The Resonance GCSO2-1 is a UV-sensitive camera that compares images in two spectral bands to produce concentration maps of SO2 plumes. This method is based on differential optical absorption spectroscopy (DOAS) methodology for remote sensing of atmospheric gases (Refs 1-12). GCSO2-1 has been under development since 2008 and the GC-SO2-1 is an elegant implementation of the method that has several unique features. It employs a single back-thinned CMOS camera, which simultaneously captures two images of the target plume in bands centered on 310 and 320 nm. Offsets due to changes between two imaging chips or moving filters are eliminated. The two images are mirrored about the optical axis of the camera, which eliminates distortion and edge dimming. A complete calibration is obtained by use of a PC-controlled SO2 gas cell wheel. Modeling and measurements show that the concentration maps from GCSO2-1 are highly specific to SO2 and are insensitive to changes in the spectrum of daylight due to solar elevation.
- Produces quantitative images of SO2 in plumes from volcanoes and stacks that can be used to determine SO2-mass fluxes in tonnes/day- Captures simultaneous images at 310 and 320 NM- Single UV lens for image stability- Single detector eliminates drift between 2 detectors- Distortion control with mirrors to cancel pincushion and barrel distortion- Callibration using COSPEC SO2 cells- Automatic dark subtraction- Uses Ratio-of-Ratios technique for calibrated ppm-m 3D image- Manual alignment adjustment through rear acces port- Connects to control laptop computer via ethernet- Powers off of external battery, DC, or AC outlet