Saharan Dust Effects on Sea Surface Radiative Fluxes and Satellite Derived SSTs Determined from Field Data Analysis and Model Simulations

Bingkun Luo

The large-scale Saharan dust outbreaks usually occur over the tropical and subtropical Atlantic Ocean and have been observed from the visible and infrared sensors on satellites for many years. The dust aerosol scattering and absorption effects the surface radiative fluxes (SRF); and the dust aerosols also increase the infrared signal attenuation and degrade the accuracy of Skin Sea-Surface Temperature (SSTskin) retrieved from infrared radiometers on satellites. Accurate quantification of the dust perturbation to the surface energy budget is fundamental to understanding critical climate feedbacks and to determine the Earth's surface energy budget. By exploiting large sets of measurements from many ship campaigns in conjunction with reanalysis products, this study characterizes the sensitivity of the SRF and SSTskin to the Saharan dust aerosols with radiative transfer model simulations. Strong SRF and SSTskin anomalies are often a consequence of Saharan dust outbreaks. <o:p></o:p> The SSTskin derived from satellite radiometers is one of the critical factors for determining ocean-atmosphere interactions in climate prediction and ocean research. Different dust aerosol vertical distributions have varying effects on the satellite-derived SSTskin. To further investigate the physical mechanisms of aerosol effects on satellite derived SSTskin, the aerosol radiative effects were studied with an analysis of field measurement, satellite data, and radiative transfer simulations. Based on the analysis of field data and simulations, we have empirically determined that the sensitivity of the MODIS retrieved SSTskin accuracies is related to 1) dust concentration in the atmosphere, 2) the dust layer altitude, and 3) the dust layer temperature. As the dust aerosol layer altitude increases, the effect on the SSTskin retrievals becomes more negative with increasing temperature contrast with the sea surface. Satellite-derived SSTskin minus surface measured SSTskin differences vary between -3 K and 1 K.<o:p></o:p>

Saharan Dust Effects on Sea Surface Radiative Fluxes and Satellite Derived SSTs Determined from Field Data Analysis and Model Simulations

Abstract

Files and links (1)

Metrics

Details