“Evaluación de la respuesta de tres índices de estrés hídrico en vegetación de la región Pampeana argentina”

HOUSPANOSSIAN JAVIER; RIVAS RAUL; VAZQUEZ PATRICIA; VIVES LUIS

Quito Ecuador

Congreso; IX Congreso Latinoamericano de Hidrología Subterránea; 2008

Asociación Latinoamericana de Hidrología Subterránea para el Desarrollo (ALHSUD)

The objective of this paper is to assess the behavior of three vegetation water stress indexes (WS) calculated by using satellite image (IS) from the Earth Observation System/MODIS with ~1Km2 of spatial resolution. These indexes estimate the water deficit in vegetation from different physical principles. Two of those indexes, the Difference Water Index (NDWI Gao, 1996) and the Difference Infrared Index (NDII Hardisky, 1983), use the Medium Infrared portion of the electromagnetic (EM) spectrum and exploit the reflectivity changes in vegetation in this portion of the EM spectrum. The third index, the Temperature Vegetation Dryness Index (TVDI; Sandholt, 2002), utilizes the changes in vegetation temperature undergoing water stress by using the Thermal Infrared (IRT) portion of the EM spectrum. The results obtained from all indexes were compared with field soil moisture data (SM) measured in a sunflower cropland located in the central area of Buenos Aires Province, Argentine. There was a significant relationship between TVDI and SM (r2=0,86), whereas the NDWI and NDII indexes do not relate significantly with SM.