Impact of densely distributed debris flow dams on river morphology of the Grand Canyon of the Nu River (upper Salween River) at the east margin of the Tibetan Plateau

Abstract. Due to their properties of bioaccumulation, toxicity, and long-range atmospheric transport, poly and per-fluoroalkylsubstances (PFASs), and cyclic volatile methyl silxoanes (cVMS) are currently being considered as emerging persistent organic pollutants (POPs) for regulation. To date, there are limited data on PFASs and cVMS in the atmosphere of the Tibetan Plateau (TP), a remote environment which can provide information on global background conditions. Sorbent-impregnated polyurethane foam (SIP) disk passive air samplers were therefore deployed for three months (May to July 2011 and 2013) at 16 locations across the TP. Using previously reported methods for estimating the air volume sampled by SIP disks, the derived atmospheric concentrations ranged as follows: 18–565 ng/m3 for ∑cVMS (including D3, D4, D5, and D6); 65–223 pg/m3 for fluorotelomer alcohols (∑FTOHs); 1.2–12.8 pg/m3 for fluorinated sulfonamides (∑FOSA); and 0.29–1.02 pg/m3 for fluorinated sulfonamidoethanols (∑FOSE). The highest ∑cVMS occurred at Lhasa, the capital city of the TP, indicating the local contribution to the emerging pollutants. Higher levels of ∑FTOHs were observed at sites close to the transport channel of the Yarlung Tsangpo Grand Canyon, indicating possible long-range atmospheric transport (LRAT). Elevated concentrations of shorter-chain volatile PFAS precursors (4 : 2 FTOH and fluorobutane sulfonamidoethanol) were found in most air samples, reflecting the shift in production from long- to short-chain PFASs in Asia. Overall, concentrations of emerging POPs at background sites of the TP were 1–3 orders of magnitude higher than those reported for legacy POPs.

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Occurrence and spatial distribution of neutral perfluoroalkyl substances and cyclic volatile methylsiloxanes in the atmosphere of the Tibetan Plateau

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-8745-2018 ◽

2018 ◽

Vol 18 (12) ◽

pp. 8745-8755 ◽

Cited By ~ 16

Author(s):

Xiaoping Wang ◽

Jasmin Schuster ◽

Kevin C. Jones ◽

Ping Gong

Keyword(s):

Tibetan Plateau ◽

Long Range ◽

Atmospheric Transport ◽

Grand Canyon ◽

Capital City ◽

Perfluoroalkyl Substances ◽

The Tibetan Plateau ◽

Transport Channel ◽

Remote Environment ◽

Global Background

Abstract. Due to their properties of bioaccumulation, toxicity, and long-range atmospheric transport, polyfluoroalkyl and perfluoroalkyl substances (PFASs) and cyclic volatile methylsiloxanes (cVMSs) are currently being considered as emerging persistent organic pollutants (POPs) for regulation. To date, there are limited data on PFASs and cVMSs in the atmosphere of the Tibetan Plateau (TP), a remote environment which can provide information on global background conditions. Sorbent-impregnated polyurethane foam (SIP) disc passive air samplers were therefore deployed for 3 months (May to July 2011 and 2013) at 16 locations across the TP. Using previously reported methods for estimating the air volume sampled by SIP discs, the derived atmospheric concentrations ranged as follows: 18–565 ng m−3 for ΣcVMS (including D3, D4, D5, and D6); 65–223 pg m−3 for fluorotelomer alcohols (ΣFTOHs); 1.2–12.8 pg m−3 for fluorinated sulfonamides (ΣFOSA); and 0.29–1.02 pg m−3 for fluorinated sulfonamidoethanols (ΣFOSE). The highest ΣcVMS occurred at Lhasa, the capital city of the TP, indicating the local contribution to the emerging pollutants. Higher levels of ΣFTOHs were observed at sites close to the transport channel of the Yarlung Tsangpo Grand Canyon, indicating possible long-range atmospheric transport (LRAT). Elevated concentrations of shorter-chain volatile PFAS precursors (4 : 2 FTOH and fluorobutane sulfonamidoethanol) were found in most air samples, reflecting the shift in production from long- to short-chain PFASs in Asia. Overall, concentrations of emerging POPs at background sites of the TP were 1–3 orders of magnitude higher than those reported for legacy POPs.

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Evaluation of a Convection-Permitting Modeling of Precipitation over the Tibetan Plateau and Its Influences on the Simulation of Snow-Cover Fraction

Journal of Hydrometeorology ◽

10.1175/jhm-d-19-0277.1 ◽

2020 ◽

Vol 21 (7) ◽

pp. 1531-1548 ◽

Cited By ~ 3

Author(s):

Yanhong Gao ◽

Fei Chen ◽

Yingsha Jiang

Keyword(s):

High Resolution ◽

Tibetan Plateau ◽

Snow Cover ◽

Land Surface ◽

Grand Canyon ◽

Added Value ◽

The Tibetan Plateau ◽

Precipitation Data ◽

Snow Cover Fraction

AbstractPrecipitation is a critical input to land surface and hydrology modeling and prediction. Dynamical downscale modeling has added value to representing precipitation, when compared with the performance of coarse-resolution reanalysis and global climate models, over the Tibetan Plateau (TP). Convection-permitting modeling (CPM) may even outperform dynamical downscale models (DDMs). In this study, 4-km CPM results were compared to 28-km DDM results for a snow season (1 October 2013–31 May 2014) over the TP. The CPM- and DDM-simulated precipitation, as well as three merged gridded precipitation datasets, were evaluated against in situ observations below 4800 m. The five precipitation datasets (CPM, DDM, CMFD, COPRPH, and TRMM) showed large differences over the TP with underestimation of TRMM and overestimation of CPM and DDM compared to observations. The most significant difference occurred in the Brahmaputra Grand Canyon. Given the substantial uncertainty in observed precipitation at high mountains, snow cover simulated by a high-resolution land data assimilation system was used to indirectly evaluate the above precipitation data using MODIS observations. Simulated snow-cover fraction was greatly underestimated using all the merged precipitation datasets. However, simulations using the DDM- and CPM-generated precipitation as input outperformed those using other gridded precipitation data, showing lower biases, higher pattern correlations, and closer probability distribution functions than runs driven by the merged precipitation. The findings of this study generally support the assumption that high-resolution CPM-produced precipitation has an added value for use in land surface and hydrology simulations in high-mountain regions without reliable in situ precipitation observations.

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