The large range rare fog process which occurred in East China from November 30 to December 4 in 2004 was analyzed, including the circulation background, its adjustment and evolvement, the climatic background, the atmospheric stratification condition and the vapor condition near surface, etc. Results show that the warm advection at the low level, the stable atmospheric stratification and the abundant vapor condition resulted in this rare fog process, and fog dissipation needs the cold air invasion with the cold front.

The previous atmospheric Circulation adjustment and development,strong frost and freeze injury Climate background, weather CharacteristiC，west wind inDex、hanged T213 objective forecast of the rare event OCurged on May 3一5 in 2004 in Cansu provence were analyzed in the paper and it will have some certain directive signific;anc;e for frost predic;tion} disaster prevention and fin fiber in the future.

A preliminary analysis on the first regional hail process which occurred on May 14 to 15 in 2004 was given,including its
atmospheric circulation,the background of previous climate and the field of physical quantities,and the conditions under which this
type of weather process occurs was established .This has certain instructing meaning to forcast such process accurately within short
and medium terms.

According to the statistical analysis of the extreme maximum temperature in Gansu province from 1951 to 2000, the climat-
ic characteristics of the temporal-spatial and region distribution of the extreme maximum temperature in Gansu were given. Based o
analysis of the atmospheric circulation characteristic of the regional extreme maximum temperature weather course, the different kind
of the high-temperature circulation situations were summed up.

According to statistical analysis of the seasonal change of the SouthAsia high，the date of the first regional precipitation over
10 mm（the first soaking rain）in spring and the date of changing to more rain period in early summer in Gansu province，the paper reveals the correlativity primarily among the South Asia high during its seasonal change and setting up above Qinghai-
Tibet Plateau，the first soaking rain in spring and changing to more rain period in early summer in Gansu especially in the east region of the River.
Analyse results indicate that there is remarkable relation between the South Asia High visiting the Middle-Southern Peninsulas during its seasonal change and the first soaking rain in spring in Gansu，and between the South Asia high setting up above Qinghai-Tibet plateau and changing to more rain period in early summer in Gansu as well.So it’s important to know the seasonal change of the South Asia high and the date of its visiting the Plateau for us to predict the appearance of the first soaking rain and the date of changing to more rain peiod accurately.