Abstract. Lofted mineral dust over data-sparse regions presents
considerable challenges to satellite-based remote sensing methods and
numerical weather prediction alike. The southwest Asia domain is replete
with such examples, with its diverse array of dust sources, dust mineralogy,
and meteorologically driven lofting mechanisms on multiple spatial and
temporal scales. A microcosm of these challenges occurred over 3–4 August 2016 when two dust plumes, one lofted within an inland dry air mass and
another embedded within a moist air mass, met over the southern Arabian
Peninsula. Whereas conventional infrared-based techniques readily detected
the dry air mass dust plume, they experienced marked difficulties in
detecting the moist air mass dust plume, becoming apparent when
visible reflectance revealed the plume crossing over an adjacent dark water
background. In combining information from numerical modeling,
multi-satellite and multi-sensor observations of lofted dust and moisture
profiles, and idealized radiative transfer simulations, we develop a better
understanding of the environmental controls of this event, characterizing
the sensitivity of infrared-based dust detection to column water vapor, dust
vertical extent, and dust optical properties. Differences in assumptions of
dust complex refractive index translate to variations in the sign and
magnitude of the split-window brightness temperature difference commonly
used for detecting mineral dust. A multi-sensor technique for mitigating the
radiative masking effects of water vapor via modulation of the split-window
dust-detection threshold, predicated on idealized simulations tied to these
driving factors, is proposed and demonstrated. The new technique, indexed to
an independent description of the surface-to-500 hPa atmospheric column
moisture, reveals parts of the missing dust plume embedded in the moist air
mass, with the best performance realized over land surfaces.