摘要
研究波段参数对NDVI估算植被生物物理参数的影响,对于提高NDVI在植被覆盖变化监测中的应用精度具有重要意义。采用无人机载Resonon Pika XC2高光谱仪获取的人工草地高光谱影像,分析红光和近红外波段位置移动与宽度变化对NDVI的影响,评估NDVI对植被盖度的敏感性和植被盖度估算精度。结果表明:波段位置固定时红光和近红外波段宽度扩展对NDVI及其敏感性影响不大,窄波段NDVI估算植被盖度的精度优于宽波段。红光和近红外波段位置向长波方向移动时对NDVI及其敏感性有不同程度的影响,随着敏感性增强NDVI抗扰动性降低,估算植被盖度的精度有所下降。窄波段NDVI的灵敏度系数及其与植被盖度线性拟合的R^(2)波动剧烈,植被盖度估算的位置稳定性较差。10 nm NDVI在不同位置处取得了较高的盖度估算精度,R^(2)最大值为0.83。4种主流卫星影像计算的宽波段NDVI对于高植被覆盖区盖度反演具有良好的适用性,但与窄波段10 nm NDVI相比其盖度反演精度仍然有一定程度的衰减。研究结果可为NDVI精确反演植被参数提供科学参考和依据。
The researches on the effects of band parameters on the biophysical parameters of vegetation estimation using the normalized difference vegetation index(NDVI)have great significance for the improvement in the application accuracy of NDVI in vegetation dynamic monitoring.Based on the hyperspectral images of artificial grassland obtained from a Resonon,Inc.Pika XC2 Hyperspectral Imaging Camera loaded by an unmanned aerial vehicle(UAV),this study analyzes the effects of the positions and width of red and near-infrared bands on NDVI and assesses the sensitivity of NDVI to fractional vegetation cover and the estimation accuracy.The results are as follows.When band positions were fixed,the width expansion of red and near-infrared bands had little effects on NDVI and its sensitivity,and the accuracy of fractional vegetation cover estimated using narrowband NDVI is higher than the accuracy based on broadband NDVI.When the red and near-infrared bands moved towards long waves,the NDVI and its sensitivity were affected to different extents.With an increase in the sensitivity,the anti-disturbance performance of NDVI decreased,and the estimation accuracy of fractional vegetation cover decreased.The sensitivity coefficient of narrowband NDVI and the R^(2)determined by the linear fitting of the sensitivity coefficient and the fractional vegetation cover greatly fluctuated,and the estimated fractional vegetation cover at various locations was unstable.High estimation accuracy of fractional vegetation was obtained at different locations using the 10 nm NDVI,with the maximum R^(2)value of 0.83.The broadband NDVI calculated using four popular satellite images can be well applied in the inversion of the fractional vegetation cover in areas with high vegetation cover.However,its inversion accuracy of fractional vegetation cover still suffered some attenuation compared with narrowband NDVI(10 nm).These results will serve as scientific references and bases for accurate inversion of vegetation parameters using NDVI.
作者
刘咏梅
范鸿建
盖星华
刘建红
王雷
LIU Yongmei;FAN Hongjian;GE Xinghua;LIU Jianhong;WANG Lei(College of Urban and Environmental Science,Northwest University,Xi’an 710127,China;Shaanxi Key Laboratory of Surface System and Environmental Carrying Capacity,Xi’an 710127,China)
出处
《自然资源遥感》
CSCD
北大核心
2021年第3期11-17,共7页
Remote Sensing for Natural Resources
基金
国家自然科学基金项目“退化高寒草甸狼毒遥感识别及其对环境的响应关系”(编号:41871335)。
