Impact of Long-Range Dust Transport on Northern California in Spring 2002

It has been well documented that spectacular dust storms in Asia (eg the events in 1998 and 2001) can affect the USA through long-range transport of dust across the Pacific. However, our observations and modeling show that the majority of dust at Lassen Nat. Park (Northern California) in spring 2002 is from long-range intercontinental transport, even in the absence of any spectacular Asian dust events.

We have implemented the interactive dust emission algorithm of Ginoux et al. (2004) into the LLNL 3-D global atmospheric chemistry and aerosol transport model (IMPACT). We then ran the model using a separate tracer for each dust emission region, using hi-resolution (1x1 degree) meteorological data from the NASA GMAO GEOS-3 assimilation system for 2001 and 2002. In addition to the modeling, we made size- and time-resolved aerosol measurements at Lassen Nat. Park in spring of 2002, as part of the ITCT 2k2 measurement campaign.

The model-predicted time-series of soil dust over Northern California agrees remarkably well with the observations, with a strong temporal correlation between the observations and intercontinental transport of dust across the Pacific in the model. Hence, the majority of dust we sampled at Lassen Nat. Park (Northern California) in spring 2002 is from long-range intercontinental transport.

This work was performed under the auspices of the U. S. Department of Energy (DOE) by the University of California, Lawrence Livermore National Laboratory (LLNL) under Contract No. W-7405-Eng-48. The project (03-ERD-021) was funded by the Laboratory Directed Research and Development Program at LLNL.