Quantitative Determination of the Optimal Scale for the Proportion of Saline-Alkali Patches of Soda Saline-Alkali Land in Northeast China

作者：Yakun Cao, Guanglei Hou, Ziqi Chen, Yanfei Gong, Jinyuan Zhou, Zhaoli Liu · 发表于：IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing · 年份：2024 · DOI：10.1109/jstars.2024.3366773 · 被引用次数：5 · 研究领域：Remote Sensing and Land Use、Climate change and permafrost、Landslides and related hazards

As an important index reflecting the degree of soil salinization and alkalization, the proportion of saline-alkali patches (PSP) is beneficial for identifying the degree of saline-alkali land on a large scale with high spatial heterogeneity. However, determining the optimal scale for observing PSP remains inconclusive. In this study, we considered a typical area of saline-alkali land, which is located in Da'an City in Northeast China, as an example and selected nine sample areas from the Sentinel-2A remote sensing images to calculate the salt index (SI). According to the semivariogram function, we obtained the spatial autocorrelation range of the average radius of saline-alkali land. By combining the Nyquist-Shannon sampling theory, we determined the optimal scale for the remote sensing monitoring of saline-alkali land in Da'an City. The PSP index is calculated using this scale. The results were as follows: (1) the optimal scale for the remote sensing monitoring of saline-alkali land in Da'an City is 41.2 m, and the calculated PSP index at this scale has the best correlation with the measured pH value data (R2 = 0.828). (2) Using the PSP index calculated at this scale, we divided the degree of saline-alkali land in Da'an City into three grades. Among them, the slightly, moderately, and severely saline-alkali lands cover areas of 90.52, 111.78, and 959.77 km2, respectively. In this study, we propose a new method for grading the degree of soil salinization and alkalization on l...