Trans-Pacific yellow sand transport observed in April 1998: A numerical simulation

A yellow sand transport episode from the Asian continent to Japan and North America which occurred in April 1998 is simulated. A new on‐line dust tracer model coupled with a regional‐scale meteorological model is developed and applied to this dust storm episode. The results for two large dust events that started during April 14–15 and 19–20, 1998, have been analyzed and discussed. The first dust storm was trapped in a cutoff vortex developed over the China plain. A modeled 3‐D structure of dust associated with this cutoff vortex agreed with an observed time‐height cross section of dust concentration. Results show that the strong subsidence at the backside of the vortex restricted the dust layer below 3 km level. Model analysis revealed that the second dust event that started during April 19–20 over inland China was the origin of a dust episode reported over North America. The trans‐Pacific dust transport simulation successfully showed the dust onset near the West Coast of North America. Elevation of the dust layer during the long‐range transport was below 3 km. The model is extended to include the transport of an Asian origin anthropogenic tracer over the North Pacific Rim. Both the natural‐origin mineral dust and the Asian‐origin anthropogenic tracer are simultaneously transported even if their emission regions are different.