关键词: 柑橘, 柑橘, 柑橘黄龙病, 发生流行, 扩散模型

Abstract: Abstract: The paper aims to research the change trend of extreme precipitation of Changzhi city under the background of climate change, to grasp its change law. This paper uses daily precipitation and temperature data over 11 county stations of Changzhi city from 1961 to 2015.And it focus on the study on extreme precipitation climate events, mainly on the variation features of heavy rain, torrential rain, heavy torrential rain, heavy snow and blizzard, as well as the interannual variability of different frequency grades. Using the factors of precipitation trend rate calculation、Morlet wavelet analysis、Mann-Kendal mutation analysis and so on to analyze precipitation frequency at all levels of Changzhi before and after the climate warming. The results showed that: 1、Changzhi city under the background of annual average temperature increase, the level of daily variation of precipitation is not the same.The most significant is the increase of light snow day and the reduce of rain day.The precipitation day (daily precipitation ≥0.1 mm) showed a trend of decrease.At the same time torrential rain, snow and blizzard days show varying degrees of increase. 2、Torrential rain, heavy torrential rain and heavy snow, blizzard has 25 to 30 years of oscillation period, in the high frequency part with two years period of oscillation, at all levels in the time series of precipitation also has 4 years, 6 years and 8 years cycle respectively.3、Extreme precipitation in 1962 changed abruptly. Abrupt change of heavy snow days happens around 1990 year, after 2006 year the heavy snow days increased even more significantly. Other grades of precipitation days have no obvious abrupt change.