Current Issue

• DESIGNING PHOTOCHEMICAL SMOG POLLUTION REGIONAL TOTAL CONTROL SCHEMES BY USING EKMA DIAGRAM
• LI Bing;CHEN Chang-he;YU Jin-xiang
• 1998 Vol. 17 (2): 111-119. 
• Abstract ( ) PDF (313KB) ( )
• Because the principal composition of photochemical smog-ozone is secondary pollutant, the control scheme to primary pollutant isn't applicable to ozone. With EKMA diagam, daily maximum ozone concentrations are controlled by cutting down precursors NO _x and HC emissions. Thus, photochemical smog can be controlled by total air pollutant emission control(or total control). There is serious photochemical pollution in Xigu industrial area of Lanzhou, so we take this area as our first attempt of O ₃ control in China. In this paper, photochemical mechanism and related parameters are given, the process of making and using method for applying EKMA diagram is described in detail. Therefore, the key to ozone control strategy,namely the relationships between emissions and air quality are solved and NO _x,HC reduction schemes are put forward. Model results show the schemes can reduce maximum ozone concentrations obviously to the national standards and the best scheme is determined by economic condition feasibility.

• THE EFFECTS OF AEROSOL AND WATER-VAPOUR’S e-TYPE ABSORPTION ON LOWER ATMOSPHERIC LONG-WAVE COOLING RATES
• SU Wen-ying;CHEN Chang-he
• 1998 Vol. 17 (2): 120-126. 
• Abstract ( ) PDF (236KB) ( )
• In this paper, we use the band model to calculate the atmospheric long-wave cooling rates. The results show in the lower atmosphere, the cooling rate of the water vapour e-type absorption of window region is less than that of non-window region and is about 1/3 of the total water vapour cooling rate. The long-wave cooling rate of aerosol is less than that of water vapour and its contribution to total atmospheric cooling rate is about 30%. The distribution of total cooling rate in the lower atmosphere is mainly determined the distribution of water vapor cooling rate.

• OBSERVATION AND ANALYSIS OF ATMOSPHERIC TURBIDITY OVER WUDAOLIANG AREA IN QINGHAI-XIZANG PLATEAUX
• YUAN Fu-mao;JI Guo-liang;MA Xiao-yan
• 1998 Vol. 17 (2): 127-134. 
• Abstract ( ) PDF (361KB) ( )
• In this paper, the characteristics of atmospheric turbidity at Wudaoliang in the Qinghai-Xizang Plateau are analysed by using the atmospheric turbidity data observed with the MS-120 sunphotometer from August 1993 to May 1995. The results show that:(1) The air is very clean, and anthropogenic effect is little over Wudaoliang, which is comparable to that obtained at the Rongbusi(5 000m above sea level) in Mount Qomolangma area and at the Antarctic area,but it is less by an order of magnitude than that in the city.(2) The characteristic of seasonal variation of atmospheric turbidity is obvious, but its diurnal variation is not obvious in Wudaoliang area.(3) The atmospheric turbidity are related not only to atmospheric state near the ground(such as wind direction, wind speed and rainfall intensity etc.), but also to the geographic environment of observation station etc.

• ELECTRICAL CHARACTERISTICS OF ATMOSPHERE IN EAST AREA OF QINGHAI-XIZANG PLATEAU
• ZHANG Yi-jun;GE Zheng-mo;CHEN Cheng-pin;MENG Qing
• 1998 Vol. 17 (2): 135-141. 
• Abstract ( ) PDF (239KB) ( )
• In this paper, the characteristics of atmospheric electricity in east area of Qinghai-Xizang w ere analyzed.The result indicates that diurnal variation of vertical electric field on the ground in the fine weather is one peak and one valley.The peak and valley occur about 4~5 and 17~18 o'clock respectively.The electric structure of thunderstorm is dipolar. About 73.3%out of thunderstorm duration shorter than 30 minutes.A little lightning occur in the thunderstorm.The electric field on the ground are not different for different thunderstorm that produce different precipitation.The proportion of positive cloud-to-ground lightning to negative C-G lightning is 1:8.About 77.8% out of negative C-G lightning produce one return stroke and all of positive C-G lightning are single return stroke.The intensity of positive C-G lightning is greater than that of negative C-G lightning.

• COLD-FRONT ACTIVITIES AND ITS INFLUENCE ON AIR POLLUTION AT URBAN DISTRICTS OF LANZHOU IN COLD HALF YEAR
• WANG Shi-gong;YANG De-bao;LI La-ping;HUANG Jian-guo;QI Bin
• 1998 Vol. 17 (2): 142-149. 
• Abstract ( ) PDF (273KB) ( )
• It has been analysed that the data of 500hPa historical synoptic maps and the data of air pollutant concentrations were monitored by automatic monitoring system in Environmental Monitoring Station of Lanzhou in the period of 1988~1991. The analysed results are as follows:under the control of two-trough and one-ridge synoptic circulation pattern the frequency of cold-front activities at Lanzhou is the highest with 54.8%. It is higher with 35.5% under the control of one-ridge and one-trough synoptic circulation pattern. In cold half year the activest stages of the strongest and stronger cold fronts are in March. The other activer stages of cold fronts are in October. The activest stages of weak cold fronts is in January. Influence of cold-front passage on SO ₂ concentrations at Lanzhou is the most remarkable. The average decreasing rate of SO ₂ concentration is about 30% to 50% and the maximum decreasing rate is about 70% to 80%. The decreasing rate of NO _x concentration is also more remarkable.In the process of cold front weather, the correlation between inversion depth and air pollutant concentration is the most remarkable. The correlations between temperature, mixing depth and air pollutant concentrations respectively are reducing in proper order. Influences of above mentioned three meteorological factors on the changes of air pollutant concentrations are different in the processes of the strongest, stronger and weak cold front weather.

• A SENSITIVITY EXPERIMENT OF PRIMITIVE EQUATION MODEL WITH MIXED p-σ COORDINATES TO THE EXCHANGE BETWEEN LAND AND AIR
• ZHAO Ming;GAO Lei
• 1998 Vol. 17 (2): 150-157. 
• Abstract ( ) PDF (293KB) ( )
• Abstract A sensitivity experiment of 5 and 9 layers primitive equation models with mixed p-σ coordinates in limited domain to the drag coefficient,which affects the flux exchange between land and air,is performed by use of a cold wave process as an example. The result shows that the model is sensitive to the value of the drag coefficient. The value of the drag coefficient over Qinghai-Xizang Plateau in original model is too small. Increasing the value of the coefficient over the Plateau can improve the predicted results of the model.

• THE EFFECTS OF THE DIURNAL VARIATION OF SOLAR RADIATION ON CLIMATE MODELING OF R15L9
• SHAO Hui;QIAN Yong-fu;WANG Qian-qian
• 1998 Vol. 17 (2): 158-169. 
• Abstract ( ) PDF (499KB) ( )
• Comparative analyses are made between the experiments with and without the diurnal variation of solar radiation by use of the R15L9 model. The simulated mean sea level pressure, 500hPa height, the surface temperature and the precipitation fields of both January and July are discussed and compared. Statistical tests are also made. The results indicate that the diurnal variation of solar radiation has significant effects on the climate modeling,particularly in the Northern Hemisphere and on the continents. Ignored diurnal variation of such physical process would certainly influence the results of the climate modelling and induce systematic errors.

• THE SPATIAL AND TEMPORAL VARIATION FEATURES OF PRECIPITATION ANOMALY DURING LATE SPRING AND EARLY SUMMER OVER NORTHWEST CHINA
• CAI Xiao-jun LI;Dong-liang;YAO Hui
• 1998 Vol. 17 (2): 170-181. 
• Abstract ( ) PDF (462KB) ( )
• The precipitation data at 90 observational stations from 1960 to 1990 are used to analyse the spatial anomaly features and time evolution rule and the mechanism in May and June over Northwest China by EOF and REOF methods. The results show that the main anomaly structures of rainfall in May and June over Northwest China present pluvial pattern or dry pattern in all the areas, and spatial changes are opposite pattern from the north to the south and the west to the east. The principal anomaly sensitive areas are the east of Northwest China,the Hexi Corridor, the east of Qinghai-Xizang Plateau, the north Xingjiang, the source areas of the Yangtze River and the Yellow River and the desert basin. The basic trend of the rainfall from 1951 to 1995 is that the precipitation in the east of Northwest China, the north Xingjiang and the source areas had a wet-dry-wet process, while an increasing trend of rainfall appeares in the Hexi Corridor, the east of Qinghai-Xizang Plateau and the desert basin areas. In the aspect of the atmospheric circulation, when the structures of 500hPa geopotential height departure field emerge evident positive PNA and negative EU patterns in May, the rainfall is below the average over Northwest China at the same time. When sensible heat increases over Qinghai-Xizang Plateau in spring, the precipitation amount increases during late spring and early summer.

• THE FEATURE OF THE SOIL TEMPERATURE GRADIENT OVER CHINA AND ITS APPLICATION IN PREDICTING SUMMER RAINFALL
• ZHANG Shan-qiang
• 1998 Vol. 17 (2): 182-189. 
• Abstract ( ) PDF (288KB) ( )
• First,it has been made that the climatological analysis of January's monthly nean 1.6~0.8m soil temperature vertical gradient field of the middle and eastern China. The results of Empirical Orthogonal Function(EOF) decomposition show that the field of the soil temperature vertical gradient departure of the middle and eastern China has meso-scale and macro-scale characteristics. Based on the climatological analysis, we use the methods of composite analysis, correlation analysis and Singular Value Decompsition(SVD) to study the relationship between soil temperature vertical gradient and general circulation of the northern hemisphere. We obtained the finding that the mutual contribution between the anomalies of the soil temperature vertical gradient and general circulation evidently exists in the same month. Through investigating coherence between the field of 1.6~0.8m soil temperature vertical gradient and the flood period precipitation in the eastern China, we make the forecasting of the eastern China in the flood period with the field of 1.6~0.8m soil temperature vertical gradient departure, the fitting of 30 years(1955~1984) and the prediction of independent sample(1985~1988). From the result of forecast, we can find that the method, which forecast the precipitation of flood periods with the field of the soil temperature vertical gradient, is effective.

• THE APPLICATION OF MEAN GENERATING FUNCTION MODEL TO RAINFALL FORECAST OVER PLATEAU IN RAINY SEASON
• XIE Ming-en;DANBA Ciren;ZHANG Wan-cheng
• 1998 Vol. 17 (2): 190-197. 
• Abstract ( ) PDF (270KB) ( )
• Utilizing mean generating function as a basic function in this paper, we have been developed three prediction models:Gram-Schmidt orthogonal model, empirical orthogonal function(EOF) model and optimun subset regression model. The precipitation in rainy season(June~August) in Kunming, Mid-Yunnan(including Kunming, Yuxi,Chuxiong) and Linzhi, Tibet, was fitted and predicted by three models. The fitting result is satisfactory, especially in case of extremes. The results of the precipitetion prediction with mean generating function model in plateau region has high accuracy, fitting accuracy is 97%~100% and actual forecasting accuracy is 60%~80%, the model has also multi-step prediction capacity.

• SATELLITE AND LIGHTNING ANALYSIS FOR A THUNDERSTORM AFFECTING BEIJING CAPITAL INTERNATIONAL AIRPORT
• GU Lei;CHEN Lu;TAO Zu-yu;TIAN Bai-jun
• 1998 Vol. 17 (2): 198-203. 
• Abstract ( ) PDF (244KB) ( )
• The images of GMS and the data of lightning positioning system were used to analyze the thunderstorms which affected Beijing Capital International Airport(BCIA) on August 2, 1994. During the thunderstorm process, there were three mesoscale convective systems(MCSs) developed and affecting BCIA about 5 hours. The analyses show that the position, frequency and polarity of lightning are related to the phases of convective system development. Therefore, the data of the lightning positioning system are an available tool to the nowcasting of MCSs in addition to the hourly images of GMS.

• SHALLOW DISCUSSION ON SOME PROBLEMS OF POLLUTION AND ITS CONTROLLING OF ATMOSPHERIC ENVIRONMENT OVER THE LANZHOU CITY
• ZHANG Qiang;HU Yin-qiao
• 1998 Vol. 17 (2): 204-210. 
• Abstract ( ) PDF (336KB) ( )
• In this paper,the physical mechanism and objective cause of formation of atmospheric pollution over Lanzhou city are analysed. And the methods and measures which are being adopted or demonstrated for controlling atmospheric pollution at present are summarized,analysed and discussed. Then,the several problems which need studing as focal point are pointed out. Finally,the preliminary views and proposals about controlling atmospheric pollution of Lanzhou city are suggested.

• THE PRELIMINARY ANALYSIS OF THE INFLUENCE OF THE CLIMATE ON THE RUNOFF IN HEXI AREA OF GANSU PROVINCE
• YUAN Yu-jiang;SANG Xiu-cheng
• 1998 Vol. 17 (2): 211-217. 
• Abstract ( ) PDF (247KB) ( )
• In the paper, using single correlation, canonical correlation, response function and stepwise regression methods, the influence of the climate on the runoff in Hexi area of Gansu province are analysed from different aspects. The mainly obtain three new ideals:(1) In Hexi area, the precipitation in hydrological year(from October of last year to September of current year) is the leading factor that influence runoff change, it's role is whole districts and it determines the spatial distribution features of runoff field. The mean temperature from May to September is assistant factor. Through melting of ice and snow in high montain area, it play mainly an role in increasing runoff in Shule River reaches of the Hexi West area.(2) The annual total of runoff in Hexi area have an notable response to precipitation in January, from April to May and from July to August of current year, the most response appear in April, May and August.(3) The correlation relationship between climate and runoff is better in the Shule River in the Hexi West area.

• THE STUDY OF AN AUTOMATIC HAIL-RAIN RECORDER
• SHI An-ying;HAN Zhi-cheng;SONG Hui-ying
• 1998 Vol. 17 (2): 218-222. 
• Abstract ( ) PDF (172KB) ( )
• In this paper,we introduce the principle, structrue and application of an automatic hail-rain recorder. The error of this kind of instrument also is discussed. The result shows that the instrument performance is steady and observational data are vary useful to study the hail generation and test the hail suppression effectiveness.