P2.22
Shortwave aerosol radiative effect over the global oceans using GOCART and satellite data
Thomas A. Jones, Univ. of Alabama, Huntsville, AL; and S. A. Christopher
Using 6 years of combined Terra CERES radiance and MODIS aerosol data, we compute the global, ocean-only, shortwave (SW) radiative effect (SWRE) as a function of aerosol species including sea-salt, mineral dust, and small-mode anthropogenic. We will first use MODIS data in cooperation with TOMS-AI, MOPITT, and GOCART model output to determine the satellite observable properties of various aerosol types, and their spatio-temporal variability. The nature of aerosol species is analyzed for several regions where, both single aerosol species are dominant (e.g. North Atlantic dust) and where a mix of aerosol types exists (e.g. Arabian Sea). These properties are used to derive the proportion of the total AOT resulting from each individual aerosol species.
We then use the quasi-linear relationship between SW flux and aerosol optical thickness (AOT) to derive a clear sky, aerosol free background for each month of study. Total aerosol SWRE is calculated by subtracting the observed SW flux value from the clear sky background. SWRE from individual aerosol components is derived using applying the ratio of the AOT from an individual aerosol species to the total AOT on a pixel-by-pixel basis. The uncertainties in the aerosol classifications will be applied to the individual SWRE statistics to determine the overall uncertainty of individual aerosol SWRE and the significance of differences in SWRE from one aerosol species to another. Preliminary results indicate that globally averaged values for individual aerosol SWRE may not be representative of their true importance. Averaged over the entire ocean-only global, SWRE from anthropogenic sources exceeds dust SWRE by a factor of nearly 2. However, dust and anthropogenic SWRE are often maximized in certain regions during certain times of the year, are negligible elsewhere. As a result, we quantify SWRE on smaller regional and temporal scales to better examine the relationship between each.
Poster Session 2, General Climate Studies: Poster Session
Monday, 21 January 2008, 2:30 PM-4:00 PM, Exhibit Hall B
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