Asian dust transported one full circuit around the globe

Mineral dust is usually transported long distances in the lower troposphere. There are examples of Asian dust being transported across the Pacific Ocean(1-7), and traces of Asian dust have also been found in ice and snow cores in Greenland(8) and the French Alps(9). Here, we use measurements from the Cloud-Aerosol Lidar with Orthogonal Polarization(10), an air parcel trajectory model and a three-dimensional aerosol transport model to map the transport of dust clouds generated during a storm in China's Taklimakan Desert during May 2007. We show that the dust-veiled clouds were lofted to the upper troposphere around 8-10 km above the Earth's surface and transported more than one full circuit around the globe in about 13 days. When the dust reached the northwestern Pacific Ocean for the second time, the subsidence of a large-scale high-pressure system caused it to descend into the lower troposphere; some of the dust was then deposited over the ocean. Our analysis also indicates that the dust particles may have acted as ice nuclei in these high-altitude clouds, leading to the formation of cirrus clouds. We suggest that Asian dust can influence the global radiation budget by stimulating cirrus cloud formation and marine ecosystems by supplying nutrients to the open ocean.