In situ observations and sampling of volcanic emissions with NASA and UCR unmanned aircraft, including a case study at Turrialba Volcano, Costa Rica

Abstract

Scientific knowledge of transient and difficult-to-access airborne volcanic emissions comes primarily from remote sensing observations, and a few in situ data from sporadic heroic or inadvertent airborne encounters. In the past, patchy knowledge of the composition and behaviour of such plumes from explosive volcanic eruptions, and associated drifting ash and gas clouds, have centrally contributed to unwanted and dangerous aircraft encounters that have put crews at risk and, in some cases, greatly damaged aircraft. Thus, improved knowledge of boundary conditions and plume composition, as inputs to both mass retrieval and predictive models for cloud trajectories, would be of benefit.In this paper, we describe how small robotic unmanned aerial vehicles (sUAVs) can address a variety of measurements that are typically beyond the reach of, and sometimes too dangerous for, manned aircraft. The direct measurements and sampling that can be achieved by sUAVs address serious gaps in knowledge of volcanic processes, and provide important validation data for estimations of volcanogenic ash and gas concentrations gleaned using remote sensing techniques. These data, in turn, constrain key proximal and distal boundary conditions for aerosol and gas transport models on which are based a number of decisions and evaluations by hazard responders and regulatory agencies.We briefly describe a case study from our ongoing field study at Turrialba Volcano in Costa Rica, where we are conducting an international campaign of systematic airborne in situ measurements of volcanogenic SO2 and other gases, as well as aerosols, with sUAVs and aerostats (e.g. tethered balloons and kites), in conjunction with data acquisitions by the Advanced Spaceborne Thermal Emission and Reflection (ASTER) radiometer onboard the NASA Terra Earth orbital platform. To our knowledge, this is the first such systematic in situ UAV- and aerostat-based observation programme for SO2 and particulates in a volcanic plume for correlation with orbital data. We preliminarily report good agreement between our UAV/aerostat and ASTER SO2 retrievals within a 5 km radius of the volcano summit, at altitudes of up to 12 500 ft (c. 3850 m) above sea level (asl) for concentrations within the range of 5–20 ppmv (ppm by volume). Additional work continues.

Remote sensing and identification of volcanic plumes using fixed‐wing UAVs over Volcán de Fuego, Guatemala

“…Some areas of interest, such as Fuego, are dangerous to approach, meaning that flight times must be longer and cruise speeds higher to reach them from a safe distance. Fixed‐wing UAVs are a natural solution to this issue, as demonstrated by Pieri et al (), who flew fixed‐wing UAVs over Turrialba, while also flying ‘tethersonde’ meteorological balloons for data verification. Primarily sensing gases, these experiments validated the use of UAVs in scientific data collection over volcanoes, specifically delta‐wing style fixed‐wing aircraft.…”

Remote sensing of volcanoes and volcanic processes: integrating observation and modelling – introduction

“…Both gas and ash measurements from satellites require ground-truthing, and in the final paper in this Special Publication, Pieri et al (2013) are concerned with the development of unmanned aerial vehicles (UAVs) to overcome some of the challenges in terms of such ground-truthing. UAVs potentially allow measurements of the parts of volcanic plumes otherwise inaccessible to manned vehicles due to safety concerns or ground-based remote sensing owing to plume height, measurement geometry constraints, plume opaqueness or other factors.…”

“…UAVs potentially allow measurements of the parts of volcanic plumes otherwise inaccessible to manned vehicles due to safety concerns or ground-based remote sensing owing to plume height, measurement geometry constraints, plume opaqueness or other factors. Pieri et al (2013) detail a programme to make in situ observations simultaneously with ASTER orbital multispectral TIR data acquisitions, in order to compare the two datastreams in terms of SO 2 mass loading and plume dispersion.…”

Unmanned Aerial Mass Spectrometer Systems for In-Situ Volcanic Plume Analysis

“…The overall objective is to better understand how volcanoes work, and specifically to better constrain estimates of persistent background and episodic eruptive trace gas (e.g., SO 2 and others) and carbon dioxide emissions. The specific calibration and validation application using small UAS has been described in a recent Geological Society of London journal paper [11]. The current article focuses on the MS systems integration to UAS platforms together with other peripheral and complementary airborne tested sensor package.…”