摘要
小麦倒伏后茎秆和叶片在探测视场中的比例及植株组分的受光条件发生了变化,其冠层光谱特性也随之发生改变,所以利用遥感监测倒伏是可能的。首先,分析了叶片和茎秆组分的光谱特点,解释了倒伏后冠层光谱的变化特点,即光谱反射率随倒伏角度的增加而增加。其次,利用倒伏后冠层光谱反射率在可见光波段的相对增幅高于近红外波段的特点,利用实测数据分析和建立了归一化差异植被指数NDVI随倒伏角度的增加而降低的规律及模型。最后,采用2003年4月7日和5月9日倒伏发生前后的2景LandsatETM卫星影像,利用倒伏前后的NDVI值的变化,成功监测了小麦倒伏的发生程度。
The ratio and illumination of wheat plant’s leaf and stalk in spectrometer’s field of view change due to wheat lodging,so it is possible to detect the lodging grade by remote sensing technique.Firstly,the spectral difference between leaf and stalk is analyzed,and how canopy spectral reflectance increases with lodge angle is explained.Secondly,because the relative increase of spectral reflectance in visible bands is larger than in near infrared bands,the significant negative correlation model between lodging angle and NDVI was built by statistical analysis.Finally,two LandSat ETM satellite images of April7(before lodging)andMay9,2003(after lodging)were selected,and the ratio of NDVI derived fromthe two images was statistically correlated to the lodging grade,and the lodging grade was successfully regressed.
出处
《遥感学报》
EI
CSCD
北大核心
2005年第3期323-327,共5页
NATIONAL REMOTE SENSING BULLETIN
基金
国家863项目(2003AA209040)
北京市自然科学基金项目(4042014)资助。
关键词
光谱
归一化差异植被指数
倒伏
多时相
spectra
normalized difference vegetation index(NDVI)
lodging
multiˉtemporal
