Northern Arizona Univ., Flagstaff, AZ (United States). Center for Ecosystem Science for Society; Northern Arizona Univ., Flagstaff, AZ (United States). Dept. of Biological Sciences; Northern Arizona Univ., Flagstaff, AZ (United States)
Univ. of Alaska, Fairbanks, AK (United States). Geophysical Inst.
Northern Arizona Univ., Flagstaff, AZ (United States). Center for Ecosystem Science for Society; Northern Arizona Univ., Flagstaff, AZ (United States). Dept. of Biological Sciences
Univ. of Florida, Gainesville, FL (United States). Agronomy Dept.
Northern circumpolar permafrost thaw affects global carbon cycling, as large amounts of stored soil carbon becomes accessible to microbial breakdown under a warming climate. The magnitude of carbon release is linked to the extent of permafrost thaw, which is locally variable and controlled by soil thermodynamics. Soil thermodynamic properties, such as thermal diffusivity, govern the reactivity of the soil-atmosphere thermal gradient, and are controlled by soil composition and drainage. In order to project permafrost thaw for an Alaskan tundra experimental site, we used seven years of site data to calibrate a soil thermodynamic model using a data assimilation technique. The model reproduced seasonal and interannual temperature dynamics for shallow (5–40 cm) and deep soil layers (2–4 m), and simulations of seasonal thaw depth closely matched observed data. The model was then used to project permafrost thaw at the site to the year 2100 using climate forcing data for three future climate scenarios (RCP 4.5, 6.0, and 8.5). Minimal permafrost thawing occurred until mean annual air temperatures rose above the freezing point, after which we measured over a 1 m increase in thaw depth for every 1 °C rise in mean annual air temperature. Under no projected warming scenario was permafrost remaining in the upper 3 m of soil by 2100. We demonstrated an effective data assimilation method that optimizes parameterization of a soil thermodynamic model. The sensitivity of local permafrost to climate warming illustrates the vulnerability of sub-Arctic tundra ecosystems to significant and rapid soil thawing.
Garnello, A., et al. "Projecting Permafrost Thaw of Sub-Arctic Tundra With a Thermodynamic Model Calibrated to Site Measurements." Journal of Geophysical Research. Biogeosciences, vol. 126, no. 6, May. 2021. https://doi.org/10.1029/2020jg006218
Garnello, A., Marchenko, S., Nicolsky, D., Romanovsky, V., Ledman, J., Celis, G., Schädel, C., Luo, Y., & Schuur, E. A. G. (2021). Projecting Permafrost Thaw of Sub-Arctic Tundra With a Thermodynamic Model Calibrated to Site Measurements. Journal of Geophysical Research. Biogeosciences, 126(6). https://doi.org/10.1029/2020jg006218
Garnello, A., Marchenko, S., Nicolsky, D., et al., "Projecting Permafrost Thaw of Sub-Arctic Tundra With a Thermodynamic Model Calibrated to Site Measurements," Journal of Geophysical Research. Biogeosciences 126, no. 6 (2021), https://doi.org/10.1029/2020jg006218
@article{osti_1850978,
author = {Garnello, A. and Marchenko, S. and Nicolsky, D. and Romanovsky, V. and Ledman, J. and Celis, G. and Schädel, C. and Luo, Y. and Schuur, E. A. G.},
title = {Projecting Permafrost Thaw of Sub-Arctic Tundra With a Thermodynamic Model Calibrated to Site Measurements},
annote = {Northern circumpolar permafrost thaw affects global carbon cycling, as large amounts of stored soil carbon becomes accessible to microbial breakdown under a warming climate. The magnitude of carbon release is linked to the extent of permafrost thaw, which is locally variable and controlled by soil thermodynamics. Soil thermodynamic properties, such as thermal diffusivity, govern the reactivity of the soil-atmosphere thermal gradient, and are controlled by soil composition and drainage. In order to project permafrost thaw for an Alaskan tundra experimental site, we used seven years of site data to calibrate a soil thermodynamic model using a data assimilation technique. The model reproduced seasonal and interannual temperature dynamics for shallow (5–40 cm) and deep soil layers (2–4 m), and simulations of seasonal thaw depth closely matched observed data. The model was then used to project permafrost thaw at the site to the year 2100 using climate forcing data for three future climate scenarios (RCP 4.5, 6.0, and 8.5). Minimal permafrost thawing occurred until mean annual air temperatures rose above the freezing point, after which we measured over a 1 m increase in thaw depth for every 1 °C rise in mean annual air temperature. Under no projected warming scenario was permafrost remaining in the upper 3 m of soil by 2100. We demonstrated an effective data assimilation method that optimizes parameterization of a soil thermodynamic model. The sensitivity of local permafrost to climate warming illustrates the vulnerability of sub-Arctic tundra ecosystems to significant and rapid soil thawing.},
doi = {10.1029/2020jg006218},
url = {https://www.osti.gov/biblio/1850978},
journal = {Journal of Geophysical Research. Biogeosciences},
issn = {ISSN 2169-8953},
number = {6},
volume = {126},
place = {United States},
publisher = {American Geophysical Union},
year = {2021},
month = {05}}