辽宁省近50年霜的气候变化特征

主要使用辽宁省35个站点1957—2006年霜的地面观测资料以及相应时间的温度资料分析了该区霜的变化特征及其受气候变暖的影响,得到如下结论:近50年辽宁省初霜日期推迟近10 d,终霜日期提前约17 d,无霜期日数增加约26 d;初、终霜日期和无霜期日数在20世纪90年代初发生突变;从空间分布来看,初霜日期明显推后、终霜日期显著提前、无霜期增多的区域主要分布在辽宁中部、西部以及辽东半岛的部分地区;初霜日期与9月份各温度因子相关性较与其他各月高,终霜日期与4月份各温度因子相关性较强,无霜期主要受4—9月间各温度因子的影响;初霜期推迟、终霜期提前以及无霜期延长都主要是由温度的升高引起的,其中平均最低地面温度、平均最低气温是最重要的影响因素;伴随气候变暖,辽宁省初、终霜发生日期以及无霜期长度的空间分布都显示出由西南向东北方向推移的特点。

Variations of Frost Under the Background of Climate Change in Liaoning Province in Recent 50 Years

Based on the surface observational data of frost from 1957 to 2006 at 35 basic stations of Liaoning Province and the corresponding temperature data, the variation characteristics of frost and the effect of climate change on frost were analyzed. The result shows that the first frost delayed about 10 days in these 50 years, and the last frost brought forward 17 days, thus the frostless period extended 26 days. Besides, there was a break point in the 1990s for the first frost, last frost and frostless period. The areas in which the first frost significantly delayed, last frost significantly brought forward, and frostless period significantly extended, are mainly distributed in the middle part and the west part of Liaoning Province and the partial area of Liaodong Peninsula. The first frost date is more related to the temperature of September, the last frost date is markedly correlated with the temperature of April, while the frostless period is significantly correlated to the temperature from April to September. First frost delaying, last frost bringing forward and frostless period extending are all mainly attributed to temperature increases, especially the increases of the average minimum surface temperature and the average minimum air temperature. Due to temperature increasing, the spatial distributions of the first frost, last frost and frostless period all displayed the characteristics of moving from southwest to northeast.