Micrometeorological Conditions for Dust-Devil Occurrence in the Atacama Desert

作者：Kurgansky Michael V^*; Montecinos Aldo; Villagran Victor; Metzger Stephen M

来源：Boundary-Layer Meteorology, 2011, 138(2): 285-298.

DOI：10.1007/s10546-010-9549-1

• Atacama Desert
• Dust devil
• Obukhov length

We report on field observations in January 2009 (austral summer) of atmospheric dust devils in the northern part of the Atacama Desert in South America (a parts per thousand 20(au broken vertical bar)S). An extremely high level of dust-devil activity over the study site has been observed, dependent on local meteorological conditions. We found a high correlation between the dust-devil frequency of occurrence and the Obukhov length scale, L, calculated from meteorological gradient measurements, with a clear tendency for this frequency to increase with decreasing -L. The upper threshold values of -L a parts per thousand 20-30 m, and the 2-m mean wind speed, V (2) a parts per thousand 8m s(-1), for dust-devil occurrence have been found, but the minimal V (2) threshold was not observed. Parallel routine meteorological measurements enabled us to calculate the main constituents of the surface energy balance, to obtain direct estimates of the surface albedo (alpha a parts per thousand 0.21 at the solar noon) and to summarize the local conditions.

• 出版日期2011-2