巴音布鲁克草原植被覆盖度估算的光谱模型及其应用

Spectral Models for Estimating Vegetation Coverage and Its Application on Bayanbulak Grassland

[目的]对新疆维吾尔自治区巴音布鲁克草原植被覆盖度进行初步划分,并对植被覆盖度等级分布进行分析,为防治该区草场退化工作提供理论参考。[方法]采用美国SOC_710便携式可见/近红外高光谱成像光谱仪,运用线性回归分析法,以实测归一化植被指数(SOC_NDVI)为媒介,建立MODIS/TERRA卫星的NDVI(MODIS_NDVI)与实测植被覆盖度(VC)之间的MODIS光谱估算模型,并对模型精度进行检验。最后,在模型反演结果上进行研究区植被覆盖度的划分与分析。[结果]MODIS光谱估算模型预测精度较高,标准误差为11.55%,总体预测精度达到88.92%。划分的5个植被覆盖度等级分别为:极高覆盖、高覆盖、中覆盖、低覆盖及极低覆盖。它们在研究区中所占比例分别为:18.87%,25.61%,31.28%,13.86%和10.38%。[结论]整体上,研究区植被覆盖度呈现出北部和西部高,东部低的趋势,中、高覆盖度区域所占比重较大,低、极低、极高覆盖度区域所占比重较小。

[Objective] Vegetation coverage in Bayanbulak grassland of Xinjiang Autonomous Region was graded and the regional vegetation coverage was determined in order to provide theoretical reference for the prevention pasture degradation. [Methods] With the help of American SOC_710 portable visible/the near infrared spectrum imaging spectrometer, the normalized difference vegetation index（SOC_NDVI） was adopted to establish the MODIS spectral estimation model between NDVI（MODIS_NDVI） and actual vegetation coverage（VC） using linear regression analysis method. The grading and determining of regional vegetation coverage were completed on the inversion coverage result of the model. [Results] The prediction accuracy of MODIS spectral estimation model was high with a standard error of 11.55%, the overall accuracy reached 88.92%. The 5 vegetation coverage levels had extreme high coverage, high, moderate, low and extreme low coverage, and these coverage proportion were： 18.87%, 25.61%, 31.28%, 13.86% and 10.38%. [Conclusion] The vegetation coverage on the whole study area was high in the north and west, and low in the east. The research area was covered mainly by middle and high coverage grades; proportions of other coverage grades as low, extreme low and extreme high, were small.