The Blowing-Dust product is even better when viewed as an image loop. Real-time examples are available on the RAMSDIS Online web page for GOES-West only, but the product only infrequently shows blowing dust, usually during the winter/spring months when strong winds stir up the lowest levels of the atmosphere and particles are available to become dust. The best examples of blowing dust occur in the western or central U.S., typically over dry terrain, during strong wind events.
In Figure 1 the surface winds at the time of the image are plotted on top of the Blowing-Dust product. The plotted winds help verify that the yellow and red portion of the image are indeed blowing dust, whipped up at the leading edge of a low pressure system centered slightly to the north and west of the (yellow and red) dust signature.
The negative temperature differences that appear yellow and red (and are indicative of blowing dust) are caused by opaque matter carried aloft by winds. That matter, which partially blocks the view of the surface, under normal conditions has a brightness temperature below that of the underlying surface. These lower temperatures are picked up preferentially by the less transparent of the two longwave window bands, and are emphasized as the negative temperature difference that is seen in the Blowing-Dust product.
The Blowing-Dust product provides a simple yet visually powerful display of areas of airborne dust whipped up by high winds. The color enhancement shows blowing dust as yellow and red, with red as thicker dust. The (red) signature of blowing dust is rather obvious for larger areas of blowing dust, but less obvious for tiny patches of dust, that may only occupy a few GOES pixels, as sometimes seen downwind of the Sierra Nevada mountains.
The main disadvantage of the product is that large portions of the southwestern U.S. have surface emissivity characteristics that give rise to negative temperature differences. These weak-but-false (yellow) dust signatures may appear during later portions of the day. While the Blowing-Dust product is not affected directly by reflected solar radiation, the solar heating during the day can result in a weak-but-false dust signal. A solution to this problem is to in observe the Blowing-Dust product over time, with a new image every 30 minutes, and to not rely on a single image for any blowing-dust signatures.
Interactions with NWS users via the Proving Ground will assist algorithm developers in improving this product, such as the desired enhancements, product scaling, etc., to best tailor this unique application to the end-user needs. The development of future, improved products will also benefit from user feedback.