Abstract In Phase III of the North American Forest Dynamics (NAFD) study an automatic workflow has been developed for evaluating forest disturbance history using Landsat observations. It has four major components: an automated approach for image selection and preprocessing, the vegetation change tracker (VCT) forest disturbance analysis, postprocessing, and validation. This approach has been applied to the conterminous US (CONUS) to produce a comprehensive analysis of US forest disturbance history using the NASA Earth Exchange (NEX) cloud computing system. The resultant NAFD-NEX product includes 25 annual forest disturbance maps for 1986–2010 and two time-integrated maps to provide spatial-temporal synoptic view of disturbances over this time period. These maps were derived based on 24,000+ scenes selected from 350,000+ available Landsat images at 30-m resolution, and were validated using a visual assessment of Landsat time-series images in combination with high-resolution and other ancillary data sources over samples selected using a probability based sampling method. The validation revealed no major biases in the NAFD-NEX maps for disturbance events that resulted in at least 20% canopy cover loss. The average user's and producer's accuracies for the disturbance class were 53.6% and 53.3%, respectively, with the individual year's user's accuracy varying from 42.8% to 73.6% and producer's accuracy from 39.0% to 84.8% over the 25-year period. The NAFD-NEX disturbance maps are available from a web portal of the Oak Ridge National Laboratory Distributed Active Archive Center (ORNL-DAAC) at https://doi.org/10.3334/ORNLDAAC/1290 .

中文翻译：

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开发基于 Landsat 的年度美国森林干扰历史地图（1986-2010）以支持北美碳计划 (NACP)

摘要 在北美森林动力学 (NAFD) 研究的第三阶段，开发了一个自动工作流程，用于使用 Landsat 观测评估森林干扰历史。它有四个主要组成部分：图像选择和预处理的自动化方法、植被变化跟踪器 (VCT) 森林干扰分析、后处理和验证。该方法已应用于美国本土 (CONUS)，以使用 NASA 地球交换 (NEX) 云计算系统对美国森林干扰历史进行全面分析。由此产生的 NAFD-NEX 产品包括 1986-2010 年的 25 张年度森林干扰图和两个时间积分图，以提供该时间段内干扰的时空综合视图。这些地图是基于从 350 个场景中选择的 24,000 多个场景得出的，000 多张 30 米分辨率的可用 Landsat 图像，并使用 Landsat 时间序列图像的视觉评估结合高分辨率和其他辅助数据源对使用基于概率的采样方法选择的样本进行验证。验证显示 NAFD-NEX 图中的干扰事件没有重大偏差，导致至少 20% 的冠层覆盖损失。平均用户和生产者对扰动等级的准确度分别为 53.6% 和 53.3%，在 25 年期间，个别年份的用户准确度从 42.8% 到 73.6% 不等，生产者准确度从 39.0% 到 84.8% 不等。NAFD-NEX 扰动图可从橡树岭国家实验室分布式活动档案中心 (ORNL-DAAC) 的门户网站获取，网址为 https://doi.org/10.3334/ORNLDAAC/1290。