Just as flowering and greening plants, migrating birds, and flooding herald the coming of spring in the Northern Hemisphere, dust storms are a sign of spring in northern China. Cold fronts from Siberia to the north bring strong winds to the deserts of Inner Mongolia. The winds pick up sand and carry it southeast over the densely populated region surrounding the Bo Hai and the Yellow Sea. In the most powerful storms, the dust may be carried all the way across the Pacific Ocean to North America. The storms subside in mid-May when warm air moves up from the southwest.
On April 20, 2005, the Terra MODIS instrument captured this true-color image of dust over the Yellow Sea. The storm that generated this dense brown cloud of dust covered much of Northern China, including Beijing, with a dusty haze. The dust blew east into Korea, where officials referred to it as the worst dust storm so far this year. The winds are expected to calm by Friday, April 22, 2005.
Not all of the brown seen in this image is caused by airborne dust. Near the shores, sediment colors the water of the Yellow Sea. The brown of the sediment fades to green as the dirt is diluted in the water, until eventually it's so dissipated that the water returns to a clear blue-black color.