New ocean dust aerosol algorithm to unite and improve Dark Target dust retrievals across platforms: MODIS, VIIRS, ABI and AHI

Over the ocean, the Dark Target (DT) aerosol retrieval algorithm for MODIS has long-standing bias in its retrievals of Aerosol Optical Depth (AOD), Angstrom Exponent (AE) and Fine Mode Fraction (FMF) for dust aerosols because non-sphericity of dust particles is not properly treated. A two-step strategy of dust detection and retrieval has been developed and implemented for the MODIS instruments to greatly improve the dust retrieval over ocean. The strategy consists of first detecting medium to heavy dusty pixels and then applying a non-spherical dust model to the identified dusty pixels. The goal is to implement this new nonspherical dust retrieval in all Dark Target aerosol retrievals over ocean in order to create a unified global representation of dust from MODIS and VIIRS, and from the geostationary sensors ABI and AHI. However, we anticipate possible challenges to the new nonspherical dust models as those models are put to the test against unfamiliar geometries presented by the geostationary sensors and missing channels for dust detection. This presentation will report the current status of dust retrievals in VIIRS, ABI and AHI using the new algorithm.