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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/acp-2017-209
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
03 Apr 2017
Review status
This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).
Reevaluating the black carbon in the Himalayan and Tibetan Plateau: concentration and deposition
Chaoliu Li1,3,4, Fangping Yan3, Shichang Kang2,4, Pengfei Chen2, Xiaowen Han1,5, Zhaofu Hu2,5, Guoshuai Zhang1, Ye Hong6, Shaopeng Gao1, Bin Qu3, and Mika Sillanpää3,7 1Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
2State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
3Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, Mikkeli 50130, Finland
4CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China
5University of Chinese Academy of Sciences, Beijing 100049, China
6Institute of Atmospheric Environment, China Meteorological Admi nistration, Shenyang 110166, China
7Department of Civil and Environmental Engineering, Florida Inte rnational University, Miami, FL-33174, USA
Abstract. Black carbon (BC) is the second most important warming component in the atmosphere after CO2. The BC in the Himalayan and Tibetan Plateau (HTP) has shaped the evolution of the Indian Monsoon and accelerated the retreat of glaciers, thereby resulting in serious consequences for billions of Asian residents. Although a number of related studies of this region have been conducted, the BC concentration and deposition indexes remain poorly understood. Because of the presence of arid environments and the potential influence of carbonates from mineral dust (MD), the reported concentrations of BC from the HTP are overestimated. In addition, large discrepancies in the deposition of BC have been reported from lake cores, ice cores, snowpits and models. Therefore, the actual BC concentration and deposition values in this sensitive region must be determined. A comparison between the BC values of acid (HCl) fumigated and original aerosol samples from the HTP showed that the BC concentrations previously reported for the Namco station (central part of the HTP) and the Everest station (northern slope of the central Himalayas) were overestimated by approximately 47 ± 37 % and 35 ± 26 %, respectively, because of the influence of carbonates from MD. Additionally, the organic carbon (OC) levels were overestimated by roughly 22 ± 10 % and 22 ± 12 % for the same reason. Based on previously reported values from these two areas, we propose that the actual BC concentrations at the Namco and Everest stations are 44 ng m−3 and 164 ng m−3, respectively. Second, a comprehensive comparison of the BC deposition levels obtained via different methods indicated that the BC deposits derived from lake cores of the HTP were mainly caused by river sediments transported from the lake basin as a result of climate change (e.g., increases in temperature and precipitation), and fewer BC deposits were related to atmospheric deposition. Therefore, previously reported BC deposition levels from lake cores overestimated the atmospheric deposition of BC in the HTP. Correspondingly, BC deposition derived from snowpit, ice core and model from the HTP were not only agree very well with each other, but also were close to those of other remote areas (e.g., Arctic), implying that the BC deposits calculated from these three methods reflect the actual values. Therefore, based on reported values of snowpits and ice cores, we propose that the BC deposits of the HTP range from 10 mg m−2 a−1 to 25 mg m−2 a−1, with high and low values appearing along the fringes and central areas of the HTP, respectively. The adjusted BC concentration and deposition values in the HTP observed here are critical for performing accurate evaluations of other indexes of BC such as atmospheric distribution, radiative forcing and chemical transport in the HTP.

Citation: Li, C., Yan, F., Kang, S., Chen, P., Han, X., Hu, Z., Zhang, G., Hong, Y., Gao, S., Qu, B., and Sillanpää, M.: Reevaluating the black carbon in the Himalayan and Tibetan Plateau: concentration and deposition, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2017-209, in review, 2017.
Chaoliu Li et al.
Chaoliu Li et al.
Chaoliu Li et al.

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Short summary
In this study, we found because of influence of carbonates, previously reported BC concentration in atmosphere of the Himalayan and Tibetan Plateau (HTP) were overestimated by approximately 40 %. Meanwhile, we found BC deposition of lake cores overestimated the atmospheric deposition of BC in the HTP; BC depositions of glacier region reflected actual values of 10–25 mg m−2 a−1. The above results are critical for studying atmospheric distribution and chemical transport of BC in and around the HTP.
In this study, we found because of influence of carbonates, previously reported BC concentration...
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