地磁活动指数的过去、现在和未来

地磁活动性是范围广、分量多、种类繁、形态异、频谱宽、原因复杂的时变过程.面对如此复杂的地磁活动性,除了分门别类逐一进行深入研究之外,根据实测资料,用简便易行的分类和简单明了的指标,对地磁活动性进行总体检阅和形态学描述也是非常必要的.于是,各种地磁活动指数应运而生.地磁指数不仅是表征地磁活动现象的重要参数,其应用范围逐渐扩展到日地能量耦合计算、电离层一磁层一太阳风空问环境状态描述、空间环境监测、空间天气预报等许多相关领域."地磁活动指数化"的思想正在向别的领域扩展,其构建原理和量算方法也在不断改进和完善.本文将现有的约50种地磁活动指数分两大类型,综述其提出背景和发展过程,分析其使用范围和优缺点,探讨地磁活动指数未来发展的趋势.

Yesterday, today and tomorrow of geomagnetic indices

Geomagnetic disturbances, or activities, are extremely complicated phenomena with broad aspects, multiple components, different morphology, wide spectra, and complicated mechanisms. It is certainly necessary to physically study each of the disturbances. However, it has proved very valuable to derive various indices on the basis of local disturbances at many individual stations, although some of them take little or no account of the structure of the disturbance field and its mechanisms. Many magnetic observatories throughout the world send their local indices to an international center at De Bilt in the Netherlands, which is linked with the Permanent Service of Geomagnetic indices at Gottingen, Germany. There the local indices are used as the basis for world indices. The indices have been applied with great success not only in the geomagnetism, but also in related fields, such as solar-terrestrial coupling, cosmic rays, and space weather prediction. In this paper about 50 magnetic indices are reviewed in two groups, respectively for the overall activity level and certain kind of disturbances. A brief overview on the history of magnetic indices, merits and drawbacks, and future perspective is given.