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• PERSISTENT ANOMALIES OF THE NORTHERN HEMISPHERE WINTERTIME STRATOSPHERIC CIRCULATION
• Li Ziqiang;Gao Youxi;Qu Zhang
• 1990 Vol. 9 (3): 235-244. 
• Abstract ( ) PDF (614KB) ( )
• Using 50 hPa geopotential height data (10×10 Lat./Lon.) for the winter seasons from 1975/1976 through 1985/1986, the observational study results of stratospheric circulation persistent anomalies are presented. The results show that there exist marked persistent anomalies in 50 hPa height fields during the period of the Northern Hemisphere wintertime, which mainly occurr over three regions: North America, the Northern Asia and the Northwest Europe, especially North America. There are also obvious See-Saw relationship between the persistent anomaly of 50 hPa height departure over North America and Northern Asia, and their teleconnection patterns over the both regions are very evident. Finally the persistent anomalies of stratospheric circulation in Northern Hemisphere wintertime are more striking and stronger than those tropospheric circulation.

• APPLICATIONS OF SECOND-ORDER CLOSURE MODEL TO AIR-POLLUTION METEOROLOGY
• Sang Jianguo;Liu Lijie
• 1990 Vol. 9 (3): 245-255. 
• Abstract ( ) PDF (658KB) ( )
• The second order closure model in the turbulent boundary layer is used to carry out a series of numerical experiments to simulate the behaviour of a continuous line source under different conditions such as atmospheric stability, surface roughness and height of source etc. The results of these experiments are as follows: whatever it is in either stable or unstable boundary layer the atmospheric diffusion ability from a higher source is lower than that from a lower source; in stable boundary layer the atmospheric diffusion ability over a rough surface is higher than that over a smooth one; while under the conditions of the same wind speed and the same surface net radiation the atmospheric diffusion ability over the rough surface is lower than that over smooth surface. Since the counter-gradient transfer may occur in the convective boundary layer K-theory is inadequate there. The experiments also show that the modified Kazanski-Monin parameter probably is a better index for the atmospheric diffusion ability than Monin-Obukhov length.

• EVALUATING OF MONTHLY RAINFALL AND CONDENSATION LATENT HEAT OVER QINGHAI-XIZANG PLATEAU IN SUMMER UTILIZING THE OLR DATA OF SATELLITE
• Xu Guochang;Li Dongliang;Jiang Shangcheng
• 1990 Vol. 9 (3): 256-264. 
• Abstract ( ) PDF (543KB) ( )
• In this paper the NOAA's monthly mean grided OLR data over the Qinghai-Xizang Plateau from June 1974 to May 1984(missed from March to December of 1978) with the grid size of 2.5°×2.5° Lat./Lon. and the observed monthly rainfall data at 83 stations over the Plateau in the same period have been analysed. The results show that there are close negative correlation between the monthly mean OLR and monthly rainfall in space and time in summer (from June to September), while there exists little influence of the numbers of Plateau surface stations and snow cover on above correlation coefficients. Based on the regression equations fitted in four sub-areas of the Plateau, the evaluating of monthly mean rainfall and their total latent heat of condensation in the Plateau rainy seasons can be well made.

• ANALYSES OF ATMOSPHERIC HEATING FIELD OVER THE TROPICS AND ITS SURROUNDING SEA AREAS OF THE WEST PACIFIC IN OCTOBER-DECEMBER 1986
• Yao Lanchang
• 1990 Vol. 9 (3): 265-276. 
• Abstract ( ) PDF (749KB) ( )
• In this paper, we have in detail computed the budgets of radiation and heat of whole air column over the tropical and its surrounding sea areas of the west? and middle-Pacific using expedition data in the west Pacific and the monthly climatic data for the world in October-December 1986. The main results are as follows: (l)The whole air column over the equator and tropical sea areas of the west-and midddle-Pacific in October-December 1986 is a strong and abroad heat source area; but over the subtropical sea areas at both south and north sides of the above area, stronger heat sink areas; over south China sea, also independent centres of source and sink of heat. (2)The formations of above heat source areas are mainly due to the very large latent heat of precipitation, and the formations of heat sink areas, large loss of radiation. (3)The inter-monthly variations of heat source areas are evident.

• THE DIAGNOSIS AND NUMERICAL SIMULATION EXPERIMENT FOR THE HEIGHT OF EQUIVALENT BAROTROPIC LAYER OVER EURASIAN CONTINENT AND NORTH PACIFIC
• Ouyang Shoucheng;Xiao Tiangui et al
• 1990 Vol. 9 (3): 277-283. 
• Abstract ( ) PDF (453KB) ( )
• In the paper the heights for equivalent barotropic layer over Eurasian continent and North Pacific have been diagnosed and two numerical experiments have been run as well.
  The results show that the mean equivalent barotropic layer height for all stations over the area is 359 hPa and is in good agreement with our ealier results (Ouyang Shoucheng et al" 1987), but the heights change a lot from place to place and from season to season. It appear to be influenced by Tibetan Plateau and westerly jet.
  The numerical experiments used by barotropic model suggest that compare with the observed, the simulated Rossby waves on 300 hPa is somewhat superior to that on 500 hPa.

• THE RELATIVE CHARACTERISTICS OF TIME AND SPACE OF MONTHLY MEAN PRECIPITATION OVER CHINA
• Li Weijing;Chou Jifan
• 1990 Vol. 9 (3): 284-292. 
• Abstract ( ) PDF (530KB) ( )
• In this paper, by using monthly mean rainfall data during 1951~1984, we have analyzed the relative characteristics of time and space of monthly mean precipitation over China. The results show that space distributions of monthly mean rainfall have three patterns in the Eastern China. One pattern is much rainfall over the Yangtze River valley; but a little rainfall over the Southern and Northern China. Another one has a opposite pattern to the first one. The third one is normal pattern, which percentage of precipitation departure is very small over the all area. It is also shown that the time characteristics of precipitation has clear semiannual phenomena of rhythms in the middle and-lower reaches of Yangtze River. Namely, the rainfall from December to January is a information period of rainfall of June~August in next years. We also show that rainfall patterns in June~August of the next year of nine El Nino years during the period of 1951~1984 are not entirely similar to each other.

• A QUASI-STATIC MODEL OF GLOBAL ATMOSPHERIC ELECTRICITY
• Zhang Yijun;Yan Muhong
• 1990 Vol. 9 (3): 293-306. 
• Abstract ( ) PDF (798KB) ( )
• The effects of the earth orography, aerosol and solar activity on atmospheric electric parameters are calculated by using a model of global atmospheric conductivity and a model of global atmospheric electric circuit. Their effects on distribution of ground electric field and current density are also evaluated. The result indicate that existence of the earth orography makes the ionospheric potential increase. The change of thunderstorm distribution has not effect on average value of atmospheric electric parameters. The aerosol concentration is positively interralated with the ionospheric potential and fair weather resistance, so does the cosmic ray with ionospyheric potential and air-earth current density. The changs of aerosol concentration and cosmic ray also affects the electric field in fair weather regions, the ground current density and the electric field. When solar proton enters into atmosphere, the global ground corrent density and electric field increase, ionospheric potential, however, does not change.

• A PARAMETERIZATION METHOD OF THE SITE ERRORS ESTIMATION OF LIGHTNING LOCATING SYSTEM
• Chen Mingli;Liu Xinsheng;Guo Changming;Ge Zhengmo
• 1990 Vol. 9 (3): 307-319. 
• Abstract ( ) PDF (752KB) ( )
• In this paper, a parameterization method of the site errors estimation in lightning locating system (LLS), using the data of multi-direction finders (DFs), has been developed. According to the method, the site errors for each DF are assumed to be a function of measured bearing and are expressed as limited-terms sinusoidal function. From Orville' s eigen technique and non-linear unconstrained minimization problem, the site errors are directly found by minimizing the objective function. Utilizing the real data of some 4900 lightning flash samples observed by LLS of three DFs in Beijing region in the summer of 1988, the site error correction curves for all DFs were found. The results show that the residual errors more than 95 percentage of the flash between the corrected and real flash directions are less than 1° after correcting. In addition, the lightning locations with the correcting are more consistent with the radar echo than those without the correcting.

• CHARACTERISTICS OF SNOW COVER OVER NORTH EURASIAN CONTINENT AND TIBETAN PLATEAU AND THEIR RELATIONSHIPS WITH TEMPERATURE AND RAINFALL OF CHINA
• Liu Xiaodong;Luo Siwei
• 1990 Vol. 9 (3): 320-326. 
• Abstract ( ) PDF (457KB) ( )
• In this paper utilizing the snow cover data for the years 1966~1983 the characteristics of snow cover over north Eurasian continent and Tibet Plateau and their relationships with temperature and rainfall in China have been investigated. The results show that the snow cover over north Eurasian continent has a large annual variation and changes smoothly; but over Tibet Plateau, a small one and changes unsmoothly. The persentages of areas coverred by snow over Tibet Plateau in summer are much larger than those over north Eurasian continent. In winter half year there are negative correlation relationships between the snow cover over north Eurasian continent and the air temperature in China in three weeks. In summer, when the snow cover over north Eurasian continent is large, the rainfall over south China and north China Plain is more than normal, over the rest of China less than normal; or vice versa.

• THE RELATIONSHIP BETWEEN THE FLUX DENSITY OF THE DIRECT SOLAR RADIATION AND THE AIR MASS OVER THE ARID REGION OF THE WEST CHINA
• Wang Yaoqi;Wei Zhigang
• 1990 Vol. 9 (3): 327-336. 
• Abstract ( ) PDF (640KB) ( )
• In this paper, based on the variation range of the atmospheric physicics state (precipitable water and turbidity) of the arid region of the west China we have computed the flux density of the direct solar radiation under various coefficients of transparency, Using the theoretical computational formula for the direct solar radiation. The computation result shows that if the coefficients of transparency ( P ₂) and the air mass ( m) are the same, the differences of the flux density of the direct solar radiation due to the different content of the water vapour and the aerosol are not large in the major time section ( m=1~3)of daily variation of solar radiation. Thus the averaged relationships between the flux density of the direct solar radiation and the air mass under various coefficients of transparency P ₂ were obtained. If the coefficients of transparency P ₂ and the mare the same, though the atmospheric physics state are different at different heights above sea-level, the flux density of the direct solar radiation are the same on the whole. All the existed relations of the flux density of the direct solar radiation to the air mass are unable to well depict the results obtained by above computation. Therefore, on the basis of the character of the variation of the flux desity of the direct solar radiation with air mass, a new expression has been presented. Finally, the secular observational data for the four solar radiation stations (Naqu, Xizang; Gelmud, Qinhai; Dunhuang and Minqin, Gansu) with different elevations above sea-level geographical landscapes have been analysed. Both the empirical and observed values agree well with each other.

• AN INTRODUCTION OF SOME ASPECTS IN THE BACKGROUND AIR POLLUTION MONITORING
• Yang Longyuan
• 1990 Vol. 9 (3): 337-346. 
• Abstract ( ) PDF (701KB) ( )