Station-based climatology of aerosols over the Caribbean islands.
Abstract
We present a climatological study of aerosols in four representative
islands’ stations of the Caribbean based on daily mean values of aerosol
optical properties for the period 2008-2016. A daily classification of
the dominant aerosol type is carried out, exploring the long-term
transport of the main types of aerosols from different sources. All
stations show a marked annual cycle in aerosol properties. Maximum
values of Aerosol Optical Depth occur in summer, coinciding with the
annual minimum in the Ångström Exponent and an increased occurrence of
dust. The opposite behavior is observed in winter, due to the
predominance of marine aerosols. Marine and dust aerosols are more
frequent in the easternmost islands of the Caribbean, and decrease
westwards due to an increasing presence of continental and mixture dust
aerosols. As a consequence, the westernmost station of Camagüey displays
the most heterogeneous composition of aerosols. Backward trajectories
indicate that winter marine aerosols and summer dust are transported by
air parcels travelling within the tropical easterly winds. The main
source region of both types of aerosols is the subtropical eastern
Atlantic, with the exception of Cuba, where the largest contributor to
winter marine aerosols is the subtropical western Atlantic. These
preferred pathways can occur under relatively weak and/or diverse
synoptic patterns, typically involving transient systems and specific
configurations of the Azores High that depend on the considered station.