Abstract ID: 3.12913 | Accepted as Talk | Talk/Oral | TBA | TBA

Mountain glaciers are melting rapidly, significantly impacting high-altitude ecosystems and human societies. In the Cordillera Blanca (Peru) accelerated glacier retreat raises concerns about potential glacier disappearance by 2080. Although increased temperatures and reduced snowfall are primary drivers (IPCC 2019, IPCC 2022), deposition of light absorbing particles (LAPs), including elemental and organic carbon, further accelerates melting by reducing snow albedo (Skiles et al., 2018).
This study investigates the spatial and temporal variability of elemental carbon and organic carbon in snow samples collected in the Cordillera Blanca. Three distinct glaciers were investigated: Shallap (N -9°29′21.3″, E -77°20′17.2″), Vallunaraju (N -9°25′55.9″, E -77°27’57.3″), and Yanapccha (N -9°01′44.0″, E -77°34′54.2″). Surface snow samples were collected once a month from May to December in both the ablation and accumulation zones during four consecutive years (2017–2020). Elemental carbon (EC) and organic carbon (OC) concentrations were determined using thermal-optical and thermal analysis. The first analysis established the EC/OC ratio, while the complementary thermal analysis quantified total carbon. Interference from hematite particles was corrected to avoid EC underestimation (Kau et al., 2021).
Surface snow samples revealed EC concentrations spanning from 0.030 (±0.003) to 4.81 (±0.16) ppm and OC concentrations between 0.48 (±0.04) and 32.72 (±0.77) ppm. EC and OC concentrations are higher in the ablation zone, likely due to melt-induced concentration, while seasonal variability in the accumulation zone, with elevated values during the dry season, was observed. Elemental carbon concentration was higher in glaciers nearby urban agglomerates (Shallap and Vallunaraju), highlighting the impact of local anthropogenic emissions.
Our findings underline the significant contribution of carbonaceous particles to snow darkening impurities in the Cordillera Blanca.

References
IPCC Special Report (2019) ‘The ocean and cryosphere in a changing climate’.
IPCC Sixth Assessment Report (2022), doi:10.1017/9781009325844.002.
Kau, D. et al. Atmos. Meas. Tech. 15, 5207–5217 (2022).
Skiles, S. M., et al. Nature Clim Change 8, 964–971 (2018).