隰县花期霜冻特征及一次极端冻害分析

Analysis of Frost Characteristics and an Extreme Frost Damage in Xixian

统计临汾市隰县1981~2020年梨果花期(4月份)0 cm月地温最低值霜冻强度和霜冻次数作为历史资料,利用气候倾向率、M-K、小波分析等方法对霜冻资料进行详细分析,结果表明:近40年来隰县花期霜冻日数各年代之间存在较大差异,整体上呈现出减少的趋势,其气候倾向率为-0.5d/10a;花期年最强霜冻等级以重霜冻为主,多数出现在4月上旬;1982年~2020年M-K突变检验中,花期年最强霜冻没有出现明显的间断点,显著增强的阶段主要集中在90年代,近几年呈现出波动增强的特点;小波周期中,花期年最强霜冻存在4 a~5 a、6 a~8 a、14 a~16 a、28 a~30 a等4个周期,但主周期为16a,及次周期29a,目前应主要关注7a周期;2018年4月6-7日的强冷空气位居近40年4月上旬的第五位,前期气温异常偏高、日照充足,处盛花期的玉露香与强冷空气叠加,是产生强冻害的主要原因.

The minimum ground temperature of 0 cm in the pear blossom period(in April)from 1981 to 2020 in Xixian county of Linfen City was taken as the historical data of the frost intensity and frost frequency.The frost data are analyzed in detail by means of climate tendency rate,M-K method and wavelet analysis.The results showed that the frost days during the blossom period in Xixian county in the past 40 years were quite dif-ferent from each years,and the overall trend was decreasing,the climate tendency rate was-0.5d/10a;The strongest frost grade in flowering year was mainly heavy frost,most of which occurred in early April.In the M-K mutation test from 1982 to 2020,there was no obvious discontinuities of the strongest frost in the flowering peri-od,the stage of significant enhancement was mainly concentrated in the 1990s,and volatility increased in recent years.In the wavelet cycle,the strongest frost in the flowering period existed in 4a~5a,6a~8a,14a~16a and 28a~30a cycles,but the main cycle was 16a and the sub cycle was 29a,the focus should be on the 7a cycle at present.The strong cold air from April 6 to 7,2018 ranked the fifth in early April of the past 40 years,the main reason for the strong freezing damage was the abnormal high temperature of the early stage,sufficient sunshine,the superposition of blooming period and strong cold air.