Tatem Andrew J, Nayar Anjali, Hay Simon I
TALA Research Group, Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
Int J Remote Sens. 2007 Feb 22;27(14):3073-3078. doi: 10.1080/01431160600589195.
This study examines the utility of NASA's circa 1990 and circa 2000 global orthorectified Landsat dataset for land cover and land use change mapping and monitoring across Africa. This is achieved by comparing the temporal and spatial variation of NDVI, measured independently by the NOAA-AVHRR at the time of Landsat scene acquisition, against the seasonal mean for each Landsat scene extent. Decadal sequences of drift-corrected NOAA-AVHRR imagery were used to calculate NDVI means and standard deviations for the periods covered by the scenes composing the c.1990 and c.2000 Landsat datasets. The specific NOAA-AVHRR NDVI values at the acquisition date of each individual Landsat scene were also calculated and the differences, both from the mean and scaled by standard deviation, were mapped for the Landsat scene footprints in the c.1990 and c.2000 datasets. The resulting maps show the temporal position of each Landsat scene within the seasonal NDVI cycle, and provide a valuable guide to assist in quantifying uncertainty and interpreting land cover and land use changes inferred from these Landsat data.
本研究探讨了美国国家航空航天局（NASA）大约1990年和大约2000年的全球正射校正陆地卫星数据集在绘制和监测整个非洲土地覆盖和土地利用变化方面的效用。通过将陆地卫星图像采集时由美国国家海洋和大气管理局（NOAA）的高级甚高分辨率辐射计（AVHRR）独立测量的归一化植被指数（NDVI）的时空变化与每个陆地卫星图像范围的季节性平均值进行比较来实现这一目标。利用经过漂移校正的NOAA-AVHRR图像的十年序列，计算构成约1990年和2000年陆地卫星数据集的各图像所覆盖时期的NDVI平均值和标准差。还计算了每个陆地卫星图像采集日期的特定NOAA-AVHRR NDVI值，并将与平均值的差异以及按标准差缩放后的差异，针对约1990年和2000年数据集中陆地卫星图像的足迹进行了制图。所得地图显示了每个陆地卫星图像在季节性NDVI周期内的时间位置，并为协助量化不确定性以及解释从这些陆地卫星数据推断出的土地覆盖和土地利用变化提供了有价值的指导。
