Landsat TM and ETM+ derived snowline altitudes in the Cordillera Huayhuash and Cordillera Raura, Peru, 1986–2005

Abstract

The Cordilleras Huayhuash and Raura are remote glacierized ranges in the Andes Mountains of Peru. A robust assessment of modern glacier change is important for understanding how regional change affects Andean communities, and for placing paleo-glaciers in a context relative to modern glaciation and climate. Snowline altitudes (SLAs) derived from satellite imagery are used as a proxy for modern (1986–2005) local climate change in a key transition zone in the Andes. <br><br> Clear sky, dry season Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+) satellite images from 1986–2005 were used to identify snowline positions, and their altitude ranges were extracted from an Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) digital elevation model (DEM). Based on satellite records from 31 glaciers, average snowline altitudes (SLAs), an approximation for the equilibrium line altitude (ELA), for the Cordillera Huayhuash (13 glaciers) and Cordillera Raura (18 glaciers) from 1986–2005 were 5051 m a.s.l. from 1986–2005 and 5006 m a.s.l. from 1986–2002, respectively. During the same time period, the Cordillera Huayhuash SLA experienced no significant change while the Cordillera Raura SLA rose significantly from 4947 m a.s.l. to 5044 m a.s.l

Tracing glacier changes since the 1960s on the south slope of Mt. Everest (central Southern Himalaya) using optical satellite imagery

“…The SLA derived from the "Hess method" for the map represents the long-term ELA and, thus, does not indicate the position of the snow line in a particular year. However, the snow line position obtained from satellite imagery represents the transient snow line of the year that varies along the year, but remains stable after the end of summer, corresponding to the end of the ablation season (Rabatel et al, 2005;Pelto, 2011). The map-based SLA was useful for understanding the representativeness of the snow line position derived from the Corona image, which has some limitations for accurately identifying the snow line because of its panchromatic nature.…”

Factors responsible for driving the glaciation in the Sarchu Plain, eastern Zanskar Himalaya, during the late Quaternary

“…The snow line altitude at the end of the ablation season is a viable alternative for the equilibrium line altitude (ELA), and consequently is reliable for mass balance and climate reconstructions (McFadden et al, 2011). The ELA represents the altitude at which annual accumulation equals annual ablation and is a more direct measure of climate compared with other glacier properties such as length, which depend on ice dynamics, bed geometry and other variables (Paterson, 1994;Rupper et al, 2009).…”

“…Comparison of present and former ELAs used in conjunction with modern meteorological data can help to determine the magnitude of climate changes required to produce the calculated variations in ELA (Burbank and Fort, 1985).The modern ELA is estimated using remotely sensed data for 56 glaciers each having an area larger than 0.5 km 2 . The ELA was mapped using multi-temporal Landsat images (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014) acquired at the end of the ablation season, when snow cover is at its annual minimum and approximates the annual ELA position (Duncan et al, 1998;McFadden et al, 2011;Guo et al, 2014). In the satellite data the ELA is demarcated by the difference in reflectance from clean ice to dirty ice.…”

Variations in Firn Line Altitude and Firn Zone Area on Qiyi Glacier, Qilian Mountains, Over the Period of 1990 to 2011

“…The GCPs had to be feature points, such as a ridge, a river bend, or bifurcation and a road junction. The GCPs were distributed around but excluded glacial margins because of their annual variability (McFadden et al, 2011). Once we obtained at least 30 GCPs that were uniformly distributed in the whole image, and by keeping the root mean square to less than 1, then we could fit them with a quadratic polynomial method.…”

“…For large-scale areas and long-term periods, an altitude shift of the firn line is a response to certain climate change behavior and can indicate the hydrologic balance (Droz and Wunderle, 2002). Firn line altitudes are also an appropriate proxy for ELA and, consequently, for mass balance and climate reconstructions (McFadden et al, 2011).…”