Five Stages of the Alaskan Arctic Cold Season with Ecosystem Implications

Olsson, Peter Q.; Sturm, Matthew; Racine, Charles H.; Romanovsky, V. E.; Liston, Glen E.

doi:10.1657/1523-0430(2003)035[0074:fsotaa]2.0.co;2

Cited by 87 publications

(85 citation statements)

References 40 publications

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“…An important biophysical transition during snow accumulation takes place when the ground surface becomes decoupled from the air temperatures (Olsson et al 2003). This decoupling has been reported to occur with snow depths of 15-20 cm (Pruitt 1957), or according to more recent work by Taras et al (2002) with snow depths of around 80 cm.…”

Section: The Potential Effects Of the Changing Cold Season On Ecosystmentioning

confidence: 97%

Observed cold season changes in a Fennoscandian fell area over the past three decades

Kivinen

Rasmus

2014

AMBIO

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We studied trends and variability in snow and climate characteristics in 1978-2012 in the Värriötunturit fell area, northern Finland. Cold season changes were examined using long-term observational data on snow depths, meteorological data, large-scale climate indices, and reindeer herders' experiences with difficult snow conditions. Snow depths declined, and temperatures increased significantly over the study period, with the largest changes observed in October-December and in April. Snow depths decreased particularly in forests at lower altitudes but not in treeless areas at higher altitudes. Interannual variability (but not the trends) in snow depths could be partially linked to large-scale climate indices. A majority of difficult reindeer grazing conditions were related to deep snow in the winter or spring. Our observations suggest that shortened duration of snow cover may facilitate reindeer grazing, whereas potentially more frequent formation of ice layers and mold growth on pastures in the future is disadvantageous for reindeer husbandry.

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Section: The Potential Effects Of the Changing Cold Season On Ecosystmentioning

confidence: 97%

Observed cold season changes in a Fennoscandian fell area over the past three decades

Kivinen

Rasmus

2014

AMBIO

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“…The air temperature and the temperature in the litterbags were measured from 15 November 2012 to 30 October 2013, and the following measures were calculated to clearly describe the temperature characteristics: daily mean temperature, positive accumulated temperature (sum of temperatures above 0 °C), negative accumulated temperature (sum of temperatures below 0 °C) [17,18], and the number of freeze-thaw cycles per day (one freeze-thaw cycle was completed when the threshold of 0 °C was crossed twice within at least 3 h) [34] of each critical period (Table 1). To quantify the cellulose and lignin concentrations in the litter at different critical periods, which were identified based on Olsson's period division of the cold season [35] and the field investigation of our previous To quantify the cellulose and lignin concentrations in the litter at different critical periods, which were identified based on Olsson's period division of the cold season [35] and the field investigation of our previous studies [17,18,36,37], we sampled the litterbags at the end of each critical period over the first year of litter decomposition on 26 December 2012 (snow formation period, SFP), 8 March 2013 (snow cover period, SCP), 24 April 2013 (snow melt period, SMP), and 30 October 2013 (growing season, GS). The litterbags were transported back to the laboratory for analysis.…”

Section: Experimental Designmentioning

confidence: 99%

Effects of Forest Gaps on Litter Lignin and Cellulose Dynamics Vary Seasonally in an Alpine Forest

Han

Yang

et al. 2016

Forests

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Abstract:To understand how forest gaps and the associated canopy control litter lignin and cellulose dynamics by redistributing the winter snow coverage and hydrothermal conditions in the growing season, a field litterbag trial was conducted in the alpine Minjiang fir (Abies faxoniana Rehder and E.H. Wilson) forest in a transitional area located in the upper reaches of the Yangtze River and the eastern Tibetan Plateau. Over the first year of litter decomposition, the litter exhibited absolute cellulose loss and absolute lignin accumulation except for the red birch litter. The changes in litter cellulose and lignin were significantly affected by the interactions among gap position, period and species. Litter cellulose exhibited a greater loss in the winter with the highest daily loss rate observed during the snow cover period. Both cellulose and lignin exhibited greater changes under the deep snow cover at the gap center in the winter, but the opposite pattern occurred under the closed canopy in the growing season. The results suggest that decreased snowpack seasonality due to winter warming may limit litter cellulose and lignin degradation in alpine forest ecosystems, which could further inhibit litter decomposition. As a result, the ongoing winter warming and gap vanishing would slow soil carbon sequestration from foliar litter in cold biomes.

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“…In PolarVPRM, snow season R is calculated according to soil temperature, rather than air temperature, because rates of subnivean respiration are driven primarily by soil temperature rather than air temperature (Grogan and Jonasson, 2006;Panikov et al, 2006;Sullivan et al, 2008;Morgner et al, 2010). Arctic field studies have shown that a large portion of annual carbon efflux can occur during the snow season (Aurela et al, 2004;Sullivan et al, 2008;Elberling and Brandt, 2003), and that the low thermal conductivity of an overlying snowpack (e.g., 0.06 W (m • C) −1 ; Sturm, 1992) substantially decouples Arctic soil and air temperatures, e.g., by 10-40 • C; (Zimov et al, 1993), or by 15-20 • C; (Olsson et al, 2003).…”

Section: Respirationmentioning

confidence: 99%

“…Arctic field studies have shown that a large portion of annual carbon efflux can occur during the snow season (Aurela et al, 2004;Sullivan et al, 2008;Elberling and Brandt, 2003), and that the low thermal conductivity of an overlying snowpack (e.g., 0.06 W (m • C) −1 ; Sturm, 1992) substantially decouples Arctic soil and air temperatures, e.g., by 10-40 • C; (Zimov et al, 1993), or by 15-20 • C; (Olsson et al, 2003). Calculating snow season R according to soil temperature, rather than setting R to a low constant value like in VPRM, is therefore likely to better capture inter-annual and seasonal variability in snow season NEE, and reduce uncertainty in annual Arctic C budgets (Luus et al, 2013c).…”

Section: Respirationmentioning

confidence: 99%

The Polar Vegetation Photosynthesis and Respiration Model: a parsimonious, satellite-data-driven model of high-latitude CO<sub>2</sub> exchange

Luus

Lin

2015

Geosci. Model Dev.

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Abstract. We introduce the Polar Vegetation Photosynthesis and Respiration Model (PolarVPRM), a remote-sensingbased approach for generating accurate, high-resolution ( ≥ 1 km 2 , 3 hourly) estimates of net ecosystem CO 2 exchange (NEE). PolarVPRM simulates NEE using polarspecific vegetation classes, and by representing high-latitude influences on NEE, such as the influence of soil temperature on subnivean respiration. We present a description, validation and error analysis (first-order Taylor expansion) of PolarVPRM, followed by an examination of per-pixel trends (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) in model output for the North American terrestrial region north of 55 • N. PolarVPRM was validated against eddy covariance (EC) observations from nine North American sites, of which three were used in model calibration. Comparisons of EC NEE to NEE from three models indicated that PolarVPRM displayed similar or better statistical agreement with eddy covariance observations than existing models showed. Trend analysis (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) indicated that warming air temperatures and drought stress in forests increased growing season rates of respiration, and decreased rates of net carbon uptake by vegetation when air temperatures exceeded optimal temperatures for photosynthesis. Concurrent increases in growing season length at Arctic tundra sites allowed for increases in photosynthetic uptake over time by tundra vegetation. PolarVPRM estimated that the North American high-latitude region changed from a carbon source (2001)(2002)(2003)(2004) to a carbon sink (2005)(2006)(2007)(2008)(2009)(2010) to again a source (2011)(2012) in response to changing environmental conditions.

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Five Stages of the Alaskan Arctic Cold Season with Ecosystem Implications

Cited by 87 publications

References 40 publications

Observed cold season changes in a Fennoscandian fell area over the past three decades

Observed cold season changes in a Fennoscandian fell area over the past three decades

Effects of Forest Gaps on Litter Lignin and Cellulose Dynamics Vary Seasonally in an Alpine Forest

The Polar Vegetation Photosynthesis and Respiration Model: a parsimonious, satellite-data-driven model of high-latitude CO<sub>2</sub> exchange

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Five Stages of the Alaskan Arctic Cold Season with Ecosystem Implications

Cited by 87 publications

References 40 publications

Observed cold season changes in a Fennoscandian fell area over the past three decades

Observed cold season changes in a Fennoscandian fell area over the past three decades

Effects of Forest Gaps on Litter Lignin and Cellulose Dynamics Vary Seasonally in an Alpine Forest

The Polar Vegetation Photosynthesis and Respiration Model: a parsimonious, satellite-data-driven model of high-latitude CO&lt;sub&gt;2&lt;/sub&gt; exchange

Contact Info

Product

Resources

About

The Polar Vegetation Photosynthesis and Respiration Model: a parsimonious, satellite-data-driven model of high-latitude CO<sub>2</sub> exchange