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• NUMERICAL SIMULATION OF DEVELOPMENT OF MONSOON CIRCULATION IN JULY
• H. L. Kuo;Y. F. Qian;Q. Q. Wang
• 1982 Vol. 1 (4): 1-27. 
• Abstract ( ) PDF (1757KB) ( )
• Eight different experiments have been carried out from 8 to 20 days. In all of the 8 experiments, land-sea contrast is always included and so is the large-scale condensation, when the radiative warming and cooling are considered in expriments,there would be also taken into account cumulus parameterization, sensible heat and evaporation from ocean surface and elevated plateau surface above 3000m.We utilize two different initial states which correspond the June monthly mean and the June monthly zonal mean fields of the meteorology elements, respectively. The methed of assessment is to compare the results from different numerical simulations with one another and with the observed July monthly mean fields.We have gotten some interesting conclusions from the comparisons.The main conclusions are as follows. (1)The mean sea level pressure distribution and low level flow pattern produced by these simulations are found to be determined mainly by the diabatic heating distribution and influenced only slightly by orography, but are almost independent of the initial state. For example, the locations and strengths of the mean July sea level low pressure troughs over Arabian Peninsula and north east Africa, along 85°E and 110°E over east coasts of India and Indo-China and the Somali jet and its eastward extension, are accurately created by all simulations which include radiative heating and other induced heating processes (designated by letter A), no matter whether the initial state is based on monthly mean June pressure (by letter I) or mean June zonal average pressure (by Ⅱ), whether orography is included (by O) or not (by N), while none of these systems is produced when radiative heating is not included (by B). (2) The low pressure systems develop faster when diurnal variation of solar radiation is taken into consideration (by A1). (3) The precipitation distribution is found to be critically influenced by all of radiative heating, orography and Initial condition. For example, without orography, maximum precipitation occurs in the coastal region of east Asia instead of the region around 100°E, 25°N found with orography, while the precipitation rate is greatly reduced both over land and over ocean without radiative heating.

• SOME IMPROVEMENTS AND FORECASTING EXPERIMENTS OF A NUMERICAL MODEL WITH P-σ INCORPORATED COORDINATES
• Qian Yongfu;Yan Hong;Wang Qianqian;Shen Zhibao;Zhang Ningdan;Guo Yongrun;Xu Yiming;Ji Mingzhu
• 1982 Vol. 1 (4): 28-45. 
• Abstract ( ) PDF (1110KB) ( )
• Some improvements made in 1977 of the numerical model which was developed in 1975 are described in this paper.A detailed summary of the forecastings with real data by improved version of the model in Cartesian coordinates is also given.

• INFLUENCES OF LAND-SEA AND TOPOGRAPHY DISTRIBUTIONS ON TEMPERATURE FIELDS IN JULY
• Gao Youxi;Li Ci;Yuan Fumao;Yang Xiuhua;Yong Xiaochun
• 1982 Vol. 1 (4): 46-59. 
• Abstract ( ) PDF (903KB) ( )
• In this paper,the influences of land-sea and topography distributions on temperature anomalies from latitudinal means are studied. The results are obtained that the Eurasia continent and Tibetan Plateau located in the eastern half part of northern hemisphere are the most warmest in all hemispheres.The direct influences of land-sea and topography are different from the size of land-sea. The extent and intensity of temperature anomalies of the land-sea influence are the biggest and the strongest over ground surface,then decrese with height,thereafter reaching the 2 nd maximum value at 200-300 mb.The above phenomena may be caused by sensible heat from ground surface and by latent heat of precipitation and sublimation.The role of the Tibetan Plateau strengthens the effect of the land-sea distribution.The effect of large-scale orography is far larger than its actual extent of topography.In addition, the problem of Plateau monsoon is discussed, too.

• THE MEAN STREAMFIELD STRUCTURES OVER THE QINGHAI XIZANG PLATEAU AND ITS NEIGHBOURHOOD IN SUMMER AND WINTER
• Luo Siwei;Chen Youyu;Sun Xiuxia
• 1982 Vol. 1 (4): 60-73. 
• Abstract ( ) PDF (888KB) ( )
• In this paper the streamfields on 300m and 900m above the surface and 1500m 3000m,4000m,and 5000m levels above the sea level are calculated with data about 100 aerological stations over the Plateau and its surroundings in January and July for 1959-1960.It shows: l.In January, there is a convergent zone which is located from the central part of Plateau to Yunnan and Guizhou Provinces. It's thickness is about 1000m above the surface. The anticyclone center near the surface is not located in the People's Republic of Mongolia and in the East China to the east side of Plateau. 2.In July, the convergent zone over the Plateau is stronger than in January and it is not a part of ITCZ over India.The axis of the anticyclone over the north side of Plateau is located at the zone of 42°-43°N below 3000m, but it moves southward to 35°N on 5000m level. These correspond with the activities of small anticyclones on daily synoptic charts. 3.Either in July or in January all the diurnal variations of wind direction are clear.In general,the wind blows toward the Plateau in the aftecrnoon. The more the station nears the Plateau, the more the wind blows toward the Plateau.The diurnal variations of wind direction for a few stations approach to 180°.

• THE ATTENUATION OF SOLAR RADIATION IN THE POLLUTED URBAN ATMOSPHERE
• Shen Zhibao;Wang Yaoqi;Ji Guoliang;Wang Wenhua;Wu Jingzhi;Shui Dengchao
• 1982 Vol. 1 (4): 74-83. 
• Abstract ( ) PDF (710KB) ( )
• In winter (December, 1980-January, 1981), simultaneous observations of solar radiation were taken at two sites, having difference of altitude of 625m, in Lanzhou and at another contrast site around the city to measure the attenuation of solar radiation and to estimate it only by aerosols in the polluted urban atmosphere especially in the lowest layer of atmosphere where air pollution is very serious The attenuation of direct solar radiation in polluted urban atmosphere in Lanzhou was stronger than that in the suburban districts, it was 72% of solar radiation within the whole atmosphere and 41% of it was concentrated in the lowest layer of 625 m thickness. The attenuation of sunlight was mainly caused by aerosols,it was 66% of the total attenuation of solar radiation within the whole atmosphere and 96% in the lowest layer. There is a close correlation between the intensity of solar radiation reaching the ground surface and the Angstrom atmospheric turbidity coefficient.Both empirical formulas have been established with which we calculate the Angstrom atmospheric turbidity coefficient from the flux density of solar radiation reaching the ground surface in arid areas or vice versa. At the last, the radiation absorption by aerosols and its heating rate in the lowest layer in winter over Lanzhou are estimated and the effect of air pollution on the net radiation on the ground surface are discussed.

• ATMOSPHERIC TURBIDITY IN WINTER OVER LANZHOU
• Wang Yaoqi;Shen Zhibao;Ji Guoliang;Wu Jingzhi;Wang Wenhua;Shui Dengchao
• 1982 Vol. 1 (4): 84-91. 
• Abstract ( ) PDF (541KB) ( )
• In winter (Dec. 1980), simultaneous measurements of atmospheric turbidity with sunphotometer were made both on the ground and at the 625 m level over Lanzhou, and the turbidity of the low atmospheric layer of 625m thickness was calculated by use of the data obtained at those two sites mentioned above. The main results are as follows: l.In winter, the turbidity over Lanzhou was high and its mean Angstrom turbidity coefficient in December was 0.44 and about 73% of aerosol particles were concentrated in the atmosphere at the lowest layer. 2.The diurnal variation of turbidity coefficient in the low layer was different from that in the upper layer. 3.The sizes of the aerosol particles are same both in the lowest layer and in the upper layer. 4.The weather with suspending particle dusts bears the characteristics of high turbidity coefficient and low wave length exponent. 5.In the valley, there is a net accumulating period of turbid particles in the night and a net dissipating period in the daytime. But the net accumulating of turbid particles is often larger than the net dissipating, so the atmospheric turbidity will still maintain in a rather high level. 6.The main turbid source is the artificial source……coal smoke, and the topography of the valley and the inversion are the two prominent natural factors which affect the atmospheric turbidity over Lanzhou.