MULTI-TEMPORAL ANALYSIS OF THE GLACIER RETREAT USING LANDSAT SATELLITE IMAGES IN THE NEVADO OF THE AMPAY NATIONAL SANCTUARY- PERU
Glaciers are humanity's most extraordinary reservoirs of water, covering approximately 10% of the total surface of the earth. The investigation of the retreat of the glacier surface in the Ampay National Sanctuary is carried out using the historical series of Landsat images and applies the normalized snow difference index between the years 1991 to 2017. To determine the situation of deglaciation and quantification from the retreat of Nevado Ampay, the meteorological data from the Tamburco and Abancay stations has been considered. The supervised classification spatial visualization method for the Landsat 2MSS image and the normalized snow difference index have been used to determine the glacier cover area with Landsat 5, Landsat 7 and Landsat 8 Operational Land Imagery /Thermal Infrared Sensor images.. The results show a significant decrease in the surface of the Ampay glacier due to the increase in temperature. The surface of the Ampay glacier in 1991 has been 2.13 km2 and in 2017 it has been 1.09 km2, showing a loss of 1.04 km2 (48.92%) in recent years as a consequence of significant climate variability (temperature and precipitation). In 2015, an apparent accumulation of snow was recorded on the Ampay glacier, reaching 2.595 km2, but in the following years it has been decreasing until reaching 1.086 km2 of the glacier surface in 2017. It is concluded that the glacial retreat of the Ampay National Sanctuary in the last 25 years it has been 1.04 km2 with a tendency to continuous deglaciation, putting the water resource at risk.