Abstract:Two dust devil events in Beijing area on 6 and 9 April 2000 are analyzed. The result shows that the two events caused by the Mongolia cyclone and the northwest trough without cyclone are different. In the area of sand source, the strong ascending movement at the middle and low level lift the sand and dust to sky vertically, then the strong northwest airstreams at 700hPa transport them to the downriver area flatly; the instable atmospheric structure could strengthen the dust devil; the distribution feature of z-helicity of the dust devil area is negative at the high level and positive at the lower, and the positive area is coincident with the satellite image.

Abstract:The heavy rainfall existed for a long time in the Jianghuai area in 2003 Meiyu period resulted in a flood. A heavy rain occurred in the Dual-Doppler coverage, up to 351.7mm rainfall in 24h from 20:00 on July 4 to 20:00 on July 5 in Chuzhou, Anhui Province. The three-dimensional wind of the heavy rain were retrieved by MUSCAT (multiple-Doppler synthesis and continuity adjustment technique) using the dual-Doppler radar volume scan data. It showed that the convergence line and the meso-cyclone at the low level play an important role in this heavy rain event. The vertical circulation is also clear in the event.

Abstract:Based on NCEP reanalysis data, the characteristics of the moisture transfer over the Jianghuai Valley during the summer of 2003 are studied. The results show that the exceptional precipitation of the Jianghuai Valley in the summer of 2003 is related to the exceptionally intense moisture transfer in the southern area of China. And the Bay of Bangle and the South China Sea are two main moisture sources for the sustained heavy rain over the Jianghuai Valley. The calculation result of the heavy rain event shows that the budget of the moisture over the Jianghuai Valley and the attribution of two main moisture sources varied at different layers. At the layer of 1000—850hPa, which is the main moisture convergent layer during the heavy rain event, the South China Sea is the most important moisture source.

Abstract:The features of low latitude circulation and its role during the 2003 heavy rain period over the Huaihe River valley are analyzed. The results show that convergence of extremely strong southern wind and extremely strong northern wind caused the heavy rain. The strong southern wind composed mainly of south-eastern wind which transported warm moisture from tropical north-west Pacific to the Huaihe River valley. During the heavy rain period, the southwest monsoon is weaker than normal. The reason of the abnormal characteristics of weak southwest monsoon and strong southeast wind are also analyzed here.

Abstract:The characteristics of the middle-high latitude circulation and the blocking high are analyzed. There were two blocking high in the middle-high latitude region of East Asia from the last ten days of June to the first ten days of July. This made the rainfall sustain in the Huaihe River Basin. In the last ten days of July, the blocking high in the Okhotsk Sea founded again and sustained in this place. So the subtropical high in western north Pacific region was in the south on an average, so the rain-belt did not advance northward and sustained mainly in the Huaihe River Basin.

Abstract:After catalyzing undercooling clouds with liquid carbon dioxide (LC), the change of microphysical parameters is analyzed by airplane particle measuring system, GPS orientation and ground radar. The results indicated that the phenomena, especially the heaving symmetrical peaks in negative temperature range observed in the 25dBz echo of radar RHI, was caused by the dynamical lifting of the coagulating growth of small ice with the latent heat releasing.

Abstract:Analysis and forecasting for hail weather's form and development are presented based on radar detection information, surface meteorological observation and computer analysis and processing.With calculation of the covered area of multicell hail's centre, and determination of hail's exact sites which is relative to different space area, the hail cloud simulation model is developed, exact place where the shell falls at length is determined. After calculation of the water contents in cloud, the height of 0℃, and cloud volume, the shooting point at the operating area are given.

Abstract:The correlation between the daily number of new cases and the meteorological conditions at the same or preceding period when the SARS broke out in the main epidemic areas of China (Beijing, Hebei Province, Hongkong, Taiwan, and Guangdong Province) from the March to May of 2003 is comparatively analyzed. Combined with the analysis of the climatic background from November, 2002 to May, 2003, it is revealed that (1)SARS virus must grow and spread within a certain range of temperature (14—28℃),and the higher or the lower temperature is disadvantageous;(2) within that range, the daily number of new cases mainly has a negative correlation with the temperature (mean temperature, maximum temperature, minimum temperature and daily range), rainfall and relative humidity, and the correlation coefficient of the daily number of new cases with minimum temperature is the biggest; (3)the meteorological conditions for preceding seven-day period have greater impacts on the occurrence of SARS than the present conditions do;(4)all the epidemic areas have undergone a lasting and severe drought. In conclusion,a certain temperature of 20℃ or so and a lasting drought are advantageous to the growth and spread of SARS virus.

Abstract:The Synoptic and climatic features during the severe acute respiratory syndrome (SARS) spreading in China in 2003 are analyzed. The results show that the warmer, humid and changed frequently temperature, are the favorable meteorological conditions for SARS spreading.

Abstract:By analyzing the environmental temperature data of Zhengzhou, the seasonal distribution of the environmental temperature and the effects of different surface environment conditions on the temperature are revealed.The feature of heat island intensity of Zhengzhou varies with time and space is also discussed. The results show that the urban construction scale and the specific surface physical feature of the city have obviously affected the environment temperature distribution in time and space. The urban environmental temperature is higher than that in the suburb. The annual and seasonal variation of heat island intensity of Zhengzhou is coincident with the cities in North China. Heat island intensity in winter is also higher than that in summer.