Fast tracking of wind speed with a differential absorption LiDAR system: first results of an experimental campaign at Stromboli volcano

Abstract

Abstract. Carbon dioxide (CO 2 ) is considered a precursor gas of volcanic eruptions by volcanologists. Monitoring the anomalous release of this parameter, we can retrieve useful information for the mitigation of volcanic hazards, such as for air traffic security. From a dataset collected during the Stromboli volcano field campaign, an assessment of the wind speed, in both horizontal and vertical paths, performing a fast tracking of this parameter was retrieved. This was determined with a newly designed shot-per-shot differential absorption LiDAR system operated in the near-infrared spectral region due to the simultaneous reconstruction of CO 2 concentrations and wind speeds, using the same sample of LiDAR returns. A correlation method was used for the wind speed retrieval in which the transport of the spatial inhomogeneities of the aerosol backscattering coefficient, along the optical path of the system, was analyzed.

The BrIdge voLcanic LIdar—BILLI: A Review of Data Collection and Processing Techniques in the Italian Most Hazardous Volcanic Areas

“…The difference between the two profiles is directly linked to the molecule abundance and this technique allows one to determine and map the concentrations of selected molecular species in ambient air [43,44]. BILLI (whose technical scheme and experimental setup are reported in Figure 1) is a monostatic-biaxial DIAL-Lidar system mounted in a small laboratory truck and is composed of a transmitter and receiver equipment [21,[37][38][39][40][41][42].…”

“…Two large motorized elliptical mirrors (major axis: 450 mm) make it possible to scan all of the angles above the horizon. The specifications of the whole system are reported in Table 1, and more details are available in previous works [21,[37][38][39][40][41][42]. From Table 1, it is possible to note that, with respect to the Pozzuoli Solfatara field campaign [21,37,38], the operative wavelengths were slightly changed during the campaign carried out at Stromboli and Mt.…”

“…In order to fill these gaps, a new DIAL system, designed to measure the volcanic CO 2 flux, was developed as part of the ERC (European Research Council) Starting Grant Project "BRIDGE". The BrIdge voLcanic LIdar (BILLI), assembled at the ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development) Research Center of Frascati by the FSN-TECFIS-DIM group (Diagnostics and Metrology Laboratory) [36], successfully retrieved three-dimensional tomographies of volcanic CO 2 concentration in the plumes at Italy's most hazardous volcanic areas: Pozzuoli Solfatara (Naples, Italy) [21,37,38], the Stromboli volcano (Aeolians Islands, Italy) [39,40], and Mt. Etna (near Catania, Italy) [41,42].…”

“…As far as we know, lidar measurements of CO 2 have been performed in volcanic plumes only in recent times, due to the previously mentioned technical challenges and the extreme environmental operating conditions [14,21,[37][38][39][40][41][42]. In the last decade, promising results have been obtained by using a variant of DIAL, known as the Integrated Path DIAL (IPDIAL), but mainly to monitor ambient CO 2 concentrations (e.g., power plants/industrial emissions), and an Open-Path laser Spectrometer (OPS) to measure volcanic CO 2 concentration and flux.…”

“…Quantifying the CO 2 output from Pozzuoli Solfatara (October 2014) [21,37,38] and Stromboli (June 2015) [39][40][41] allows for the interpretation, and if possible, the forecast, of the upcoming development of the volcano scenario, with huge benefits to the population living nearby. These examples show the huge social values of lidar systems in monitoring gas emissions.…”