Reflectance and temperature characteristics of semiarid rangeland surfaces

Abstract

Spectral and surface temperature measurements were made of various rangeland surface conditions using a hand-held radiometer and an infrared thermometer. Three different soil series, each with three plots with varying surface conditions were studied. T-tests, simple-linear regression analysis, and principal components analysis were used to relate rangeland surface features to spectral and thermal measurements. Vegetation was the feature that had the most effect on surface temperature under dry conditions, and vegetated plots had a lower percent change in daily temperature than bare plots. Under wet conditions, there were no significant differences in temperature between plots with differing surface conditions. Correlation coefficients showed that the hue of the soil was highly correlated with the percent reflectance in all four spectral bands, and the green grass cover decreased the reflectance in bands one, two and three. There were high correlation levels among the spectral bands showing an overlap of spectral information.