Saharan dust storms over the Canary Islands during winter 1998 as depicted from the advanced very high-resolution radiometer

One of the largest Saharan dust outbreaks of the decade, over the Canarian Archipelago, took place between January and March 1998. A series of advanced very high-resolution radiometer (AVHRR) images corresponding to this event were studied to characterize short-term (days) variability of aerosol atmospheric load. Multispectral radiometric performance of this type of aerosol was analysed to define a classification strategy for dust detection. Optical parameters related to size distribution were calculated from the images. The monitoring of the Angstrِm exponent during this event shows how its variability is correlated to the short-term history of the aerosols. Assuming that Saharan aerosol behaves optically as a typical Junge size distribution, the variance of the Angstrِm exponent is interpreted in terms of the variability in the particle size distribution and related to intesifications and relaxations of dust conditions.