Abstract: In order to evaluate the risks of autumn continuous precipitation in Anhui province objectively and accurately,the statistic characteristic quantities of autumn continuous precipitations were calculated according to different regions and different period of time by use of daily precipitation and sunshine data from September 1 to October 20 from 1966 to 2005 of 75 stations.Furthermore,the spatial-temporal variation of autumn continuous precipitation occurrence in Anhui province and its influence on autumn harvesting and planting were analyzed.The results showed that: in the period of autumn harvesting,the occurrence of continuous precipitation in mountainous area was more than those in plain,which in the south were more than those in the north.The frequency of seriously continuous precipitation year in mountainous area was larger than that in plain,which in the south was a little larger than that in the north.The frequency and higher value of primary statistic characteristic quantities presented ascend trend from year to year,especially in the zone along the Huai River and the north of the Huai River,which caused great yield reduction of autumn harvesting crop.The geographical distribution rule of each statistic characteristic quantities of continuous precipitation in the period of autumn planting was same as that in the period of autumn harvesting,while the temporal distribution rule was the opposite.The influence of continuous precipitation on autumn planting was little.

Key words: Autumn continuous precipitation, Law of occurrence, Autumn harvesting and planting