摘要:冻土在气候系统中起重要作用，研究并揭示冻土时空变化对于增加陆气相互作用的理解具有重要意义。本研究利用包含土壤冻结融化界面动态变化的陆面过程模式CAS-LSM（Chinese Academy of Sciences Land Surface Model），采用0.9°（纬度）×1.25°（经度）分辨率，结合4种大气强迫数据（全球土壤湿度项目强迫数据集GSWP3、美国国家大气研究中心/美国国家环境预报中心强迫数据集CRU-NCEP、普林斯顿全球强迫数据集Princeton、全球变化以及水文观测项目强迫数据集WFDEI）针对1960～2009年进行全球模拟，研究不同大气强迫作用下多年冻土活动层厚度变化趋势及其不确定性。通过与活动层厚度观测数据比较，陆面过程模式CAS-LSM模拟的活动层厚度与观测值比较接近。结果表明：在1960～2009年期间，不同大气强迫作用下多年冻土活动层厚度基本呈现增加的趋势，基于强迫数据WFDEI模拟的活动层厚度增加趋势最大。不同大气强迫数据模拟的活动层厚度区域平均和变化趋势范围为1.1～1.25 m和0.27～0.51 cm/a，相对变化的不确定性范围为11.2%～23.5%。其中青藏高原地区、北美地区、欧亚大陆北部地区的活动层厚度区域平均和变化趋势范围分别为2.26～2.81 m、1.07～1.31 m、1.32～1.48 m和0.47～1.0 4 cm/a、0.29～0.48 cm/a、0.25～0.55 cm/a。通过对地表温度以及气温的变化趋势分析表明：大气强迫数据中气温的差异是造成这些差异的主要原因。
关键词:多年冻土/
活动层厚度/
气象强迫/
陆面模式
Abstract:Permafrost plays an important role in the climate system, which is of great significance in revealing the temporal and spatial variation of frozen ground to increase the understanding of land–air interaction. In this study, the Chinese Academy of Sciences Land Surface Model (CAS-LSM) was adopted, which contains the dynamic changes of the soil freezing and thawing fronts. Four different atmospheric forcing data, CRU-NCEP (Climatic Research Unit-NCEP forcing data), GSWP3 (Global Soil Wetness Project forcing dataset), Princeton (Princeton meteorological forcing dataset), and WFDEI (water and global change forcing data methodology applied to ERA-Interim data), were used to drive the CAS-LSM. The simulation time of the four groups of the simulation experiments was from 1960 to 2009 with a resolution of 0.9°×1.25°. The variation trend and uncertainty of permafrost active layer thickness under different atmospheric forcing were studied. The simulated active layer thickness compared well with the observed data. Results reveal an increasing trend of the active layer thickness under different atmospheric forcings. The variation trend of the forcing data WFDEI simulation is the largest. The regional average active layer thickness and variation trend range of different atmospheric forcing simulations were 1.1–1.25 m and 0.27–0.51 cm/a, respectively, with the relative changes of 11.2%–23.5%. The range of regional average active layer thickness and variation trend in Qinghai–Tibet plateau region, North America, and north of Eurasia are 2.26–2.81 m, 1.07–1.31 m, 1.32–1.48 m, and 0.47–1.04 cm/a, 0.29–0.48 cm/a, 0.25–0.55 cm/a. The difference in air temperature in the atmospheric forcing data is the main reason for these variations.
Key words:Permafrost/
Active layer thickness/
Atmospheric forcing data/
Land surface model
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