RESUMO
Polarized laser remote-sensing measurements that correlate the yield, the normalized difference vegetation index, and the leaf area index with the depolarized backscattered radiation from corn plots grown with eight different nitrogen fertilization dosages are presented. A polarized Nd:YAG laser emitting at 1064 and 532 nm is used. Depolarization increased significantly with increasing fertilization at the infrared wavelength, and there was a decrease in the depolarization at the green wavelength. The depolarization spectral difference index, defined as the absolute difference in the depolarization at the two wavelengths, is introduced as a parameter that is an indicator of the condition of the internal leaf structure.
RESUMO
Measurement of atmospheric temperature through the monitoring of laser energy absorption at the center of an O(2) resonant absorption line near 770 nm has been demonstrated using a dual frequency system. The average temperature of a 1-km path can be determined to better than 1.0 degrees C with a noise level of 0.3 degrees C. An iterative algebraic expression for determining temperature from the measured absorption was developed and shown to be applicable in the troposphere. The effects of pressure and humidity on temperature determination are clear from the algorithm and found to be small near the earth's surface.
