气候变暖背景下南方早稻春季低温灾害的发生趋势与风险

基于《早稻播种育秧期低温阴雨等级》行业标准,利用南方双季早稻种植区178个站点1961—2010年的逐日气温资料,对各站点早稻春季低温灾害发生次数进行突变性分析,根据突变检验结果将研究时段划分为1961—1990年和1991—2010年两个时段,对比分析两个时段内早稻春季低温灾害发生趋势和发生风险的地理分布变化特征。结果表明,与前30a相比,近20a研究区早稻春季低温灾害的发生总体上呈现为由增加趋势转变为减少趋势的特征,低温灾害风险指数高值区以及各等级低温灾害发生概率高值区的范围和大小均有所减小,其中以轻度低温灾害的发生概率最高且概率减小范围最大。可为南方早稻春季低温灾害的动态评估和早稻种植的合理布局提供依据。

Trends and risk of spring low-temperature damage to early rice in southern China against the background of global warming

Against the background of global warming, although the frequency of low-temperature disasters varies among different hazard-bearing bodies and areas in China, the intensity of such events does not diminish. Double-cropping early rice is the main crop in southern China, which is often affected by unexpected cold weather during sowing and transplanting. There have been numerous studies on low-temperature damage to various crops in southern China except for early rice during its sowing and transplanting. To reduce the yield loss of early rice, we studied the occurrence trends and the risk of spring low-temperature damage to early rice. According to the daily average temperature data of 178 weather stations from 1961 to 2010 and the Grade of Cold and Rainy Weather during the Seeding-Raising Stage of Early Rice, we studied mutation-related characteristics of spring low-temperature damage to early rice in early-rice cultivating areas in southern China. According to the mutational-analysis results, we evaluated the distribution of trends and risk of spring low-temperature damage to early rice during two periods (from 1961 to 1990 and from 1991 to 2010). The results showed that compared to the first period, the frequency of low-temperature disasters changed its trend from increasing to decreasing in the recent 20 years. The scope and size of the high value area of the risk index for low-temperature disasters and the probability for each level of low-temperature disasters were both decreasing. Mild low-temperature disasters showed the highest probability of occurrence and the highest probability of the decreasing scope. Our findings may serve as the basis for dynamic evaluation of the occurrence of low-temperature damage to early rice and for rational planning of early-rice planting.