Artículo de revista
Investigation of a nocturnal cold-air pool in a semiclosed basin located in the Atacama desert
Fecha
2020Registro en:
Journal of Applied Meteorology and Climatology Volume: 59 Issue: 12 Pages: 1953-1970 Dec 2020
10.1175/JAMC-D-19-0237.1
Autor
Flores, Federico
Arriagada, Andrés
Aviles Donoso, Nicolás Patricio
Martínez, Andrés
Viscarra, Aldo
Falvey, Mark
Schmitz, Rainer
Institución
Resumen
In desert environments, intense radiative cooling of the surface during the night leads to rapid cooling of
the adjacent air, resulting in a strong temperature inversion conducive to cold-air-pool formation. In this
work observations are analyzed to investigate the structure of a nocturnal cold-air pool inside a
semiclosed basin located near Sierra Gorda in the Atacama Desert in Chile and its effect on dust
dispersion in the area. The measurement campaign was conducted over a 5-day period (14-19 August) in
2017 and included ceilometer data, vertical profiles of temperature, a grid of fixed ground stations, and
mobile temperature sensors. We focus our attention on the conditions during periods of high levels of
dust pollution, in order to understand the atmospheric conditions that contribute to these episodes. The
analysis of the available data confirms the development of an intense nocturnal cold-air pool, which is
reflected in a strong nocturnal potential temperature inversion (18 K in 150m) and a 30 degrees C
diurnal temperature range. A comparison of the vertical distribution of dust and temperature shows that
the capping inversion controls the location of the dust cloud. As a consequence, the highest dust
concentrations were observed inside the cold pool, below the capping inversion, proving that within the
basin the dust is confined to the layer where its source is located.