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Title: Characterizing permafrost soil active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska

An important feature of the Arctic is large spatial heterogeneity in active layer conditions, which is generally poorly represented by global models. In this study, we developed a spatially integrated modelling and analysis framework combining field observations, local scale (~ 50 m) active layer thickness (ALT) and soil moisture maps derived from airborne low frequency (L + P-band) radar measurements, and global satellite environmental observations to investigate the ALT sensitivity to recent climate trends and landscape heterogeneity in Alaska. Model simulated ALT results show good correspondence with in-situ measurements in higher permafrost probability (PP ≥ 70 %) areas (n = 33, R = 0.60, mean bias = 1.58 cm, RMSE = 20.32 cm). The model results also reveal widespread ALT deepening since 2001, with smaller ALT increases in northern Alaska (mean trend = 0.32 ± 1.18 cm yr -1) and much larger increases (> 3 cm yr -1) across interior and southern Alaska. The positive ALT trend coincides with regional warming and a longer snow-free season (R = 0.60 ± 0.32). Uncertainty in the spatial and vertical distribution of soil organic carbon (SOC) was found to be the most important factor affecting model ALT accuracy. Here, potential improvements in characterizingmore » 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 permafrost active layer conditions.« less
Authors:
 [1] ;  [1] ; ORCiD logo [2] ;  [2] ;  [3] ;  [4] ; ORCiD logo [5] ;  [5]
  1. The Univ. of Montana, Missoula, MT (United States)
  2. Univ. of Southern California, Los Angeles, CA (United States)
  3. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
  4. Argonne National Lab. (ANL), Argonne, IL (United States)
  5. San Diego State Univ., San Diego, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
The Cryosphere Discussions
Additional Journal Information:
Journal Volume: 2017; Journal ID: ISSN 1994-0440
Publisher:
European Geosciences Union
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
National Aeronautic and Space Administration (NASA); USDOE
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; Active layer; Permafrost
OSTI Identifier:
1402081

Yi, Yonghong, Kimball, John S., Chen, Richard, Moghaddam, Mahta, Reichle, Rolf H., Mishra, Umakant, Zona, Donatella, and Oechel, Walter C.. Characterizing permafrost soil active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska. United States: N. p., Web. doi:10.5194/tc-2017-87.
Yi, Yonghong, Kimball, John S., Chen, Richard, Moghaddam, Mahta, Reichle, Rolf H., Mishra, Umakant, Zona, Donatella, & Oechel, Walter C.. Characterizing permafrost soil active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska. United States. doi:10.5194/tc-2017-87.
Yi, Yonghong, Kimball, John S., Chen, Richard, Moghaddam, Mahta, Reichle, Rolf H., Mishra, Umakant, Zona, Donatella, and Oechel, Walter C.. 2017. "Characterizing permafrost soil active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska". United States. doi:10.5194/tc-2017-87. https://www.osti.gov/servlets/purl/1402081.
@article{osti_1402081,
title = {Characterizing permafrost soil active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska},
author = {Yi, Yonghong and Kimball, John S. and Chen, Richard and Moghaddam, Mahta and Reichle, Rolf H. and Mishra, Umakant and Zona, Donatella and Oechel, Walter C.},
abstractNote = {An important feature of the Arctic is large spatial heterogeneity in active layer conditions, which is generally poorly represented by global models. In this study, we developed a spatially integrated modelling and analysis framework combining field observations, local scale (~ 50 m) active layer thickness (ALT) and soil moisture maps derived from airborne low frequency (L + P-band) radar measurements, and global satellite environmental observations to investigate the ALT sensitivity to recent climate trends and landscape heterogeneity in Alaska. Model simulated ALT results show good correspondence with in-situ measurements in higher permafrost probability (PP ≥ 70 %) areas (n = 33, R = 0.60, mean bias = 1.58 cm, RMSE = 20.32 cm). The model results also reveal widespread ALT deepening since 2001, with smaller ALT increases in northern Alaska (mean trend = 0.32 ± 1.18 cm yr-1) and much larger increases (> 3 cm yr-1) across interior and southern Alaska. The positive ALT trend coincides with regional warming and a longer snow-free season (R = 0.60 ± 0.32). Uncertainty in the spatial and vertical distribution of soil organic carbon (SOC) was found to be the most important factor affecting model ALT accuracy. Here, 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 permafrost active layer conditions.},
doi = {10.5194/tc-2017-87},
journal = {The Cryosphere Discussions},
number = ,
volume = 2017,
place = {United States},
year = {2017},
month = {5}
}