松花江流域最大冻土深度的时空分布及对气温变化的响应

The spatial-temporal distribution of maximum depth of frozen soil and its response to temperature change in the Songhuajiang River Basin

利用松花江流域内及周边的56个气象站点资料,采用气候统计学分析方法,对1960-2004年松花江流域最大冻土深度的时空变化及其与气温的关系进行了分析。结果表明:流域年最大冻土深度分布整体呈由南向北增加的趋势。月最大冻土深度有明显的季节变化,最大值多出现在3月,且高纬度地区最大冻土深度均大于低纬度地区。1960-2004年松花江流域年最大冻土深度呈明显下降趋势,变化率为-8.25 cm/10a,与冻土同期的年均气温呈显著升高趋势,变化率为0.41℃/10a。年最大冻土深度在1980s中期发生突变,突变年前后最大冻土深度减小了35 cm。此外,年最大冻土深度和年均气温在时间和空间尺度上均呈显著负相关,高纬度地区最大冻土深度比低纬度地区对气候变暖的响应滞后。

In the Songhuajiang River Basin seasonal frozen soil is extensively distributed. Frozen soil is defined as a soil temperature of 0℃ or below 0℃ where the soil freezes causing changes in soil characteristics, soil structure and hydrological processes. Based on data from 56 meteorological stations in the Songhuajiang River Basin and surrounding areas, the temporal and spatial distribution of the maximum depth of frozen soil in the Songhuajiang River Basin from 1960 to 2004 and its relationship with air temperature were analyzed using climate statistical analysis methods. We found that the annual maximum depth of frozen soil north of the region is higher than that in the south. The monthly maximum depth of frozen soil in the basin shows seasonal variation, with the maximum occurring in March. At the same time, the maximum depth of frozen soil in high latitude area was higher than in a low latitude area. There was a distinct decrease from 1960 to 2004 across the basin, with regression coefficients of-8.25 cm per year, and the annual mean air temperature of the frozen period has increased with variation of 0.41 ℃ per decade. There was an abrupt change of the maximum depth of frozen soil in mid 1980s, and the maximum depth of frozen soil was reduced by 35 cm. This study also found that the maximum depth of frozen soil and annual mean temperature are negatively correlated at spatial and temporal scales and the response of the maximum depth of frozen soil at high latitudes to climate warming is slower at lower latitudes.