Search

Your search keyword '"Shao, Yaping"' showing total 538 results
Start Over Author "Shao, Yaping"
538 results on '"Shao, Yaping"'

14. CFD simulation of the wind field over a terrain with sand fences: Critical spacing for the protected soil area

Author

Lima, Izael A., Parteli, Eric J. R., Shao, Yaping, Andrade Jr., José S., Herrmann, Hans J., and Araújo, Ascânio D.

Subjects
Physics - Fluid Dynamics
Abstract

Sand fences are often erected to reduce wind speed, prevent aeolian soil erosion, and induce sand deposition and dune formation in areas affected by sand encroachment and desertification. However, the search for the most efficient array of fences by means of field experiments alone poses a challenging task given that field experiments are affected by weather conditions. Here we apply Computational Fluid Dynamic simulations to investigate the three-dimensional structure of the turbulent wind field over an array of fences of different sizes, porosity and spacing. Our goal is to perform a quantitative analysis of this structure in the absence of saltation or suspension transport, as first step toward the development of a continuum simulation of the aeolian soil in presence of the fences. We find that the area of soil protected against direct aerodynamic entrainment has two regimes, depending on the spacing $L_x$ between the fences. When $L_x$ is smaller than a critical value $L_{xc}$, the wake zones associated with each fence are inter-connected (regime A), while these wake zones appear separated from each other (regime B) when $L_x$ exceeds this critical value of spacing. The system undergoes a second order phase transition at $L_x = L_{xc}$, with the cross-wind width of the protected zone scaling with $\left[{1-{L}_x}/{L}_{xc}\right]^\beta$ in regime A, with $\beta \approx 0.32$. Our findings have implication for a better understanding of aeolian transport in the presence of sand fences, as well as to develop optimization strategies for measures to protect soils from wind erosion., Comment: 35 pages, 13 figures

Published
2018

18. Using Iron Stable Isotopes to Quantify the Origins of the Cryoconite Iron Materials in Western China and Exploring Controlling Factors.

Author

Dong, Zhiwen, Wei, Ting, Parteli, Eric J. R., Liu, Xiaoli, Ren, Jiawen, and Shao, Yaping

Subjects
IRON isotopes, ANTHROPOGENIC effects on nature, BIOGEOCHEMICAL cycles, LIQUID fuels, ATMOSPHERIC deposition
Abstract

Iron (Fe) has profound impacts on Earth's ecosystem and global biogeochemical cycles. Fe deposited onto glacier surfaces reduces snow and ice albedo, thereby accelerating glacier melting, and supplying downstream ecosystems with dissolved Fe. However, the origins of atmospheric Fe deposition in glacier regions of western China remain unclear. This study presents novel insights into Fe isotopic composition (refer to δ56Fe) and origins, gained from geochemical analysis of large‐scale cryoconite samples collected from glaciers in western China, which encompass the Tibetan Plateau (TP) and the Tianshan Mountains. Results showed that cryoconite δ56Fe ranged from −1.06 ± 0.07‰ to 0.33 ± 0.04‰, regardless of their concentration. Moreover, anomalous δ56Fe values deviating significantly from the upper continental crust values (with an average of 0.09‰) were detected, indicating a significant impact of anthropogenic Fe materials on the investigated glaciers. This impact was particularly prominent in the margin regions of the TP and its surroundings, but was less apparent in the interior and southern of the plateau. Using MixSIAR isotope mixing model, we determined that coal combustion and other anthropogenic combustion sources (such as liquid fuel combustion and steel smelting) contributed to cryoconite Fe in the range of 6.9%–43.1% and 0.8%–23.4%, respectively. Among these, coal combustion was the predominant anthropogenic source of cryoconite Fe in western China's glaciers. Compared with other sink areas in the Northern Hemisphere, glaciers in western China are obviously affected by anthropogenically sourced Fe. This study has significant implications for understanding glacier‐fed downstream ecosystems and the regional biogeochemical cycle. Plain Language Summary: Iron (Fe) has profound impacts on snow/ice albedo and the biogeochemical cycle of downstream ecosystems in glacier basins. However, the origins of atmospheric Fe deposition in remote glacier regions of western China remain unclear. Fe isotopes (refer to δ56Fe), serve as a distinctive tool for tracing the sources of aerosol Fe materials that leave their mark on glaciers. Based on a comprehensive data set of Fe isotopes within cryoconite samples collected from 12 high‐altitude glaciers spanning a broad spatial range in western China, this study found that remote glaciers in western China are significantly affected by anthropogenically sourced Fe, with potential implications for glacier‐fed downstream ecosystems and the regional biogeochemical cycle. Key Points: Remote glaciers in western China are significantly affected by anthropogenically sourced FeAnthropogenic Fe impact is particularly prominent in the marginal glacier regions of western ChinaCoal combustion provides the main anthropogenic source of cryoconite Fe in western China's glaciers [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results