1260～1911年晋陕蒙毗邻地区寒冻灾害及与气候变化关系

Characteristics of freezing disasters and climate change from 1260 to 1911 in adjacent areas of Shanxi-Shaanxi-Inner Mongolia

通过对气候敏感的晋陕蒙毗邻地区历史文献资料的搜集和统计分析,利用最小二乘法、小波分析等方法,对1260-1911a该区寒冻灾害等级,寒冻灾害发生的频次与县次的趋势与周期,和寒冻灾害与气候变化关系进行研究。结果表明:1260-1911a晋陕蒙毗邻地区寒冻灾害共发生116次,平均5.61年发生1次。将寒冻灾害分为轻度、中度、重度三级,各占总灾害频次的10.4%,73.8%和15.8%。寒冻灾害在秋季发生频率最高(71.8%),而霜冻集中在秋季(85.8%),低温在冬季(52.0%),雪灾多发于春、冬两季(66.7%)。整体而言,寒冻灾害的发生可分为明显减少-波动增加-显著增加3个阶段,灾害的频次上存在200a的周期,规模上则存在180a、55a和25a的周期。寒冻灾害空间差异显著,榆林、佳县为高频中心,兴县为低频中心。晋陕蒙毗邻地区寒冻灾害的发生与气候变化具有良好的对应关系,气候转折期及偏冷的时段,研究区寒冻灾害县次数更多,气候偏暖的时段则较少的特征。寒潮或强冷空气活动引起的降温,是引发区域大范围寒冻灾害的主要原因。

Based on the statistics and analysis of freezing disasters from 1260 to 1911 in adjacent areas of Shanxi-Shaanxi-Inner Mongolia,the temporal variations of freezing disasters were obtained by using least squares and wavelet analysis method. There were 116 recorded freezing disasters in these areas,approximately once every5. 61 years on average. The mild,moderate and severe disasters accounted for 10. 4%,73. 8% and 15. 8%,respectively. In August and autumn,freezing disasters occurred most frequently,accounting for 34. 1% and 71. 9%of the total,respectively. The freezing disaster experienced three stages,namely significant decreasing,fluctuating and rapid increasing. Wavelet analysis showed that freezing disaster cycle was 200 a in frequency,and 180 a,55 a,25 a on the scale. The freezing disaster varied distinctly in spatial distribution,Yulin and Jiaxian were the high-frequency disaster center,while Xingxian was the low-frequency disaster center. The occurrence of freezing disasters corresponded to the long-term climate change obviously. During the climate-transition period and the cold period,there were more counties occurred disasters,but during the mild period there were less of them. Cold caused by cold wave and strong cold air was the main cause of the large-scale freezing disaster in the region.