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

Abstract

AbstractPedoclimate monitoring in the Central Andes is key to understanding climatic change in arid high‐mountain low‐latitude environments. We carried out a study of the thermal–hydric regimes of three soils along an altitudinal gradient in the Licancabur Volcano, northern Chile. In situ measurements of soil and air temperature and water content were collected over 19 months, via temperature and moisture probes installed from 5 to 100 cm depths, at 5,061, 4,728 and 4,426 m a.s.l. All soils show a periglacial thermal regime, but without permafrost. The contrasting behavior regarding soil water content and temperature regime along the gradient was attributed to climate, geomorphic features and varying soil attributes. Altitude‐related factors (air temperature and precipitation) drive the overall thermal regime of soils, but the mid‐altitude site showed the coldest soil thermal regime. Here, local landform characteristics (south aspect, mid‐slope location) impose lower solar radiation, influencing the soil thermal regime. Aridity drives unusual periglacial processes, with low frost shattering, no cryoturbation and particular landscape evolution. The thermal behavior affects soil moisture, with the lowest water contents recorded in the winter period due to water freezing at colder sites. Higher clay content results in greater soil moisture, despite the lower rainfall, shallow depth of the wetting front and large variability in water content. The study period included an extreme climatic event, and as such the monitored data do not represent the typical regional seasonal variation. Pedoclimate is more important in driving soil development than altitude‐related factors.