保定市无霜期的气候特征分析

Analysis of the Climatic Characteristics of Frost-free Period in Baoding City

为了充分了解保定地区无霜期的气候特征,为农业气象服务提供可靠依据,利用保定市13个气象站的观测资料,详细分析保定市近50多年霜的分布特征和变化趋势。结果表明:保定市初终霜日、无霜期的分布具有明显的地域特征,西北部山区的终霜日期明显晚于平原地区,初霜日期明显早于平原地区。保定各地的无霜期长度相差很大,顺平无霜期最长,为194天,西北部山区的涞源无霜期最短,只有139天,二者相差达55天。保定绝大多数站点终霜日提前,初霜日推迟,无霜期增长,涞源无霜期增长趋势比平原更加明显,气候倾向率达5.84 d/10 a。保定地区平均无霜期增长率3.98 d/10 a,是终霜日提前、初霜日延后共同作用的结果,而终霜日提前对无霜期增长的贡献更大些。

The paper aims to fully understand the climate characteristics of frost-free period in Baoding Area,and provide a reliable basis for agricultural meteorological service. The author analyzed the distribution characteristics and changing trend of frost in Baoding in recent 50 years based on the observation data from 13 weather stations in Baoding. The results indicated that in Baoding Area, the first frost, last frost and frost-freeperiod had obvious geographical distribution characteristics. The last frost date of the northwest mountainousarea was later than that of the plain area, and the first frost date was earlier in the plain area. The length offrost-free period varied greatly across Baoding. Shunping＇s frost-free period, which lasted 194 days, was the longest in Baoding, while the shortest was 139 days, which was in Laiyuan that lied in the mountainous area ofthe northwest Baoding. There was a big difference of 55 days between the two. For most weather stations inBaoding, the frost-free period had become longer with delayed first frost and earlier last frost. Thisprolongation of frost-free period is more obvious in Laiyuan, whose climate tendency rate was 5.84 d/10 a. Theprolongation was the coordinated effect of delayed first frost and earlier last frost. Moreover, earlier last frost contributed more to the prolongation of frost-free period than delayed first frost.