Atmospheric dust intrusions from the peninsular region into the Northern Gulf of California: case study

Abstract

Through atmospheric transport, coming from the mainland, an important amount of dust arrives to surface waters of open-ocean regions and many coastal zones. Semi-arid and desert areas tend to act as important sources of dust. The Gulf of California (GC) is one of the most productive marginal seas of the world, and it is surrounded by the semi-arid deserts located in Baja California Peninsula, United States, and Sonora (Mexico). Dust fluxes coming from the BCP during the summer are relevant due to biological impact on the California Gulf. In the northern region of the BCP, meteorological events have not been well studied. These events are known in popular slang as "El Torito". The characterization of a dust event that originated in the Baja California Peninsula (BCP) on June 14, 2016, is presented. Meteorological variables (from North American Regional Reanalysis -NARR), daily sea surface temperature, and aerosol optical thickness (from MODIS) are used to explain the dust event genesis, are used. Results suggest that sea surface temperature fluctuations in the Pacific Ocean off the coast of the BCP generate changes in hydrometeorological variables (wind, relative humidity, and atmospheric pressure) that can give rise to dust events. The June 14 dust storm originates in the San Felipe desert and disperses aeolian to the northern Gulf of California, as shown by aerosol optical thickness images and trajectories simulated with the HYSPLIT model, which establishes vertical distributions with predominant heights between 0 and 500 m.