通辽国家基本气象观测站近50年最大冻土深度变化特征及其与地温和气温的相关分析

摘要

Using the descriptive analysis,linear trend fitting and cumulative anomaly methods,the annual maximum depth of frozen soil,the average minimum air temperature and the average minimum ground temperature in each winter month(from October to the next February) at Tongliao National Basic Meteorological Observation Station during 1962-2011 were compared and analyzed.The results showed that the maximum depth of frozen soil at Tongliao Station for many years on the average reached 131.7 cm.And the maximum value appeared in February of 1977 and the minimum value appeared in February of 2007,and the maximum value was 1.4 times as the minimum.Under the background of the global climate warming,the maximum depth of frozen soil at Tongliao Station had obvious age change characteristics.At the terminal stage of 1960s-1970s,the maximum depth of frozen soil showed a gradual increasing trend.And the maximum depth of frozen soil showed a gradual decreasing trend after 1980s.At time scale of 50 years,the maximum depth of frozen soil at Tongliao Station had twice mutations,which occurred in the winter of 1971-1972 and 2005-2006.The maximum depth changes of the frozen soil at Tongliao Station showed significant negative correlations with the changes of the average minimum air temperature and minimum ground temperature.The lower the air temperature and ground temperature were,the thicker the layer of frozen soil was,and vice versa.The appearing time of the maximum depth of frozen soil was 1-2 months later than that of the minimum air temperature and ground temperature.%利用描述分析、线性趋势拟合和累积距平方法对通辽国家基本气象观测站（以下简称通辽站）1962—2011年50年的年最大冻土深度、冬季（10月—翌年2月）各月平均最低气温和平均最低地面温度资料进行了对比分析。结果表明,通辽站最大冻土深度多年平均可达131.7cm,最大值出现在1977年2月,最小值出现在2007年2月,两者相差1.4倍;在全球气候变暖的大背景下,通辽站最大冻土深度的年代际变化特征明显,在20世纪60—70年代末期,最大冻土深度呈逐渐增大趋势,80年代以后该值逐年减小;在50年时间尺度上,通辽站最大冻土深度存在2次突变过程,突变时间点在1971/1972年冬季和2005/2006年冬季。该地区最大冻土深度的变化与冬季平均最低地温和平均最低气温的变化呈显著的负相关关系,气温和地温低则冻土层厚,否则冻土层薄,最大冻土深度出现的最大值月份比最低气温和地温出现月要滞后1～2个月。