陕西关中西部近50年无霜期气候特征分析

为了研究气候变化背景下陕西关中西部无霜期变化特征及其影响，选取宝鸡市11个气象站1961—2010年气温、初（终）霜日等观测资料，应用气候变化理论统计分析。结果表明：近50年来，宝鸡市平均初霜日以1.77 d/10 a倾向率延后，而终霜日以1.72 d/10 a的倾向率提前，影响无霜期以3.11 d/10 a的倾向率显著延长。初霜日在1974年、终霜日和无霜期在1982年分别发生了明显的转折。无霜期延长对农业生产有积极作用。

Climate Characteristics of Frost-Free Period: In Recent 50 Years in Western Guanzhong

The paper aims to study the change laws of frost-free period and its influence in western Guanzhong, Shaanxi Province, under the background of climate change. The author chose the temperature and the first (last) frost day data of 11 meteorological stations in Baoji from 1961 to 2010, and used climate change theory to conduct statistical analysis. The results showed that: in recent 50 years, the first frost day was delayed with a tendency rate of 1.77 d/10 a on average in Baoji, and the last frost day advanced with a tendency rate of 1.72 d/10 a, which made the frost-free period significantly extend with a tendency rate of 3.11 d/10 a. The first frost day, the last frost day, and frost-free period had a turning point in 1974, 1982, 1982, respectively. The extension of frost-free period had positive effects on agricultural production.Key words: change characteristics; first (last) frost day; frost-free period; western Guanzhong