DOI: 10.5194/cp-15-169-2019
Scopus记录号: 2-s2.0-85060844948
论文题名: Precipitation δ18O on the Himalaya-Tibet orogeny and its relationship to surface elevation
作者: Shen H. ; Poulsen C.J.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2019
卷: 15, 期: 1 起始页码: 169
结束页码: 187
语种: 英语
英文摘要: The elevation history of the Himalaya-Tibet orogen is central to understanding the evolution and dynamics of both the India-Asia collision and the Asian monsoons. The surface elevation history of the region is largely deduced from stable isotope (δ18O, δD) paleoaltimetry. This method is based on the observed relationship between the isotopic composition of meteoric waters (δ18Op, δDp) and surface elevation, and the assumption that precipitation undergoes Rayleigh distillation under forced ascent. Here we evaluate how elevation-induced climate change influences the δ18Op-elevation relationship and whether Rayleigh distillation is the dominant process affecting δ18Op. We use an isotope-enabled climate model, ECHAM-wiso, to show that the Rayleigh distillation process is only dominant in the monsoonal regions of the Himalayas when the mountains are high. When the orogen is lowered, local surface recycling and convective processes become important, as forced ascent is weakened due to weaker Asian monsoons. As a result, the δ18Op lapse rate in the Himalayas increases from around -3 to above -0.1‰km, and has little relationship with elevation. On the Tibetan Plateau, the meridional gradient of δ18O decreases from ∼ 1 to ∼ 0.3‰o-1 with reduced elevation, primarily due to enhanced sub-cloud reevaporation under lower relative humidity. Overall, we report that using δ18Op or δDp to deduce surface elevation change in the Himalayan-Tibetan region has severe limitations and demonstrate that the processes that control annual-mean precipitation-weighted δ18Op vary by region and with surface elevation. In summary, we determine that the application of δ18O paleoaltimetry is only appropriate for 7 of the 50 sites from which δ18O records have been used to infer past elevations. © Author(s) 2019. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/122248
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, 48109, United States
Recommended Citation:
Shen H.,Poulsen C.J.. Precipitation δ18O on the Himalaya-Tibet orogeny and its relationship to surface elevation[J]. Climate of the Past,2019-01-01,15(1)