辽宁西北部霜冻特征变化及致灾风险强度研究

霜冻事件是与农业相关的最严重的极端事件之一。研究霜冻的变化趋势和强度变化有利于提高人们对霜冻的认识，对农业结构调整有一定的参考价值。利用朝阳、阜新地区1951—2020年气象资料和农作物苗期、果树开花及成熟期物候资料，应用气候诊断分析方法，分析霜冻发生时间和频率等，研究辽宁西北部霜冻致灾风险强度。结果表明：5月1日之后的春季霜冻致灾强度>80%，终霜冻致灾风险强度平均为41.6%，重度致灾(70%<ST≤100%)概率为20.0%；因终霜日期以-0.438 d/10 a倾向率提前，春霜冻致灾风险强度线性下降9.4个百分点，而2001—2020年春季霜冻致灾风险强度平均下降5.2个百分点。9月15日之前的秋季霜冻致灾强度>80%，初霜冻致灾风险强度平均为27.7%，重度致灾(70%<ST≤100%)概率为5.7%；因初霜日期以1.734 d/10 a倾向率明显后推，致灾风险强度线性下降34.0个百分点，而2001—2020年秋季霜冻致灾风险强度平均下降24.9个百分点。年度霜冻致灾风险强度线性下降25.6个百分点；2001—2020年下降17.1个百分点。结果说明受气候变暖的影响，辽宁西北地区年度霜冻致灾风险强度总体在减弱，而终霜日提前趋势不稳定，调整作物播种期需谨慎。1991—2020年初霜冻致灾风险强度下降明显，因此，秋季热量资源存在开发利用空间。

Study on the Variation of Frost Characteristics and the Intensity of Disaster-causing Risk in Northwestern Liaoning

Frost events are among the most severe meteorological extreme events associated with agriculture. The study on frost variation trend and intensity is conducive to improving people's understanding of frost and has certain reference value for agricultural structure adjustment. Using meteorological data and phenology data of crop seedling stage and fruit tree flowering and ripening stage from 1951 to 2020 in Chaoyang and Fuxin of Liaoning Province, the authors applied climate diagnostic analysis methods to analyze frost occurrence time and frequency, and study the intensity of disaster-causing risk of frost in northwestern Liaoning. The results showed that the disaster intensity of spring frost after May 1 was >80%, the risk intensity of the last frost was 41.6% on average, and the probability of severe disaster (70%<ST≤100%) was 20.0%. Because the last frost date was earlier by -0.438 d/10 a, the spring frost disaster risk intensity linearly decreased by 9.4 percentage points, while the spring frost disaster risk intensity decreased on average by 5.2 percentage points from 2001 to 2020. Before September 15, the disaster intensity of autumn frost was greater than 80%, the average risk intensity of the first frost was 27.7%, and the probability of severe disaster (70%<ST≤100%) was 5.7%. Because the first frost date was delayed by 1.734 d/10 a, the disaster risk intensity decreased linearly by 34.0 percentage points, while the frost disaster risk intensity in autumn of 2001 to 2020 decreased by an average of 24.9 percentage points. The annual frost disaster risk intensity decreased linearly by 25.6 percentage points; from 2001 to 2020, it decreased by 17.1 percentage points. The results indicate that under the influence of climate warming, the annual frost disaster risk intensity in northwestern Liaoning has been generally weakened, while the advance trend of the last frost date is unstable, and it is necessary to be cautious in adjusting the planting date of crops. From 1991 to 2020, the first frost disaster risk intensity decreased obviously, so there is room for development and utilization of heat resources in autumn.