DeFlorio, M. J., I. D. Goodwin, D. R. Cayan, A. J. Miller, S. J. Ghan, D. W. Pierce, L. M. Russell and B. Singh, 2016:
Interannual modulation of subtropical Atlantic boreal summer dust variability by ENSO
Climate Dynamics,
46, 585-599.
Abstract.
Dust variability in the climate system has been
studied for several decades, yet there remains an incomplete
understanding of the dynamical mechanisms controlling
interannual and decadal variations in dust transport.
The sparseness of multi-year observational datasets has
limited our understanding of the relationship between climate
variations and atmospheric dust. We use available
in situ and satellite observations of dust and a century-length
fully coupled Community Earth System Model
(CESM) simulation to show that the El Nino/Southern
Oscillation (ENSO) exerts a control on North African
dust transport during boreal summer. In CESM, this relationship
is stronger over the dusty tropical North Atlantic
than near Barbados, one of the few sites having a multidecadal
observed record. During strong La Nina summers
in CESM, a statistically significant increase in lower
tropospheric easterly wind is associated with an increase
in North African dust transport over the Atlantic. Barbados
dust and Pacific SST variability are only weakly correlated
in both observations and CESM, suggesting that
other processes are controlling the cross-basin variability
of dust. We also use our CESM simulation to show that
the relationship between downstream North African dust
transport and ENSO fluctuates on multidecadal timescales
and is associated with a phase shift in the North Atlantic
Oscillation. Our findings indicate that existing observations
of dust over the tropical North Atlantic are not extensive
enough to completely describe the variability of dust
and dust transport, and demonstrate the importance of
global models to supplement and interpret observational
records.
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