youyu;Wang Wenha;Shui Dengchao;Wu Jingzhi;Ma Qinghua
• 1984 Vol. 3 (2): 42-50. 
• Abstract ( ) PDF (684KB) ( )
• Through the analysis to the observational wind field data over the urban area of lanzhou in winter 1980 and also some relevant historical records it is found that in the urban area in winter the thermal valley wind circulation plays the leading role, the vertical flow field shows a east-west-east pattern distribution, the lower layer air stream ascends and the upper layer one sinks, and there is an evident effect of heat island due to the existence of a populated city.

• THE MULTI-LEVEL RECURSION LONG-RANGE FORECASTING MODELS OF THE SUMMER CHARACTERISTIC QUANTITIES FOR THE WESTERN PACIFIC SUBTROPICAL HIGH The long-range forecast of the characteristic quantities of the subtropical high(Ⅰ)
• Zhang Enshu;Mao Yuying;Han Zhigang;Tang bingyong
• 1984 Vol. 3 (2): 51-56. 
• Abstract ( ) PDF (440KB) ( )
• We have made a long-range forecast by using the multi-level recursive forecasting method for the summer characteristic quantities of the Western Pacific subtropical high. The experimental result shows that both the percentage of accuracy and the precision of the tendency of forecast are greatly improved as compared with the method of multiple regression.

• CALCULATION OF THE LIGHT PHASE FUNCTION BY HEXAGONAL ICE CRYSTALS
• Cai Qiming;Kuo-Nan Liou
• 1984 Vol. 3 (2): 57-65. 
• Abstract ( ) PDF (619KB) ( )
• Hexagonal ice crystal are the basic form of the particles in cirrus.In this paper, the emphasis is given to discuss the computational results of the scattering phase matrices for infrared light with absorption by making use of the model developed.The comparisons of the results have been made between infrared and visible light as well as between hexagonal cylinders and equivalent spheroids and spheres.It shows that the effects of light absorption on the phase function cause the decrease of the scattering energy in the backscattering and its near directions, and that the halo and rainbow-similar peaks which are produced by refractions and internal reflections are weakened.There is a general agreement of the scattering phase functions for the ice crystals with different shapes, but the scattering in the side and backscattering directions are less strong as compared with hexagons.lt is believed that these features would have influence on detection of cirrus and radiation transfer in the atmosphere.