Abstract:

Based on the daily minimum temperature data at 5 meteorological stations in Shenyang of Liaoning Province from 1960 to 2016, the temporal and spatial variation characteristics of the first and the last dates of frost and frostless period were statistically analyzed. The results showed that the first date of frost delayed with the rate of 0.9 day per 10-year, while the last date of frost brought forward significantly with the rate of 1.9 day per 10-year, and the frostless period prolonged significantly with the rate of 2.8 day per 10-year in the past 57 years in Shenyang of Liaoning Province, which was conducive to the prolonging of crop growing season and increase of heat resources. The frost fluctuated unsteadily during 1960-2016 in Shenyang, which increased the risk of frost damage and was harmful to agricultural production. The instability of frost was successively frostless period, the last date of frost and the first date of frost. It was found that the frequency of extremely early events for the first date of frost ranged from 5 to 6 times in other stations of Shenyang except for Kangping with 3 times, while that of extremely late events for the last date of frost ranged from 4 to 7 times, and the value in Xinmin station was the most.

Key words: the first and last date of frost, frostless period, variation character

摘要：

基于1960—2016年沈阳地区5个气象观测站逐日最低气温资料，采用气候统计学方法，分析该地区霜冻初、终日和无霜冻期的时空特征及其对农业的影响。结果表明：近57 a来，沈阳地区霜冻初日呈推迟趋势，平均每10 a推迟0.9 d，而终日呈显著提前趋势，平均每10 a提前1.9 d，导致无霜冻期显著延长，平均每10 a延长2.8 d，有利于作物生长季延长、热量资源增加；霜冻变化存在不稳定性波动，对农业生产极为不利，不稳定性由大到小依次为无霜冻期、霜冻终日、霜冻初日；霜冻极早初日除康平出现3次，其他地区出现频数为5~6次，极晚终日发生频数为4~7次，新民最多。

关键词: 霜冻初、终日, 无霜冻期, 变化特征