High-Resolution Image

When strong winds blow over the desert, mineral dust gets lifted from the surface and into the atmosphere. Since these airborne particles sometimes travel very far distances from their source regions, they can impact the environments along their transport pathway. For instance, transported mineral dust is believed to provide the source of iron to fertilize phytoplankton growth in the ocean.

Using the recently developed Deep Blue algorithm, aerosol optical thickness and Angstrom exponent products are now available from Terra and Aqua MODIS over desert and semi-desert regions. View paper. The ability to compare and contrast Terra (10:30 AM equatorial crossing time) and Aqua (1:30 PM equatorial crossing time) results from these products provides us with a powerful new method to track the movements and evolution of aerosol plumes that were previously hard to detect over bright-reflecting source regions such as deserts. In this figure, the RGB images and the retrieved aerosol optical thickness at 500 nm are shown over the Middle East for both sensors on 12 September 2004. In the Terra images, we can see a few prominent dust plumes began to develop over Iraq. By the time Aqua passes overhead, the dust storm had grown to cover an extensive area. We can also see the dispersal of a dust plume in southern Saudi Arabia, while the intensity and location of dust clouds over Sudan remain fairly constant.

(By N. Christina Hsu, Si-Chee Tsay, Michael King, and Jennifer Wei)