Glacier mapping in the Cordillera Blanca, Peru, tropical Andes, using Sentinel‐2 and Landsat data

Abstract

Sentinel‐2 images were used for mapping debris‐free glaciers for the first time in Cordillera Blanca. Landsat‐8 and Sentinel‐2 data were compared for glacier area estimation in 2016, obtaining comparable results. It was observed that normalized difference snow index method for glacier mapping using MSI data is less sensitive to cast shadows and steep terrain compared with Landsat data. Estimated total glacier areas in 1975, 1994, and 2016 were 726 ± 20.3 km2, 576.9 ± 15.1 km2 and 482.8 ± 7.4 km2, respectively. Glacier area in 2016 using Landsat was slightly lower (475.7 ± 16.8 km2) compared to the area estimated using MSI data. Observed glacier shrinkage between 1975 and 2016 was 33.5 per cent, which is lower compared to observed glacier area loss in the eastern cordilleras of Peru. Glacier shrinkage was higher at northern and northeastern slopes (47.9 per cent and 48.1 per cent, respectively) compared to the south‐western slopes (11.1 per cent).

Changes of the tropical glaciers throughout Peru between 2000 and 2016 – Mass balance and area fluctuations

“…This can be attributed to the fact that more low lying, small glaciers with mean aspects facing southwards still exist (Figure 4 and S5-S12). Higher retreat rates in general were observed for north-orientated glaciers before 2000 (Veettil et al, 2017a;Veettil, 2018), leading already to the disappearance of small north-facing glaciers before the start of our observation periods. In total, we discovered that 177 glaciers disappeared in our observation period, of which most disappeared after 2013 and were south facing (Table 1 and Figure S10-S12).…”

The influence of ENSO and PDO on tropical Andean glaciers and their impact on the hydrology of the Amazon Basin

“…Quelccaya Ice Cap, Cordillera Vilcanota), glaciers in this region are relatively smaller compared to those in Cordillera Blanca (e.g. Silverio & Jaquet, ; Racoviteanu et al ., ; Veettil, ) and mass loss occuring in smaller glaciers is faster compared to that occurring in larger ones (Ramirez et al ., ). Another factor is the altitude; glaciers in the eastern cordilleras are located at relatively lower altitudes compared to many glaciers in the western cordilleras.…”

“…To establish the trends in glacier surface changes along the eastern cordilleras of Bolivia and Peru, which is important in the hydrology of the Amazon Basin, a compilation of glacier surface changes in this region was gleaned from literature (Albert et al, 2014;ANA-URGH, 2014;Cook et al, 2016;Veettil & Souza, 2017;Veettil et al, 2017a;2017b;2018). In order to reduce the errors in glacier area estimation due to seasonal snow in the tropical Andes, all satellite data used in the above-mentioned studies were acquired during the austral winter (May−October).…”

Análisis De La Variación Temporal Y Espacial De La Cobertura Glaciar Del Nevado Cayambe, Ecuador, Mediante Fotografías Aéreas E Imágenes Landsat

“…Es importante notar que, a menudo, el conocimiento del área de estudio y el trabajo de campo se presentan como los únicos procedimientos con cierto grado de confiabilidad; es por ello que las técnicas de teledetección nunca deben entenderse como substitutas sino como complementarias del conocimiento directo de la realidad. Distintos estudios abogan por complementar distintos procedimientos y métodos de trabajo, así como fuentes de información (Veettil y Camp, 2017;Veettil, 2018).…”

“…Con respecto a las imágenes satelitales, cabe señalar que el área de estudio está influenciada por el régimen climático de la Amazonía, que se caracteriza por la existencia de elevados valores de humedad, manifestados por densos mantos nubosos; tal como han señalado otros estudios (Calispa, 2012), la existencia de cobertura nubosa entorpece considerablemente la identificación de las cubiertas terrestres. Nuevas generaciones de sensores de teledetección pueden ayudar a corregir estas desviaciones (Veettil, 2018). Por otra parte, en muchas zonas fue posible discriminar acumulaciones de nieve importantes, motivo por el cual resultó necesaria una corrección del contorno glaciar con el fin de eliminar polígonos que pudiesen alterar el cálculo de la superficie glaciada.…”