Shelley's Draft Notebooks

Goslee, Nancy Moore

doi:10.1093/oxfordhb/9780199558360.013.0015

Cited by 1 publication

(2 citation statements)

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“…The SL is identified from a graph of the NIR band against the red band. The function for bare soil line (BSL) was used to calculate it from Landsat package in R [46] for each site. This algorithm uses the quantile method to take the lowest set of points, those with an NIR/red ratio less than the limit-th quantile, in this case, defined as 0.1.…”

Section: Soils Reflectance Characteristicsmentioning

confidence: 99%

“…Then, these points were used in a linear regression to estimate the slope that is identified as BSL. This line serves as a reference line and is useful to distinguish different land covers from soil until the full canopy point (maximum vegetation) in which NIR/red ratio greater than the limit-th quantile, and with high NIR values [46,47]. From the BSL line, the slope of this linear function represents each sensed region and differences from this slope between regions, suggest that soil reflectance can be because of different soil properties or unique soil type [48][49][50].…”

Section: Soils Reflectance Characteristicsmentioning

confidence: 99%

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Multiscaling NDVI Series Analysis of Rainfed Cereal in Central Spain

et al. 2021

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Vegetation indices time series analysis is increasingly improved for characterizing agricultural land processes. However, this is challenging because of the multeity of factors affecting vegetation growth. In semiarid regions the rainfall, the soil properties and climate are strongly correlated with crop growth. These relationships are commonly analyzed using the normalized difference vegetation index (NDVI). NDVI series from two sites, belonging to different agroclimatic zones, were examined, decomposing them into the overall average pattern, residuals, and anomalies series. All of them were studied by applying the concept of the generalized Hurst exponent. This is derived from the generalized structure function, which characterizes the series’ scaling properties. The cycle pattern of NDVI series from both zones presented differences that could be explained by the differences in the climatic precipitation pattern and soil characteristics. The significant differences found in the soil reflectance bands confirm the differences in both sites. The scaling properties of NDVI original series were confirmed with Hurst exponents higher than 0.5 showing a persistent structure. The opposite was found when analyzing the residual and the anomaly series with a stronger anti-persistent character. These findings reveal the influences of soil–climate interactions in the dynamic of NDVI series of rainfed cereals in the semiarid.

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Section: Soils Reflectance Characteristicsmentioning

confidence: 99%