NRL Monterey Aerosol Page

	Dust Storm in Sahara, February 3-4, 1999 and Transport to N. Atlantic and South America

Observations:

Surface Observations, Sahara showing origins of event on Feb 3 in Algeria, Mali and Mauritania. Dust and low visibility reports are shown in cyan.
METEOSAT Vis (Feb 4 loop, 1.5 Mb) showing two different dust plumes leaving Africa: one already between 20 and 30W, the other leaving Western Sahara
METEOSAT, Loop of composite of Vis and IR, Feb 4 by Mr. Tom Lee, NRL, showing a close-up of the two plumes and plumes over the continent
METEOSAT Vis (Feb 3-11 loop, 1.5 Mb) showing transport northward into the Central Atlantic, and WSW to South America
Surface Observations, South America showing dust arriving in French Guiana on Feb 10-11
NOAA Aerosol Retrieval Loop showing evidence of the northward transport on the 4th and 5th and WSW transport on the 8th and reaching South America on the 11th. Plume appears to jump due to infrequent updates of pixel values due to clouds, sun glint, etc.
GSFC TOMS Aerosol Residual Loop showing evidence of northward on the 4th and 5th, and WSW transport on the 8th - 10th. The presence of clouds does not prevent retrieval, but does suppress the aerosol residual (i.e. dust could be present even when residual is low).

Dynamical Forcing:

NOGAPS Sahara Loop showing development of stong NE and ENE surface winds and friction velocity (red shaded areas in lower-right panel) over west Africa ahead of a strong high approaching Spain

Aerosol Analysis:

NAAPS Sahara Loop showing development of the dust storm and the beginning of the NW transport over the Atlantic (left panels)
NAAPS World Loop showing northward transport over Atlantic and WSW transport to South America (lower-left panel)
SST Anomaly (12Z Feb 5) showing impact of radiatively cool dust on satellite-based SST retrievals if the retrieval method does not screen-out dust regions. The cool anomaly at 30N,30W corresponds with the location of the dust plume in NAAPS.

Naval Research Laboratory
Marine Meteorology Division
7 Grace Hopper Avenue, Stop 2
Monterey, CA 93943-5502
(831) 656-4613

Dust Storm in Sahara, February 3-4, 1999 and Transport to N. Atlantic and South America