TOMS and METEOSAT satellite records of the variability of Saharan dust transport over the Atlantic during the last two decades (1979-1997)

[1] We combined aerosol observations of TOMS/Nimbus-7 (1979-1993) and Meteosat/ VIS (1984-1997) to investigate the variability of Saharan dust transport over the Atlantic over nearly 20 years. We first used three years (1986-1988) of coincident daily Meteosat images over the northern tropical Atlantic (15-30degreesN, 5-30degreesW) to convert the TOMS semi-quantitative index into dust optical thickness by means of two ("winter'' and "summer'') linear relationships. We then processed the whole TOMS/Nimbus-7 archive and found that both seasonal and interannual variability of the mean dust optical thickness over the Atlantic retrieved by TOMS and Meteosat are consistent. This consistency offers an unique opportunity to monitor the export of Saharan dust over the Atlantic during the last two decades. This analysis provides the first evidence of the high year-to-year variability of dust transport during winter, and confirms the importance of meteorological factors, through the North Atlantic Oscillation, in affecting its occurrence at this season.