基于距平指标的白银市晚霜冻强度及终霜日变化特征

Change Characteristics of the Late Frost Intensity and Last Frost Dates in Baiyin City Based on the Anomaly Index

根据白银市春季气候特征及农业生产实际,以最低地温负距平为指标对晚霜冻强度进行等级划分,在此基础上,分析晚霜冻及终霜日变化规律。结果表明,白银市晚霜冻日数以会宁最多,占全市霜冻总日数的29.2%;白银次之,占总日数的27.4%;景泰占总日数的23.5%;靖远最少,占总日数的19.9%。晚霜冻日数越往后期越少,但对作物的危害程度后期更为严重,5月出现霜冻都会对作物造成严重危害。白银市各站终霜日均有提前趋势,全市平均提前率为1.91d/10a。终霜日景泰和白银均存在2年左右的显著周期,靖远有显著的5年左右平均周期,会宁没有明显的周期性。

Based on climatic feature of spring and agricultural production practices of Baiyin City, we used negative anomaly of surface minimum temperature as the index, the grades of late frost intensity were ranked, the characteristic of late frost intensity and the last frost dates were analyzed. The results showed that the number of late frost days in Baiyin City was the largest in Huining , accounting for 29.2% of the total days, the next was Baiyin district,accounting for 27.4%,Jingtai accounts for 23.5%,and Jingyuan was the least, accounting for 19.9%. The days of late frost was less in later stage but it had serious harmful effects on crop, especially the frost appeared in May.The last frost date of all stations in Baiyin City was ahead, the average rate was 1.91 d/10 a. There were 2 years significant period in Baiyin and Jingtai, and 5 years significant period in Jingyuan.