Abstract:Results of the Maximum Entropy Spectrum analysis and thefiltering analysis are given by using the ECMWF analysis data of the 500 hPa geopotential height over the Qinghai-Xizang Plateau and its surrounding areas during the summer half year.It is shown that the 30-60 day oscillations are significant over the Plateau and its vicinity.The center of the 30-60 oscillations is found in the eastern part of the Plateau. The annual variations are also discussed.

Abstract:Analysis is made of the May-September averaged circulationof the model atmosphere(referred to as the background circulation inthis paper)from the general circulation model(GCM)developed by theInstitute of Atmospheric Physics(IAP), Academia Sinica. Results showthat during an E1 Nino episode, a variety of important systems(SouthernOscillation. the Walker and Hadley circulations, the western Pacificsubtropical high and ITCZ)and extensive rainfall all undergo consider-able anomalies and the abnormalities occur mainly in the NH westernPacific tropical and subtropical latitudes.Analyses presented here arein good agreement with those of observational data, thereby demonstrating the prospects of the GCM in the research on low-latitute circulations.

Abstract:A two-level primitive equation spectral model is developedfor investigating the dynamic effects of the Qinghai-Xizang Plateau onthe atmospheric low-frequency oscillations in the summer flow pattern.Conclusions are drawn as follows:(1)Topography can stimulate low-fre-quency oscillations, which have obvious geographical characteristics.(2)Low-frequency oscillations assume a barotropic structure on thenorthern side of the mountains and a baroclinic structure on the southern side. (3)Wave propagation shows characteristics of quasi-stationary Rossby waves.

Abstract:In this paper, air-sea thermal teleconnection is analyzed. Results show that there exists a definite space-time teleconnection in theair-sea system and the teleconnection between summer sea and winterair is of global characteristics. The strongest teleconnection month varies with sea area, but the thermal teleconnection at 5-7 month intervals is the most common.

Abstract:In this paper the quasi-geostrophic omega equation involvingcondensational heating is solved to discuss its aplicabilitv to summercyclones over the Changjiang-Huaihe Valley. The contributions of the adiabatic and diabatic processes arealso analysed. The following conclu-sions are thus deduced:(1) The equation can accurately determinethe ascending and descending regions and the locations of their maincentres; (2) The direction of the vertical motion is generally decidedby the adiabatic process while the condensational heating amplifies theupward velocity; (3) Stable precipitation is more important than convection to the formation of the surface depression; (4) Calculation of 500hPa divergence can be used to predict the rain belt, area ofheavy rain and the most possible location of cyclogenesis.

Abstract:An investigation is conducted of the summer (June-August)global mean divergent circulation in the tropics during the 1982-1983 ENSO episode. Three divergent and three convergent centers are ob-served at the 200 hPa level, which are closely rolated to the distributionof large-scale zonal circulation in the tropics. It is found that the summer divergent circulation in 1982 is significantly weaker than theone in 1983. This difference may have something to do with the summersea temperature anomaly in the tropics during the strong ENSO episode.

Abstract:Tree ring indexes and temperature in western China areexpanded by the EOF method. On this basis, the features and structuresof the space field and time coefficients of tree ring indexss and temperature are examined by means of the canonical field and spectrum analysis. Results indicate a close relation in both space and time betweentree ring indexes and temperature in western China. In the end, the transformation function of time coefficients between tree ring indexesand temperature is derived by robust regression.

Abstract:Based on the temperature data of the atmospheric boundarylayer below 500m in the northern suburbs and outskirts of Nanjing,the temperature profile in different degrees of stability is analysedand fitted. It is shown that the logarithmic-linear law is good in precision and there also exists an inversion centre in the lower boundarylayer in the flatlands. The thickness evolution model of nocturnalrdiation inversion suggested by Anfossi is found to be applicable.

Abstract:The concept of diffusing index of direct solar radiation onthe greenhouse plastic surface is proposed in this study. Based on thedata of solar radiation observed inside and outsite the greenhouse,the diurnal variations and daily averages of the parameters includingthe albedo, transmissivity, diffusing index of direct solar radiation and the ratio of short-wave radiation inside the greenhouse to that outside are calculated and analysed.

Abstract:The effects of meteorological conditions on the winter grassyield are studied using the grass yield date at the north slope of the Tianshan Mountains. Investigations are made of the key period andfactors for the grass yield formation and the cycle of the historicalseries of grass yield and meteorologi Gal elements. A predicting modelfor grass yield is established based on the comprehensive considerationof the number of livestock and the meteorological conditions which may affect the grass yield.

Abstract:An experimental study is made on the selection of parametersof the correlation function, the relationship between the observational station distribution and the interpolation coefficients, the method of determining interpolation coefficients, and the influence of the first guess field on the interpolation in the objective analysis method of theoptimum interpolation. A scheme is thus established for the mono-element and multi-element interpolation in the 12-layer variable area and gridof four elements. The analysis of the elements and that of the elementlayers in the scheme are both variable. In the multi-element scheme,the multivariate optimum interpolation is used for the height and wind component (u, v), whereas the mono-element interpolation is used forthe relative humidity.

Abstract:On the R-meter principle proposed by W. Rutkowski and Fleisher (1955), the Doppler velocity spectrum parameter σ_v;. is extracted from the fluctuating echoes observed by a conventional weather radar (radar 713) and displayed in pseudo-color on a microcomputer.Under certain conditions, the spectrum width σ_v, is just the turbulentvelocity. Observations show that the error in R meter measurements caused by unsteady radar frequency is almost negligible.

Abstract:The R-S five band radiation scheme is commonly used tocalculate infrared radiation in numerical studies of the nocturnal boundary layer. If integration is conducted only to the top of the boundary layer model, errors will occur in downward radiation (5-8%) and net radiation (12-20%), and mask strong radiation cooling will result nearthe model top. In this paper, the source of errors is examined and asimple, effective correcting method presented.

Abstract:By using multiple-time data, a barotropic nondivergent vorti-city equation is applied to the prediction of the NH atmospheric circulation. The undetermined coefficient given in the dynamic-statistic spectral model is the function of time and space. The model is applicableto the forecasting of the trough and ridge in the westerly belt.

Abstract:In this study the construction of the yield component systemis regarded as the grey dynamic procedure in which all the yield elements are related to each other. Based on the data generation and model-building theory of the grey system, the yield component grey system model is constructed using the data from separate seeding date tests atequal intervals in a year. The impact of different seeding dates on the yield component system is simulated by Runge-Kutta method .The results are satisfactory.