Impact of Vegetation Structure on Drought Indices Based on MODIS Spectrum
DU Ling-tong1,2, TIAN Qing-jiu2, WANG Lei1,2
1. Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in North-Western China of Ministry of Education, Ningxia University, Yinchuan 750021, China 2. International Institute for Earth System Science, Nanjing University, Nanjing 210093, China
Abstract：The drought indices based on MODIS spectral reflectance data are widely used for drought characterization and monitoring in agricultural context. Based on the PROSAIL model and MODIS observational data in Shandong in 2010, the present paper studied the impact of vegetation structure of leaf area index and physiological growth cycle on MODIS spectral drought index. The results showed that the reflectance of three MODIS bands in spectrum of near-infrared and shortwave infrared changes significantly with leaf water content of vegetation. Therefore, the five kinds of MODIS spectral drought index constructed by those MODIS bands can be used to monitor the leaf water content of vegetation. However, all drought indices are affected by leaf area index. In general, the impact is serious in the case of low LAI values and is weakened with the increase in LAI value. The study found that physiological vegetation growth cycle also affects the magnitude of MODIS spectral drought indices. In conclusion, the impact of vegetation structure must be carefully considered when using MODIS spectral drought indices to monitor drought. The conclusion of this study provides a theoretical basis for remote sensing of drought monitoring.
Key words：Vegetation structure;MODIS;Spectral drought index;Leaf water content;PROSAIL
杜灵通1，田庆久2，王 磊1, 2 . 植被结构特征对MODIS光谱干旱指数的影响 [J]. 光谱学与光谱分析, 2015, 35(04): 982-986.
DU Ling-tong1,2, TIAN Qing-jiu2, WANG Lei1,2 . Impact of Vegetation Structure on Drought Indices Based on MODIS Spectrum. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2015, 35(04): 982-986.
[1] TIAN Qing-jiu, GONG Peng, ZHAO Chun-jiang, et al(田庆久, 宫 鹏, 赵春江, 等). Chinese Science Bulletin(科学通报), 2000, 45(24): 2645. [2] ZHANG Jia-hua, XU Yun, YAO Feng-mei, et al(张佳华, 许 云, 姚凤梅, 等). Science China Technological Sciences(中国科学: 技术科学), 2010, 40(10): 1121. [3] LI Hua-peng, ZHANG Shu-qing, GAO Zi-qiang, et al(李华朋, 张树清, 高自强, 等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2013, 33(3): 756. [4] YANG He-qun, BAI Hua, WANG Wei(杨何群, 柏 桦, 王 蔚). Journal of Arid Land Resources and Environment(干旱区资源与环境), 2012, 26(8): 161. [5] YANG Fei, SUN Jiu-lin, ZHANG Bai, et al(杨 飞, 孙九林, 张 柏, 等). Transactions of the Chinese Society of Agricultural Engineering(农业工程学报), 2010, 26(4): 192. [6] Jacquemoud S, Baret F. Remote Sensing of Environment, 1990, 34(2): 75. [7] CAI Bo-feng, SHAO Xia(蔡博峰, 绍 霞). Remote Sensing for Land & Resources(国土资源遥感), 2007，19(2): 39. [8] Gao B C. Remote Sensing of Environment, 1996, 58(3): 257. [9] Chen D, Huang J, Jackson T J. Remote Sensing of Environment, 2005, 98(2-3): 225. [10] Wang L, Qu J J. Geophysical Research Letters, 2007, 34(20): L20405. [11] Ghulam A, Qin Q M, Zhan Z M. Environmental Geology, 2007, 52(6): 1045.
