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Lara MJ, McGuire AD, Euskirchen ES, Genet H, Yi S, Rutter R, Iversen C, Sloan V, Wullschleger SD. Local-scale Arctic tundra heterogeneity affects regional-scale carbon dynamics. Nat Commun 2020; 11:4925. [PMID: 33004822 PMCID: PMC7529807 DOI: 10.1038/s41467-020-18768-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 09/01/2020] [Indexed: 02/03/2023] Open
Abstract
In northern Alaska nearly 65% of the terrestrial surface is composed of polygonal ground, where geomorphic tundra landforms disproportionately influence carbon and nutrient cycling over fine spatial scales. Process-based biogeochemical models used for local to Pan-Arctic projections of ecological responses to climate change typically operate at coarse-scales (1km2-0.5°) at which fine-scale (<1km2) tundra heterogeneity is often aggregated to the dominant land cover unit. Here, we evaluate the importance of tundra heterogeneity for representing soil carbon dynamics at fine to coarse spatial scales. We leveraged the legacy of data collected near Utqiaġvik, Alaska between 1973 and 2016 for model initiation, parameterization, and validation. Simulation uncertainty increased with a reduced representation of tundra heterogeneity and coarsening of spatial scale. Hierarchical cluster analysis of an ensemble of 21st-century simulations reveals that a minimum of two tundra landforms (dry and wet) and a maximum of 4km2 spatial scale is necessary for minimizing uncertainties (<10%) in regional to Pan-Arctic modeling applications.
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Affiliation(s)
- M J Lara
- Plant Biology Department, University of Illinois, Urbana, IL, 61801, USA.
- Geography Department, University of Illinois, Urbana, IL, 61801, USA.
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK, 99775, USA.
| | - A D McGuire
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK, 99775, USA
| | - E S Euskirchen
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK, 99775, USA
| | - H Genet
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK, 99775, USA
| | - S Yi
- Institute of Fragile Ecosystem and Environment, School of Geographic Science, Nantong University, Nantong, China
| | - R Rutter
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK, 99775, USA
| | - C Iversen
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - V Sloan
- School of Civil, Aerospace and Mechanical Engineering, Queens's Building, University of Bristol, Bristol, UK
| | - S D Wullschleger
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, USA
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Wilson EL, DiGregorio AJ, Villanueva G, Grunberg CE, Souders Z, Miletti KM, Menendez A, Grunberg MH, Floyd MAM, Bleacher JE, Euskirchen ES, Edgar C, Caldwell BJ, Shiro B, Binsted K. A portable miniaturized laser heterodyne radiometer (mini‑LHR) for remote measurements of column CH 4 and CO 2. Appl Phys B 2019; 125:11. [PMID: 31920221 PMCID: PMC6951259 DOI: 10.1007/s00340-019-7315-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 09/27/2019] [Indexed: 05/25/2023]
Abstract
We present the design of a portable version of our miniaturized laser heterodyne radiometer (mini-LHR) that simultaneously measures methane (CH4) and carbon dioxide (CO2) in the atmospheric column. The mini-LHR fits on a backpack frame, operates autonomously, and requires no infrastructure because it is powered by batteries charged by a folding 30 W solar panel. Similar to our earlier instruments, the mini-LHR is a passive laser heterodyne radiometer that operates by collecting sunlight that has undergone absorption by CH4 and CO2. Within the mini-LHR, sunlight is mixed with light from a distributive feedback (DFB) laser centered at approximately 1.64 μm where both gases have absorption features. The laser scans across these absorption features roughly every minute and the resulting beat signal is collected in the radio frequency (RF). Scans are averaged into half hour and hour data products and analyzed using the Planetary Spectrum Generator (PSG) retrieval to extract column mole fractions. Instrument performance is demonstrated through two deployments at significantly different sites in interior Alaska and Hawaii. The resolving power (λ/∆λ) is greater than 500,000 at 1.64 μm with precisions of better than 20 ppb and 1 ppm for CH4 and CO2, respectively. Because mini-LHR instruments are portable and can be co-located, they can be used to characterize bias between larger, stationary, column observing instruments. In addition, mini-LHRs can be deployed quickly to respond to transient events such as methane leaks or can be used for field studies targeting geographical regions.
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Affiliation(s)
- E. L. Wilson
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, USA
| | - A. J. DiGregorio
- Science Systems and Applications, Inc., 10210 Greenbelt Rd, 20, Lanham, MD 20706, USA
| | - G. Villanueva
- Planetary Systems Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, USA
| | - C. E. Grunberg
- Center for Research and Exploration in Space Science and Technology (CRESST), University of Maryland, College Park, MD 20740, USA
| | - Z. Souders
- Center for Research and Exploration in Space Science and Technology (CRESST), University of Maryland, College Park, MD 20740, USA
| | - K. M. Miletti
- Center for Research and Exploration in Space Science and Technology (CRESST), University of Maryland, College Park, MD 20740, USA
| | - A. Menendez
- Center for Research and Exploration in Space Science and Technology (CRESST), University of Maryland, College Park, MD 20740, USA
| | - M. H. Grunberg
- Center for Research and Exploration in Space Science and Technology (CRESST), University of Maryland, College Park, MD 20740, USA
| | - M. A. M. Floyd
- Planetary Environments Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, USA
| | - J. E. Bleacher
- Planetary Geology, Geophysics, and Geochemistry Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, USA
| | - E. S. Euskirchen
- Institute of Arctic Biology, University of Alaska Fairbanks, 902 N. Koyukuk Dr, P.O. Box 757000, Fairbanks, AK 99775, USA
| | - C. Edgar
- Institute of Arctic Biology, University of Alaska Fairbanks, 902 N. Koyukuk Dr, P.O. Box 757000, Fairbanks, AK 99775, USA
| | - B. J. Caldwell
- Exploration Class Management, 414 Bayoo View Drive, El Lago, TX 73472, USA
| | - B. Shiro
- Department of Earth Sciences, University of Hawai‘i at Mānoa, POST Building, Suite 701, 1680 East - West Road, Honolulu, HI 96822, USA
| | - K. Binsted
- Department of Information and Computer Sciences, University of Hawai‘i at Mānoa, POST Building Suite 303D, 1680 East - West Road, Honolulu, HI 96822, USA
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Euskirchen ES, McGuire AD, Chapin FS, Yi S, Thompson CC. Changes in vegetation in northern Alaska under scenarios of climate change, 2003-2100: implications for climate feedbacks. Ecol Appl 2009; 19:1022-43. [PMID: 19544741 DOI: 10.1890/08-0806.1] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Assessing potential future changes in arctic and boreal plant species productivity, ecosystem composition, and canopy complexity is essential for understanding environmental responses under expected altered climate forcing. We examined potential changes in the dominant plant functional types (PFTs) of the sedge tundra, shrub tundra, and boreal forest ecosystems in ecotonal northern Alaska, USA, for the years 2003-2100. We compared energy feedbacks associated with increases in biomass to energy feedbacks associated with changes in the duration of the snow-free season. We based our simulations on nine input climate scenarios from the Intergovernmental Panel on Climate Change (IPCC) and a new version of the Terrestrial Ecosystem Model (TEM) that incorporates biogeochemistry, vegetation dynamics for multiple PFTs (e.g., trees, shrubs, grasses, sedges, mosses), multiple vegetation pools, and soil thermal regimes. We found mean increases in net primary productivity (NPP) in all PFTs. Most notably, birch (Betula spp.) in the shrub tundra showed increases that were at least three times larger than any other PFT. Increases in NPP were positively related to increases in growing-season length in the sedge tundra, but PFTs in boreal forest and shrub tundra showed a significant response to changes in light availability as well as growing-season length. Significant NPP responses to changes in vegetation uptake of nitrogen by PFT indicated that some PFTs were better competitors for nitrogen than other PFTs. While NPP increased, heterotrophic respiration (RH) also increased, resulting in decreases or no change in net ecosystem carbon uptake. Greater aboveground biomass from increased NPP produced a decrease in summer albedo, greater regional heat absorption (0.34 +/- 0.23 W x m(-2) x 10 yr(-1) [mean +/- SD]), and a positive feedback to climate warming. However, the decrease in albedo due to a shorter snow season (-5.1 +/- 1.6 d/10 yr) resulted in much greater regional heat absorption (3.3 +/- 1.24 W x m(-2) x 10 yr(-1)) than that associated with increases in vegetation. Through quantifying feedbacks associated with changes in vegetation and those associated with changes in the snow season length, we can reach a more integrated understanding of the manner in which climate change may impact interactions between high-latitude ecosystems and the climate system.
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Affiliation(s)
- E S Euskirchen
- Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska 99775, USA.
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Chapin FS, Sturm M, Serreze MC, McFadden JP, Key JR, Lloyd AH, McGuire AD, Rupp TS, Lynch AH, Schimel JP, Beringer J, Chapman WL, Epstein HE, Euskirchen ES, Hinzman LD, Jia G, Ping CL, Tape KD, Thompson CDC, Walker DA, Welker JM. Role of Land-Surface Changes in Arctic Summer Warming. Science 2005; 310:657-60. [PMID: 16179434 DOI: 10.1126/science.1117368] [Citation(s) in RCA: 322] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A major challenge in predicting Earth's future climate state is to understand feedbacks that alter greenhouse-gas forcing. Here we synthesize field data from arctic Alaska, showing that terrestrial changes in summer albedo contribute substantially to recent high-latitude warming trends. Pronounced terrestrial summer warming in arctic Alaska correlates with a lengthening of the snow-free season that has increased atmospheric heating locally by about 3 watts per square meter per decade (similar in magnitude to the regional heating expected over multiple decades from a doubling of atmospheric CO2). The continuation of current trends in shrub and tree expansion could further amplify this atmospheric heating by two to seven times.
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Affiliation(s)
- F S Chapin
- Institute of Arctic Biology; University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
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