Shallow ground temperature measurements on the highest volcano on Earth, Mt. Ojos del Salado, Arid Andes, Chile

Abstract

Mt. Ojos del Salado (6893 m a.s.l.) lies within the Andean Arid Diagonal, on the Chilean-Argentinean border. Due to the extremely arid climate, surface ice is not widespread on Mt. Ojos del Salado and at similar high-altitude massifs in the region, although ice-bearing permafrost might be present. However, the thermal regime of the ground is relatively unknown in the region, especially outside of rock glaciers at high elevations north of 30°S. To study ground thermal regimes, in-situ shallow ground temperature and snow coverage from satellite imagery have been surveyed for four years (2012-2016) at six sites between the elevations of 4200-6893 m a.s. l. on Mt. Ojos del Salado (27°07′S, 68°32′W). According to the ground temperature and snow coverage data at the six monitoring sites, the presence of permafrost is unlikely below 4550 m a.s.l. but likely above 5250 m a.s.l. on Mt. Ojos del Salado.In addition, the active layer becomes extremely thin around 6750 m a.s.l.

Toward the Detection of Permafrost Using Land-Surface Temperature Mapping

“…This paper does not reach so far as to identify permafrost, but simply establishes that precursor maps of the zero curtain are feasible to make with satellite-borne TIR imagers. We tested our approach in an arid region of the Atacama Andes near the Ojos del Salado volcano, close to the border between Chile and Argentina, where previous studies had documented the presence of frozen ground and near-surface permafrost [15][16][17][18].…”

Pedoclimate monitoring in the periglacial high mountain soils of the Atacama Desert, northern Chile

“…The Puna de Atacama (28°S–22°S) has the highest theoretical equilibrium‐line altitude (at around 7,000 m a.s.l.) on the Earth due to its extremely dry climate, and glaciers are rare . In the Atacama Desert of northern Chile, snow only falls over the highest peaks, so that climate changes in the Central Andes are not associated with traditional processes observed in common cryospheric systems, although these arid high mountains remain poorly known.…”

“…Extensive permafrost is improbable below 4,550 m a.s.l., but likely above 5,250 m a.s.l. and the regolith becomes wet recurrently through spring/autumn in the elevation range of 5,250–5850 m a.s.l . Marked climatic anomalies occur during El Niño‐Southern Oscillation (ENSO) events, in which interannual climatic variability due to El Niño/La Niña events leads to less precipitation over the Altiplano and the western slopes, and a tendency to higher temperatures in El Niño years .…”

“…In the high Andes, this lack of knowledge is greater, and the Central Andes cryosphere is a zone of growing interest . Long‐term in situ measurements of periglacial processes north of 30°S in the Andes are still missing, and permafrost outside rock glaciers remains unexplored . Pedoclimate in tropical and subtropical latitudes (usually remote and poorly studied areas), and its social and environmental effects need to be further investigated.…”

“…and the regolith becomes wet recurrently through spring/autumn in the elevation range of 5,250-5850 m a.s.l. 1 Marked climatic anomalies occur during El Niño-Southern Oscillation (ENSO) events, 6 in which interannual climatic variability due to El Niño/La Niña events leads to less precipitation over the Altiplano and the western slopes, and a tendency to higher temperatures in El Niño years. 2 Instrument-based measurements indicate that temperatures have been increasing at a rate of 0.10-0.11°C per decade since 1939 in the Altiplano, with more rapid warming over the last 25 years.…”