Relations between Soil Color and Landsat Reflectance on Semiarid Rangelands

Abstract

The reflectance of radiant energy from the earth's surface in sparsely vegetated arid rangelands is determined by the characteristics of the soil and geologic material on the land's surface. This study measured the color characteristics of earth surface materials collected from a semiarid rangeland in southeastern Arizona and compared these colors to digital numbers recorded by Landsat. Other parameters including particle size, slope, and vegetation were also evaluated, but the color characteristics of the fine earth soil and rock fragments measured with a colorimeter were most strongly correlated to Landsat digital numbers. The numerical values of the color components (hue, value, and chroma) for three different soil and rock fragment size fractions were related in a multiple linear regression equation to Landsat digital reflectance numbers. The R2 for Band 4 (0.5–0.6 µm), Band 5 (0.6–0.7 µm), Band 6 (0.7–0.8 µm), Band 7 (0.8–1.1 µm), and the sum of the four bands were 0.85, 0.69, 0.71, 0.68, and 0.75, respectively. The color of earth surface features in sparsely vegetated land areas should be precisely and accurately determined because of its very strong correlation with remotely sensed spectral data. The use of colorimeters to quantify the color of earth surface features will significantly help in evaluating remotely sensed data, particularly for land‐scapes in arid regions.

Colour space models for soil science

“…10). The subjective nature of the measurements, the need for more than one observer to estimate soil colour and the resulting lack of precision is a major drawback of Munsell soil colour measurements (Post et al, 1994). There are various other studies suggesting the use of spectrophotometers (e.g.…”

Mapping vegetation in a heterogeneous mountain rangeland using landsat data: an alternative method to define and classify land-cover units

“…Variability in the type and shape of rock outcrops, age of the exposed rock (rocks exposed longer have darker, outcrop-like color), together with differences in lichen composition and cover on rock surfaces, are probable causes for the confusions. It is well known that soil and rock color strongly influence reflectance in sites with sparse vegetation (Post et al, 1994). Errors within the grassland domain could be due to high precipitation during the summer, which floods flat lawns during short periods, thus reflecting light like hydromorphic lawns.…”

Avaliação de atributos de Latossolo Bruno e de Terra Bruna Estruturada da região de Guarapuava, Paraná, por meio de sua energia refletida

“…Nesse caso, as diferenças observadas estão relacionadas com as propriedades de reflectância da matéria orgânica e óxidos de ferro (entre outros) que influenciam a cor. Por sinal, o matiz, valor e croma da cor apresentaram correlação significativa com a reflectância na faixa do visível (Quadro 5), concordando com regressões realizadas por Post et al (1994).…”