TGO Ramfjordmoen Ionosonde Data July 1987

About this dataset: This dataset contains ionograms in PNG format and covers data from July 01-31, 1987.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），覆盖1987年7月1日至31日的数据。

关于特罗姆瑟电离层测高仪（Tromsø Ionosonde，1984-1992）：1984-1992年间，该电离层测高仪位于挪威特罗姆瑟附近的拉姆峡湾（Ramfjordmoen），坐标为北纬69°35′、东经19°13′，由特罗姆瑟大学极光观测站运营。该仪器于1984年前便在此处运行，且截至2018年仍在该地点运行；详情请参见相关出版物。该仪器为全数字化设备，基于惠普（Hewlett Packard）21MX计算机构建。低功率发射器与互补码传输（complementary code transmission）的组合，使得特罗姆瑟电离层测高仪在性能上等同于当时配备20微秒脉冲和16千瓦峰值功率的传统电离层测高仪。常规运行模式为每20分钟生成一幅电离图，频率扫描范围为1 MHz至12 MHz，扫描时长为2至3分钟。对于100公里高度区域，散见E层（sporadic E layer）高度的测定精度为±3公里。电离图存储于磁带上。计算机程序中的噪声判别程序将存储数据量压缩至原始数据的10%以下。通过这种方式，一盘2400英尺的磁带可存储约1300幅电离图，相当于18天的数据量。读取这些磁带时，其已使用4至11年，导致在向其他介质传输过程中约有20%的数据丢失。目前，数据存储于在线磁盘，并通过多种介质进行离线归档。