HR: 0800h
AN: OS11A-0195    [Abstracts]
TI: Response of Sea Surface Temperature and Chlorophyll-a Concentration to Sahara dust storms over the eastern subtropical Atlantic
AU: * Martinez Avellaneda, N
EM: nidia.martinez@zmaw.de
AF: University of Hamburg, Inst. fuer Meereskunde Bundesstr. 53, Hamburg, 20146, Germany
AU: Stammer, D
AF: University of Hamburg, Inst. fuer Meereskunde Bundesstr. 53, Hamburg, 20146, Germany
AB: Satellite retrievals of MODIS aerosol optical thickness (AOT), TMI sea surface temperature (SST) and SeaWiFS chlorophyll-a (Chl-a) concentrations are analyzed jointly to investigate the impact of Saharan dust on SST and primary productivity on the eastern subtropical Atlantic. For that purpose, SST and Chl-a weekly anomaly fields are investigated with respect to their evolution before, during and after intra-seasonal storm events during the period 2000 through 2004. The talk will focus on strong dust outbreaks during 2003 and 2004 between Cape Verde and Canary Islands, during which SST decreases locally under regions of high AOT concentrations by 0.2 to 1.6 °{C}. Using the forcing efficiencies results from Li et al. (2004) and Yoon et al. (2005), reduction of solar irradiance associated with the dust events amounts to 60 W/m2. Based on a simple mixed layer assumption, the observed SST response is consistent with this reduced surface heating due to AOT concentrations. The Chl-a fields show that in several occasions its concentration increases after strong dust events. However, those occasions seem to happen primarily during spring, while in other seasons, other processes seems to impact productivity more strongly than the dust-induced fertilization. Likewise we find also most evidences of dust-induced surface cooling during spring, while during summer and fall internal ocean processes seems to dominate the evolution of SST.
DE: 4200 OCEANOGRAPHY: GENERAL
DE: 4275 Remote sensing and electromagnetic processes (0689, 2487, 3285, 4455, 6934)
DE: 4294 Instruments and techniques
DE: 4504 Air/sea interactions (0312, 3339)
DE: 4855 Phytoplankton
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting