Pacific arctic sea-ice observations from U.S. Federal logbooks (1900-1938)

This historical sea ice database is constructed from first-hand observations extracted from the logbooks of U.S. federal vessels operating in the Pacific Arctic, and covers the period from 1900 to 1938. During this period the U.S. Revenue Cutter Service (becoming the U.S. Coast Guard in 1915) made annual patrols to Arctic Alaska and Siberia, continuing a practice that began in 1880 and that has persisted in a nearly unbroken series to the present day. These data were transcribed by a team of citizen-scientists participating in the Old Weather project, using a collection of high-resolution photographs of the primary sources held by the National Archives and Records Administration in Washington D.C. Additional work, including reconstruction of the ships’ tracks to hourly resolution from detailed navigational information in the logbooks (e.g. compass bearings, course and distance data), aligning ice observations to the tracks, and compiling and analyzing descriptive sea ice terminology, was jointly produced by experienced Old Weather citizen-scientists and the research team. Descriptive observations are converted into a simple index of ice presence that is presented with a matrix of sea ice and vessel operating terminology recorded in the logbooks. The database also preserves National Archives hyperlinks to the logbook images at the page level in order to facilitate public access and research in the future.

本历史海冰数据库的原始数据取自太平洋北极海域作业的美国联邦船舶航海日志中的一手观测记录，涵盖1900年至1938年时段。在此期间，美国缉私船务局（U.S. Revenue Cutter Service，1915年改组为美国海岸警卫队（U.S. Coast Guard））每年都会前往北极阿拉斯加与西伯利亚执行巡逻任务，这一始于1880年的传统至今仍以近乎不间断的形式延续。本数据集由参与「Old Weather（老天气项目）」的公民科学家团队转录完成，他们依托藏于华盛顿特区美国国家档案与文件署（National Archives and Records Administration）的原始文献高清照片集开展转录工作。后续补充工作则由经验丰富的Old Weather公民科学家团队与研究团队共同完成，内容包括依据航海日志中的详细导航信息（如罗经方位、航向与距离数据）将船舶航迹重构为小时级分辨率的航迹序列、将海冰观测数据与航迹进行匹配，以及整理并分析描述性海冰术语。描述性观测记录将被转换为简易海冰存在指数，并配合日志中记录的海冰与船舶作业术语矩阵予以呈现。本数据库还保留了指向各页面层级航海日志影像的美国国家档案与文件署官方超链接，以便未来公众开展查阅与研究工作。