Effects of Elevated Air Temperatures on Soil Thermal and Hydrologic Processes in the Active Layer in an Alpine Meadow Ecosystem of the Qinghai-Tibet Plateau

被引:0
作者
BAI Wei 1
机构
基金
美国国家科学基金会;
关键词
Thermal and hydrologic process; Temperature; Open-top chambers; Alpine meadow; Qinghai-Tibetan Plateau;
D O I
暂无
中图分类号
P339 [水文循环与水文气象];
学科分类号
081501 ;
摘要
In this study,effects of elevated air temperatures on thermal and hydrologic process of the shallow soil in the active layer were investigated. Open-top chambers(OTCs)were utilized to increase air temperatures 1-2℃ in OTC-1 and 3-5℃ in OTC-2 in the alpine meadow ecosystem on the Qinghai- Tibetan Plateau.Results show that the annual air temperatures under OTC-1 and OTC-2 were 1.21℃ and 3.62℃ higher than the Control,respectively.The entirely-frozen period of shallow soil in the active layer was shortened and the fully thawed period was prolonged with temperature increase.The maximum penetration depth and duration of the negative isotherm during the entirely-frozen period decreased, and soil freezing was retarded in the local scope of the soil profile when temperature increased.Meanwhile, the positive isotherm during the fully-thawed period increased,and the soil thawing was accelerated.Soil moisture under different manipulations decreased with the temperature increase at the same depth. During the early freezing period and the early fully- thawed period,the maximum soil moisture under the Control manipulation was at 0.2 m deep,whereas under OTC-1 and OTC-2 manipulations,the maximum soil moisture were at 0.4-0.5 m deep. These results indicate that elevated temperatures led to a decrease of the moisture in the surface soil.The coupled relationship between soil temperature and moisture was significantly affected by the temperature increase.During the freezing and thawing processes, the soil temperature and moisture under different manipulations fit the regression model given by the equationθV=a/{1+exp[b(TS+c)]}+d.
引用
收藏
页码:243 / 255
页数:13
相关论文
共 41 条
  • [1] Alpine Meadow Ecosystem and Global Chang. Zhao XQ. Science Press . 2009
  • [2] 青藏高原典型寒冻土壤对高寒生态系统变化的响应
    王一博
    王根绪
    程玉菲
    李元寿
    [J]. 冰川冻土, 2006, (05) : 633 - 641
  • [3] 近40年来青藏高原典型高寒湿地系统的动态变化
    王根绪
    李元寿
    王一博
    陈玲
    [J]. 地理学报, 2007, (05) : 481 - 491
  • [4] Thawing sub-arctic permafrost: Effects onvegetation and methane emissions. Christensen TR,Johansson TR,Akerman HJ, et al. Geophysical Research Letters . 2004
  • [5] Vegetation-soil-thaw-depth relationships along a low arctic bioclimate gradient, Alaska: synthesis of information from the ATLAS studies. D.A. Walker,G.J. Jia,H.E. Epstein. Permafrost and Periglacial Processes . 2003
  • [6] Climate effects on mountain plants. Grabherr G,Gottfried M,Pauli H. Nature . 1994
  • [7] Influence of vegetationcoverage on water and heat processes of the active layer inpermafrost regions of the Tibetan Plateau. Liu GS,Wang GX,Hu HC,et al. Journal ofGlaciology and Geocryology . 2009
  • [8] Short-term response of methane fluxes and methanogen activity towater table and soil warming manipulations in an Alaskan peatland. Turetsky, M.R,Treat, C.C,Waldrop, M.P,Waddington, J.M,Harden, J.W,McGuire, A.D. Chinese Journal of Geophysics . 2008
  • [9] Impact of snow cover on soil temperature and its simulation in a boreal aspen forest. Zhang Y S,Wang S S,Barr A G,et al. Cold Regions Science and Technology . 2008
  • [10] Heat and water difference of active layers beneath different surface conditions near Beiluhe in Qing- hai-Xizang Plateau. Lu Z J,Wu Q B,Sheng Y, et al. J Glaciol Geocryol . 2006