Analysis of Permafrost Thermal Dynamics and Response to Climate Change in the CMIP5 Earth System Models
Analysis of Permafrost Thermal Dynamics and Response to Climate Change in the CMIP5 Earth System Models
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DOI：
10.1175/jcli-d-12-00228.1
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发表时间：
2013-03-01
影响因子：
4.9
通讯作者：
Stern, Alex
中科院分区：
文献类型：
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作者：
Koven, Charles D.;Riley, William J.;Stern, Alex
作者分析了全球气候模型对土壤温度的预测[来自耦合模型相互比较项目第5阶段（CMIP 5）数据库]，以评估模型对当前气候土壤热动力学的代表性及其对21世纪冻土融化的预测。作者将模型的预测与活动层厚度、气温和土壤温度的观测结果进行了比较，并与理论上预期的活动层厚度与气温年平均和季节周期振幅之间的关系进行了比较。模型显示了目前广泛的永久冻土区，活跃层统计（累积分布，与年平均气温的相关性，季节性气温周期的幅度），并能够准确地模拟土壤和空气温度之间的耦合在高纬度地区。许多模型之间的差异可以追溯到近地表空气和浅层土壤温度或浅层和深层（1米）土壤温度之间的耦合差异，这反过来又反映了雪物理学和土壤水文学的差异。该模型与观测数据集进行比较，基准的几个方面的永久冻土相关的物理模型。遵循多个代表性浓度路径（RCP）的CMIP 5模型显示了对多年冻土流失的广泛预测：RCP 2.6为2%-66%，RCP 4.5为15%-87%，RCP 8.5为30%-99%。在RCP4.5情景中，将永久冻土损失量与高纬度变暖量标准化，模型预测每高纬度变暖1摄氏度，永久冻土绝对损失160 +/-70万km（2），或损失6%-29%摄氏度-1
The authors analyze global climate model predictions of soil temperature [from the Coupled Model Intercomparison Project phase 5 (CMIP5) database] to assess the models' representation of current-climate soil thermal dynamics and their predictions of permafrost thaw during the twenty-first century. The authors compare the models' predictions with observations of active layer thickness, air temperature, and soil temperature and with theoretically expected relationships between active layer thickness and air temperature annualmean- and seasonal-cycle amplitude. Models show a wide range of current permafrost areas, active layer statistics (cumulative distributions, correlations with mean annual air temperature, and amplitude of seasonal air temperature cycle), and ability to accurately model the coupling between soil and air temperatures at high latitudes. Many of the between-model differences can be traced to differences in the coupling between either near-surface air and shallow soil temperatures or shallow and deeper (1 m) soil temperatures, which in turn reflect differences in snow physics and soil hydrology. The models are compared with observational datasets to benchmark several aspects of the permafrost-relevant physics of the models. The CMIP5 models following multiple representative concentration pathways (RCP) show a wide range of predictions for permafrost loss: 2%-66% for RCP2.6, 15%-87% for RCP4.5, and 30%-99% for RCP8.5. Normalizing the amount of permafrost loss by the amount of high-latitude warming in the RCP4.5 scenario, the models predict an absolute loss of 1.6 +/- 0.7 million km(2) permafrost per 1 degrees C high-latitude warming, or a fractional loss of 6%-29% degrees C-1