近50年山西终霜冻的时空分布及其影响因素

利用山西62 个气象观测站1961-2010 年的逐日最低地温资料，分析了山西终霜冻的时空分布特征，结果表明：（1）山西近50 年平均终霜冻日为4 月12 日，总体上呈现南部早北部晚的规律，但具体分布还受地形及地理位置的影响；平均终霜冻日与纬度和海拔高度均呈显著的正相关，且纬度对平均终霜冻日的影响要大于海拔高度。（2）M-K突变检验表明，大部分站点的终霜冻日都发生了显著的气候突变，突变时间在1975-1996 年之间；突变年份与海拔高度和纬度均为负相关，且与纬度的相关程度比海拔高度更为密切。（3）山西近50 年终霜冻变化趋势的分布具有明显的区域差异，提前幅度较大的地区主要位于中西部和南部的广大地区，推后幅度较大的地区集中在西北部以及中东部；变化趋势与海拔高度和纬度均为负相关，海拔高度对变化趋势的影响大于纬度。（4）山西正常终霜冻的出现概率为54%~74%，出现概率最大的地区位于东南部以及北中部等地；偏晚终霜冻出现概率为2%~22%，北部和东南部是偏晚终霜冻出现概率最大的地区；特晚终霜冻的出现概率为14%~36%，出现概率较大的地区集中在北中部和中西部。（5）海拔高度与偏晚终霜冻发生概率呈负相关关系，纬度与特晚终霜冻发生概率呈正相关关系；纬度、海拔高度与正常终霜冻发生概率的相关都不密切；纬度对不同程度终霜冻发生概率的影响要大于海拔高度。

Spatial and temporal distribution and its impact factors of the last frost over Shanxi Province from 1961 to 2010

Based on each day's minimum ground temperature data of 62 meteorological stations in Shanxi from 1961 to 2010, the spatial and temporal distribution characteristics of the province's last frost dates are analyzed. The results show: (1) Shanxi's average last frost date is April 12, the last frost date of the southern part is generally earlier than that of the north, but for a particular site, "early" or "late" of the last frost date also depends on its topography and location. The average last frost date has obvious positive correlations with altitude and latitude, and the correlation with altitude is closer than that with latitude. (2) M-K mutation test shows that the last frost date of most meteorological stations had obvious mutations from 1975 to 1996, and that the mutation year has negative correlations with altitude and latitude, and that the correlation with latitude is closer than that with altitude. (3) The changing trend of last frost dates has apparent regional difference, the large advancing scope region is located in the central-western and southern parts, while the large delaying scope region is observed in the northwestern and central-eastern parts. The changing trend has negative correlations with altitude and latitude, and the correlation with altitude is closer than that with latitude. (4) Probability of the normal last frost in this province is 54%-74%, and the maximum probability appears in the southeastern and northern-central parts. Probability of the later last frost in Shanxi is 2%-22%, and the maximum probability appears in the northern and southeastern parts of the province. Probability of the latest last frost in Shanxi is 14%-36%, and the larger probability area is located in the northern-central and central-western parts. (5) Altitude has negative correlation with later last frost probability, and latitude has positive correlation with the latest last frost probability, and there is little correlation between altitude (or latitude) and normal last frost probability. Latitude has greater impacts on all degrees' last frost probability than altitude.