Abstract:Fine particles in atmospheric aerosols(PM₁₀, PM_2.5) are a key of study on atmospheric aerosols in recent years. There are multiple of chemical elements and compounds in fine particles. The chemical elements would change with spatial and temporal variability in fine particles. It is found that the fine particles come mainly from vehicle exhausts, fossil, oil-bearing and biomass fuel combustion made by mankind and secondary polluted products in atmosphere.

Abstract:Using the modelling experiment, the responses of soil drought stress on A. ordosica, a dominant species of Maowusu sandland plant community, under high concentration of CO₂ carried in green house,is studied. Maowusu sandland is a typical one of arid and semi-arid sandland in China. Water is the most limited factor to A. ordosica growth and development. The results show that the different scales of soil drought stress made the growth and biomass of A. ordosica to be decreased, and the negative impact increased with the drought degree aggravated. The increase of atmospheric CO₂ concentration can be treated as a function of ″fertilization″ for growth of A. ordosica. Although, the impact of high concentration of CO₂ and soil drought stress on A. ordosica was negative, there existed still the ″fertilization function″ .Its physiological mechanism is that the CO₂ concentration increasing promoted the photosynthesis rate.

Abstract:According to the Meiyu data of mid-lower reaches of Changjiang River during 1885 to 2000 and the principal rainfall pattern during 1951 to 2000, Meiyu characteristics of the summer drought/flood pattern(SDFP) Ⅰ、Ⅱ、Ⅲ in China are statistically analyzed, and the causes of formation of the abnormal Meiyu and the abnormal drought/flooding after 1980s are studied. As a result, the Eastern Asian blocking high has been more frequently active since 1980s, which is unfavorable to the northward seasonal movement of west Pacific subtropical high. That is the reason why the Meiyu precipitation is rather rich in summer and the rainbelt is located on the southern China, but the further reason remains to be continued to study.

Abstract:Technical fundamentals of the new generation information storage and service system of climate data, including database, data warehouse, data mining, world wide web and intelligent agent techniques are given. And the structure and functions of the system, as well as system implemental strategy are also described.

Abstract:Using the singular spectrum analysis method,the features of summer precipitation nearly one hundred years in Shijiazhuang city are analyzed.The results show that the feature of tendency variation of summer precipitation is not marked,main oscillation periods are 5-6 years,about 10 years and 30-40 years respectively,and time variables (amplitude and phase) of rebuild arrays are characterized by interdecade.The prediction result of summer precipitation based on the rebuild arrays during 1998-2001 are better.

Abstract:During the course of weather modification by airplane seeding on March 14,2000,the real time remote sensing data of a polar orbiting meteorological satellite produce the evidences for artificial precipitation enhancement.The catalyzer diffusion after the airplane flying is analyzed.The wind transportation for catalyzer and the effect of precipitation enhancement over the ground are discussed.The preliminary results show that:(1) after the course about one hour and 23 minutes,the maximum diffusion windth caused by the random movement is 11 km,the catalyzer's diffusion area of the random movement is about 2508 km²,and there is a sunk area about 1505 ³ in the top of the cloud;(2) According to the analysis of satellite data,the affected area by the wind transportation is about 7500 ²,it is three times as much as the diffusion area of the random movement.It is obvious that the wind transportation is the key factor of catalyzer diffusion.

Abstract:The primary physical factors,such as plateau meteorological factor,westerlies system,subtropical high and so on,which impact on summer precipitation over the southwest region of China,are analyzed.Then based on the relationship between the physical factors and predictand,the predictive models of precipitation in Sichuan basin are developed.The forecast accuracy of operational experiments in recent years is improved.

Abstract:Based on the correlation of 500hPa altitude field,teleconnection patterns in the Northern Hemisphere are investigated with their respective intensity indices calculated from 1956 to 2000.Then the relationship between each teleconnection pattern and the recipitation Guangdong Province,especially in Zhongshan is described.It is found that its relationship with the North-Pacific teleconnection in April and the North and West Atlantic Teleconnection in June are close.In addition,the West Atlantic teleconnection in June can be used to predict the rainfall next year in Guangdong.

Abstract:Based on the infrared images and conventional data,a Squall weather process on 18,June 2001 is diagnosed.The results show that since a longitudinal Inner Mongolia low vortex turned into latitudinal pattern in the eastward and southward process,a severe northerly cold flow went down to the northern Henan Province,and then,the air was getting more instable.In the lower layer,because the inflow of a tongue of potential pseudo-equivalent temperature made air warmer and wetter,a potential instablility stratification was formed.The positive vorticity advection in the southwest of the low vortex in the upper layer and wind shear between Zhengzhou,Henan Province and Xingtai,Hebei Province provided the dynamical conditions for the occurrence of severe convective weather.

Abstract:The conditions for the strong wind extreme value of the cold wave in Beijing Capital Airport are analyzed. The result shows that when the trough position from the low level to the middle and upper level is vertical or forward tilting, the values of the strong wind speed have a positive correlation with the intensity of frontal zone and the parallel depth between stratification curve and dry adiabat.

Abstract:Using the recent observation data from 1992 to 2000, the characteristics of meteorological radiation in Hainan Island are discussed.The results show that both total radiation and reflection radiation have a feature of parabola distribution, and net radiation is positive all year. Nine year mean of radiation has a feature of double maximum.

Abstract:A sampling station for observing solar ultraviolet radiant intensity was set up in Shanghai in August 1998.The surface solar ultraviolet radiation data collected by an American Eppley Ultra-Violet Radiometer from August 1998 to July 1999 are analyzed.The relationship between ultraviolet radiation and some factors that may affect its variation is studied.

Abstract:The temporal and spatial distribution characteristics of the low horizontal visibility (lower than 1000 m) in Beijing are studied, which is chosen as an index that would affect urban traffic and transportation. According to both mean daily variation over many years and mean daily, monthly and seasonal variation in a year of low visibility frequency, Beijing is divided into three different parts, the southeastern plain area, the northwestern mountainous area, and northeastern to southwestern transitional area. The effect of some synoptic phenomena, such as fog, fly ash, and so on, upon the low visibility in Beijing is also discussed. It is shown that fog is the main factor affecting visibility.