Current Issue

• THE VORTICITY CHANGE-RATE AND ITS HEAT SOURCE FOR DEVELOPMENT OF MESO-α SCALE VORTEX DURING A PERSISTENT HEAVY RAIN OF 14-22 AUGUST 1981
• Cheng Linsheng
• 1991 Vol. 10 (4): 337-350. 
• Abstract ( ) PDF (895KB) ( )
• During the period of 14-22 August 1981, a persistent heavy rain event occurred over the adjacent region of the Shaanxi-Gansu-Sichuan Province. This heavy rain event was directly related to a persistent development of a meso-α scale vortex with shear line. Diagnoses of the vorticity change-rate reveal rhat the positive vorticity change-rate center originated over the lower levels of the Qinghai-Xizang Plateau lee side, and then a process of the superposition and coupling and vertically joining-up of the vorticity change-rate centers over upper-and lower-levels was occurred. The vertical structure and evolution of the positive vorticity change-rate centers are basically consistent with the vertical structure and evolution of the positive vorticity centers of the formation and development of the shear line-vortex. In the factors of contributing to the vorticity change-rate, the relative numeric of the nonlinear interactive vorticity change-rate is the most component;the time-mean vorticity change-rate owing to topographic forcing is important only for the formation and maintenance of the shear line-vortex;the contribution of the perturbation vorticity change-rate is worth notice only when the shear line-vortex is under an intensive development. Diagnoses of the mesoscale heat and moisture budgets reveal that the vertical integrated high value regions of the apparent heat source Q1 and apparent moisture sink Q2 are basically consistent with regions of developing shear line-vortex and heavy rain. The vertical profiles of temporal-and spatial-averaged Q1 and Q2 indicate that the maximum heating interval of the Q1 appears between 570 hPa and 400 hPa, while the maximum interval of the Q2 appears between 650 hPa and 550 hPa. The heating due to convective eddy flux convergence of the sensible and latent heat is about half the amount of latent heat due to condensation.

• THE RADIATION CONDITIONS IN THE BAY OF MANILA AND PORT GULF OF LAE
• Yao Lanchang;Cai Ying;Ma Zhuguo;Yuan Fumao;Zhang Licai
• 1991 Vol. 10 (4): 351-361. 
• Abstract ( ) PDF (676KB) ( )
• In this paper the diurnal variations of components of radiation in the Bay of Manial and Port Gulf of Lae and differences between regions are analysed by using a few expedition data of radiation in these regions. Differences of radiation characteristics between the water surface in the bay(port gulf) and the land surface of its surrounding sea island are revealed. The information may be very helpful to analysis and computation of sea-air heat exchange in the above regions.

• THE TRANSPORTATION AND DISPERSION OF AIR POLLUTANTS CONTROLLED BY MOUNTAIN-VALLEY CIRCULATION:TWO-DIMENSIONAL NUMERICAL SIMULATION
• Qiu Chongjian;Pu Zhaoxia
• 1991 Vol. 10 (4): 362-370. 
• Abstract ( ) PDF (545KB) ( )
• In this paper, a two-dimensional numerical micro-scale model is given in the background of real terrains of Lanzhou city. The mountain-valley wind caused by heating difference, and the process of air pollutants transportation and dispersion from elevated source are simulated using this model. It shows that there are two factors to bring about serious air pollution, one is a transition of the mountain-valley wind around sunrise and sunset, the other is the strong downdraft caused by mountain-valley circulation over the valley at daytime.

• MULTISPECTRAL PROPERTIES AND IDENTIFICATION OF CLOUD AND SNOW OVER THE WEST OF CHINA
• Wei Li;Zhong Qiang
• 1991 Vol. 10 (4): 371-380. 
• Abstract ( ) PDF (631KB) ( )
• All five AVHRR channels data of NOAA-9 and NOAA-11 are used to extract the multispectral properties of cloud, snow and land surface over the west of China-including Qinghai-Xizang Plateau and desert area. An algorithm for cloud and snow detection is developed based on the multi-threshold method. It is shown that the 3.7μm(channel 3) measurements are significant for cloud and snow detection as some authors have pointed out. Some tests of this algorithm applied to Qinghai-Xizang Plateau have shown reasonable classification results.

• ANALYSIS OF THE RELATIONSHIP BETWEEN THE OLR AND THE SURFACE EFFECTIVE RADIATION OVER THE QINGHAI-XIZANG PLATEAU
• Wang Keli;Zhong Qiang;Hou Ping
• 1991 Vol. 10 (4): 381-390. 
• Abstract ( ) PDF (600KB) ( )
• Combining the NOAA OLR data and the simultaneous effective radiation measurement data over the Qinghai-Xizang Plateau region during the period from August 1982 to July 1983, the relationship between them is investigated and a empirical method is presented for deriving surface effective radiation from OLR. In addition, the spatial distribution of the surface effective radiation and the annual variation of the long-wave radiative divergence of the atmospheric layer and the mean radiative cooling rate of the atmospheric column over the Qinghai-Xizang Plateau region are presented in this paper, too.

• EFFECTS OF TEMPERATURE CORRECTION AND CO ₂ CONCENTRATION ON CALCULATIONS OF LONG WAVE RADIATION IN THE ATMOSPHERE
• Qian Yongfu;Mao Huiting
• 1991 Vol. 10 (4): 391-399. 
• Abstract ( ) PDF (546KB) ( )
• A series of experiments on the effects of temperature and CO ₂ concentration upon the calculations of mean slab long wave radiation transmissivity in the atmosphere are made in this paper. It is shown that tabulation and interpolation methods can be used in the calculations in order to save computing time, required accuracy can also be obtained. The effect of temperature is obvious, therefore it should be taken into account in the computations of the atmospheric temperature change rates induced by long wave radiative process. Finally, the effects of CO ₂ concentration are studied and some interesting results are obtained.

• GRAPHIC DISPLAY SYSTEM OF LIGHTNING LOCATION SYSTEM
• Zhang Guangshu
• 1991 Vol. 10 (4): 400-405. 
• Abstract ( ) PDF (365KB) ( )
• This system is designed to run on IBM PC AT 286 or compatible computers that support EGA graphics. The real-time mode is used to process, display and store all lightning positions data. The display receives flash data from the Position Analyzer(PA), checks transmission data format, and sends processed flash data to users in real-time or after every pre-set interval. The lightning activity and moving path with different geographic background can be monitored conveniently on the screen. In the data inquiring mode, the lightning data of any time interval, any where within the maximum region may be inquired, displayed, and calculated for total number of negative and positive. The sectional region may be amplified by setting the coordinate of region on main menu. The screen also can show the total lightning numbers of every hour of the day inquired. The display system supports eight pen ploter(SPL-450). The lightning graphics displayed on the screen can be plotted on a plotter or printer.

• THE ANALYSIS OF THE OSCILLATION OF ATMOSPHERIC TOTAL OZONE DURING THE PERIOD FROM JAN. 1958 TO DEC. 1986
• Wu Tongwen;Zheng Guang;Qu Zhang;He Huixia
• 1991 Vol. 10 (4): 406-412. 
• Abstract ( ) PDF (428KB) ( )
• In this paper, using the monthly mean total ozone data of 116 ozone observational stations over the Northern Hemisphere during the period from Jan. 1958 to Dec. 1986 and by harmonic analysis, the averaged characteristics of the periodic oscillation of the total ozone for a year, half a year, quasi-biennial, quasi-quadrennial and quasi-11 years have been exposed. These periodic variations closely relate to general circulation, temperature and solar activity.

• A SYNOPTIC ANALYSIS METHOD FOR 24 HOUR VARIABLE ENERGY OVER THE TIBET PLATEAU
• Song Xiaoyu
• 1991 Vol. 10 (4): 413-419. 
• Abstract ( ) PDF (417KB) ( )
• In this paper, the relationship between local variation of total energy and synoptic system over the Tibet Plateau are discussed. The results show that by the analysis for 24-hour voriable energy over the Tibet Plateau, we can distinguish the activities of the cold high and the thermal low over the Tibet Plateau.

• A COMPREHENSIVE INDEXES RECOGNITING HAIL CLOUD BY USING WEATHER RADAR IN MOUNTAIN AREA OF SOUTH NINGXIA
• Xu Yangchun
• 1991 Vol. 10 (4): 420-425. 
• Abstract ( ) PDF (353KB) ( )
• In this paper, 151 hailstorm cases in Liu-Pan mountain area are studied by using multiple-factor correlation probability method, two parameter scatter diagram method. Quantitative indexes recogniting hail cloud by using weather radar are determined. The results show accuracy is 92.1% when the comprehensive index is equal to 2.9.

• RELATIONSHIP BETWEEN THE INTERANNUAL CHANGE OF THE EARLY SUMMER RAINFALL OVER DONG-TING LAKE AND MONTHLY ARCTIC ICE AREA
• Ye Yuyuan
• 1991 Vol. 10 (4): 426-428. 
• Abstract ( ) PDF (172KB) ( )
• By using the data of early summer rainfall and the monthly Arctic ice area during 1953-1977, we calculated the cross-correlation for both, and found that there is an apparent positive correlation relationship between the early summer rainfall over Dong-Ting Lake and the monthly Arctic ice area in North Pacific-Arctic in October for the last year. The correlation coefficient is equal to +0.4882 and degree of confidence is 0.05.

• COMPUTATIONAL SCHEMES OF SCATTERING RADIATION AND CLIMATE EFFECTS OF AEROSOLS
• Qian Yongfu
• 1991 Vol. 10 (4): 429-441. 
• Abstract ( ) PDF (741KB) ( )
• A detailed introduction to the computational schemes of atmospheric scattering radiation and radiative heating rates is made in this paper. The concepts, radiative properties and climate effects of aerosols are also discussed. An iterative method for radiation flux densities is developed. The paper gives the theoretical base for inclusion of climate effects of aerosols in various numerical models.