干旱区生态环境知识资源中心(Arid): Water tracks intensify surface energy and mass exchange in the Antarctic McMurdo Dry Valleys

Arid

DOI	10.5194/tc-13-2203-2019
	Water tracks intensify surface energy and mass exchange in the Antarctic McMurdo Dry Valleys
	Linhardt, Tobias 1; Levy, Joseph S.2; Thomas, Christoph K.1,3
通讯作者	Linhardt, Tobias
来源期刊	CRYOSPHERE
ISSN	1994-0416
EISSN	1994-0424
出版年	2019
卷号	13 期号:8 页码:2203-2219
英文摘要	The hydrologic cycle in the Antarctic McMurdo Dry Valleys (MDV) is mainly controlled by surface energy balance. Water tracks are channel-shaped high-moisture zones in the active layer of permafrost soils and are important solute and water pathways in the MDV. We evaluated the hypothesis that water tracks alter the surface energy balance in this dry, cold, and ice-sheet-free environment during summer warming and may therefore be an increasingly important hydrologic feature in the MDV in the face of landscape response to climate change. The surface energy balance was measured for one water track and two off-track reference locations in Taylor Valley over 26 d of the Antarctic summer of 2012-2013. Turbulent atmospheric fluxes of sensible heat and evaporation were observed using the eddy-covariance method in combination with flux footprint modeling, which was the first application of this technique in the MDV. Soil heat fluxes were analyzed by measuring the heat storage change in the thawed layer and approximating soil heat flux at ice table depth by surface energy balance residuals. For both water track and reference locations over 50 % of net radiation was transferred to sensible heat exchange, about 30 % to melting of the seasonally thawed layer, and the remainder to evaporation. The net energy flux in the thawed layer was zero. For the water track location, evaporation was increased by a factor of 3.0 relative to the reference locations, ground heat fluxes by 1.4, and net radiation by 1.1, while sensible heat fluxes were reduced down to 0.7. Expecting a positive snow and ground ice melt response to climate change in the MDV, we entertained a realistic climate change response scenario in which a doubling of the land cover fraction of water tracks increases the evaporation from soil surfaces in lower Taylor Valley in summer by 6 % to 0.36 mm d(-1). Possible climate change pathways leading to this change in landscape are discussed. Considering our results, an expansion of water track area would make new soil habitats accessible, alter soil habitat suitability, and possibly increase biological activity in the MDV. In summary, we show that the surface energy balance of water tracks distinctly differs from that of the dominant dry soils in polar deserts. With an expected increase in area covered by water tracks, our findings have implications for hydrology and soil ecosystems across terrestrial Antarctica.
类型	Article
语种	英语
国家	Germany ; USA
开放获取类型	Green Submitted, gold, Green Published
收录类别	SCI-E
WOS记录号	WOS:000481989700003
WOS关键词	TAYLOR VALLEY ; POLAR DESERT ; ACTIVE-LAYER ; PERMAFROST ; LANDSCAPE ; HEAT ; FLUX ; GEOCHEMISTRY ; TEMPERATURE ; ECOSYSTEMS
WOS类目	Geography, Physical ; Geosciences, Multidisciplinary
WOS研究方向	Physical Geography ; Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/215004
作者单位	1.Univ Bayreuth, Micrometeorol Grp, Bayreuth, Bavaria, Germany; 2.Colgate Univ, Dept Geol, Hamilton, NY 13346 USA; 3.Univ Bayreuth, Bayreuth Ctr Ecol & Environm Res BayCEER, Bayreuth, Bavaria, Germany
推荐引用方式 GB/T 7714	Linhardt, Tobias,Levy, Joseph S.,Thomas, Christoph K.. Water tracks intensify surface energy and mass exchange in the Antarctic McMurdo Dry Valleys[J],2019,13(8):2203-2219.
APA	Linhardt, Tobias,Levy, Joseph S.,&Thomas, Christoph K..(2019).Water tracks intensify surface energy and mass exchange in the Antarctic McMurdo Dry Valleys.CRYOSPHERE,13(8),2203-2219.
MLA	Linhardt, Tobias,et al."Water tracks intensify surface energy and mass exchange in the Antarctic McMurdo Dry Valleys".CRYOSPHERE 13.8(2019):2203-2219.