大气校正对滨海湿地Sentinel-2影像NDVI的影响

Effects of Atmospheric Corrections on NDVI of Sentinel-2 Images of Coastal Wetlands

为消除卫星影像成像过程中受到的大气干扰,还原真实的地物反射率,大气校正已成为定量遥感分析研究中的关键环节。本文基于2018—2022年间5期黄河三角洲的Sentinel-2影像,通过对比分析大气校正前后的NDVI值,探究大气校正对NDVI计算的必要性。结果发现:(1)大气校正能够对滨海湿地Sentinel-2影像的整体NDVI和不同地类NDVI均产生显著影响,但对不同年份黄河NDVI的影响存在不确定性;(2)大气校正前后NDVI在不同地类间波谱特征变化无较大差异,但大气校正有效增强NDVI极差范围,提高了不同地类NDVI区分度。该研究为大气校正对NDVI存在影响的相关研究提供了参考依据。

In order to eliminate the atmospheric interference during the imaging process of satellite images and restore the real feature reflectivity,atmospheric correction has become a key link in quantitative remote sensing analysis research.In this paper,based on the Sentinel-2 images of the Yellow River Delta for 5 periods from 2018 to 2022,we explored the necessity of atmospheric correction for NDVI calculation by comparing and analyzing the NDVI before and after atmospheric correction.The results are as follows.(1)the atmospheric correction can significantly affect the overall NDVI of the Sentinel-2 images of coastal wetlands,as well as the NDVI of different land classes,but there is uncertainty in the effect on the NDVI of the Yellow River in different years;(2)there is no significant difference in the changes of spectral characteristics of NDVI between different land classes before and after atmospheric correction,but the atmospheric correction effectively enhances the range of NDVI extreme deviation and improves the differentiation of NDVI between different land classes.This study provides a reference basis for research on the effect of atmospheric correction on NDVI.