基于NDVI的近20年包头市植被覆盖度时空变化研究

Study on spatiotemporal changes of fractional vegetation cover in Baotou City based on NDVIin the past 20 years

摘要:

【目的】 评估包头市2000-2021 年近20 年生态修复治理成效。【方法】 基于2000-2021 年5期植被生长旺季的LandSat TM/OLI 影像数据，利用归一化植被指数（NDVI）和像元二分模型法研究包头市2000-2021 年植被覆盖度时空动态变化特征，并利用2021 年同时段土默特右旗地区的“珠海一号”OHS 影像数据进行精度评价。【结果】 1）精度评价显示，利用2021 年同时段的LandSat-8 数据和OHS 数据对土默特右旗地区不同等级植被覆盖度进行估算，其空间分布和覆盖面积具有较高的相似性，相似度达到86. 96%；2）包头市2000-2021 年植被覆盖度类型整体以低和中植被覆盖度为主，二者占总植被覆盖面积的65% 以上；3）包头市2000-2021 年植被覆盖度变化平均值为0. 052 8，不同时期的平均植被覆盖度变化量表现为先负后正，相对植被覆盖面积先减小后增大，植被覆盖情况总体上表现为先轻度退化后轻度改善。【结论】 2000-2021 年，包头市植被覆盖度整体呈现先减少后增大的趋势，全市生态环境状况表现为先退化后改善，包头市植被覆盖度变化研究对其生态环境修复治理成效具有重要的指示性意义。

Abstract:

【Objective】 This paper aimed to evaluate the effectiveness of ecological restoration and governance in‐Baotou City over the past 20 years，from 2000 to 2021.【Method】 The study analyzed Fractional Vegetation Cover （FVC） and its spatiotemporal dynamic changes using the Normalized Differential Vegetation Index （NDVI） anddimidiatepixel model，based on the LandSat TM/OLI image data from five periods of peak vegetation growth between2000 to 2021. Additionally OHS image data from“Zhuhai-1” satellite for the Tumet Right Banner in 2021were used for accuracy evaluation.【Result】 Accuracy evaluation showed that Land Sat-8 data and OHS data fromthe same period in 2021 exhibited high similarity in the spatial distribution and coverage area at different FVC levelsin the Tumote Right Banner area，with a similarity of 86. 96%. This suggests that the FVC inversion using LandSatdata was accurate and feasible. From 2000 to 2021，the FVC types in Baotou City were predominantly low and medium，accounting for over 65% of the total FVC. The average change in FVC during this period was 0. 052 8. FVCchanged over different periods exhibited an initial decrease followed by an increase，indicating a general trend of slightdegradation followed by slight improvement in vegetation coverage.【Conclusion】 During the period from 2000 to2021，Baotou City’s vegetation coverage initially decreased and then increased，reflecting a period of ecological degradationfollowed by improvement. This research highlights the significant implications for ecological environmental remediationin Baotou City.