Development of a Gas Correlation Camera for Improved Ground-Based Monitoring of Volcanic SO2 Emissions

Michigan Technological University, Houghton MI

Investigators

Abstract

0321869 Watson This grant supports the development and field testing of a lightweight (ca. 3 kg.) portable gas correlation camera for the measurement of SO2 in volcanic gas plumes. The camera will be based on an Apogee AP8P digital camera with a 1024 x 1024 charge coupled device (CCD) detector, fitted with a 100 mm focal length lens and bandpass filter to select for UV radiation at a wavelength that has a strong SO2 absorption band (318 nm), ad maintained in an aluminum housing which would allow a filter wheel mechanism to pass gas cells with known concentrations of SO2 in front of the lens. The difference between an image shot through a reference cell of know SO2 concentration and a blank reference cell with no SO2 is proportional to the line-of-sight SO2 burden. The CCD array design will facilitate spatial mapping of large areas of plumes and an associated field laptop running customized software will allow for near real-time interpretation and visualization of the data. The instrument will be laboratory calibrated and then tested at a coal-fired power plant in Montana that independently records SO2 concentrations in their smokestack effluent. These tests will attempt to validate laboratory calibrations and asses the detection limits of the instrument. Typical coal-fired power plant effluents have SO2 fluxes that are often an order of magnitude less than typical volcanic gases (e.g., 25-100 tonnes/d vs. 200-1000 tonnes/d, respectively). The instrument will also be tested at the active Soufriere Hills volcano on Montserrat where independent techniques for monitoring SO2 in the volcanic plume already exist (i.e., COSPEC and DOAS). The ability to accurately image the dynamics of SO2 in the atmosphere in near real-time and to accurately estimate SO2 fluxes is a critical need in volcanological and atmospheric chemistry research and a potentially useful tool in industrial environmental monitoring. The development and testing of this instrument will involve a graduate student and faculty at Michigan Technological University and collaborations with scientists at NASA-JPL and the Montserrat Volcanological Observatory. ***