Mid-East, Asian and Saharan Dust in Europe? April 1-4 and 8-10, 1999
TOMS, NOAA, and NAAPS Analysis:
12-day loop of NOAA Aerosol Optical Depth
:
(1) high AOD appearing over the Atlantic on the 1st-3rd,
(2) second tongue of high AOD appearing over North Sea on the 1st through 4th,
and
(3) a third tongue of Saharan dust heading north along 30W on 7th-8th.
12-day loop of TOMS Aerosol Index,
NOAA Aerosol Optical Depth,
Combined with NAAPS 00Z Optical Depth Analysis
TOMS shows hints of the 1st and 2nd features.
NAAPS shows
(1) Asian dust transported across N. America and the Atlantic and
correlating well with the timing and location seen in the NOAA AOD
(2) dust from Mid East and Central Asia transported
to the North Sea on 1st through 4th and
(3) the ongoing incursion of Saharan dust into North Atlantic on the 7th and 8th.
Dynamical Forcing:
12-day NOGAPS World Loop
: A strong low over southern Europe during the first several days pumps the
aerosol from the Mid East and central Asia to the NW over northern Europe.
Then another low over the Atlantic
pumps it further NW, out over the North Sea on the 1st-3rd.
This second low is also responsible for transporting the Asian dust NE across the Atlantic
towards Europe.
The late pulse of Saharan dust is lifted on the 4th-7th (high friction velocities
are red in the lower-right image), and then advected
northward in the northerly surge of warm air behind an unusually steep ridge and
ahead of a cold front.
