沧州地区霜冻灾害变化特征及其趋势预测

利用1972—2021年沧州市14个气象站常规观测资料，采用趋势系数、Mann Kendall检验、Hurst指数和Morlet小波分析方法，分析了河北省沧州地区霜冻日数、初霜冻、终霜冻的变化特征和趋势预测情况。结果表明：沧州市平均霜冻日数呈减少、初霜冻呈推迟、终霜冻呈提前趋势，且在2000年左右分别发生由多到少、由早到晚、由晚到早的显著突变。在空间上，霜冻日数、初霜冻、终霜冻大体由西北向东南分别减少、推迟、提前；三者变化趋势全区表现一致，但趋势强度空间分布不均。霜冻日数分别在11—13 a和28 a时间尺度上存在7—8 a和18—19 a的明显周期，初霜冻在25 a时间尺度上存在16—18 a的明显周期，而终霜冻在10—15 a时间尺度上存在6—7 a的明显周期。未来沧州市霜冻日数将在大幅波动中持续下降，初霜冻将平缓的持续推迟，而终霜冻将在大幅波动中持续提前。

Variation Characteristics and Trend Prediction of Frost Disaster in Cangzhou

Based on the conventional observation data of 14 meteorological stations in Cangzhou City from 1972 to 2021, the variation characteristics and trend prediction of frost days, first day and last day of frost in Cangzhou City were analyzed using linear trend estimation, Mann Kendall test, Hurst index and Morlet wavelet analysis. The results showed that: in the past 50 years, the average frost days in Cangzhou City decreased, the first frost day delayed, and the last advanced, and the significant mutation occurred from more to less, from early to late, and from late to early around 2000, respectively. The number of frost days, first and last frost days decreased, delayed and advanced from northwest to southeast, respectively, the trends of which were consistent throughout the region, but the spatial distribution of trend intensity was uneven. The frost days presented obvious cycles of 7-8 a and 18-19 a on the time scale of 11-13 a and 28 a, the first frost day exhibited an obvious cycle of 16-18 a on the time scale of 25 a, and the final frost day showed an obvious cycle of 6-7 a on the time scale of 10-15 a. In the future, the number of frost days in Cangzhou will continue to decrease in a large fluctuation, the first frost day will continue to delay gently, and the final frost day will continue to advance in a large fluctuation.