关键词: 烤烟, 烤烟, 叶表面提取物, 萜烯类, 西柏三烯醇

Abstract:

In order to explore the changes of area details of the local area in the north China in extreme precipitation events and study the changing rules of the extreme precipitation events, according to the data of daily precipitation in Rizhao City from 1955 to 2009, the extreme precipitation events were analyzed. The results showed that: (1) the average annual maximum one day precipitation of Rizhao City had not significantly deceased in the recent 55years. The maximum of the analysis period appeared in 2008; (2) the amount and its’ contribution and days of extreme precipitation showed a declining trend and 1975 was the mutational site. The intensity of extreme precipitation had increased weakly and no significant mutation, but there was an upward trend after 2006. The changes of extreme precipitation amount were mainly affected by extreme precipitation days change; (3) the total frequency of general average dry events and severe dry events were in the trend of increasing along with the decreasing of the heavy rains days. These results indicated that the extreme precipitation events tended to reduce and the dry events tended to increase in Rizhao City in the recent 55 years. But in the 21st century, the precipitation trended to the extreme events.