Abstract:The monthly and seasonal diabatic heating anomaly fields in the atmosphere over the Northern Hemisphere during 6 E1 Nino and 6 anti-E1 Nino years (1967-1985) are calculated by using spectral representation. Results suggest that E1 Nino events have a significant influence upon the diabatic heating anomalies in the atmosphere. The atmosphere response is characterized by the well-organized positive and negative centers of diabatic heating in the lower and mid-high latitudes, with their phase and intensity having features of low frequency oscillation and difference centers showing quasi-bimonthly fluctuations. During anti-E1 Nino years the atmospheric distributions are the same as during E1 Nino years except for the anti-phase of the anomaly center values.As shown from the analysis of correlationship between sea surface temperature (SST) and atmospheric variables, the anomaly of SST is the dominant reason for the diabatic heating anomaly in the atmosphere.

Abstract:Based on monthly rainfall data from 80 stations of China for the period of January 1951-February 1985 and using the maximum entropy spectrum and EEOF techniques, the spatial and temporal features of quasi-biennial oscillation(QBO) in the rainfall over China are investigated in a detailed manner, with some results of interest acquired.

Abstract:Based on the ana1ysis of the long-range variation of the Northern Hemisphere mean temperature(NHMT), the effect of the NHMT variation on the climate in China is discussed. It is shown that there is a significant positive correlation between the temperature anomalies in China and the NHMT, and the temperature anomaly in the middle and lower reaches of the Changjiang River and the North China Plain is about 1.4-1.6 times in magnitude as large as the NHMT anomaly. It is also shown that the precipitation anomaly in China is correlated with the NHMT,The significant difference of the 500hPa atmospheric circulation over Eurasia between the warm and cold years in the Northern Hemisphere shows that the statistical correlation between the climate in China and the NHMT can be interpreted by some physical processes.

Abstract:A three-dimensional numerical model is used for simulating cloud and aerosol effects on climate, with stress laid on ana lyzing the cloudand aerosol effects on surface, soil and air temperatures and the related surface pressure. Results show that neither cloud aerosols nor other kinds of aerosols change the basic characteristics of summer climate and only slight modification is observed. It is found, however, that they have significant influences on the surface, soil and air temperatures and the related surface pressure. In general, clouds and aerosols decrease surface and soil temperatures and increase the temperature in the layer containing aerosols but decrease the temperature in the layers above and below.Aerosols in the boundary layer cause the increase of the temperature in the layer and the decrease of the surface pressure. Cloud and aerosol effects on climate are complicated, depending not only on the physical properties of the underlying surface and the optical thickness of aerosols but also on the circulation background. The values of surface and soil temperature changes can reach a general order of 1-5K.

Abstract:The Principle of Singular Value Decomposition(SVD)and its application in the investigation of the linear relationship between two fields are examined.The SVD is employed to study the relationship between SST and 500 hPa geopotential height standard anomalies over the North Atlantic in winter months.The results indicate that the SST patterns are well correlated with the teleconnection patterns at the 500 hPa height. It is shown that the method of SVD is very effective in studying the linear relationship between two fields.

Abstract:Analysis is done of the divergence component of the monthly mean wind field at 850 hPa for a period of roughly 10 years. Results show that three convergent and three divergent zones are observed in the monthly climatic velocity potential fields for each of the four seasons with marked seasonal change occurring over the South-Asian Plateau, South America and Africa and slight variation taking place in the Eastern Indian Ocean and the low-latitude Pacific. The interannual anomalies of these divergent wind fields are found to bear a close relation with E1 Nino/anti-E1 Nino events. During the 1982-1983 E1 Nino episode,for instance, the wind field shows an anomalous process associated with it.

Abstract:Comprehensive investigation is made of the longitudinal and latitudinal variations in the large-scale circulation from May to June in terms of spherical expansion.It is found that the spectrum features of the mean large-scale circulation are different at various levels and a spherical wave can be found as the sample for the longitudinal wave at each level. The variations in the features of spherical wave spectrum reflect the at mospheric circulation catastrophe in June, which develops from the 100hPa to 500hPa level, and is most significant at the 500hPa level. The characteristics of spherical spectrum are different in wet and dry years and there exists a pronounced difference between the phase of the predominant wave before the beginning of the Mei-yu season and the conversion wave after the period.

Abstract:The temporal variation features of spectrum parameters ofthe 500hPa ultra-long waves in the Northern Hemisphere are investigated based on the run theory and Markov model. Information of the persistence and translation of amplitude increase/decrease and phase advance/retreat is obtained, thus providing a statistical climatological background for long-range weather forecasting.

Abstract:In this paper a stepwise selection of variables for logistic discriminatory analysis by using the maximum likelihood estimation is based on likelihood ratio tests for the discriminatory coefficients. The tests are used in a forward selection and a backward elimination at each step. Thc use of the selection procedure is illustrated with several examples.

Abstract:Discussion is first made of the application of automatic water supply ET equipment in the area of Nanjing and the problems thus arising. Then, based on farmland ET data, comparison is made between several current calculation methods in applicability for farmland ET. Finally, water requirement and crop coefficients for winter wheat, red bean, etc.are determined.

Abstract:In this study, a numerical model of one-dimensional nonsta-tionary boundary layer over a sloped terrain is established. Emphasis is put on the characteristics of Ekman spirals over the sloped terrain.Conditions in which Ekman spirals move counterclockwise (ccw) and the relationship between frictional force and Ekman spiral pattern are given as well.

Abstract:In this paper, Monte Carlo method is used for analyzing and comparing the precision of vector method and horizontal projection method in processing wind data from double-theodolite. Results show that vector method has higher precision. In addition, effects of baseline length on the precision of the processed wind data are examined, with a conclusion that baseline of 700-1000m is the best.

Abstract:The correlation of the sea surface temperature anomaly (SSTA) of the East Pacific with the activities of subtropical high pressure in the West Pacific and the tythoon cyclonic precipitation in China is analyzed in this paper. Results show that summer typhoon rainfall in China is plentiful in the south and scarce in the north when the sea surface tem-perature (SST) of the East Pacific increases anomalously, and reverse situation occurs when the SST decreases. The dependence of the typhoon rainfall distribution pattern on the SSTA can be attributed to the variation of the atmospheric circulation caused by the E1 Nino event, thus influencing the activities of subtropical high pressure and tropical cyclones.

Abstract:using the model DL-8318 multichannel optical particle counter, the atmospheric aerosols were observed at the Huangshan Weather Station in September, 1988 and May, 1989. Preliminary study shows rather low concentration of atmospheric aerosol particles at Mt. Huangshan and the coincidence of its spectrum distribution with the function of the power exponential law distribution proposed by Junge,with the average relative error being 19% and the correlation coefficient 0.99.

Abstract:In the first part of this paper, the structure and function of rain and evaporation gauges with a rectangular opening are described,which appeared in Ceyuan Tujie (A Diagrammatic Study of Measuring Circles) written by Dai Yuan (1761) during the reign of Emperor Hong Li (Qian Long).Then the two gauges are compared with those used in Europe and America before and after the year of 1761. In the secondpart the evolution of the gauges with their openings changing from therectangular to circular form is examined and the nature of the book Ceyuan Tujie is analyzed.It is concluded that the gauges recorded inCeyuan Tujie were introduced from Paris to China by the Jesuits-Pretre Francais and used for rainfall and evaporation measurements in Beijing, the capital of China in the Qing dynasty just before the year of 1761. Though the gauges were not invented by the Chinese, the record is still of significance in the history of meteorological instruments in China.