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首页> 外文期刊>Climatic Change >Permafrost thaw accelerates in boreal peatlands during late-20th century climate warming.
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Permafrost thaw accelerates in boreal peatlands during late-20th century climate warming.

机译：在20世纪后期的气候变暖期间，多年冻土在北方泥炭地的融化加速。

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Permafrost covers 25% of the land surface in the northern hemisphere, where mean annual ground temperature is less than 0 degrees C. A 1.4-5.8 degrees C warming by 2100 will likely change the sign of mean annual air and ground temperatures over much of the zones of sporadic and discontinuous permafrost in the northern hemisphere, causing widespread permafrost thaw. In this study, I examined rates of discontinuous permafrost thaw in the boreal peatlands of northern Manitoba, Canada, using a combination of tree-ring analyses to document thaw rates from 1941-1991 and direct measurements of permanent benchmarks established in 1995 and resurveyed in 2002. I used instrumented records of mean annual and seasonal air temperatures, mean winter snow depth, and duration of continuous snow pack from climate stations across northern Manitoba to analyze temporal and spatial trends in these variables and their potential impacts on thaw. Permafrost thaw in central Canadian peatlands has accelerated significantly since 1950, concurrent with a significant, late-20th-century average climate warming of +1.32 degrees C in this region. There were strong seasonal differences in warming in northern Manitoba, with highest rates of warming during winter (+1.39 degrees C to +1.66 degrees C) and spring (+0.56 degrees C to +0.78 degrees C) at southern climate stations where permafrost thaw was most rapid. Projecting current warming trends to year 2100, I show that trends for north-central Canada are in good agreement with general circulation models, which suggest a 4-8 degrees C warming at high latitudes. This magnitude of warming will begin to eliminate most of the present range of sporadic and discontinuous permafrost in central Canada by 2100.
机译：多年冻土覆盖了北半球25％的陆地表面，那里的年平均地面温度低于0摄氏度。到2100年，气温升至1.4-5.8摄氏度，很可能会改变大部分地区年平均气温和地面温度的迹象。北半球零星和不连续的多年冻土区域，导致广泛的多年冻土融化。在这项研究中，我结合树木年轮分析记录了1941年至1991年的融化率，并直接测量了1995年建立并于2002年重新测量的永久基准，研究了加拿大曼尼托巴省北部泥炭地不连续多年冻土的融化率我使用仪器记录的平均年度和季节性气温，平均冬季降雪深度以及整个马尼托巴北部气候站的连续积雪持续时间来分析这些变量的时空趋势及其对解冻的潜在影响。自1950年以来，加拿大中部泥炭地的多年冻土融化速度显着加快，与此同时，该地区20世纪末的平均气候变暖也达到+1.32摄氏度。曼尼托巴北部的变暖存在强烈的季节性差异，冬季（+1.39摄氏度至+1.66摄氏度）和春季（+0.56摄氏度至+0.78摄氏度）的最高升温速率在多年冻土融化的地区最快。预测到2100年的当前变暖趋势，我表明加拿大中北部的趋势与一般环流模型吻合良好，后者表明在高纬度地区会变暖4-8摄氏度。到2100年，这种变暖的程度将开始消除加拿大中部目前大部分的零星和不连续多年冻土。

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