Feature: Measuring and predicting vog

Vog Diagram
Recent model forecast of sulfur dioxide output

Living up to its title as one of the world’s most active volcanoes, Kilauea’s recent eruption on the Big Island is spewing forth more than just a spectacular show of nature. Its bubbling cauldron of fire is also stoking concern about volcanic emission hazards—posing a risk to air quality, and thus affecting everything from crop production to the ability to breathe.

Vog or volcanic air pollution, which is primarily a mixture of sulfur dioxide gas and sulfate aerosol, has been a constant in Hawai‘i since January 1983, when Kilauea began erupting sporadically at Pu‘u ‘Ō‘ō. The relatively remote vent on the volcano’s east rift zone became constant in 1986. Now, coupled with the opening of a second vent at the summit in March 2008, Kilauea continues to emit large volumes of sulfur dioxide gas. The one-two punch has resulted in increased emissions, thereby leading to escalating worries about air quality and its impact on the health and well-being of humans and nature.

Enter the Vog Measurement and Prediction (VMAP) project, which offers a high-tech mitigation option and learning tool in the form of accurate vog forecasting. Two members of the University of Hawai‘i at Mānoa’s Department of Meteorology were involved in its development: principal investigator Steven Businger and lead vog modeler Roy Huff. Scientific collaborators include Keith Horton and John Porter, both of the Hawai‘i Institute of Geophysics and Planetology. The U.S. Geological Survey’s Hawaiian Volcano Observatory funded the initial phase of the project through a cooperative agreement with UH Mānoa that ends on September 30, 2011.

“We expect that people will find the animated vog forecast maps that show the extent of the vog to be the most useful,” said Businger. The website also includes separate forecasts for sulfur dioxide gas and visible sulfate aerosol, and a written forecast that describes how the vog distribution is expected to change with time over the coming couple of days and why. Observed concentrations provided by the Hawai‘i State Department of Health and the National Park Service are displayed on the website and are used to validate and improve the vog model predictions.

VMAP is an ongoing investigation, with the long-term goal to offer accurate vog forecasting. Since the project is in its initial phase, the forecast discussions, vog model predictions, and model validation graphics on the website provide limited service and reliability. Users of the VMAP website should have no expectation of accuracy or timeliness, and vog model forecasts should not be used for health-related decision-making purposes.

To learn more about the VMAP project, visit: http://weather.hawaii.edu/vmap, which includes contact information for project collaborators and links to cooperating state and federal agencies.

For more information, contact Steven Businger at (808) 956-2569 or businger@hawaii.edu.

Top photo: Eruption of Halema`uma`u vent at Kilauea by Mila Zinkova.