TGO Ramfjordmoen Ionosonde Data December 1984

About this dataset: This dataset contains ionograms in PNG format and covers data from December 01-31, 1984.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（ionogram），涵盖1984年12月1日至31日的观测数据。关于特罗姆瑟电离测高仪（1984-1992）：1984至1992年间，该电离测高仪部署于挪威特罗姆瑟附近的拉姆峡湾（Ramfjordmoen），地理位置为北纬69°35′、东经19°13′，由特罗姆瑟大学极光观测台负责运维。该仪器早在1984年之前便已在此处运行，截至2018年仍持续运作，详细信息可参阅相关公开出版物。仪器采用全数字化架构，基于惠普（Hewlett Packard）21MX计算机搭建。其低功耗发射机与互补码传输技术的组合方案，使得该特罗姆瑟电离测高仪的性能等效于当时配备20μs脉冲、峰值功率16kW的传统电离测高仪。日常运行模式为每20分钟获取一幅电离图，频率扫描范围覆盖1MHz至12MHz，单次扫描耗时2至3分钟。在100km海拔高度区间内，偶发E层（sporadic E layer）的高度测定精度可达±3km。早期该类电离图均存储于磁带上，计算机程序内置的噪声判别程序可将存储数据压缩至原始数据的10%以内。按此压缩比例计算，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。这批磁带在读取时已存放4至11年，因此在转存至其他介质的过程中出现了约20%的数据丢失。目前，本数据集已实现在线磁盘存储，并辅以离线多介质归档存储。