Greenwich Magnetic Observatory Magnetograms

Magnetograms are records of variations in the strength and direction of the Earth’s magnetic field. Historically these magnetograms were recorded on paper using photographic techniques. In the UK, measurements were made at eight long-running observatories; Abinger, Eskdalemuir, Falmouth, Greenwich, Hartland, Kew, Lerwick, and Stonyhurst. BGS also hold magnetogram records from the Cape Evans observatory that ran continuously at Robert Falcon Scott’s Antarctic base camp during the British Antarctic Expedition 1910–13. The magnetogram collection, one of the longest running geomagnetic series in the world, provides a continuous record of more than 160 years of UK measurements. These magnetograms start in the 1840s and end in 1986 at which time digital recording of the magnetic field took over and magnetograms can be produced by computer graphic. The plots show variation in the Earth's magnetic field, typically over a 24-hour period. The collection is a valuable, partly untapped data resource for studying geomagnetic storms, space weather and the evolution of the Earth’s magnetic field. The magnetograms provide insight into: • the Earth’s outer core: long-term change (years to centuries) in the dynamo that sustains our magnetic field • space weather: short-term changes (seconds to days) in near-Earth space and on the ground • space climate: long-term change (decades to centuries) in solar activity and consequences for Earth’s environment All the above have an impact on human activities. For example, bad space weather affects technologies that we increasingly rely on, such as electrical power and GPS networks. In response to the threat of loss from degradation due to age and a desire to preserve and exploit old data, BGS undertook a programme of work to digitally photograph, archive and preserve the analogue paper records of magnetic field variation in the United Kingdom. Between 2009 and 2013, high-quality digital images of every available magnetogram were taken. These images are available to search online. Scientists and the general public around the world can now gain easy access to this historical dataset.

地磁图是记录地球磁场强度和方向变化的记录。从历史角度看，这些地磁图曾通过摄影技术记录在纸张上。在英国，测量工作在八个历史悠久的天文台进行；包括阿宾格、埃斯卡达尔穆尔、法尔茅斯、格林尼治、哈特兰、基尤、勒威克和斯托尼赫斯特天文台。英国地质调查局（BGS）还保存了来自凯普伊文斯天文台的地磁图记录，该天文台在1910-13年的英国南极探险期间持续运作于罗伯特·斯科特南极基地。这一地磁图收藏，作为世界上最悠久的地磁系列之一，为英国超过160年的测量数据提供了连续记录。这些地磁图始于19世纪40年代，并于1986年结束，当时数字记录磁场技术取代了传统方法，地磁图可以通过计算机图形生成。图表展示了地球磁场的变动，通常涵盖24小时周期。该收藏是一笔宝贵且部分未被充分开发的宝贵数据资源，对于研究地磁风暴、太空天气以及地球磁场演变具有重要意义。地磁图提供了对以下方面的洞察：•地球的外核：维持我们磁场的地球磁发电机在数年至数百年时间尺度上的长期变化；•太空天气：近地空间和地面上的短期变化（秒至数天）；•太空气候：数十年至数百年时间尺度上太阳活动及其对地球环境的长期变化。所有这些均对人类活动产生影响。例如，恶劣的太空天气会影响我们日益依赖的技术，如电力和GPS网络。为了应对因年代久远而导致的退化风险，以及保存和利用旧数据的愿望，BGS开展了一项工作计划，对英国磁场变化的模拟纸张记录进行数字化摄影、存档和保护。在2009年至2013年期间，对每一个可用的地磁图都进行了高质量数字图像的拍摄。这些图像现在可以在网上进行搜索。世界各地的科学家和公众现在可以轻松访问这一历史数据集。