INIBIOMA   20415
INSTITUTO DE INVESTIGACIONES EN BIODIVERSIDAD Y MEDIOAMBIENTE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Assessment of the impact of the Cordón Caulle 2011 tephra fall on vegetation: an NDVI analysis
Autor/es:
BAUMANN, VALERIE; BIASS, SEBÀSTIEN; DOMÍNGUEZ, LAURA; BRAN, DONALDO MAURICIO; BONADONNA, CONSTANZA; LAMBERTI, MARÍA CLARA; FRISCHKNECHT, CORINE; BRAN, DONALDO EDUARDO
Lugar:
Puerto Varas
Reunión:
Congreso; Cities on Volcanoes 9; 2016
Institución organizadora:
SERNAGEOMIN
Resumen:
Theimpact assessment of the 2011 tephra fallout on Patagonian vegetation wascarried out through the analysis of the Normalized Difference Vegetation Index(NDVI). For a preliminary stage, a regional study was carried out using the MOD13Q1product with a 250 m spatial resolution. This data was acquired by the ModerateResolution Image Spectro-radiometer (MODIS). The NDVI data products used inthis study have been acquired during the month of January, as thephotosynthetic activity and growth rates of the studied vegetation reachmaximum values during this month of the summer season. The evaluation was doneover a time series that encompasses eight years, from 2009 to 2016. Bi-temporalanalyses of the NDVI were carried out, comparing year-to-year changes on NDVI indicesof the selected area, which has about 100,000 km2. While smallchanges in the index are observed for the first two inter-annual periods, asignificant decrease can be identified for the 2011 ? 2012 interlude, forming aNW ? SE trending broad strip. When compared with the isopach maps of the tephradeposit and the prevailing orientation of the plume during the eruptive event,it can be seen that this abrupt change in the index clearly reflects a decay onthe vegetation activity due to the primary tephra fallout. Since then,vegetation does not show a constant recovery rate. Secondary processes, such asash re-mobilization and re-deposition, especially important in the windy semiarid steppe, also affected vegetation. In addition, a strong drought period hasbeen affecting the Patagonian steppe for over 15 years.