Abstract:Characteristic features of the atmospheric transparency and its affecting factors are analyzed based on insolation data over the Tibetan Plateau and its adjacent regions from May through August of 1979. A detailed account is given of the descriptive method for analyzing the atmospheric transparency over the Plateau and of the physical implication of its various quantities.The spacial distribution of the atmospheric transparency over the Plateau and the empirical equations for calculation are also given. Finally a discussion is made of the Kastrov coefficient(Коаффечиет Кастровас С).

Abstract:Aanlysis has been made of the features of temperature and pressure fields with respect to sea/land breezes along the coast of South China during May, 1978. It is shown from the analysis that the vector of sea/land breezes is approximately perpendicular to the isolines of temperature and pressure anomalies, pointing from the cold high to the warm low. Both temperature and pressure have the greatest gradients along the coastal area with sea/land breezes reaching the maximum. The transitional period from the building-up of temperature and pressure fields with respect to sea/land breezes to the formation of the latter is very brief. It is found that sea/land breezes have an abating effect on the temperature and pressure fields, thus setting a limit to their own development. It is also found that the convergence field due to sea/land breezes is closely related to the center of precipitation along the coast of South China.

Abstract:In 1979,the water vapor transport field over monsoon Asia underwent significant changes with the onset of the Indian summer monsoon. Strong water vapor transport extended from the Arabian Sea, across Southern India, the Bay of Bengal,the South ChinaSea(10°-15°N),then northward into Southern China and Japan. There was heavy rain with intense convergence of vertically integrated water vapor flux (Q₂).Over the Bay of Bengal and the South China Sea,the Q₂ convergence increased rapidly between June 16 and 20. During the same period, in the Bay of Bengal, the South China Sea, and the Philippines, the outgoing longwave radiation (OLR) decreased sharply and the index of convection (I_e). increased suddenly. These changes indicate that the onset date is nearly the same over India, the Bay of Bengal, the South China Sea and the Philippines.Over East Asia, the strong water vapor transport, which is controlled by the West Pacific high, developed south of Japan around June 5. Concurrently, Q₂ convergence intensified, OLR decreased and I_c increased. These changes imply that the rainy season in Japan begins approximately two weeks before the monsoon onset in India.The Q₂ differences between the pre- and post-onset periods clearly indicate the existence of two channels of water vapor transport. One is related to the South Asia monsoon and the other to the East Asia monsoon. Analysis of Q₂, OER, and I_c data indicates that in 1979, the East Asia monsoon and South Asia monsoon were relatively independent of each Other.

Abstract:It is indicated in this paper that quasi-37-year, quasi-2-year and some other quasi-periodic climatic oscillations revealed from the analy sis of observational data can be explained by means of quasi-periodic regularity of the Moon’s motion relative to the Earth and the Sun. As an application of this viewpoint, some characteristic parameters are selected for the trajectory of the Moon’s motion and hence several methods are presented for the superlong-range prediction of the rainfall amount in the middle-lower reaches of the Yangtze River during the rainy season and of the transitional date for the east-west wind direction at the height of 23 km near the equator. The results obtained quite coincide with the reality.

Abstract:Statistical analysis has been made of the surface and upper-air meteorological conditions responsible for the drought and flood in the middle-lower Yangtze River reaches during summer by using the 1950-1980 weather data. Predictors are chosen based on the correlation coefficient and Mahalanobis distance between predictors and Predictand, thus obtaining some key meteorological critcria, months and regions which may affect the precipitation during the rainy season. The use of stepwise multiple regression and discrimination techniques for rainfall prediction in summer has proven, after being tested with independent samples, to have good results.

Abstract:No Mai-yu rainfall was recorded over the middle-lower reaches of the Yangtze River in the early summer of 1978 and a spell of severe drought lasted from mid-summer to early September.Consequently, there occurred three periods of sustained high temperature from late June to early September which had never been observed in the past hundred years. This happened mainly due to the anomalous development of the subtropical high. A mean pentad subtropical high ring belt at 500 mb surrounding almost the whole northern hemisphere collapsed unstably and then an intense subtropical high cell which had formed over the west Pacific moved westward,intensified and extended pentad by pentad. At the same time, a powerful warm high moved eastward from the Iranian-Tibetan Plateaus. These two high centers then merged into One, intensified and dominated a great part of China, with exceptional high temperatures occurring twice over the Yangtze River reaches once in early July and the other in early September. The anomalous development of the subtropical long’wave systems was also responsible for the sweltering summer in 1978. Analysis indicates that there existed a quasiperiodic change for about one month in the subtropical high and sustained high temperature.

Abstract:A two-dimensional stationary model is used to examine the dynamical effects produced by the flow over mountainous areas of three horizontal scales. Results from numerical simulation show:(1)large-scale orograph may produce subsidence of air flow upstream of the mountain ridge, thus resulting in dry climate;(2)meso-scale mountain ranges may cause wave motion downstream which may influence aircraft in flight;and(3)small-scale hilly areas(or architectural complexes)may have some influence on the aerosol diffusion in the flow. A better knowledge of the characteristic features of the small-scale orographic flow would help to plan the rational distribution of factories in the mountainous areas and the proper sitting of the rice seedling beds during the seedling stage.

Abstract:Three cases of the southwesterly low-level jet stream during the Meiyu season have been analyzed,showing that the kinetic energy of the jet stream is generated by the kinetic energy production of the divergence wind and the effect of the cumulus convection. The main physical factors affecting the rate of divergence wind kinetic energy production are latent heating, temperature advection and the role of the divergence term in the ω equation.

Abstract:Several methods are presented for the determination of accumulative amount of precipitation at a single location by means of Z-I relations,such as raindrop size spectra, Z_r-I_g, mean of value A and mean value of A. Data from the three processes of precipitation in 1981 were used to determine Z-I relations and verify the data obtained on June 24 and July 9, 1980.It is found that the accuracy of these methods are quite satisfactory.If only the accuracy in measuring I and Z can be improved and the Z-I relations classified according to the type of rainfall after the value is properly chosen for b in the relations, greater accuracy of the last two methods may be achieved.