HR: 16:15h
AN: A24B-02    [Abstracts]
TI: The potential influence of Saharan dust on the latitude and intensity of the Atlantic ITCZ
AU: * Wilcox, E M
EM: eric.m.wilcox@nasa.gov
AF: Laboratory for Atmospheres NASA Goddard Space Flight Center, Code 613.2, Greenbelt, MD 20771, United States
AU: Lau, W K
EM: William.K.Lau@nasa.gov
AF: Laboratory for Atmospheres NASA Goddard Space Flight Center, Code 613.2, Greenbelt, MD 20771, United States
AU: Kim, K
EM: kmkim@climate.gsfc.nasa.gov
AF: Laboratory for Atmospheres NASA Goddard Space Flight Center, Code 613.2, Greenbelt, MD 20771, United States
AU: Reale, O
EM: oreale@postit.gsfc.nasa.gov
AF: Laboratory for Atmospheres NASA Goddard Space Flight Center, Code 613.2, Greenbelt, MD 20771, United States
AB: The latitudinal distribution and intensity of cumulus convection in the Tropical Atlantic is investigated in nine years of satellite observations and general circulation model simulations including the climatology and radiative forcing of Saharan dust. We explore the impact of the direct radiative forcing by Saharan dust on the latitude and intensity of the ITCZ in the eastern and central tropical Atlantic Ocean. The northward migration of the ITCZ through the boreal summer season corresponds closely with the seasonal variations in sea surface temperature (SST). Saharan dust is transported over the Atlantic Ocean to the north of the ITCZ in synoptic plumes associated with the passage of African easterly waves. The direct radiative forcing of dust aerosols results in a cooling of SST to the north of the ITCZ, and solar absorption results in mid-tropospheric heating. This heating acts to displace the ITCZ to the north of where it would be in the absence of the aerosols and slightly enhance the intensity of convection in the ITCZ in idealized GCM experiments with and without Saharan dust. The GCM results are explored and compared with satellite data of rainfall, SST, and aerosol optical depth during the TRMM/Terra period in order to estimate the potential variations in ITCZ location and activity attributable to the direct radiative forcing by Saharan dust.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0360 Radiation: transmission and scattering
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting