TGO Ramfjordmoen Ionosonde Data January 1988

About this dataset: This dataset contains ionograms in PNG format and covers data from January 01-31, 1988.About the Tromsø Ionosonde (1984-1992): During the period 1984-1992 the Ionosonde was situated at 69° 35' N, 19° 13' E at Ramfjordmoen near Tromsø, Norway and operated by the Auroral Observatory of the University of Tromsø. The instrument operated at this location prior to 1984, and still operates there (as of 2018); see the related publication for details. The instrument was fully digitized and based on a Hewlett Packard 21MX computer. The combination of a low power transmitter and complementary code transmission made the Tromsø ionosonde equivalent to a conventional ionosonde (at the time) with 20 µs pulses and 16 kW peak power. Routine operation was one ionogram every 20 min with a frequency sweep from 1 MHz to 12 MHz lasting between 2 and 3 min. For the 100 km altitude region the precision of determining the height of a sporadic E layer is ± 3 km. The ionograms were stored on magnetic tape. A noise discrimination routine in the computer program reduced the stored data to less than 10% of the raw data. In this way one 2400' tape held about 1300 ionograms, equivalent to 18 days' data. The tapes were 4-11 years old when they were read, resulting in around 20% data-loss during the process of transferring to other media. Today, storage is on online disk and with offline an archive on a variety of media.

关于本数据集：本数据集包含PNG格式的电离图（ionograms），涵盖1988年1月1日至31日的观测数据。
特罗姆瑟电离测高仪（Tromsø Ionosonde，1984-1992年）概况：1984年至1992年期间，该电离测高仪部署于挪威特罗姆瑟附近的拉姆峡湾莫恩（Ramfjordmoen），地理坐标为北纬69°35′、东经19°13′，由特罗姆瑟大学极光观测台负责运行维护。该仪器自1984年以前便在此处投入运行，截至2018年仍在该位置正常运作；详细信息可参阅相关学术出版物。
该仪器实现全数字化，基于惠普（Hewlett Packard）21MX计算机搭建。其采用低功率发射机与互补编码传输技术的组合方案，使得本特罗姆瑟电离测高仪的性能等效于当时配备20微秒（µs）脉冲、峰值功率16千瓦（kW）的传统电离测高仪。常规作业模式为每20分钟生成一幅电离图，扫频范围覆盖1兆赫（MHz）至12兆赫，单次扫频耗时2至3分钟。在100千米高度区间内，偶发E层（sporadic E layer）的高度测量精度可达±3千米。
早期所有电离图均存储于磁带介质上。计算机程序内置的噪声甄别程序可将原始数据压缩至原体量的10%以内。按此存储方案，一盘2400英尺长的磁带可存储约1300幅电离图，相当于18天的观测数据总量。在开展数据迁移工作时，这批磁带的已存放时长为4至11年，因此在介质转换过程中约有20%的数据发生丢失。目前，该数据集已实现在线磁盘存储，并辅以多介质离线归档保存。