Труды сотрудников ИЛ им. В.Н. Сукачева СО РАН

[Text] / W. . Eugster [et al.] // Glob. Change Biol. - 2000. - Vol. 6. - P84-115, DOI 10.1046/j.1365-2486.2000.06015.x. - Cited References: 132 . - 32. - ISSN 1354-1013РУБ Biodiversity Conservation + Ecology + Environmental Sciences

Аннотация: This paper summarizes and analyses available data on the surface energy balance of Arctic tundra and boreal forest. The complex interactions between ecosystems and their surface energy balance are also examined, including climatically induced shifts in ecosystem type that might amplify or reduce the effects of potential climatic change. High latitudes are characterized by large annual changes in solar input. Albedo decreases strongly from winter, when the surface is snow-covered, to summer, especially in nonforested regions such as Arctic tundra and boreal wetlands. Evapotranspiration (Q(E)) of high-latitude ecosystems is less than from a freely evaporating surface and decreases late in the season, when soil moisture declines, indicating stomatal control over Q(E), particularly in evergreen forests. Evergreen conifer forests have a canopy conductance half that of deciduous forests and consequently lower Q(E) and higher sensible heat flux (Q(H)), There is a broad overlap in energy partitioning between Arctic and boreal ecosystems, although Arctic ecosystems and light taiga generally have higher ground heat flux because there is less leaf and stem area to shade the ground surface, and the thermal gradient from the surface to permafrost is steeper. Permafrost creates a strong heat sink in summer that reduces surface temperature and therefore heat flux to the atmosphere. Loss of permafrost would therefore amplify climatic warming. If warming caused an increase in productivity and leaf area, or fire caused a shift from evergreen to deciduous forest, this would increase Q(E) and reduce Q(H). Potential future shifts in vegetation would have varying climate feedbacks, with largest effects caused by shifts from boreal conifer to shrubland or deciduous forest (or vice versa) and from Arctic coastal to wet tundra. An increase of logging activity in the boreal forests appears to reduce Q(E) by roughly 50% with little change in Q(H), while the ground heat flux is strongly enhanced.

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Держатели документа:
Univ Bern, Inst Geog, CH-3012 Bern, Switzerland
McMaster Univ, Sch Geog & Geol, Hamilton, ON L8S 4K1, Canada
Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA
Univ Calif Berkeley, Dept Integrat Biol, Berkeley, CA 94720 USA
NOAA, ERL, ATDD, Oak Ridge, TN 37831 USA
Natl Ctr Atmospher Res, Boulder, CO 80307 USA
Univ Alaska, Inst Arctic Biol, Fairbanks, AK 99775 USA
Russian Acad Sci, Inst Forestry, Krasnoyarsk 660036, Russia

Доп.точки доступа:
Eugster, W...; Rouse, W.R.; Pielke, R.A.; McFadden, J.P.; Baldocchi, D.D.; Kittel, TGF; Chapin, F.S.; Liston, G.E.; Vidale, P.L.; Vaganov, E...; Chambers, S...