Recent changes in the active layer thickness across the northern hemisphere
Recent changes in the active layer thickness across the northern hemisphere
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北半球活动层厚度的近期变化
DOI：
10.1007/s12665-015-5229-2
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发表时间：
2016-04-01
影响因子：
2.8
通讯作者：
Gao, Siru
中科院分区：
文献类型：
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作者：
Luo, Dongliang;Wu, Qingbai;Gao, Siru
为了更好地了解生态和水文对气候和冰冻圈变化的响应，需要仔细研究活动层厚度（ALT）的时空变化。基于环极活动层监测网的230多个站点，研究了1990-2015年北方ALT的时空特征。结果表明，ALT在整个北方半球表现出很大的空间变化，从北极和亚北极地区的约30厘米到中纬度山区永久冻土区的10米以上。阿拉斯加的ALT区域平均值为48厘米，加拿大为93厘米，北欧国家（包括格陵兰岛和斯瓦尔巴群岛）和瑞士为164厘米，蒙古为330厘米，哈萨克斯坦为476厘米，青藏高原（QTP）为230厘米。在俄罗斯，欧洲北部、西西伯利亚、中西伯利亚、东北西伯利亚、楚科奇和堪察加的ALT区域平均值分别为110、92、69、61、53和60厘米。ALT的升高趋势在观察记录中并不一致。在73个研究中心观察到ALT显著变化，约占可用于统计分析的169个研究中心的43.2%。不到25%的阿拉斯加研究中心和约33%的加拿大研究中心显示ALT显著升高。在QTP上，几乎所有部位均显示ALT显著升高。在北方的某些地区观察到ALT的不显著升高甚至降低，例如，蒙古，阿拉斯加和加拿大的部分地区。气温、地温、植被、底质、微地形、土壤水分等因素对ALT的时空变化起着决定性作用，但它们之间的关系较为复杂，有待进一步研究。
To better understand the ecological and hydrological responses to climatic and cryospheric changes, the spatiotemporal variations in the active layer thickness (ALT) need to be scrupulously studied. Based on more than 230 sites from the circumpolar active layer monitoring network, the spatiotemporal characteristics of the ALT across the northern hemisphere during 1990-2015 were investigated. Results indicate that the ALT exhibits substantial spatial variations across the northern hemisphere, ranging from approximately 30 cm in the arctic and subarctic regions to greater than 10 m in the mountainous permafrost regions at mid-latitudes. Regional averages of ALT are 48 cm in Alaska, 93 cm in Canada, 164 cm in the Nordic countries (including Greenland and Svalbard) and Switzerland, 330 cm in Mongolia, 476 cm in Kazakhstan, and 230 cm on the Qinghai-Tibetan Plateau (QTP), respectively. In Russia, the regional averages of ALT in European North, West Siberia, Central Siberia, Northeast Siberia, Chukotka, and Kamchatka are 110, 92, 69, 61, 53 and 60 cm, respectively. Increasing trends of ALT were not uniformly present in the observational records. Significant changes in the ALT were observed at 73 sites, approximately 43.2 % of the investigated 169 sites that are available for statistical analysis. Less than 25 % Alaskan sites and approximately 33 % Canadian sites showed significant increase in the ALT. On the QTP, almost all the sites showed significant ALT increases. Insignificant increase and even decrease in the ALT were observed in some parts of the northern hemisphere, e.g., Mongolia, parts of Alaska and Canada. The air and ground temperatures, vegetation, substrate, microreliefs, and soil moisture in particular, play decisive roles in the spatiotemporal variations in the ALT, but the relationships among each other are complicated and await further studies.