Identification and Characterization of Dust Source Regions Across North Africa and the Middle East Using MISR Satellite Observations

The 15+ years of data from the Multi-angle Imaging SpectroRadiometer (MISR) instrument on the polar-orbiting Terra satellite provide a unique, independent source of information for studying dust emissions. MISR's multiple view angles allow the simultaneous retrieval of dust plume top height and dust motion winds during the seven minutes a scene is in view. In addition, MISR retrieves aerosol properties over bright surfaces, and such retrievals have been shown to be sensitive to the non-sphericity of dust aerosols. We perform joint analysis of the MISR operational stereo products (CMV), MISR aerosol optical depth (AOD), and AOD nonspherical fraction (dust AOD) products over the relatively cloud-free desert regions of North Africa and the Middle East. We evaluate the realism of the MISR characterization of dust source-specific emissions against AERONET and meteorological data. Utilizing the strengths and accounting for biases in MISR aerosol and stereo products over the desert areas, we investigate multi-year spatial and temporal behavior of dust in terms of frequency of plume occurrence, plume heights, dust moving winds, and AOD/dust AOD. In particular, we examine the multi-annual mean pattern and seasonal cycle in dust emissions in relation to various meteorological factors. Our analysis demonstrates that the MISR CVM product identifies the Bodélé depression as the most important dust source, consistent with previous studies; and that the seasonal distribution of North African dust sources is largely driven by the climatology of wind and precipitation. In addition, we show that MISR observations together with surface station data identify Iraq and Kuwait as dust source regions during Middle Eastern Shamal wind events.