气候变化领域集成服务门户(CCPortal): Characterizing permafrost active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska

CCPortal

DOI	10.5194/tc-12-145-2018
	Characterizing permafrost active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska
	Yi Y.; Kimball J.S.; Chen R.H.; Moghaddam M.; Reichle R.H.; Mishra U.; Zona D.; Oechel W.C.
发表日期	2018
ISSN	19940416
卷号	12 期号:1
英文摘要	An important feature of the Arctic is large spatial heterogeneity in active layer conditions, which is generally poorly represented by global models and can lead to large uncertainties in predicting regional ecosystem responses and climate feedbacks. In this study, we developed a spatially integrated modeling and analysis framework combining field observations, local-scale ( ∼ 50m resolution) active layer thickness (ALT) and soil moisture maps derived from low-frequency (Lband) airborne radar measurements, and global satellite environmental observations to investigate the ALT sensitivity to recent climate trends and landscape heterogeneity in Alaska. Modeled ALT results show good correspondence with in situ measurements in higher-permafrost-probability (PP ≥ 70%) areas (n Combining double low line 33; R Combining double low line 0.60; mean bias Combining double low line 1.58cm; RMSE Combining double low line 20.32cm), but with larger uncertainty in sporadic and discontinuous permafrost areas. The model results also reveal widespread ALT deepening since 2001, with smaller ALT increases in northern Alaska (mean trend Combining double low line 0.32±1.18cmyr-1) and much larger increases (> 3cmyr-1) across interior and southern Alaska. The positive ALT trend coincides with regional warming and a longer snow-free season (R Combining double low line 0.60±0.32). A spatially integrated analysis of the radar retrievals and model sensitivity simulations demonstrated that uncertainty in the spatial and vertical distribution of soil organic carbon (SOC) was the largest factor affecting modeled ALT accuracy, while soil moisture played a secondary role. Potential improvements in characterizing SOC heterogeneity, including better spatial sampling of soil conditions and advances in remote sensing of SOC and soil moisture, will enable more accurate predictions of active layer conditions and refinement of the modeling framework across a larger domain. © Author(s) 2018.
学科领域	active layer; climate feedback; ecosystem response; global warming; heterogeneity; in situ measurement; landscape change; permafrost; radar; remote sensing; sensitivity analysis; soil moisture; soil organic matter; spatial analysis; trend analysis; vertical distribution; Alaska; Arctic; United States
语种	英语
scopus关键词	active layer; climate feedback; ecosystem response; global warming; heterogeneity; in situ measurement; landscape change; permafrost; radar; remote sensing; sensitivity analysis; soil moisture; soil organic matter; spatial analysis; trend analysis; vertical distribution; Alaska; Arctic; United States
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119238
作者单位	Numerical Terradynamic Simulation Group, University of Montana, Missoula, MT, United States; Department of Electrical Engineering, University of Southern CaliforniaCA, United States; Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, MD, United States; Environmental Science Division, Argonne National Laboratory, Argonne, IL, United States; Department of Biology, San Diego State University, San Diego, CA, United States
推荐引用方式 GB/T 7714	Yi Y.,Kimball J.S.,Chen R.H.,et al. Characterizing permafrost active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska[J],2018,12(1).
APA	Yi Y..,Kimball J.S..,Chen R.H..,Moghaddam M..,Reichle R.H..,...&Oechel W.C..(2018).Characterizing permafrost active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska.Cryosphere,12(1).
MLA	Yi Y.,et al."Characterizing permafrost active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska".Cryosphere 12.1(2018).