Aerosol from Asian sources is hypothesized to contribute substantially to the aerosol burden over the Northern Pacific and to contribute to aerosol burden and optical depth in North America.
We have previously described a transport and transformation model for aerosol sulfate that is driven by observationally-derived meteorological data to produce three-dimensional distributions of sulfate as a function of time that can be compared with observations at specific times and locations.
Here we present results for the time period June 17 - July 24 1997 to examine the distribution of sulfate produced from Asian sources.
The accompanying animations show the sulfate plumes (vertical integral of concentration) resulting from Asian emissions, and from all sources, during June and July, 1997, as represented in an Eulerian model driven by observation-derived meteorological data.
During this period there was substantial west-to-east flow across the North Pacific resulting in evident plumes of sulfate from Asian sources across the Pacific. It is possible to follow individual puffs, as shown in the figure, which represents the model output for July 9, 1997, at 0000UT. Note also the evident wave structure in the sulfate loading.
The second figure shows the total sulfate, that is sulfate from all sources, for the same time. Note the overall increase in sulfate, even in the central and eastern North Pacific, indicative of contributions from all sources, including biogenic and volcanic.
The third figure shows the sulfate from volcanic sources, for the same time. Note in particular the volcanic plume from the Mexican volcano Popocatepetl (98.62 deg W, 19.02 deg N), extending westward from Mexico.
The animations are in Quicktime 
format (.mov files). If you have the appropriate plug-in they can be viewed directly from your browser. Otherwise they can be downloaded and viewed with suitable software 
.
The animations are set to play back at 4 frames a second. Note: 4 frames represent one day of model time. To be fully appreciated the movie as a whole or a portion of particular interest should be played as a repeating loop.
All movies include only analysis time period EXCEPT the volcanic sources, which starts at the beginning of the simulation to demonstrate dispersal of the volcanic plumes.
NOTE: The file sizes are 11 - 44 Mbytes.
| Asian Sulfate  |
North American Sulfate |
European Sulfate |
Volcanic Sulfate |
Total Sulfate |
Also available are the animations for SO2 column burden. Note that SO2 is much more localized to the source region than is sulfate, a consequence of the shorter residence time against dry deposition and conversion to sulfate.
| Asian SO2 |
North American SO2 |
European SO2 |
Volcanic SO2 |
Total SO2 |
We are in the process of acquiring observational data with which to compare the model output. We welcome leads on acquiring suitable observational data. Please send email to Carmen Benkovitz or Stephen Schwartz
References:
Sulfate over the North Atlantic and adjacent continental regions: Evaluation
for October and November 1986 using a three-dimensional model driven by
observation-derived meteorology. Benkovitz, C. M., Berkowitz, C. M., Easter, R. C.,
Nemesure, S., Wagener, R., and Schwartz, S. E. J. Geophys. Res. 99,
20725-20756 (1994).
file)
Effects of Sulfur Emissions from Popocatepetl Volcano on the Central U.S. in June 1997. Benkovitz C. M., Miller M. A., Schwartz S. E., and Easter R. E.. American Geophysical Union Fall Meeting, San Francisco, December 15-19, 2000.
This page was last updated 2006-01-10.