Mapping the fractional cover of nonphotosynthetic vegetation and its spatiotemporal variations in the Xilingol grassland using MODIS imagery (2000−2019)
Mapping the fractional cover of nonphotosynthetic vegetation and its spatiotemporal variations in the Xilingol grassland using MODIS imagery (2000−2019)
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利用MODIS影像绘制锡林郭勒草原非光合植被覆盖度及其时空变化（2000年—2019年）
DOI：
10.1080/10106049.2020.1801860
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发表时间：
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影响因子：
3.8
通讯作者：
Zhoulong Wang
中科院分区：
文献类型：
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作者：
Guoqi Chai;Jingpu Wang;Mengquan Wu;Guoqing Li;Li Zhang;Zhoulong Wang
准确获取草地非光合植被覆盖度（fNPV）信息对于监测土壤侵蚀风险、评估草地生产力和管理草地生态系统至关重要。然而，很少有研究监测的NPV在锡林郭勒草原地区（XGR）及其时空变化的基础上，中分辨率成像光谱仪（MODIS）图像。在这项研究中，我们确定了上死燃料指数（DFI）阈值的净现值在XGR。在此基础上，建立了基于地面实测植被净现值和MODIS影像DFI的植被净现值遥感反演模型。基于反演模型，我们得到了2000 - 2019年净现值的空间分布和时空变化。结果表明，DFI能够反映XGR中的净现值，其上限为27.2。DFI-fNPV线性回归模型表现出良好的性能，决定系数（R2）为0.60，留一交叉验证（RMSECV）的均方根误差为0.1574。此外，NPV的空间分布具有明显的异质性，从XGR东北部到XGR西南部呈递减趋势。2000-2019年，XGR年际净现值总体趋势呈波动上升趋势。66.92%的XGR的fNPV增加，相对较小的比例（18.21%）的XGR的fNPV减少。
Obtaining accurate information on the fractional cover of non-photosynthetic vegetation (NPV) (fNPV) on grasslands is essential for monitoring soil erosion risk, assessing grassland productivity and managing grassland ecosystems. However, few studies have monitoredfNPVin the Xilingol grassland region (XGR) and its spatiotemporal variations based on Moderate Resolution Imaging Spectroradiometer (MODIS) images. In this study, we determined the upper dead fuel index (DFI) threshold for NPV in the XGR. Then, a remote-sensing inversion model forfNPVwas established based on the ground-measuredfNPVand the DFI derived from MODIS images. Based on the inversion model, we obtained the spatial distribution and spatiotemporal variations infNPVfrom 2000 to 2019. The results indicated that the DFI can reflect the NPV in the XGR with an upper threshold of 27.2. The DFI-fNPVlinear regression model showed a good performance, with a coefficient of determination (R2) of 0.60 and a root mean square error of leave-one-out cross-validation (RMSECV) of 0.1574. Furthermore, the spatial distribution offNPVexhibited significant heterogeneity, andfNPVdecreased from the northeastern XGR to the southwestern XGR. The overall trend of the interannualfNPVin the XGR increased in a fluctuating manner during 2000–2019. ThefNPVincreased in 66.92% of the XGR and decreased in a relatively small proportion (18.21%) of the XGR.