Spatial and temporal variability in active layer thickness over the Russian Arctic drainage basin
Spatial and temporal variability in active layer thickness over the Russian Arctic drainage basin
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DOI：
10.1029/2004jd005642
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发表时间：
2005-08
影响因子：
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通讯作者：
Tingjun Zhang;O. Frauenfeld;M. Serreze;A. Etringer;C. Oelke;J. McCreight;R. Barry;D. Gilichinsky-D.-Gilichins
中科院分区：
文献类型：
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作者：
Tingjun Zhang;O. Frauenfeld;M. Serreze;A. Etringer;C. Oelke;J. McCreight;R. Barry;D. Gilichinsky-D.-Gilichins
[1]北方高纬度多年冻土区活动层厚度（ALT）的变化对地表能量平衡、水文循环、大气-地表碳交换、植物生长乃至整个生态系统都有重要影响。本研究探讨了20世纪的变化ALT的鄂毕河，叶尼塞河和勒拿河流域。ALT是根据17个站点（1956-1990年，仅Lena盆地）的历史土壤温度测量值估计的，这是一个基于地表空气温度数据（1901-2002年）和数值模拟（1980-2002年）的年度解冻指数。后两者提供空间场。根据解冻指数，长期平均（1961-1990年）ALT在Ob约为1.87米，在Yenisey约为1.67米，在Lena盆地约为1.69米。过去几十年来，三个流域的ALT均呈积极趋势，但幅度不同。根据17个测站的数据，1956年至1990年，Lena的ALT增加了约0.32米。在某种程度上，基于土壤温度的结果代表地面的“真相”，ALT从解冻指数和数值模拟得到的低估。人们普遍认为，ALT将随着全球变暖而增加。然而，这一假设需要进一步完善，因为ALT主要响应夏季气温，而观测到的变暖主要发生在冬季和春季。它还表明，ALT表现出复杂的和不一致的反应，积雪的变化。
[1] Changes in active layer thickness (ALT) over northern high-latitude permafrost regions have important impacts on the surface energy balance, hydrologic cycle, carbon exchange between the atmosphere and the land surface, plant growth, and ecosystems as a whole. This study examines the 20th century variations of ALT for the Ob, Yenisey, and Lena River basins. ALT is estimated from historical soil temperature measurements from 17 stations (1956–1990, Lena basin only), an annual thawing index based on both surface air temperature data (1901–2002) and numerical modeling (1980–2002). The latter two provide spatial fields. Based on the thawing index, the long-term average (1961–1990) ALT is about 1.87 m in the Ob, 1.67 in the Yenisey, and 1.69 m in the Lena basin. Over the past several decades, ALT over the three basins shows positive trends, but with different magnitudes. Based on the 17 stations, ALT increased about 0.32 m between 1956 and 1990 in the Lena. To the extent that results based on the soil temperatures represent ground “truth,” ALT obtained from both the thawing index and numerical modeling is underestimated. It is widely believed that ALT will increase with global warming. However, this hypothesis needs further refinement since ALT responds primarily to summer air temperature while observed warming has occurred mainly in winter and spring. It is also shown that ALT exhibits complex and inconsistent responses to variations in snow cover.