MODIS Image-derived ice surface temperature assessment in the Southern Patagonian Icefield

Abstract

Ice surface temperature (IST) is one of the most relevant parameters when it comes to estimating the effects of climate change on glaciers. This study aims to estimate the IST for the Southern Patagonian Icefield (SPI) during the 2001–2016 period and, in so doing, to contribute to the assessment of the MOD11A1 product in this area. We evaluated IST performance by comparing it with that of automatic weather stations (AWSs). In addition, the glaciological significance of the results is presented through 1) IST trends, 2) annual IST anomalies, 3) IST behavior at different altitudes and orientations and 4) a comparison with Santa Cruz River flow records. The correlation coefficients obtained between the IST and AWSs ranged between 0.66 and 0.85. In addition, we report on the mean absolute differences between them, ranging between 0.6 ± 3.6°C and 9.4 ± 1.9°C. In this sense, we observed the lowest differences at the AWSs that were located in a homogeneous environment. Stated in glaciological terms: 1) only 1% of the pixels had a statically significant IST trend ( p-value ≤ 0.05): between 0.01 and 0.05°C/month; 2) we found that most of the IST anomalies ranged between –1 and 1°C throughout the period of this study; 3) the results suggest that the altimetric gradient was the most influential variable of the IST, mostly in north-oriented glaciers; and 4) the SPI IST showed an annual periodicity, which, in turn, shows a high correlation with the Santa Cruz River flow ( R = 0.86). This study is the first in estimating the SPI’s IST and contributes to enhance our knowledge of glacier dynamics and, therefore, the management of the water resource. Despite this, some MOD11 filtering is required in regions with high cloud cover frequency.

Surface ablation and its drivers along a west–east transect of the Southern Patagonia Icefield

“…In the ablation zones, mean glacier surface temperatures were close to 0°C (and surface water vapour pressure close to 6.11 hPa; Figs 4b, d). Lo Vecchio and others (2019) estimated colder surface temperatures using MODIS products in the lower part of O'Higgins Glacier, reaching −2.4 to −5.2°C between 500 and 1300 m a.s.l., while our estimation for the same elevation range was between −0.1 and −1.7°C. Western-facing glaciers comprised of a larger elevation range below the 0°C isotherm (Fig.…”

Projected increases in surface melt and ice loss for the Northern and Southern Patagonian Icefields

“…This scenario has already been proposed for the future evolution of Jorge Montt Glacier in the SPI; if the ongoing retreat continues, the glacier front will stabilise above the fjord level, reducing frontal ablation overall 31 . Evidence found in the Patagonian Icefields, however, seems to suggest further positive feedbacks related to the increases in surface melt, and associated dynamic adjustments in calving glaciers 32 and the appearance of supraglacial melt ponds 17 , which would serve to decrease the local surface albedo. Several studies 32,44 have evidenced acceleration of glaciers in response to an increase of the basal sliding due to an input of meltwater percolating to the base.…”

Cambio de área glaciar en el volcán Maipo (Andes Centrales), una aproximación morfométrica: 4 décadas de registros satelitales

“…En efecto, se sugiere que el comportamiento glaciar no solo responde a la variabilidad climática, por el contrario, la exposición y geometría glaciar han probado ser relevantes (elevación, pendiente y orientación) (Caro et al, 2020;Rabatel et al, 2013). Las diferencias locales en la radiación recibida por un mismo glaciar condicionan las temperaturas superficiales y, en efecto, los eventos de fusión supraglaciar y la distribución espacial del área glaciar (Lo Vecchio et al, 2019;Lo Vecchio, 2020). De hecho, en la vertiente pacífica la magnitud del cambio de área glaciar estuvo influenciada por las condiciones locales, al menos desde la segunda mitad del siglo XX (Rivera et al, 2000).…”