MODIS-derived aerosol height for air quality application

Aerosol height plays a critical role in air quality application when using satellite measurements. Up to date, no systematic methods are available to provide aerosol vertical profiles except lidar technology. However the current satellite-based lidar measurements are limited to a narrow line when satellite overpasses. It would need an ensemble of lidar measurements collected from a period of time or from multi-platforms to cover a region such as the United States. With one snapshot, the MODIS-estimated aerosol (top) layer height (hereinafter aerosol height) can provide the 1st order approximation of the vertical extent of aerosol loading derived from the visible spectrum, giving a virtual 3-D view of pollution transported from source to downwind regions. Aerosol height index is developed to show a relative measure between near-surface (aerosol index=0) and elevated aerosol layers (aerosol height index = 2). Aerosol height is estimated to intercompare with ground-based, air- and space-borne lidar measurements. In addition to INTEX-A field campaign period (July 1 - August 15, 2004), a suite of pollution events from 2000 to 2007 will be illustrated in detail along with meteorological fields and trajectory analyses. The immediate applications, in addition to air quality monitoring, include smoke injected height of forest fires (for modeling purpurse) and the conversion of aerosol optical depth to PM2.5 mass concentration.