Abstract:A general survey is made of the research on the Chinese meteor-ological history during the past sixty years after the presentation ofpersonal view about the significance, aim. mission, and subject matter of the research. Urgency for carrying on the research is empha-sized and suggestions are made about how to develop the research inthis field.

Abstract:The equation of kinetic energy is used to calculate the averagekinetic energy budget over the low-latitude area of East Asia duringthe period of time when summer monsoon advanced northward. It isfound that an abrupt change took place in the atmospheric circula-tion over this area during June 17-20, 1979(the onset of the plum rainseason). Meanwhile both the average and turbulent kinetic energies in-creased rapidly and the updraft velocity with the convective precipi-tation intensified over the area. The average kinetic energy originatedmostly from the work done by the pressure gradient force and therapid increase of the average kinetic energy was mostly determinedby the decreased friction term, i.e., by the conversion of the kineticenergy of sub-grid scale to that of grid scale. The development of cu-mulus convection played an important role in the process. The atmos-pheric motion systems of the subtropical westerly jet and easterlyjet on both sides of the South Asia high, the low-level southwestmonsoon over Southeast Asia. the southeast monsoon over the West Pacific and the cross-equator flow near 105°E and 125°E all madesubstantial contributions to the average kinetic energy budget.

Abstract:It is shown by the principal component analysis of the annual andseasonal mean temperature series of 42 stations in China during theperiod of 1881-1981 that the whole country can be divided into fiveareas according to the spatial distribution of the variance contribu-tion of the principal components to the temperature series in eachstation. During the past hundred years the trend of the annual andseasonal mean temperature in the most part of China was very simi-lar to that of the mean temperature in the northern hemisphere. It isalso shown by the analysis of variance spectrum of the first threeprincipal components that the significant statistical period was variedfor different components, but most of them were concentrated in thethree wave bounds, i.e.. wave bounds of 18.4-28.9, 2.9-3.0 and 2.2-2.3 years and the periodic component of 18.4-28.9 years coincidedwith the phase of the double 11-year sunspot cycle.

Abstract:Based on FGGE Level Ⅲb data a composite technique is employedto investigate the changes in the circulation with a 40-50 day periodand the associated moisture transport. It is found that the northwardand eastward passage of the 40-50 day perturbations is related to thephase changes between the active and break monsoons over centralSouth Asia and Southeast Asia. The active (break) monsoon is char-acterized by the maximum (minimum) cross-equatorial moisture fluxesover the western Indian Ocean. and by the maximum (minimum) east-ward moisture fluxes over the eastern Arabian Sea (75°E), the maxi-ma (minima) together with the Q₁ maximum (minimum ) and the OLRminimum (maximum), propagate eastward and northward. The fluc-tuation in cross-equatorial moisture transport related to Somali Jetexerts an influence on the summer monsoon precipitation over SouthChina via the propagation of the 40-50 day perturbation, the time lagbeing about 10-12 days.

Abstract:Starting from the three-dimensional atmospheric dynamic equationsand based upon the phase path method, the linear transformation method is used here for transferring the nonlinear three-dimensional problem into a nonlinear two-dimensional problem. The nonlinear termsare expanded to the third order by a Taylor’s series in the neighbour-hood of the equilibrium point of the equations. Thus the nonlinear two-dimensional equations are all solved and explicit analytic solutionsto the three-dimensional nonlinear inertia-gravity waves are obtained.Analysis shows that with the nonlinear terms to the second order,the solutions are composed of the superposition of a cosine wave anda cnoidal wave, and with the nonlinear terms to the third order, the three-dimensional nonlinear inertia-gravity waves are satisfied by themodified Kortweg-de Vries equation and under given conditions, the solutions are composed of the superposition of two solitary waves. Inaddition, one exact implicit solution is found. The dynamic propertiesof all the solutions as mentioned above are discussed.

Abstract:The effect of the disturbance due to the joint action of theQinghai-Tibet Plateau aud the heat source field of the same size onthe tropospheric general circulation has been simulated by using a two-layer potential vorticity equation model. The heat sources fall, according to geographical location, into three regions: i) the one coin-cident with the massive terrain, i. e., the plateau itself; ii) the adjacent region, corresponding to the heat source from southeast Tibetto the Bay of Bengal; and iii)the heat source from the Yellow Sea toJapan. What is simulated, i.e, the establishment of the upper-tropo-spheric SAH and its seasonal movement, as well as the primary characteristic features of the cyclonic circulation and its shear line in thelower troposphere reflect mainly the actual synoptic occurrences.Results suggest that the thermal process of the underlying surface inthe regions involved is a key factor for the winter-to-summer transition of the Asian atmospheric circulation pattern in addition to thedynamics of the massive terrain. The three heat sources in the thermal field each have their own implications in the seasonal variationof the general circulation.

Abstract:Case studies have been carried out of the heavy rain occurring inthe areas of the left-rear quadrant of the lower-level jet stream atits maximum speed and of the right-front quadrant of the upper-leveljet stream at its maximum speed by detailed analyses of the meteor-ological data during the period of June 21-30, 1975. And on thisbasis the cause for this kind of heavy rain are further analysed.

Abstract:It is shown from the measured raindrop size spectra in precipita-tion of convective cloud and stratus that they can be approximated byexponential function with the intercept N₀ and slope Λ. The parame-ters N₀ and Λ are related to the mean rainfall rate diameter, whichis defined here, and the relationship between them is in good agree-ment with the theoretical expression derived. Based on the above results, a method for estimating N₀ and Λ interms of reflectivity factor and rainfall rate is suggested. The valuesof N₀ and Λ calculated by the method basically consist with thoseanalysed from real data.

Abstract:The microstructure of hailstones is determined by the growth con-ditions. By analysis of the microstructure. the growth conditions couldbe deduced and the dcductive method is discussed. By interpreting theair bubble and crystal data of "5.1" hailstones (whih were observedover lower Yangtze in May Day, 1981), the growth trajectory, environmental liquid content and vertical velocity are quantitatively analysed.

Abstract:Hail spectrum samples collected successively from the six hailstormsoccurring in the region of Zhaosu, Xinjiang during July of 1982 wereclassified. From the analysis of their spatial and time series distribu-tion, the mathematical expression of the averaged spectra was given.The results obtained have proved to be of importance for studying thehail formation mechanism, designing hail suppression and testing itseffect in the said region.

Abstract:Enhanced satellite IR cloud pictures have made possible the usefulcloud data from qualitative to quantitative analysis. The enhancing ofthe GMS IR cloud pictures and their temperature checking application are discussed. From the relationship between the gray-scale of theenhanced IR cloud pictures and the amount of precipitation, a methodis suggested for estimating the cloud-cover area, the temperature gra-dient at the cloud top, and the amount of precipitation.

Abstract:The correction of the readings of the video integrator for the Model 713 weather radar with the aid of a microprocessor is discussed. Anew method using the standard deviation after the echoes are aver-aged is suggested and the results are quite satisfactory. The method isfound to be practical. convenient and of great significance value tothe design, adjustment and theoretical study of video integrators ofvarious kinds.