[Empleo de sensores remotos de corto alcance y aerotransportados en la fenología de los cultivos y variables biofísicas seleccionadas]
Institución:University of Nebraska
The purpose of the thesis was to assess the utility of remote sensing for the measurement of biophysical variables (leaf area index, vegetation fraction, and chlorophyll content) associated with corn, sorghum and soybean crops, during two growing seasons. The research was undertaken at the University of Nebraska-Lincoln Agricultural Research and Development Center (ARDC, near Mead, NE) on experimental plots. Close-range hyperspectral data were collected on 5 dates in 1998, and 5 dates in 1999, using a Spectron SE-590. Both the LAI and chlorophyll content were measured in-situ during collection of spectral information. Vegetation fraction was calculated by screen digitizing and digital processing (unsupervised classifications) of photographs taken above the canopy. Several aircraft overflights were executed during the 1998 and 1999 growing seasons with an ADAR-5500 multispectral (4 channels) sensor system at 2 and 1 m spatial resolution, respectively. The objectives of the thesis were to: 1) relate data transformations, such as red normalized difference vegetation Index (NDVI), green NDVI, and narrow band ratios (i.e. 700 nnV 550nm, 670 nm / 500 nm, NIR/700, MR/550) to biophysical parameters including leaf area index (LAI), vegetation fraction (VF), and chlorophyll conteni (CHL) at the canopy level; and 2) relate results obtained with narrow-band sensors operated at close-range to those obtained with broad-band, aircraft-mounted sensors.