近50年山西终霜冻变化特征分析

Analysis of the variation features of last frost over latest 50 years in Shanxi Province

利用山西62个测站1961-2010年的逐日最低地温资料，分析了终霜冻的历年变化规律和空间分布特征。结果表明：（1）1961-2010年平均终霜冻日呈现提早结束的趋势，并伴有明显的波动变化；21世纪的10年是平均终霜冻波动最为剧烈的时期。（2）山西省1961-2010年平均终霜冻日为4月12日，其分布整体呈现南早北晚的特征，从3月中旬到5月中旬，终霜冻自南向北相继结束。（3）山西省正常终霜冻的发生概率为54％～74％，从东北到西南的分布为“小-大”相间分布，概率较大的地区主要位于中部和东南部；偏晚终霜冻的发生概率为2％～22％，南部和北部是其发生概率最大的地区；特晚终霜冻的发生概率为14％～36％，概率较大的地区主要集中在北中部。（4） M-K突变检验表明，山西平均终霜冻在1990年发生了一次显著的气候突变；1975-1996年，山西大部分站点的终霜冻日都发生了显著的气候突变。（5）1961～2010年山西终霜冻变化趋势的分布具有明显的区域差异，从南到北呈“大-小”相间分布，提前幅度较大的地区主要位于中西部和南部，推后幅度较大的地区集中在西北部以及中东部。（6）2001-2010年山西轻微、中度和重度终霜冻的主周期分别为15a、12a和7a；次周期分别为1a、1a和5a。

Based on each day’s minimum ground temperature data of 62 meteorological stations from 1961 to 2010 in Shanxi Province ,has analyzed yearly variation features and spatial distribution characteristics of the last frost .The re-sults showed that ：（1 ） The average last frost day presented an advancing trend in 1961 to 2010 with obvious wave varia-tion ,during 2001-2010 was the most volatile stage .（2 ） The average last frost day was Apr .12 ,whole distribution pre-sented a property of early in South and late in North .The last frost day will be finished at the middle ten days in March to the middle ten days in May from the South to the North .（3） The probability of the end of normal last frost was 54%~74% in Shanxi Province .its distribution was alternately “small-large”from Northeast to Southwest ,the bigger prob-ability area was located in the Central and the Southeast .The probability of the later frost was 2% ~22% ,the maximal probability appeared in the South and the North .The probability of the most late frost was 14% ~36% ,the larger prob-ability area was located in the Northern central region .（4 ） The M-K mutation test showed that the average last frost day in Shanxi Province had an obvious mutation in 1990 .The last frost day in most meteorological stations had obvious muta-tions from 1975 to 1996 .（5） The distribution of the last frost changing trend in Shanxi Province possessed apparent re-gional difference ,from the South to the North ,it appeared in altemately“large-small”distribution ,the large advancing region was located in the Midwest and the South ,the large delaying region was concentrated in the Northwest and the Mideast .（6） The primary cycle of the mild ,moderate and severe last frost was 15 ,12 and 7 years ,respectively ;the secondary cycle of the mild ,moderate and severe last frost was 1 ,1 and 5 years ,respectively .