1CNRS Grenoble 1, Laboratoire de Glaciologie et Géophysique de l'Environnement, LGGE – UMR5183, 38041 Grenoble, France
2UJF Grenoble 1, Laboratoire de Glaciologie et Géophysique de l'Environnement, LGGE – UMR5183, 38041 Grenoble, France
3Laboratoire des Sciences du Climat et de l'Environnement, IPSL, CEA-CNRS-UVSQ, Gif-sur-Yvette, France
4Laboratoire de Météorologie Dynamique, IPSL, CNRS, Paris, France
5IRD/UJF – Grenoble 1/CNRS/U. Savoie/INPG/IFSTTAR/CNRM, Observatoire des Sciences de l'Univers de Grenoble, OSUG – UMS222, 38041 Grenoble, France
6CNR-ISAC-Institute of Atmospheric Sciences and Climate, Bologna, Italy
7EV-K2-CNR Committee, Bergamo, Italy
8IRD/UJF – Grenoble 1/CNRS/G-INP, LTHE – UMR5564, LGGE – UMR5183, 38402 Grenoble, France
9ICIMOD, G.P.O. Box 3226, Kathmandu, Nepal
Received: 23 Oct 2013 – Discussion started: 27 Nov 2013
Abstract. We applied a climate-chemistry global model to evaluate the impact of black carbon (BC) deposition on the Himalayan snow cover from 1998 to 2008. Using a stretched grid with a resolution of 50 km over this complex topography, the model reproduces reasonably well the remotely sensed observations of the snow cover duration. Similar to observations, modelled atmospheric BC concentrations in the central Himalayas reach a minimum during the monsoon and a maximum during the post- and pre-monsoon periods. Comparing the simulated BC concentrations in the snow with observations is more challenging because of their high spatial variability and complex vertical distribution. We simulated spring BC concentrations in surface snow varying from tens to hundreds of μg kg−1, higher by one to two orders of magnitude than those observed in ice cores extracted from central Himalayan glaciers at high elevations (>6000 m a.s.l.), but typical for seasonal snow cover sampled in middle elevation regions (<6000 m a.s.l.). In these areas, we estimate that both wet and dry BC depositions affect the Himalayan snow cover reducing its annual duration by 1 to 8 days. In our simulations, the effect of anthropogenic BC deposition on snow is quite low over the Tibetan Plateau because this area is only sparsely snow covered. However, the impact becomes larger along the entire Hindu-Kush, Karakorum and Himalayan mountain ranges. In these regions, BC in snow induces an increase of the net short-wave radiation at the surface with an annual mean of 1 to 3 W m−2 leading to a localised warming between 0.05 and 0.3 °C.
Revised: 27 Feb 2014 – Accepted: 20 Mar 2014 – Published: 28 Apr 2014
Ménégoz, M., Krinner, G., Balkanski, Y., Boucher, O., Cozic, A., Lim, S., Ginot, P., Laj, P., Gallée, H., Wagnon, P., Marinoni, A., and Jacobi, H. W.: Snow cover sensitivity to black carbon deposition in the Himalayas: from atmospheric and ice core measurements to regional climate simulations, Atmos. Chem. Phys., 14, 4237-4249, doi:10.5194/acp-14-4237-2014, 2014.