Boletín de la Sociedad Geológica Mexicana Volumen 70, núm. 3, 2018, p. 709- 729 http://dx.doi.org/10.18268/BSGM2018v70n3a7

Comparación del flujo de emisión de SO₂ derivadas de COSPEC y MODIS y su complementariedad en el monitoreo volcánico: caso de estudio en el Volcán Popocatépetl (México)

José Carlos Jiménez-Escalona¹, Alejandro Monsivais-Huertero¹, Hugo Delgado-Granados², Oliver Maciel Huerta-Chávez¹

¹Escuela Superior de Ingeniería Mecánica y Eléctrica Unidad Ticomán, Instituto Politécnico Nacional, Av. Ticomán 600, San José Ticomán, Delegación Gustavo A. Madero, 07340 CDMX, México. 
²Instituto de Geofísica, Universidad Nacional Autónoma de México, Circuito de la investigación Científica s/n, Ciudad Universitaria, Delegación Coyoacán, 04510 CDMX, México.

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Abstract

One of the main elements monitored in volcanic emissions is SO₂ due to the contrast of concentrations between the volcanos compared to the background of the atmosphere. Different methodologies have been developed from remote sensing techniques from the ground and from space. In particular, the COSPEC technique has been used efficiently from terrestrial vehicles, allowing the emission rate of SO₂ with estimated relative errors of ± 13% to ± 42% to be obtained. However, the logistics required to carry out continuous measurement campaigns in the Popocatepetl area, allows exclusively 2 or 3 measurements a month and only during daylight hours. Another type of methodology based on remote sensing is the processing of satellite images in the thermal infrared. In this case, the use of MODIS images allows obtaining daily SO₂ information both in images taken at daylight hours or during the night period, which gives a maximum temporal resolution of images for the sensor in the study area (maximum 4 images per day). In order to construct time series from both techniques, the flux of SO₂ derived from the COSPEC sensor are used as a reference, which allows the MODIS image identification within the area of the plume that was sampled with the COSPEC sensor. We aim to propose an adjustment methodology to reconstruct the information with the aforementioned values. Between November 2006 to February 2007 in the Popocatepetl volcano area, we found a good match between the two techniques, which indicates that the adjustment methodology proposal to obtain data calibration equations could be applied during periods of time when simultaneous data from both sensors are available.

Keywords: volcano monitoring, remote sensing, MODIS, COSPEC.