Vol.2, NO.1, 1991

Display Method:
Numerical Simulation of Air Pollutant Transport and Diffusion in Guiyang City
1991, 2(1): 1-12.
The Monte-Carlo model is used to predict the ground level concentration distribution (GLCD) of SO2 in mountainous city—Guiyang city. In order to accomplish the numerical simulation of the area source in the city, the concentration count and horizental diffusion in the Mont-Carlo model are studied. The wind fields used as the background or the input parameters are obtained from the objective analysis according to the three dimentional wind observations, and the turbulent parameters are determined by the parameterized formulas which have been adjusted with the local experimental data in Guiyang city. It is shown that the wind profile is not highly coincided with the ordinary features, there is usually an ‘extremum’ between the layers of 50 and 500m, there are the typical features of atmospheric diffusion under the light wind in Guiyang city, the spectral peak values of the velocity components u and v shift to the lower frequencies and the horizental diffusion remarkably increase. Additionally, the modeling verification both with other theories and the experiments have been done. The GLCD of homogeneous turbulence consists with that obtained from K-theory or Gaussian model. For the daily average values of GCLD in winter, the correlation coefficient between prediction and observation is 0.96. The GLCD simulated shows that the air-pollutant transport and diffusion in Guiyang city is mainly depended on the very unstable weather condition or the aeration effect of the ‘extremum’ wind layer.
A Case Study of the Aerosol Characteristics in the Lower Troposphere During a Dust Storm Event
1991, 2(1): 13-21.
Using the data observed by an instrumented aircraft during a dust storm originated from the western part of Inner Mongolia of China on 10 June 1983, the particle spectra, dust content and the CCN concentration are analysed. Some problems with the vertical and horizontal transports of the dust particles are also discussed based on the spatial distribution characteristics.
A Regional Satellite Atmosphere Sounding Data Operational Processing System
1991, 2(1): 22-31.
It is a brief introduction of the construction, algorithm and products of a regional satellite atmosphere sounding data operational processing system. Comparisons of retrieved products with conventional data show that the root mean square error (RMSE) of the temperature retrievals is about 2.45℃, the RMSE for the water vapor ratio is about 1.47 g/kg, about 21.4 geopotential meters for the layer mean thickness, the accuracy of the total ozone amount is about 10% compared to values derived from Dobson measurements. The RMSE of long-wave radiative flux is about 1.7 W/m2
Numerical Study on Mechanism of Artificial Modification of Cumulonimbus Clouds
1991, 2(1): 32-39.
A series of numerical experiments have been done to test the seeding effect of artificial icecristals or raindrop embryos using a one-dimentional time dependent cumulonimbus cloud model. Some effects of precipitation enhancement or hail reduction are achieved by seeding in different cases. Analysis results show that the artificial modification can change the leading microphysical process of precipitation element formation.
Features of Quasi–3.5 Year Oscillation of Zonal Wind in Troposphere
1991, 2(1): 40-51.
Using the monthly zonal wind data at 700 and 200 hPa during 1968—1985 analyzed by NMC, the features of quasi–3.5 year oscillation are discussed. It is found that the oscillation is mainly in the sourthern and northern hemispheres of 180 o—150oW and in the belt of 25o—35oN. It moves eastward over the equator and the midlatitude, and moves westward over the subtropics. For the meridional propagation, it is northward over the Pacific and there is no obvious propagation direction over the region of 50 o—90oE. The results of CEOF analysis show that the variance of oscillation is mainly concentrated at the first and second main component. In this paper, the evolution of oscillation and its relation to the 3.5 year oscillation of SSTA in the equatorial eastern Pacific are also discussed
A Study on the Periodicity Freeze Injury of Orange in China
1991, 2(1): 52-58.
In this paper, the negative accumulated temperature (daily minimum temperature < 0oC) ≤-90oC and the extreme minimum temperature ≤8oC are used as the orange heavy freeze injury index. The relationship between the orange freeze injury and different cold wave paths, intensity and spatial distribution of the extreme minimum temperature are calculated. Using the spectrum analysis, it is found that there are the period lengths of 9—10 and 3—6 years of orange heavy freeze injury caused by the negative accumulated temperature and the extreme minimum temperature in Yangtze river valley, and their regional difference is bigger. Furthermore, the forecasting for the heavy freeze injury of orange and making proposals for the orange culture have been done.
The Vorticity Entrophy of Barotropic Large Scale Motion
1991, 2(1): 59-64.
In this paper, on he basis of introducing the concept ‘vorticity entrophy’, the production of vorticity entrophy in the barotropic large scale mothion under the inviscid and adiabatic conditions was discussed. It is indicated that the beta effect, topographic effect and the divergence of motion might cause the production of vorticity entrophy. Moreover, the vorticity entrophy was applied to describe the formation process of dipole blocking in the atmosphere. Therefore, it can improve our understanding of the formation process.
A Case Study of the Impact of Satellite Sounding Data on Numerical Weather Analysis and Forecast
1991, 2(1): 74-82.
A case study of the impact of satellite sounding data on the numerical weather analysis and forecast has been done in the northern hemisphere operational numerical weather analysis and forecast system of National Meteorological Center, SMA. The thickness data from NOAA meteorological satellite, derived from satellite temperature soundings. have been used in the experiments. The results reveal that satellite soundings make an improvement on the numerical weather analysis and forecast. The impact of satellite soundings on the numerical weather analysis is related to the region and synoptic system, this impact mainly occurs in the sparse conventional data area and in the vicinity of strong weather systems. Also, the impact on numerical weather forecast is bound up with the evolution of synoptic systems, and this impact substantially occurs is developing systems.
The Relationship between the Near-surface Meso-β Scale Circulation Systems and the Heavy Rainfall Events in the Sanxia Gorge Region of the Changjiang River
1991, 2(1): 83-90.
In this paper, the heavy rainfall events in the Sanxia Gorge region of the Changjiang River and the southwestern region of Hubei Province during the summers 1983—1987 are analyzed. It is found that about 80% of the events are associated with meso-β scale cyclones are anticyclones with mean diameters of 97 and 114 km respectively. These meso-β scale cyclones are anticyclones are respectively concentrated in different areas essentially without overlapping. The areas are coincided with the meso-β scale cyclones or anticyclones system on the mean surface streamline chart and with the climatological distribution of the rainfall and heavy rainy day in the region. Compared the areas of high frequency of occurrence of the meso-β cyclones and anticyclones with the topographical features, it is demonstrated that the terrain plays a crucial role in producing the meso-β cyclones or anticyclones
A Potential Mechanism of the Warm Vortex Genesis in Southwest China
1991, 2(1): 91-99.
According to the thermal wind adjustment theory under non-adiabatic and frictional effects, the genesis mechanism of the warm low vortex in southwest China is discussed in this paper, and two cases are analysed and calculated. The results show that there is an obvious area of positive non-thermal wind vorticity in the vicinity of vortex source 12 hours before the vortex formation. The surface sensible heat and warm advection play an important role in the generation of positive non-thermal wind vorticity. Because the warm low vortex is a shallow system in the initial stage, the condition L>L0 may be satisfied when the lapse rate of temperature is larger. Therefore, the effect of thermal wind adjustment can make the warm low vortex generated in the lower layer
A Relationship between the Distribution of Aerosols and the Tropical Circulation in the Equatorical Western Pacific
1991, 2(1): 100-105.
A relationship between the distribution of aerosols and the tropical circulation under the different tropical circulation conditions during the TOGA experiment form 1985—1987 were studied. The concentration of aerosols has a value 10 μg/m3 or less in the tropical convergence zone due to the rain washout, and its distribution is independent on wind velocity. But, the concentration value under the rainless region in one order of magnitude larger than that under the rainfall zone. The distribution of the aerosols is inhomogeneous in the hurricane circulation. The lower value (100μg/m3) in the dry zone.
A Study of Rational Distribution of the Evaporation Networks in the Sichuan Basin
1991, 2(1): 106-112.
The daily evaporation data of 36 stations in the Sichuan basin form 1980 to 1984 are used in this paper. By calculation the correlation functions (only dependent on the distance between two points) of the evaporation data for four months which represent four seasons respectively, the statistical relationship between the relative interpolation standard errors and the correlation functions is concluded. Also, according to the rule that the relative interpolation standard error is not larger than the observational random error, the rational distance between the evaporation networks in this area can be estimated.
Strategies on Use of Multiple Processors in Time Integration for Global Multilevel Primitive Equation Model
1991, 2(1): 65-73.
A global multilevel spectral primitive equation model has been reduced to several sets of shallow water type equations by means of verticle normal modes. Then, most part of computational amount can be simultaneously performed by multiple processors in a time step. Finally, a flow graph is shown.