Examining multidecadal relationships between the saharan air layer and large-scale atlantic hurricane environment

Massive Saharan dust outbreaks over the North Atlantic transpire in a warm and dust-laden air mass, the Saharan Air Layer (SAL), modulating oceanic and atmospheric conditions over a hurricane's main development region (MDR). Recent research suggests the SAL influences sea surface temperature (SST) variability on interannual and multidecadal time scales; however, it is unclear how distinct SAL characteristics modulate thermodynamic and kinematic fields on the same time scale and in turn, how this variation is connected to hurricane activity and tropical climate patterns. Findings from a multi-decadal (1955-2008) analysis investigating SAL character and environmental variables suggest periods of high dust (1970-90) coincide with enhanced low-level subsidence, mid-level cooling, and low-level warming and drying, all of which are unfavorable for TC development. In addition, results demonstrate during anomalously high dust years, mid-level easterly flow south of 10°N takes precedence over persistent strong mid-level westerlies.