Current Issue

• SOME ASPECTS OF FORMATION OF BLOCKING RIDGES OVER THE CENTRAL NORTH PACIFIC
• Li Maicun;Luo Zhexian
• 1986 Vol. 5 (2): 101-115. 
• Abstract ( ) PDF (984KB) ( )
• In this paper, Lorenz's moist low-order two-layer quasigeostrophic spectral model with beta-plane geometry ^[1] was improved. Using the improved model, we have carried out five experiments ex tended(more than 75-day) integrations. The model physics are orography, moisture process, time-dependent vertical stability, land surface heat budget, contrast between land and sea, climatic mean distribution of solar radiation absorbed by the land and sea surface in winter and parameterizations of long-wave radiation. From these experiments, it seems that the formation of blocking high is related to the nonlinear adjustment between flow fields and diabatic processes with moisture, and the nonlinear interaction of zonal currents and wave components under orographic forcing. Comparing flow patterns of blocking ridges proposed by Charney and Straus ^[2] from equilibrium state theory, the simulated blocking ridges over the Central North Pacific were much closer to reality.

• THE SNOW COVER ON TIBET PLATEAU AND ITS EFFECT ON THE MONSOON OVER EAST ASIA
• Guo Qiyun;Wang Jiqin
• 1986 Vol. 5 (2): 116-124. 
• Abstract ( ) PDF (601KB) ( )
• The data set of number of days with snow in 43 stations on Tibet Plateau for the period from January 1962 to December 1979 are analyzed using Empirical Orthogonal Function(EOF) technique. The spatial distribution, interannual variability and persistence of snow cover and its effect on the general atmospheric circulation and monsoon over East Asia are studied. The main results are as follows;(1) A spatial pattern with large positive(or negative) anomalies centered in Tanggula mountain and Bayankla mountain(i.e. first EOF) has higher frequency.(2) The interannual variation of number of days with snow cover is obvious illustrated in the curve of anomalies, the quasi-biennial oscillation was pronounced in 60'S and an upward trend was observed in 70'S, meanwhile, the monthly number of days with snow cover has higher persistence in winter, but the duration of the time interval with high persistence is varied from one station to another.(3)The amplitudes of ultra-long waves at 500 hPa in subtropical zone are closely linked with the number of days with snow cover; the amplitude of first harmonic is larger in years with greater snow cover than that in the years with less snow cover.(4) The characteristics of monsoon circulation over East Asia in early summer(from May to June) is obviously associated with the number of days with snow cover on Tibet Plateau from November last year to March this year.

• A STUDY ON THE MOVING EASTWARD LOWS OVER QINGHAI-XIZANG PLATEAU
• Liu Fuming;Fu Meijuan
• 1986 Vol. 5 (2): 125-134. 
• Abstract ( ) PDF (727KB) ( )
• Based on the statistical analysis of the movement characters of Plateau lows on 500hPa surface for June-August of 1965-1982, the causes of the moving eastward lows had been studied. Three elemental circulation patterns of the cyclogenesises and its eastward movements of the lows were given. This paper pointed out that the area of the positive divergence differences between 200hPa and 500hPa occurred in east part of the lows is the most important characters for the moving eastward lows. In other words, the positive divergence field on 200hPa over the east part of the lows is the most important factor for the moving eastward lows. The causes of the formation of the favouring divergence fields are quite different among the above three circlation patterns.

• A RE-ANALYSIS OF THE MEAN PRESSURE FIELD OVER THE QILIAN MOUNTAIN REGION
• Tang Maocang
• 1986 Vol. 5 (2): 135-142. 
• Abstract ( ) PDF (527KB) ( )
• Using the monthly mean data near 30 years until 1980, the mean pressure and wind field over the Qilian Mountain region was re-analysed. It is confirmed that there are really five mean meso-pressure systems existing in the Qilian Mountain pointed out by the author of this paper 23 years ago ^[1], although the strengths are rather weak than the previous analysis. There is a small depressiom(≈100km) over the Qinghai Lake during the winter time. In the summer time, the Lenglongling high located in the east part of Qilian Mountain is separated from the plateau momsoon's high located in the He Xi Corridor by a distinguishable low pressure trough and a wind shear line oriented west to east.

• THE MEASUREMENT, COMPUTATION AND SOME CHARACTERISTICS OF SOIL HEAT FLUXES IN GARZE IN THE SUMMER 1983
• Shui Dengchao
• 1986 Vol. 5 (2): 143-154. 
• Abstract ( ) PDF (836KB) ( )
• The data of the soil heat flux in different depthes in the summer 1983, which are obtained during the field scientific experiment of the heat sources in Qinghai-Xizang Plateau from August 1982 to July 1983, is used to com pare some conventional methods of computing soil heat fluxes. The results show that the present method is more accurate for computing the surface soil heat flux. Furthermore some characteristics of the soil heat fluxes are discussed.

• THE CHARACTERISTICS OF THE SURFACE AND ATMOSPHERIC HEATING FIELDS OVER THE QINGHAI-XIZANG PLATEAU IN SUMMER OF 1983
• Ji Guoliang;Pu Ming;Xi Yunyu
• 1986 Vol. 5 (2): 155-166. 
• Abstract ( ) PDF (778KB) ( )
• This paper computes and analyses the surface and atmospheric heating fields over the Qinghai-Xizang Plateau in summer by using the observational data of the solar radiation obtained from August 1982 to July 1983. The results are as follows. In summer, the main part of the plateau acts as a strong heat source, the center of heating field is over the south-eastern of the plateau, there is a center of the surface heating at Ngingchi and at Garze, respectively, and the maximum intensity of the surface heating fields appears in June and in July, From April to September, the main fart of the plateau acts as a heat source for the atmospheric heating pields, the centers of the heat source are over the eastern and central part of the plateau, and the maximum intensity of the atmospheric heating fields appears in July. In the total of the atmospheric heating, main term is the latent heat of condensation from the precipitation over the eastern part of the plateau and is the surface effective radiation over the central, western and southern part of the plateau.

• THE OBSERVATIONS OF ATMOSPHERIC ICE NUCLEI IN LANZHOU
• Ge Zhengmo;Zhou Chunke
• 1986 Vol. 5 (2): 167-171. 
• Abstract ( ) PDF (343KB) ( )
• Observations of atmospheric ice nuclei in the Lanzhon City in May, 1982-January, 1983 are presented. In this paper, the relationships between the concentration of ice nuclei and other meteorological elements are analysed.

• THE ANALYSIS OF INVERSION LAYER FEATURE OF HAILSTORMS
• Liao Yuancheng
• 1986 Vol. 5 (2): 172-179. 
• Abstract ( ) PDF (490KB) ( )
• Data of 660 radio-soundings launched at 9 o'clock during June, July and August, 1971-1978 and data of weather radar and surface observations in the same period in Yongdeng Hail Suppression Test site have been analysed. The results show that different weather systems have different inversion layer features. The thickness, intensity of upper inversion layer and its altitude and corresponding temperature indicate the severity of hailstorms. The more the tropopause descends and the more the inversion layer is close to or breakthrough the tropopause, the more the severity of hailstorm is. The paper discusses the inversion layer feature of hailstorms and the role it plays. The could be helpful to forecast correctly hailstorms and provide basis for further revealing the background of hailstorms.