Abstract:Analysis is made of rainstorms which are associated with the low-level jet stream and shearline over the Changjiang (Yangtze)-Huaihe Valley butare not accompanied by noticeable cold air activities near the surface.Physical mechanism of formation is discussed. Collocation of rainstormarea with fields of various meteorological elements and physical quantitiesis investigated. A scheme for forecasting the location of the rainstormarea is presented.

Abstract:The anomalies of surface pressure and geopotential height at 500 hPa and 100 hPa in northern hemisphere are computed for grid points forthose years when the sea surface temperature on the eastern EquatorialPacific is abnormally high or low. Attention is focused on the correlation between the sea surface temperature anomaly (SSTA) and the circulation anomaly in the tropical and subtropical areas. It is revealed that the response of subtropical systems to SSTA varies in summer and winter. This may, in part, account for the weakening in summer and intensification in winter of the trade winds in the tropics during an El Niño year. Finally, a qualitative discussion of the interaction between the SSTA and the circulation anomaly is given.

Abstract:Based on the study described in Part Ⅰ, a further discussion is made on the empirical method for calculating effective radiation. By simplifying the theoretical formula proposed by Berland M.E. and Berland T. G., an improved empirical formula, which is compact in structure and easy to manipulate, is derived. The monthly effective radiation scomputed in this way for 101 stations scattered throughout the countryare in good agreement with the results obtained in Part Ⅰ of this paper.On the basis of the computation, the distribution of the effective radiation over China in the significant months is graphically represented and qualitatively analysed. It is found that the effective radiation over China is, in the main greater on the plateaus than on the plains, overarid regions than over humid areas. In North China, it is greater insummer than in winter whereas in the southeast of the Qinghai-Tibet Plateau, it is greater in winter than in summer. Over the Changjiang-Huaihe Valley, it is quite constant througut the year.

Abstract:Two wind maxima with jet-stream characteristics often occur, one above the other, in the lower troposphere by the south side of the rainstorm area over South China in summer.The lower one lying in the boundary layer above the surface friction is designated as the Southerly Boundary Layer Jet (SBLJ). Its structure and formation are investigat-ed in connection with its overlying counterpart, the Low Level Jet(LLJ). It is found that the general trend of higher pressure to the eastand low to the west in the surface layer provided by the western Pacific Subtropical High and the Indian Monsoon Low gives rise to the large-scale southerly flow while the secondary vertical circulation cellforced by the LLJ and the associated frontal shearline superimposes asub-synoptic southerly current on the general flow. The combination ofthese currents result in the SBLJ. Any fluctuation of the LLJ will be reflected on the activity of the SBLJ.

Abstract:In order to investigate the effects of topography and diabatic heating,especially the wet diabatic processes such as condensation, feedback by cloud of radiation and cumulus convection etc., five kinds of experiments are made for the ‘active’ periods and ‘breaks’ of the monsoon in India by means of the 5-layer primitive-equation model. The topography incorporated approximates the real setting whereas the initial data are taken from the FGGE-3B records.The experiments show that the diabatic heating including the wet processes plays an important role on the structure and intensity of the vertical circulation along about 80°E. For example, when the moisture content is reduced or when the cumulus convection or all the diabatic processes are neglected, both the extent and the intensity of the monsoon vertical cell decrease. Moreover, the effect of mountains during the break differs from that in the active period. During the former, weaker circulation and less precipitation are found over the mountains in central India but the reverse is true for the active monsoon period.

Abstract:The terminal velocity of free-falling hailstones of conical shape, which are often found in Xinjiang region of China, has not been much inves tigated. Our experiment measures this velocity of conical hailstone models. An equation expressing this velocity with respect to the geometric parameters is derived. Both experiment and theoretical inference showthat the terminal velocity of the conical hailstones differs from that ofthe spherical ones. The former is not a simple function of mass andsize but a function of mass and geometric parameters such as the conicalangle and the curvature of the base of the cone.