(Volcano Watch is a weekly article written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

Vog is made up of two principal components — sulfur dioxide gas, emitted by the active Kilauea volcano, and acid sulfate aerosols, produced by a reaction of sulfur dioxide gas, oxygen, and sunlight.

A new Vog Measurement and Prediction (VMAP) project Web site, created by scientists at the University of Hawaii at Manoa, shows forecasts for the concentrations of both components.

This website can be accessed at http://weather.hawaii.edu/vmap/index.cgi

The VMAP project is led by Drs. Steven Businger and Roy Huff, members of UH-Manoa’s Department of Meteorology. Steven is also the principal investigator for the Mauna Kea Weather Center, or the Hokukea project, which forecasts astronomical viewing conditions on Mauna Kea (http://mkwc.ifa.hawaii.edu/index.cgi).

The idea for vog forecasting has been around for years, but interest was renewed in early 2008, when the Halemaumau vent began spewing elevated sulfur dioxide emissions.

All the components to pursue the idea were available: HVO was monitoring emission rates and an earlier research paper led by Annette Baerman laid the groundwork for a Kilauea vog prediction tool. This tool can be used with several widely available wind field models employed by weather forecasters.

Vog forecasting models rely on volcanic gas emission rates measured by HVO. Currently, each emission rate measurement requires six or more passes beneath the gas plume with a UV absorption spectrometer, which is done several times per week, weather permitting.

To measure emission rates more efficiently and accurately, HVO gas geochemists Jeff Sutton and Tamar Elias and UH geologist/spectroscopist Dr. Keith Horton and software engineer Harold Garbeil considered using multiple fixed spectrometers that would run continuously during sunlight hours to get more data in near real-time measurements. But a crucial ingredient was missing: money.

In a rare turn of events, just as the need for money arose, a potential source of funding appeared in the form of the American Recovery and Reinvestment Act (ARRA), better known as the Stimulus Act.

HVO received $3.3 million in ARRA funds to upgrade its hazards monitoring networks, a fraction of which was invested to fund the VMAP project forecasting effort and the experimental gas emission rate monitoring experiment.

The VMAP project Web site is currently operational, and the experimental equipment deployment will start in the coming months. The next step is to determine whether the forecast products available on the Web site are useful.

Pages on the VMAP Web site include animated maps of vog plumes, which can provide a quick assessment of where vog might go in the next several hours, and a summary of current air quality measurements from sensors installed by the state Department of Health and the National Park Service.

Because VMAP is a feasibility project, one Webpage is devoted to “Model Performance,” on which two types of graphs compare forecast values with observed values.

A discussion of these results can also be found on the “Vog Forecast Discussion” webpage for people who would rather read text than interpret graphs.

The final piece of this feasibility effort will be to incorporate the near real-time sulfur dioxide emission rate measurements into the vog forecasting model. This should occur by summer when HVO’s ARRA project approaches its legislated conclusion. If the study proves useful, we hope that the needed funding can be found to continue this ambitious effort.

The VMAP project folks want to know how they can improve their informational products. The Web site includes contact information for project collaborators and links to cooperating state and federal agencies.

Answer to question in last week’s Volcano Watch article: Kuili — a puu makai of Highway 19 between Makalawena and the resort community of Kukio — is a primary vent.