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• A FIVE-LAYER PRIMITIVE EQUATION MODEL WITH TOPOGRAPHY(A DETAILED DOCUMENTATION OF THE MODEL)
• Qian Yongfu
• 1985 Vol. 4 (s1): 1-28. 
• Abstract ( ) PDF (1502KB) ( )
• Many numerical models have been developed in the world to study the earth's atmospheric circulations. The author also developed in 1979-1980 a five-layer numerical model with the help and collaboration of Prof. H.L.

• A p-σ FIVE-LAYER HYDROSTATIC PRIMITIVE EQUATION MODEL WITH C-TYPE STAGGER GRID
• Peng Ge
• 1985 Vol. 4 (s1): 29-41. 
• Abstract ( ) PDF (754KB) ( )
• In this paper, the c-type stagger grid is introduced into a p-σ five-layer hydrostatic primitive equation model.The numerical experiments have been performed by using the five-layer model, including two forms, one is the c-type stagger grid, and the another, the A-type which is the fundamental model.Period of the forecasting experiments are more than 36 hours.The experiments show that the model with c-type grid is stable in computing. The ability of forecasting is not less than that of fundamental model.In some ways, the new model is much beteer.

• A CUMULUS PARAMETERIZATION SCHEME WITH ACCUMULATION OF WATER
• Nai Kang
• 1985 Vol. 4 (s1): 42-51. 
• Abstract ( ) PDF (641KB) ( )
• On the basis of Kuo's cumulus parameterization scheme, a modified scheme taking into account the water accumulation in the cloud is proposed. The calculations by assumed data show that after consideration of water accumulation the precipitation intensity is enhanced and the timeis delayed, that the temperature stratification in the environment in important.

• NUMERICAL SIMULATION AND ANALYSIS OF INTER-MONTHLY VARIATION FROM APRIL TO JUNE OF EAST ASIAN CIRCULATION
• Fu Erxuan
• 1985 Vol. 4 (s1): 52-64. 
• Abstract ( ) PDF (954KB) ( )
• A numerical model and GFDL data are used to simulate the inter-monthly variation from April to June.It is found that the simulation is quite successful, for example, the formation and the development of the Tibetan Thermal Low, the "quasi-monsoon cell" to the south of the Plateau in April, the set-up of the 100mb Tibetan High in June, the with drawal of the westerly jet and the appearance of the eastely jet, the precipitation distribution along the Yangtz River and so on are all fairly simulated. Discussions are also given to (1) The quasi-monsoon cell and the thermal effect of Plateau, (2) the effects of the surface albedo in Plateau area on the transfer of sensible heat, the atmospheric heating and circulation, (3) the water vapour sources for precipitations over East China, southern and southeastern parts of Plateau and southwestern part of China.

• A COMPARATIVE STUDY OF WEATHER AND CLIMATE BACKGROUNDS IN EAST ASIA AND NORTH AMERICA IN MAY AND JUNE
• Li Weijing
• 1985 Vol. 4 (s1): 65-76. 
• Abstract ( ) PDF (919KB) ( )
• GFDL ten-year average data and FGGE-Ⅳ _b data are used to compare the large-scale circulations in East Asia and North America in May and June.Analysis indicates that the very different weather in the two regions resulted from the instability over North America is greater than that in East Asia.The triggering mechanisms are also different. A numerical simulation shows that those differences are caused by the different topography in the two regions.

• A NUMERICAL SIMULATION OF DIABATIC HEATING EFFECT ON TRANSITION OF INDIAN SOUTHWEST MONSOON FROM BREAK TO ACTIVENESS
• Li Jun;Qu Zhang;Wang Anyu;Gao Youxi
• 1985 Vol. 4 (s1): 77-86. 
• Abstract ( ) PDF (677KB) ( )
• A p-σ incorporated coordinate numerical model is used in this paper to simulate the transition process from break to activeness of the Indian southwest monsoon under the conditions with and without diabatic heating in July, 1979. The purpose of the simulation is to check the importance of the effect of diabatic heating on the variation of monsoon circulation. The initial data are taken from the FGGE-Ⅳb set. The simulation doma'in is in 0°-180°E, 22.5°S-57.5°N area. The simulated results show the importance of diabatic heating in the transition of monsoon circulation. When diabatic heating is included in the model, the monsoon circulation which is consistent with the real one can be produced.Therefore in the diabatic experiment the tropical monsoon trough and the vertical monsoon cell over India are well simulated. The southwest monsoon prevails and more precipitation takes place over mid India.The tropical circulation in the middle latitudes changes to the pattern similar to that in the active phase of monsoon. On the contrary, in the experiment without diabatic heating, the monsoon trough shifts to the Bengal area, a relatively high pressure region exists over mid India, the vertical monsoon cell disappears, the low-level southwest monsoon weakens and the break feature of monsoon at and below the 500mb level remains unchanged.

• INFLUENCE OF MID-LATITUDE BLOCKINGS ON DEVELOPMNT OF MONSOON
• Zhao Jingxia;Wang Anyu;Gao Youxi
• 1985 Vol. 4 (s1): 87-98. 
• Abstract ( ) PDF (818KB) ( )
• The inflnence of mid-latitude blockings on the development of Indian monsoons for a short range has been investigated by the use of a 5-layer numerical model developed dy Kuo and Qian.The results show that the influence of the mid-latitude blockings is quite important at the beginning of Indian monsoons. It delays the development of monsoon, weakens the intensity therefore, results in a thin and weak monsoon depression, an indistinct monsoon trough and less precipitation over mid Indian. Besides, the Tibetan hot low at the 500mb level disappears, precipitation over the plateau decreases and the southwest monsoon over East Asia weakens as well, when blockings are out of existence, then the opposite situations take place and are similar to the many-year averages.

• SOME NUMERICAL FORECASTINGS BY A 5-LAYER PRIMITIVE EQUATION MODEL
• Dong Anxiang;Sun Juanzhen;Chen weimin;Wang Anyu;Li Suhua
• 1985 Vol. 4 (s1): 99-109. 
• Abstract ( ) PDF (767KB) ( )
• Some numerical forecastings by a 5-layer primitive equation model are discussed in this paper.Results show that the model has certain capability to predict various processes of development of weather systems. Some disadvantages of the model are depicted and opinions for improvement are also proposed.

• THE EFFECTS OF THE QINGHAI-XIZANG PLATEAU ON THE MEAN GENERAL CIRCULATION IN EAST ASIA IN THE TRANSITONAL SEASON
• Li Ci;Wang Anyu;Wang Qianqian
• 1985 Vol. 4 (s1): 110-120. 
• Abstract ( ) PDF (704KB) ( )
• A group of numerical simulations has been conducted in order to investigate the effects of the Tibetan Plateau on the mean circulation in East Asia in the transitional season.The results show that the relative importance of the dynamic and the thermal effects of the plateau is chaged dramatically from May to June. In May as in winter the dynamic effect of the plateau plays a determinative role in the mean general circulation. However, in June the dynamic effect is reduced, the thermal effect becomes superior to it.Only when the thermal effect is taken into account in the model, the main systems of the general circulation can be fairly pro duced.

• NUMERICAL STUDY OF THE EFFECTS OF DIFFERENT UNDERLYING SURFACES ON THE MEAN CIRCULATION AND PRECIPITATION IN SOUTHEAST ASIA IN JUNE
• Luo Siwei;Fu Erxuan
• 1985 Vol. 4 (s1): 121-134. 
• Abstract ( ) PDF (1008KB) ( )
• In this paper we use a six-layer hydrostatic primitive equation model in combined p and sigma coodinates which includes the diurnal change of solar radiation and the precipitation of larg;e scale and cumulus convection to study the effects of different underlying surfaces on the circulation and precipitation in southeast Asia in June.We perform five simuiations in region from 0° to 180° E and from 20° S to 60°N at grid points with resolution 5°×5° in both latitude and longitude by using the climatic June zonal meteorological fields averaged from 0°-180°E as the initial states:(1)with ocean overall; (2)with actual land-sea distribution but no orography;(3) with actual land-sea distribution and orography together; (4)with albedo changed and(5)with northward movement of planetary wind system.After analysis in contrast to one another we have got some interesting understanding about their effects on the circulation and precipitation. (1)In the lower troposphere there is a cold subtropical high over the west Pacific Ocean which is essentialy generated by the land-sea distribution without relation to the Tibetan Plateau.The long wave trough near the coastal area in east Asia in upper troposphere is mainly produced by the effect of land-sea distribution, the Plateau gi.ves a little contribution to its strengthening.In upper troposphere the south Asia anticyclone is generated by the effect of the land-sea distribution and the Plateau together;the jet stream cores of west and east wind, located north and south of the Plateau respectively, are only determined by the effect of the Plateau, while the low pressure center at sea level in south Asia is essentially pro duced by the effect of the Plateau. (2)The meridional monsoon circulation cell south of the Plateau is only affected by the heating of the Plateau.The circulation cell near the coastal area which consists of summer monsoon and land-sea wind is essentially produced by the effects of the different heating of land and sea and is limited in the lower layer of troposphere. The meridional circulation over the Pacific Ocean is only generated by the sea surface effect. (3)In the simulation with ocean there is only one belt of larger precipitation in low latitudes.In those with land-sea distribution but no orography the second new belt of large precipitation occurs near the coastal area over the ocean which is larger than that in low latitudes,and with land-sea distribution and orography together there appears the third strongest belt of precipitation near the Plateau with center in Assam which extends NNW-ward to the south part of the Plateau and eastward to the south part of Yantze River, while the southern precipitation near the coastal area is somewhat weakened.The third belt of precipitation disappears as soon as the surface albedo of the Plateau is strengthened and it is increased when the planetary wind system moves northward. Some other interesting questions are also discussed in this paper.

• EXPERIMENTAL NUMERICAL FORECAST FOR CASE STUDY OF COLD WAVE
• Qu Zhang;Chen Zhonghua
• 1985 Vol. 4 (s1): 135-144. 
• Abstract ( ) PDF (637KB) ( )
• In this paper, the comparison between several numerical forecasting models for the case study of cold wave is described. The result shows, the 5-layer model ^[1] for the NG model considering both the nonadiabatic and topographic effects is capable of predicting the crucial transferm of general circulation at the earlier stage of a cold wave.Its application to the 48-hr forecast at 500mb over Tibetan Plateau and its surroundings gives fewer absolute deviation values than the Japanese model ^[2]. The MG model, which considers the topographic influence but results merely in a large scale condensation, is not so efficient as compared with NG, indicating that the radiation heating by long and short waves and the sensible heating are very important in weather forecast.The less importance of large scale condensation may be verified through a conparison between MG and the dry adiabatic or DG models. In the NN model, the nonadiabatic process is involved while the topographic effect is ignored.Its trial test for the 48hr forecast at the west of Tibetan Plateau leads to approximately the same result as NG model. However, this model when used for the forecast over the plateau and its neighbouring regions or at the front and the south of a trough gives a result not as good as NG.This shows that the forecasting quality differs very much depending on topographic conditions.