Calendar Event Details
AEROCENTER: Andrew Sayer
Event Date: Tuesday, May 27, 2014
Location: G133
Time: 11:00 AM
MODIS C6 ‘Deep Blue’ and ‘Dark Target’ aerosol data, and their merge: comparisons and towards usage recommendations
The MODIS Collection 6 Atmospheres product suite includes refined versions of both ‘Deep Blue’ (DB) and ‘Dark Target’ (DT) aerosol algorithms, with the DB dataset now expanded to include coverage over vegetated land surfaces. This means that, over much of the global land surface, users will have both DB and DT data to choose from. A ‘merged’ dataset is also provided, as a more gap-filled dataset, which takes retrievals from either or both algorithms based on regional and seasonal climatologies of normalized difference vegetation index (NDVI). This talk presents some comparisons of these two C6 aerosol algorithms and the merged dataset, focusing on AOD at 550 nm derived from MODIS Aqua measurements, with each other and with Aerosol Robotic Network (AERONET) data, with the intent to facilitate user decisions about the suitability of the datasets for their desired applications. DB and DT provide similar views of the global aerosol system, with the same basic hotspots and seasonality on global and regional scales. Differences between them are generally smaller than their expected uncertainties, which is one of several reasons that the two should not be considered as entirely independent. There is no clear ‘winner’ when it comes to comparisons against AERONET. The merged product does not appear to offer increased skill as compared to the individual datasets. DB continues to be the only option for coverage over bright arid regions, while DT continues to provide the only over-ocean dataset. These are likely to be the main motivating factors in determining which dataset a user might choose. Where possible, we suggest users perform their analyses using both datasets separately, and their agreement (or lack thereof) may provide additional insight into the research questions asked.
Posted or updated: Wednesday, April 30, 2014
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