Seasonal and spatial variations of snow chemistry on Mount Logan

• Main Authors: Kumiko Goto-azuma, Roy M. Koerner, Michael N. Demuth, Okitsugu Watanabe
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: North Atlantic sector. The North Pacific sector; where; Mount Logan; Pacific; ice core; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.634.7789; http://www.igsoc.org/annals/43/a43a141.pdf

5340ma.s.l. in 2002. Prior to ice-core drilling, we collected snow-pit and shallow core samples from Mount Logan in 2001 to study seasonal and spatial variations of snow chemistry. We dug snow pits at six sites between 2420 and 5340ma.s.l. before the beginning of the melt season, with the exception of a pit at 3180ma.s.l., where the melt season had just started but had affected only the near-surface stratigraphy. Three of the pits were extended deeper with a shallow core. The snow-pit and core samples were analyzed for ion chemistry and d18O. A series of depth profiles of ions and d18O shows spatial variations, though characteristic peaks can usually be traced across all the profiles. Concentrations and deposition fluxes of Na+ and Cl–, which are mainly of sea-salt origin, decrease with altitude. On the other hand, deposition fluxes of NO3 –, SO4 2–, Ca2+ and NH4 + show a weak positive relationship with elevation below the summit plateau. Stable isotopes (d18O) decrease with altitude, with a distinctive jump between 3200 and 4500ma.s.l., as was reported previously. Stable isotopes (d18O), Cl–, CH3SO3 – (MSA), Na+ and Ca2+ show clear seasonal variations, which would enable us to date the cores by annual-layer counting.