Grazing effects on seasonal dynamics and interannual variabilities of spectral reflectance in semi-arid grassland in Inner Mongolia
Grazing effects on seasonal dynamics and interannual variabilities of spectral reflectance in semi-arid grassland in Inner Mongolia
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DOI：
10.1007/s11104-010-0448-5
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发表时间：
2011-03
期刊：
影响因子：
4.9
通讯作者：
L. Fan;B. Ketzer;Huizhi Liu;C. Bernhofer
中科院分区：
文献类型：
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作者：
L. Fan;B. Ketzer;Huizhi Liu;C. Bernhofer
研究土地管理对草地反射率季节动态和年际变化的影响，有助于监测放牧对草地生态系统的影响，具有重要的科学意义和实用价值。在2005年和2006年的生长季节，我们进行了光谱反射率测量，在五个不同的放牧地点在内蒙古，中国，使用便携式，高分辨率光谱仪。通过对实测地表反射率光谱和推导出的可见光波长和NDVI的分析，发现放牧影响了反射率光谱的形状，影响了可见光波长和NDVI的季节格局;放牧地的可见光波长和NDVI对降水的敏感性高于未放牧地。此外，我们观察到一个明确的线性关系之间的总短波和可见光（PAR）的净辐射，与R = 0.83和R = 0.94，分别为2005年和2006年，和NDVI和总短波净辐射与R =-0.92。因此，在处理不同的放牧强度时，归一化差异植被指数光谱仪测量值和短波总日射强度计测量值是可以互换的。
Detecting the influences of land management on seasonal dynamics and interannual variabilities of grassland surface reflectance is of scientific and practical importance as it can help to monitor grazing effects on the grassland ecosystem. We conducted spectral reflectance measurements at five differently grazed sites in Inner Mongolia, China, during the growing seasons of 2005 and 2006 using a portable, highly resolving spectrometer. Through analyses of the measured surface reflectance spectra and the derived visible albedo and NDVI, we found that grazing influences the reflectance spectrum shape and affects the visible albedo and NDVI seasonal pattern; visible albedo and NDVI of grazed sites are more sensitive to precipitation than that of ungrazed sites. In addition, we observed a well-defined linear relationship between total shortwave and visible (PAR) albedo, withR= 0.83 andR= 0.94 for 2005 and 2006, respectively, and between NDVI and total shortwave albedo withR= −0.92. Thus, NDVI spectrometer measurements and total shortwave albedo pyranometer measurements are interchangeable when addressing different grazing intensities.