Climate and Dynamics
Uplift of Saharan dust south of the intertropical discontinuity
Article first published online: 4 NOV 2008
Copyright 2008 by the American Geophysical Union.
Journal of Geophysical Research: Atmospheres (1984–2012)
Volume 113, Issue D21, 16 November 2008
How to Cite
2008), Uplift of Saharan dust south of the intertropical discontinuity, J. Geophys. Res., 113, D21102, doi:10.1029/2008JD009844., , , , and (
- Issue published online: 4 NOV 2008
- Article first published online: 4 NOV 2008
- Manuscript Accepted: 11 AUG 2008
- Manuscript Revised: 3 JUL 2008
- Manuscript Received: 21 JAN 2008
- Saharan dust;
- cold pool outflow;
 In situ observations from a flight made during the Geostationary Earth Radiation Budget Intercomparison of Longwave and Shortwave Radiation (GERBILS) field campaign (June 2007) show significant dust uplift into the monsoon flow immediately south of the intertropical discontinuity in the western Sahara. Dust loadings were highest in the moist monsoon air and the observations are consistent with dust uplift by the nocturnal monsoon winds. There is some evidence that cold pools within the monsoon flow contributed to the dust uplift: regions of elevated dust, water vapor, and ozone within the monsoon air are consistent with precipitation cooling and moistening air from upper levels and the resultant dusty cold pools propagating northward. However, only southward propagating cold pool outflows could be observed in satellite imagery. Using European Centre for Medium-Range Weather Forecasts analyses and satellite data, it is shown that the asymmetry in the seasonal dust cycle is closely related to the downdraft convective available potential energy (DCAPE) from convective storms. There is both more dust and more DCAPE during monsoon onset than during retreat. The larger DCAPE values during monsoon onset, as well as the stronger nocturnal monsoon flow and the stronger heat trough circulation, are expected to contribute to the higher dust loadings at this time. Both the monsoon flow and cold pool outflows within it result in dust uplift in the western Sahara during the monsoon onset, which is when the maximum dust uplift occurs. For dust modeling, this shows the importance of accurately modeling not only the monsoon flow itself but also deep convection and cold pools.