1IRD/Univ. Grenoble Alpes/CNRS/Univ.Savoie/INPG/IFSTTAR/CNRM, Observatoire des Sciences de l'Univers de Grenoble (OSUG), UMS222, Grenoble, 38041, France
2Univ. Grenoble Alpes, Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), UMR5183, Grenoble, 38041, France
3CNRS, Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), UMR5183, Grenoble, 38041, France
4Météo France/CNRS, Centre d'Etude de la Neige (CEN) CNRM-GAME, UMR3589, 38041, Grenoble, France
5IRD/CNRS/UM1/UM2, HydroSciences Montpellier (HSM), UMR5569, Montpellier, 34095, France
6IRD/UGA/CNRS/INPG, Laboratoire d'étude des Transferts en Hydrologie et Environnement (LTHE), UMR5564, Grenoble 38041, France
7ICIMOD, GPO Box 3226, Kathmandu, Nepal
8CNR – Institute for Atmospheric Sciences and Climate, Bologna, Italy
9EvK2CNR, Bergamo, 24126, Italy
Received: 04 Nov 2013 – Discussion started: 13 Dec 2013
Abstract. A shallow ice core was extracted at the summit of Mera Peak at 6376 m a.s.l. in the southern flank of the Nepalese Himalaya range. From this core, we reconstructed the seasonal deposition fluxes of dust and refractory black carbon (rBC) since 1999. This archive presents well preserved seasonal cycles based on a monsoonal precipitation pattern. According to the seasonal precipitation regime in which 80% of annual precipitation falls between June and September, we estimated changes in the concentrations of these aerosols in surface snow. The analyses revealed that mass fluxes are a few orders of magnitude higher for dust (10.4 ± 2.8 g m−2 yr−1 than for rBC (7.9 ± 2.8 mg m−2 yr−1). The relative lack of seasonality in the dust record may reflect a high background level of dust inputs, whether from local or regional sources. Over the 10-year record, no deposition flux trends were detected for any of the species of interest. The data were then used to simulate changes in the surface snow albedo over time and the potential melting caused by these impurities. Mean potential melting caused by dust and rBC combined was 713 kg m−2 yr−1, and for rBC alone, 342 kg m−2 yr−1 for rBC under certain assumptions. Compared to the melting rate measured using the mass and energy balance at 5360 m a.s.l. on Mera Glacier between November 2009 and October 2010, i.e. 3000 kg m−2 yr−1 and 3690 kg m−2 yr−1 respectively, the impact of rBC represents less than 16% of annual potential melting while the contribution of dust and rBC combined to surface melting represents a maximum of 26%. Over the 10-year period, rBC variability in the ice core signal primarily reflected variability of the monsoon signal rather than variations in the intensity of emissions.
Revised: 02 Jul 2014 – Accepted: 04 Jul 2014 – Published: 14 Aug 2014
Ginot, P., Dumont, M., Lim, S., Patris, N., Taupin, J.-D., Wagnon, P., Gilbert, A., Arnaud, Y., Marinoni, A., Bonasoni, P., and Laj, P.: A 10 year record of black carbon and dust from a Mera Peak ice core (Nepal): variability and potential impact on melting of Himalayan glaciers, The Cryosphere, 8, 1479-1496, doi:10.5194/tc-8-1479-2014, 2014.