Synoptic analysis and simulation of an unusual dust event over the Atacama Desert

• Main Authors: Mark Reyers, Mehdi Hamidi, Yaping Shao
• Format: Article
• Language: English
• Published: Wiley 2019-06-01
• Series: Atmospheric Science Letters
• Subjects: analysis; Atacama Desert; dust event; dynamic/processes; simulation; wind
• Online Access: https://doi.org/10.1002/asl.899

Abstract An unusual dust event over the Atacama Desert occurred in July 2016. Here, a synoptic study of the event is carried out using the NCEP FNL analysis data and WRF‐chem simulations. The “zonalization” of a mid‐tropospheric trough leads to the formation of a horizontal convergence band over the Northern Atacama and thus downward wind below it. As the descending air masses warm adiabatically, strong temperature contrasts to the colder air over the western Andes occur and intensify the down‐valley winds, thus leading to extraordinary strong easterly winds in the Atacama. Simulations with WRF‐chem indicate that these surface winds are sufficient for large‐scale dust emission, and simulated dust plumes traveling far over the eastern South Pacific agree well with the observations. As the integrated dust load is comparable with the load observed in major dust sources of the world, our findings highlight the importance of such unusual events.