Validation of MISR Aerosol Optical Thickness Measurements Using AERONET Observations over the Contiguous United States

Aerosol optical thickness (AOT) data derived by the Multi-angle Imaging SpectroRadiometer (MISR) from Jan 2001 to Feb 2002 were compared with AOT measurements from 16 Aerosol Robotic Network (AERONET) sites over the contiguous United States. Overall, MISR and AERONET AOTs were strongly correlated (correlation coefficient = 0.81). Regression analysis showed that MISR AOT retrievals had a positive error of approximately 0.10 with no systematic bias across the data range. Importantly, our findings showed that the positive errors in MISR AOT were greater during the spring and summer. Additionally, the presence of coarse particles in the aerosol led to increased errors which weakened the association between MISR and AERONET. Finally, it is unlikely that the current results will vary when using alternative MISR AOT parameters since our analysis also showed the MISR AOT parameters (best fit, regional mean, and weighted regional mean AOTs) to be interchangeable. Together these results suggest that MISR AOT measurements may be suitable for quantitative analysis of aerosol abundance.