1981-2000年水稻生长季相对极端高温事件及其气候风险的变化

Change of relative extreme high temperature events and climate risk in rice growing period in China from 1981 to 2000

在全球气候变化背景下,研究作物生长期发生的相对极端温度的时空变化格局和气候风险的变化是非常必要的。从近20年的逐日温度观测资料中提取水稻开花期的相对极端高温事件信号,进而对这些相对极端高温事件发生的频率和强度进行了分析。结果表明:20世纪90年代和80年代相比,长江以北单季稻开花期高温频率增大,其强度减小,这一区域受高温胁迫造成的减产年份增多,单季稻气候风险增大。长江流域以南早稻大部分站点生长关键期高温频率和强度呈增大趋势,双季早稻气候风险增大;四川平原大部分站点无明显变化;华南早稻大部分站点生长关键期高温频率和强度的减小的幅度相对比较大,这一区域受高温胁迫造成减产的年份减少,双季早稻气候风险减小。

Under global climate change, it is necessary to evaluate the effect of change of relative extreme temperature events and climate iisk on crop growing and development periods. 35℃ is usually adopted as critical threshold of damage to rice. The relationship between high temperature in flowering period and sterility of rice is established. High temperature is the main factor to effect on rice yields. The decadal change of high temperature frequency and its intensity was analyzed by comparing them for 1991 -2000 and 1981 -1990 in China. It shows that , for early rice season on the north of Yangtze River, the frequency of daily high temperature increases and intensity decreases, and climate risk to rice increases; for early rice season on the South of Yangtze River, the frequency of daily high temperature and intensity increase, and climate risk to rice increases; for early rice season in the southern China, the frequency and intensity of daily high temperature decrease, climate risk to rice decreases; and the fre- quency and intensity of high temperature for rice crop have not evidently change in Sichuan Plain.