基于多源遥感影像的盐碱地治理效果

将Landsat-8 OLI影像与Sentinel-2号影像结合，利用光合有效辐射比率（FPAR），构建适用于MODIS植被总初级生产力（GPP）影像空间分辨率提高的逐层逐像元修正因子，实现内蒙古巴彦淖尔市赵贵圪旦组盐碱地农田改良前后的植被长势监测，同时结合不同深度土壤的含盐量数据，采用转移矩阵方法与热点分析方法分别分析了全局土壤含盐量变化与植被长势变化的局部差异。结果表明：（1）12-20号地块内土壤含盐量改良效果最明显，且研究区改良效果随土壤深度增加而逐渐降低。土壤深度0-20cm，盐土向中度盐土转入面积最大；土壤深度20-40cm，强度盐土向中度盐土转入面积最大；土壤深度40-60cm，强度盐土与盐土的转入面积大于转出面积，其他土壤的转入面积小于转出面积。（2）研究区内，GPP提升区域比降低区域面积约多60.36hm²，占研究区面积的42.88%；同时，对改良前植被GPP低值区域提高效果更明显。（3） GPP提升区域中热点区域集中分布在12-17、25-27、34号地块内，该区域改良效果显著；GPP降低区域中冷点区域集中分布在6、12-14、22-23、27-28、30-31号地块内，该区域改良效果差。

Effectiveness of improving saline-alkali soil based on multi-source remote sensing images

In this paper, Landsat-8 OLI images were combined with Sentinel-2 images, and the Fraction of Photosynthetic Active Radiation (FPAR) was used to construct the pixel-by-layer correction factor that was applied to improve the spatial resolution of the MODIS Gross Primary Production (GPP) images. Based on this, the vegetation growth status before and after the improvement of saline-alkali farmland was studied in Zhaogui Gedan formation in Bayannur City, the Inner Mongolia. At the same time, combined with the data of soil salinity at different depths, this paper used the transfer matrix method and hot spot analysis method to study the global changes in soil salinity and the local differences in changes of vegetation growth. The results showed that:(1) the most obvious improvement effect of soil salinity was found in the plots 12-20, and the improvement effect gradually decreased with the increase of soil depth. In the soil depth 0-20 cm, the conversion area of the saline soil to the moderately saline soil was the largest; In the soil depth 20-40 cm, the conversion area of the severely saline soil to the moderately saline soil was the largest; In the soil depth 40-60 cm, the area transferred in of the severely saline soil and the saline soil was larger than the area transferred out, while the area transferred in of the other soil types was smaller than the area transferred out. (2) The lifting area of GPP was about 603.6 thousand m² more than the lowering area, accounting for 42.88% of the study area. Meanwhile, the improvement effect was more obvious in the area with low GPP before improvement. (3) The hot spots in the lifting area of GPP were concentrated in the plots 12-17, 25-27, and 34, indicating that the improvement effect of this area was significant. The cold spots in the lowering area of GPP were concentrated in the plots 6, 12-14, 22-23, 27-28, and 30-31, indicating that the improvement effect in this area was poor.