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21 results on '"Niu, Hewen"'

5. A Study of Chemical Processes of Nitrate in Atmospheric Aerosol and Snow Based on Stable Isotopes.

Author

Chen, Mengxue, Niu, Hewen, and Xiang, Yankun

Subjects
*CHEMICAL processes, *ATMOSPHERIC aerosols, *STABLE isotopes, *SNOW chemistry, *POLLUTANTS
Abstract

Nitrate (NO3−) is a prominent atmospheric pollutant and a key chemical constituent of snow and ice, which plays a crucial role in the atmosphere and significantly impacts regional climate and environment conditions through a series of complex chemical processes. By summarizing the recent research progress on the nitrate chemical process (particularly on the isotopic measurements of NO3− (δ15N, Δ17O and δ18O)) in atmosphere and glacier snow, this study mainly investigated the chemical compositions and chemical processes, formation pathways, and photochemical reactions of nitrate in snow and atmosphere. Our results identified that the main ways of atmospheric nitrate formation are the hydrolysis of N2O5 and the reaction of ·OH with NO2; the spatial distribution of Δ17O and δ18O values of atmospheric nitrate have a significant latitudinal trend between 30° N–60° N; the study of stable isotopes (δ15N and δ18O) and the oxygen isotope anomaly (Δ17O) of nitrate have mainly been carried out over the densely populated and coastal mega cities; there exist significant gaps in the study of chemistry processes of nitrate in snow and ice and the air–snow interfaces across glaciated regions. This study provides a basic reference for more robust observations and research of nitrate in glacier areas in the future. [ABSTRACT FROM AUTHOR]

Published
2024
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8. Black carbon and organic carbon dataset over the Third Pole

Author

Kang, Shichang, primary, Zhang, Yulan, additional, Chen, Pengfei, additional, Guo, Junming, additional, Zhang, Qianggong, additional, Cong, Zhiyuan, additional, Kaspari, Susan, additional, Tripathee, Lekhendra, additional, Gao, Tanguang, additional, Niu, Hewen, additional, Zhong, Xinyue, additional, Chen, Xintong, additional, Hu, Zhaofu, additional, Li, Xiaofei, additional, Li, Yang, additional, Neupane, Bigyan, additional, Yan, Fangping, additional, Rupakheti, Dipesh, additional, Gul, Chaman, additional, Zhang, Wei, additional, Wu, Guangming, additional, Yang, Ling, additional, Wang, Zhaoqing, additional, and Li, Chaoliu, additional

Published
2022
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12. Carbonaceous aerosol characteristics on the Third Pole: A primary study based on the Atmospheric Pollution and Cryospheric Change (APCC) network

Author

Chen, Pengfei, primary, Kang, Shichang, additional, Li, Chaoliu, additional, Zhang, Qianggong, additional, Guo, Junming, additional, Tripathee, Lekhendra, additional, Zhang, Yulan, additional, Li, Gang, additional, Gul, Chaman, additional, Cong, Zhiyuan, additional, Wan, Xin, additional, Niu, Hewen, additional, Panday, Arnico K., additional, Rupakheti, Maheswar, additional, and Ji, Zhenming, additional

Published
2019
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19. A long-term increasing aridification and cooling trend at the Chinese Loess Plateau during the Pliocene

Author

Zhao, Guoyong, Liu, Xiuming, Chen, Qu, Lu, Bin, Chang, Liao, Niu, Hewen, Li, Pingyuan, Guo, Hui, Liu, Zhi, Zhao, Guoyong, Liu, Xiuming, Chen, Qu, Lu, Bin, Chang, Liao, Niu, Hewen, Li, Pingyuan, Guo, Hui, and Liu, Zhi

Abstract

The development of Asian aridification and cooling is a research hotspot nowadays. Loess-Red Clay sequence in the Chinese Loss Plateau provides an excellent terrestrial archive of such paleoclimatic evolution. This paper applied the magnetic "unmixing" te

Published
2013

21. Analysis of herbaceous plant succession and dispersal mechanisms in deglaciated terrain on Mt. Yulong, China.

Author

Chang L, He Y, Yang T, Du J, Niu H, and Pu T

Subjects
China, Plant Preparations isolation & purification, Ecosystem, Grassland, Ice Cover, Plant Preparations classification, Plants classification
Abstract

Ecological succession itself could be a theoretical reference for ecosystem restoration and reconstruction. Glacier forelands are ideal places for investigating plant succession because there are representative ecological succession records at long temporal scales. Based on field observations and experimental data on the foreland of Baishui number 1 Glacier on Mt. Yulong, the succession and dispersal mechanisms of dominant plant species were examined by using numerical classification and ordination methods. Fifty samples were first classified into nine community types and then into three succession stages. The three succession stages occurred about 9-13, 13-102, and 110-400 years ago, respectively. The earliest succession stage contained the association of Arenaria delavayi + Meconopsis horridula. The middle stage contained the associations of Arenaria delavayi + Kobresia fragilis, Carex capilliformis + Polygonum macrophyllum, Carex kansuensis, and also Pedicularis rupicola. The last stage included the associations of Kobresia fragilis + Carex capilliformis, Kobresia fragilis, Kobresia fragilis + Ligusticum rechingerana, and Kobresia fragilis + Ligusticum sikiangense. The tendency of the succession was from bare land to sparse vegetation and then to alpine meadow. In addition, three modes of dispersal were observed, namely, anemochory, mammalichory, and myrmecochory. The dispersal modes of dominant species in plant succession process were evolved from anemochory to zoochory.

Published
2014
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