Abstract:
This study investigates the influence of the 2015
Calbuco eruption (41.2◦ S, 72.4◦ W; Chile) on the total
columnar aerosol optical properties over the Southern Hemisphere. The well-known technic of sun photometry was
applied for the investigation of the transport and spatiotemporal evolution of the optical properties of the volcanic plume. The CIMEL sun photometer measurements performed at six South American and three African sites were
statistically analysed. This study involves the use of the satellite observations and a back-trajectory model. The passage of
the Calbuco plume is statistically detectable in the aerosol
optical depth (AOD) observations obtained from sun photometer and MODIS observations. This statistical detection
confirms that the majority of the plume was transported over
the northeastern parts of South America and reached the
South African region 1 week after the eruption. The plume
impacted the southern parts of South America to a lesser
extent. The highest AOD anomalies were observed over the
northeastern parts of South America. Over the South African
sites, the AOD anomalies induced by the spread of the plume
were quite homogeneously distributed between the east and
west coasts. The optical characteristics of the plume near the
source region were consistent with an ash-bearing plume.
Conversely, sites further from the Calbuco volcano were influenced by ash-free plume. The optical properties discussed
in this paper will be used as inputs for numerical models for
further investigation of the ageing of the Calbuco plume in a
forthcoming study.
