The Ground CO2 Mapper. An innovative tool for the rapid and precise mapping of CO2 leakage distribution

The recently developed Ground CO2 Mapper (“Mapper” for short) is an inexpensive, light, robust, and low power consuming tool for determining the distribution of CO2 at the soil-atmosphere contact as an indicator of CO2 leakage. The basic premise behind the Mapper is that the contact between the ground surface and the atmosphere represents an interval where CO2 leaking from the subsurface can accumulate in anomalous concentrations due to two mechanisms, the higher density of CO2 with respect to air and the tendency of wind speed (and thus mixing) to approach zero near the ground surface due to frictional drag. Because of its measurement target and the tool’s very rapid response time, Mapper surveys can be conducted very quickly at a high sampling density, yielding accurate maps of CO2 spot anomalies. The unit can be used by anyone and deployed within only 5-10 minutes after sensor and GPS signal warm-up. Here we describe the Mapper and present results from a site of natural diffuse CO2 degassing in central Italy.