Intercomparing CO2 amounts from dispersion modeling, 1.6 μm differential absorption lidar and open path FTIR at a natural CO2 release at Caldara di Manziana, Italy
M. Queißer1, D. Granieri1, M. Burton1,*, A. La Spina2, G. Salerno2, R. Avino3, and L. Fiorani41Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Pisa, Pisa, Italy 2Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Catania, Catania, Italy 3Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Napoli, Napoli, Italy 4Diagnostics and Metrology Laboratory, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Frascati, Italy *now at: School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, UK
Received: 18 Mar 2015 – Accepted for review: 12 Apr 2015 – Discussion started: 29 Apr 2015
Abstract. We intercompare results of three independent approaches to quantify a vented CO2 release at a strongly non-uniform CO2 Earth degassing at Caldara di Manziana, central Italy. An integrated path differential absorption lidar prototype and a commercial open path FTIR system were measuring column averaged CO2 concentrations in parallel at two different paths. An Eulerian gas dispersion model simulated 3-D CO2 concentration maps in the same area, using in situ CO2 flux input data acquired at 152 different points. Local processes the model does not account for, such as small-scale and short-lived wind eddies, govern CO2 concentrations in the instrument measurement paths. The model, on the other hand, also considers atmospheric effects that are out of the field of view of the instruments. Despite this we find satisfactory agreement between modeled and measured CO2 concentrations under certain meteorological conditions. Under these conditions the results suggest that an Eulerian dispersion model and optical remote sensing can be used as an integrated, complementary monitoring approach for CO2 hazard or leakage assessment. Furthermore, the modeling may assist in evaluating CO2 sensing surveys in the future. CO2 column amounts from differential absorption lidar are in line with those from FTIR for both paths with a mean residual of the time series of 44 and 34 ppm, respectively. This experiment is a fundamental step forward in the deployment of the differential absorption lidar prototype as a highly portable active remote sensing instrument probing vented CO2 emissions, including volcanoes.
Queißer, M., Granieri, D., Burton, M., La Spina, A., Salerno, G., Avino, R., and Fiorani, L.: Intercomparing CO2 amounts from dispersion modeling, 1.6 μm differential absorption lidar and open path FTIR at a natural CO2 release at Caldara di Manziana, Italy, Atmos. Meas. Tech. Discuss., 8, 4325-4345, doi:10.5194/amtd-8-4325-2015, 2015.