Seasonal variation and light absorption property of carbonaceous aerosol in a typical glacier region of the southeastern Tibetan Plateau

Abstract

Abstract. Deposition and accumulation of light-absorbing carbonaceous aerosol on glacier surfaces can alter the energy balance of glaciers. In this study, 2 years (December 2014 to December 2016) of continuous observations of carbonaceous aerosols in the glacierized region of the Mt. Yulong and Ganhaizi (GHZ) basin are analyzed. The average elemental carbon (EC) and organic carbon (OC) concentrations were 1.51 ± 0.93 and 2.57 ± 1.32 µg m −3 , respectively. Although the annual mean OC / EC ratio was 2.45 ± 1.96, monthly mean EC concentrations during the post-monsoon season were even higher than OC in the high altitudes (approximately 5000 m a.s.l.) of Mt. Yulong. Strong photochemical reactions and local tourism activities were likely the main factors inducing high OC / EC ratios in the Mt. Yulong region during the monsoon season. The mean mass absorption efficiency (MAE) of EC, measured for the first time in Mt. Yulong, at 632 nm with a thermal-optical carbon analyzer using the filter-based method, was 6.82 ± 0.73 m 2 g −1 , comparable with the results from other studies. Strong seasonal and spatial variations of EC MAE were largely related to the OC abundance. Source attribution analysis using a global aerosol-climate model, equipped with a black carbon (BC) source tagging technique, suggests that East Asia emissions, including local sources, have the dominant contribution (over 50 %) to annual mean near-surface BC in the Mt. Yulong area. There is also a strong seasonal variation in the regional source apportionment. South Asia has the largest contribution to near-surface BC during the premonsoon season, while East Asia dominates the monsoon season and post-monsoon season. Results in this study have great implications for accurately evaluating the influences of carbonaceous matter on glacial melting and water resource supply in glacierization areas.

Distributions and light absorption property of water soluble organic carbon in a typical temperate glacier, southeastern Tibetan Plateau

“…While the mean OC concentration in surface aged snow and granular ice was 2090 ± 568 ng g À1 and 4304 ± 358 ng g À1 , respectively. BC and OC deposited on the snow and glaciers were widely considered as insoluble light-absorbing impurities (ILAIs) (Wang et al, 2017;Niu et al, 2018). ILAIs combined with WSOC in snow and glacier can be defined as lightabsorbing matter (LAM), which considerably reduces snow spectral albedo, absorbs large amount of solar energy, and accelerates the retreat of glaciers.…”

In Situ Observations of Light‐Absorbing Carbonaceous Aerosols at Himalaya: Analysis of the South Asian Sources and Trans‐Himalayan Valleys Transport Pathways

“…In the past decade, aerosol measurements in the HTP were mostly conducted at observation stations far from the trans‐Himalayan valleys (Kang et al, 2019; B. Liu et al, 2017; Niu et al, 2018; J. F. Wang et al, 2017; G. M. Wu et al, 2018). Various samplers and online instruments could be run steadily at the observation stations with continuous electric power supply.…”

Deposition of Organic and Black Carbon: Direct Measurements at Three Remote Stations in the Himalayas and Tibetan Plateau

“…Currently, research on carbonaceous matter in the Himalayas and Tibetan Plateau has become a hot spot due to its important role in the climate system and the effect on the albedo of ice and snow in the glacier region after deposition (He, Li, Liou, Takano, et al, ; He, Li, Liou, Zhang, et al, ; He et al, ; Kaspari et al, ; Ming et al, ; Qian et al, ). To date, many studies related to carbonaceous matter have been conducted in this area, with a focus on sources, concentration variations (Cao et al, ; Chen et al, ; Cong et al, ; Ming et al, , ; Xu et al, ; Zhang et al, ), optical properties (Li, Yan, Kang, Chen, Hu, et al, ; Li, Yan, Kang, Chen, Hu, et al, ; Niu et al, ; Wang et al, ; Yan et al, ), carbon isotopic compositions (Huang et al, ; Li, Bosch, et al, ; Li, Chen, et al, ), and historical profiles (Kaspari et al, ). Nevertheless, direct measurements of the wet and dry depositions of carbonaceous matter in this remote and sensitive region are limited.…”