Spatial and temporal variations in the atmospheric aerosol optical depth at the ARM CART site

In an effort to better characterize the inputs to radiative transfer models and research-grade global climate simulation models (GCMs) the columnar aerosol loading, measured as the aerosol optical depth (AOD), has been computed for five facilities within the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site. Characterization of the AOD reported here show clear evidence that the spatial and temporal gradient exists at a much finer linear scale than those of the CART site. The annual variations of median AOD are on the order of 0.30 at all five facilities. The Spearman correlation and varimax-rotated PCA indicated the AOD values vary consistently across the CART site. The Northwest corner facility (EF-1) was the single facility that behaved differently from the rest. This sub-GCM grid variation can not be ignored if the model it to be used to accurately predict future climate change.