9614703 Williams This is a proposal to develop further a new instrument (GASPEC) as a true remote sensor capable of measuring quantitatively CO2 emissions from volcanoes. The prototype instrument was developed in the past 4 years and has as a final goal to test eruption forecasting models and produce a monitoring tool for active volcanoes. The first step for this project will be to use a coal-fired power plant in N. Arizona as an acessible natural laboratory. In this step, it is proposed to work on deconvoluting the complex raw numbers obtained by the GASPEC into signals caused by CO2, H2O vapor, clouds, ash, temperature changes, etc. which represent the reality of the atmosphere near volcanoes. The second step will be to take the instrument to Etna, as this is a very well-known active volcano, thought to be the major source of volcanic CO2 in the world. During this stage of the project, the focus will be on long-term observation and comparison of the changes in CO2/SO2 as obtained by GASPEC and other remote and direct sensors that are currently available. The planned research will allow a more friendly use of the instrument and should be capable of deconvoluting the complexity of infrared in the lower atmosphere, which may make the GASPEC a standard monitoring tool in volcanoes.