Vol.2, NO.2, 1991

Display Method:
Preliminary Analysis of Climatic Change During the Last 39 Years in China
1991, 2(2): 164-174.
The preliminary analysis of climatic change in China during the last 39 years has been made in this paper. The results show that although the global climate is getting warmer, some parts of China are cooling. The warming only occurs in northeast, north and west part of northwest China while the areas between about 35oN and Nanling mountain, east of Tibetan Plateau in China are getting cooler. The cooling centers are located in Sichuan, the south part of Shanxi and the north part of Yunnan, respectively. Under the greenhouse effect, the precipitation becomes more in low and high latitudes and less in middle latitude. But, the precipitation in the most parts of China becomes less, especially in north and northwest China
The Propagation of the Winter Monsoon During Clod Air Outbreaks in East Asia and the Associated Planetary-scale Effect
1991, 2(2): 124-132.
The present paper has delt with the characteristics of propagation of the winter monsoon during cold air outbreaks for 19 cases of 1980—1984 in East Asia as well as the associated planetary-scale effect. It has been revealed that the propagation of cold air mainly shows a mode of 10—20 day period oscillation. Furthermore, the Siberian cold high associated with outbreaks of cold air may lead to the response of a chain of planetary-scale events. This mainly shows up in the fact that the branch of upward motion of the divergent circulation rapidly shifts from the Indonesia-Malaysian region eastward to the eastern Pacific, thus causing the normal-type Walker circulation to reverse its sense. This condition is very similar to the movement of divergent circulation from non-El Nino year to El Nino year. From the dynamic viewpoint, this kind of divergent circulation is favorable to the synoptic development over the eastern Pacific and the western coast of North America.
The Numerical Simulation on the Formation and Evolution Process of the Asian Continental High in Winter
1991, 2(2): 133-139.
Using the two-layer spectral model involving radiation parameterization, continental heat equilibrium, convective parameterization and topography, we simulated the formation and evolution process of the Asian continental cold high in winter. The distributions of sea-level pressure, temperature and vertical velocity in the mid-troposphere in the three development stages, i. e. formation, southward movement and transformation of the cold high, are given in this paper. The results correspond with the observational facts. In addition, we simulated the variation of subtropical and tropical planetary circulation caused by the evolution process of continental cold high.
The Formation and Features of Fog in Shanghai Urban Area
1991, 2(2): 140-146.
This paper deals with the formation and classification of the fog in Shanghai urban area. By analysing the records 27 fog days during 1984, it is found that there are four types of fogs: frontal fog (accounting for 40.7%), radiation fog (accounting for 29.7%), advection radiation fog (accounting for 18.5%), and advection fog (accounting for 11.1%). Each type is explained in detail with some examples. In addition, using the Shanghai fog day data during 1951—1988, it is pointed out that : (1) In Shanghai urban area, the mean fog day becomes fewer, (2) Shanghai urban fog is closely related to the urban moisture island, (3) The urban “pollutant fog” with the low relative humidity frequently occurs in Shanghai.
An Analysis of Extremely Strong Rainstorm Occurred by the Tropical Cloud Cluster in Eastern Zhejiang
1991, 2(2): 147-155.
In this paper an extremely strong rainstorm process on 29—30 July 1988 in eastern Zhejiang is analysed. The maximum precipitation is 533 mm. It was occurred by the mesoscale convection cloud cluster, which was developed by the interactions between the easterly disturbances in the two sides of subtropical high in the lower troposphere, and between the easterly disturbances in the lower and higher troposphere. The cloud cluster was maintained by the interaction between the cold air caused by the convection precipitation and the tropical easterly system
The Study of Recent Climatic Fluctuation in the Maowusu Sand Region
1991, 2(2): 175-183.
Based on the meteorological data of seventeen stations in the Maowusu sand region in the recent 40 years, we investigated climatic characteristics of radiation, heat, precipitation and wind sand and revealed that spring is the most severe season of desertification in the region. We also discussed in detail climatic evolution tendencies of various factors related to desertification processes. The power spectra were analysed for the time series (1955—1988) of annual precipitation and aridity degree in the four stations of Etoke, Dongsheng, Yanchi and Yulin, respectively. The pronounced oscillation periods are quasi-triennial and eight to nine years. The quasi-triennial vibration may be associated with the periodic variations of SST, subtropical high, temperature of Tibetan Plateau and cold air activity of the northern hemisphere
A Calculation Method of the Total Solar Radiation Received by Wall Surfaces in China
1991, 2(2): 184-190.
This paper deals with the annual variation of the total radiation received by the wall surfaces and its variation law with different orientation in China based on the calculation methods. Also, its distribution all over the country is analyzed in detail
A Calculation Formula of the Terminal Velocity of Water Drops in the Atmosphere
1991, 2(2): 191-199.
In this paper, for the terminal velocity v of a spheric water drop (with a radius r) falling in the fluid medium, an analytical solution is theoretically derived. The constants a and b in the formula are determined by the experimental velocity data of water drops in the atmosphere: a =0.53563, b=1.37358 with a maximum relative calculating error of 24%. This semi=theoretical formula is compared with the other empirical formulas. Three new statistical formulas in the form of are recommended. They divided r (0~2900μm) into 3,4 and 5 ranges with a maximum relative error of 11%, 7% and 4%, respectively
Measurement of Water Vapor and Cloud Liquid Water Content in the Troposphere by Ground-based Microwave Remote Sensing
1991, 2(2): 200-207.
The design principal and structure features of a new type dual-channel ground-based microwave radiometer for measurement of water vapor and liquid water in the troposphere are discussed. A method independent of radiosonde data is employed for the absolute system calibration. A statistical method for retrieving the total water vapor and cloud liquid water content and a nonlinear iterative algorithm for retrieving the water vapor profiles in the troposphere are discussed. Some experimental results of the Operational Experiment on Mesoscale Meteorology conducted in the summer of 1989 are presented, and the profiles have been compared with the radiosonde data. The results are satisfied
The Relationship Between the Establishment of the Summer Dry Circulation Systems in North China and the Disposal of Tide-generating Force
1991, 2(2): 208-212.
This paper analyses relationship between the general circulation systems in the summer dry seasons in north China and the resonances of tide-generating forces. Some results are significant
A Preliminary Analysis on the Relationship Between Outgoing Longwave Radiation and Drought/Flood over North China
1991, 2(2): 213-217.
Based on the outgoing longwave radiation (OLR) data and precipitation data from 17 stations in north China during 1974 through 1986, the temporal and spatial distribution features of the OLR anomaly patterns corresponding to drought or flood cases over north China have been discussed in this paper. It is pointed out that the disposal of the OLR anomaly patterns between the drought and flood cases during the pre-winter or the summer is quite different, and the evolution of the OLR over two key regions, the equatorial central Pacific and the marine continent, can influence the distribution of the drought or flood in north China. By carrying out the multi-spectral analysis between the precipitation over north China and the OLR field over the equatorial central Pacific, a common quasi-biennial oscillations is significant, and the OLR field appear ten months prior to the precipitation.
An Approach to Drawing Meteorological Element Cross Section Diagram by Computer
1991, 2(2): 218-223.
In this paper, an approach to drawing the meteorological vertical cross section was introduced by using are sounding data. The methods of searching station points, choosing stations from their projections and drawing wind signals were explained. Some program flowcharts were also given.