Observations and Machine-Learned Models of Near-Surface Permafrost along the Koyukuk River, Alaska, USA

This dataset contains GeoTIFs (raster) and GeoPackages (vector) that map observations of near-surface permafrost and not-permafrost from a field campaign conducted near the village of Huslia, AK along the Koyukuk River and its floodplain in July 2018. These data were collected as part of a campaign to understand if and how permafrost impacts riverbank erosion. This problem cannot be assessed without knowing where permafrost exists. Permafrost was observed via frost probing (to a maximum depth of one meter), coring (to a maximum depth of two meters) and bank/bar excavations. An additional boat survey was performed wherein expert (Joel Rowland) judgment assessed the presence or absence of distinctive permafrost features (e.g., overhanging tundra mats, thermoerosional niching, ice wedges, active drainage of ice melt from soils). This dataset also contains the input features and results of two machine learning models (random forest and convolutional neural network) that extrapolate the observations to the full floodplain that may be useful for building, testing, or validating other machine-learned permafrost models. Permafrost data are provided as georasters of the same shape and geovectors (polylines/polygons) and are all projected into EPSG:32605. All data can be visualized with a GIS (QGIS, ArcGIS, etc.).

本数据集包含GeoTIFF 栅格文件（GeoTIF）与地理包（GeoPackage）矢量数据，映射了2018年7月在美国阿拉斯加州胡斯利亚村（Huslia）附近、库尤库克河（Koyukuk River）及其河漫滩开展的野外调查中获取的近地表永久冻土与非永久冻土观测结果。本次数据采集旨在探明永久冻土是否影响河岸侵蚀及其具体作用机制，而若未明确永久冻土的分布范围，则无法开展该问题的相关评估。本次永久冻土观测通过三种手段完成：冻土探测（frost probing，最大探测深度达1米）、取芯（coring，最大取芯深度达2米）以及岸坡/沙洲开挖（bank/bar excavations）。此外还实施了一项船载调查，由专家乔尔·罗兰德（Joel Rowland）凭借专业判断评估标志性永久冻土特征的存在与否，此类特征包括悬垂苔原垫、热侵蚀凹穴、冰楔以及土壤融冰的主动排水现象。本数据集还包含两类机器学习模型的输入特征与训练结果，分别为随机森林（random forest）模型与卷积神经网络（convolutional neural network）模型，二者可将野外观测结果外推至整个河漫滩区域，该外推成果可用于构建、测试或验证其他机器学习驱动的永久冻土模型。永久冻土数据以空间维度一致的地理栅格与地理矢量（多段线/多边形）形式提供，所有数据均投影至EPSG:32605坐标系。所有数据均可通过地理信息系统（GIS，如QGIS、ArcGIS等）进行可视化展示。