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 ma.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 m2 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 pre-monsoon 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.
Highlights
Carbonaceous aerosols play an important role in Earth’s climate system and energy budget (Bond et al, 2007, 2013; Schuckmann et al, 2016)
The winter season and post-monsoon season had higher concentrations of carbonaceous matter in the total suspended particulates (TSP) during the 2 years, which is consistent for elemental carbon (EC), organic carbon (OC), and POC
It is quite likely that frequent rainfall events with occasional dust (e.g., Dong et al, 2011; Niu et al, 2014) from anthropogenic activities (Shrestha et al, 2000) during the monsoon in 2015 are responsible for this unusual phenomenon
Summary
Carbonaceous aerosols play an important role in Earth’s climate system and energy budget (Bond et al, 2007, 2013; Schuckmann et al, 2016). In the low-latitude and high-elevation areas, extensive incoming solar radiation and large amount of carbonaceous aerosol deposited on snowpack and glaciers result in surface albedo reduction and the retreat of glaciers in the TP, and this further affects Asian hydrological cycle and monsoon climate (Qian et al, 2011; Qu et al, 2014; Li et al, 2016a). This is closely related to water resources for a large population of local habitants in South Asia (Ramanathan et al, 2005, 2007). It is rather important and necessary to carry out carbonaceous aerosol studies in glacierization regions
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