Abstract
Abstract. The deposition of insoluble light-absorbing particles (ILAPs) on snow and ice surfaces can significantly reduce albedo, thereby accelerating the melting process. In this study, 67 ice samples were collected from seven glaciers located on the Tibetan Plateau (TP) between May 2013 and October 2015. The mixing ratios of black carbon (BC), organic carbon (OC), and mineral dust (MD) were measured with an integrating sphere/integrating sandwich spectrophotometer (ISSW) system, which assumes that the light absorption of MD is due to iron oxide (Fe). Our results indicate that the mass-mixing ratios of BC, OC, and Fe exhibit considerable variability (BC: 10–3100 ng g−1; OC: 10–17 000 ng g−1; Fe: 10–3500 ng g−1) with respective mean values of 220±400 ng g−1, 1360±2420 ng g−1, and 240±450 ng g−1 over the course of the field campaign. We observed that for wavelengths of 450–600 nm, the measured light absorption can be largely attributed to the average light absorption of BC (50.7 %) and OC (33.2 %). Chemical elements and selected carbonaceous particles were also analyzed for source attributions of particulate light absorption based on a positive matrix factorization (PMF) receptor model. Our findings indicate that on average, industrial pollution (33.1 %), biomass or biofuel burning (29.4 %), and MD (37.5 %) constitute the principal sources of ILAPs deposited on TP glaciers.
Highlights
The specific light absorption of black carbon (BC) is higher in snow than in the atmosphere because of the higher degree of sunlight scattering in the former (Chylek et al, 1984), and a wealth of evidence confirms that the snow albedo is dominated by BC at visible wavelengths (Warren and Wiscombe, 1980, 1985; Brandt et al, 2011; Hadley and Kirchstetter, 2012)
By using an integrating sphere/integrating sandwich spectrophotometer (ISSW) system coupled with chemical analysis, we evaluated the particulate light absorption of BC, organic carbon (OC), and mineral dust (MD) before exploring the relative contributions of their respective emission sources via a positive matrix factorization (PMF) receptor model
We propose that the clear difference in vertical profiles between QY and XD glaciers is a function of insoluble light-absorbing particles (ILAPs) deposition
Summary
The specific light absorption of black carbon (BC) is higher in snow than in the atmosphere because of the higher degree of sunlight scattering in the former (Chylek et al, 1984), and a wealth of evidence confirms that the snow albedo is dominated by BC at visible wavelengths (Warren and Wiscombe, 1980, 1985; Brandt et al, 2011; Hadley and Kirchstetter, 2012). Numerous surveys have sought to evaluate the light-absorption capacity of ILAPs (Xu et al, 2009a, b; Doherty et al, 2010; Huang et al, 2011; Wang et al, 2013; Dang et al, 2014) and their potential source attribution in snow and ice (Hegg et al, 2010; Zhang et al, 2013a; Doherty et al, 2014; Jenkins et al, 2016; Li et al, 2016; Pu et al, 2017) In their 2009 study, Hegg et al (2010) used a positive matrix factorization (PMF) receptor model to establish that ILAPs deposited in Arctic snow originate predominantly from biomass burning, pollution, and marine sources. By using an integrating sphere/integrating sandwich spectrophotometer (ISSW) system coupled with chemical analysis, we evaluated the particulate light absorption of BC, OC, and MD before exploring the relative contributions of their respective emission sources via a PMF receptor model
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