Solar Terrestrial Physics facilities supported by STFC

930 MHz UHF transmitter/receiver at Tromso, Norway.

930 MHz UHF receivers at Kiruna, Sweden and Sodankyla, Finland

224 MHz VHF transmitter/receiver at Tromso, Norway.

500 MHz two-dish UHF transmitter/receiver at Longyearbyen, Svalbard (ESR)

HF Heater (frequencies 3.85 to 8 MHz) at Tromso, Norway.

Frequency-Agile Advanced Sounder (Dynasonde) at Tromso, Norway.

The UHF, VHF and ESR radars measure incoherent scatter signals from altitudes between the middle atmosphere and the topside ionosphere (an altitude range from 70 to >1000km).

Dynasonde measures HF reflected signals from E and F regions.

Heater does not make independent measurements but is used to create ionospheric perturbations observed in the other systems.

From the incoherent scatter spectrum, the following ionospheric parameters can be obtained directly: Electron Density, Electron temperature, Ion temperature, Line-of-Sight Velocity, Ion-Neutral Collision Frequency, Ion Composition.

The following additional parameters can be obtained with some assumptions: Neutral Density, Neutral Temperature, Neutral Velocity, Pedersen and Hall Conductivity, Current Density, Heat Flux.

The Dynasonde measures phase delay, Doppler velocity, angle of arrival, and polarisation of received signals. From these, horizontal position information (skymaps) and drift velocities can be calculated. Special Dynasonde modes allow operation as a HF radar or Partial Reflection Instrument.

UHF radars up to 1000 km range around Tromso and Longyearbyen. VHF radar up to 2000 km range within 15 degrees of Tromso meridian (north to vertical only). Coverage for both systems depends on the solar cycle (greatest at solar maximum). Heater effects can extend some hundreds of km around Tromso Dynasonde echo location works over a few hundred km around Tromso.

Experiment dependant Can vary from a few hundred metres to hundreds of kilometres according to selected pulse schemes.

Typical pre-integration times are of order 5 to 10 seconds. Much shorter integration times (less than a second) are possible in certain specialised experiments. Further post-integration can be carried out by the user to obtain data of the desired accuracy.

Addresses the whole range of STP science from studies of the solar wind (via IPS) through reconnection effects, magnetospheric, auroral, and ionospheric physics to mesopause/middle atmosphere studies.

A whole range of events are observable from solar wind irregularities, reconnection and pressure pulse events and ionospheric effects of substorms on the macroscale to generation of small-scale instabilities and anomalous thermal velocity distribution on the microscale.

The UK EISCAT database at RAL contains many thousands of hours of Common and Special Programme data recorded. UHF data are available from 1981, VHF data from 1986 and ESR data from 1996. The mainland radars run for about 2000 hours per year in total, and the ESR for about 1000 hours per year. The data are divided evenly between Common and Special Programmes. Raw data are available at RAL for all UK Special Programmes and much of the Common Programme data. Analysed Common Programme data (and some Special Programme data) are available on-line via the Madrigal database.

Yes, by arrangement with EISCAT staff.

A very extensive data archive is available. Analysed data are usually available very quickly after they are taken. Raw data from UK Special Programmes are returned at the end of each campaign. Raw CP data can take longer, depending on demand and speed of distribution of EISCAT HQ. Dynasonde data are transferred automatically from Tromso to RAL every night and made available the following day.

The Madrigal database holds a large amount of analysed EISCAT data in the form of downloadable files, together with plots, logs etc. It can be accessed at www.eiscat.uit.no. Plots of analysed data from the UK EISCAT archive can be accessed via the RAL EISCAT group's website (link opens in a new window). The raw data cannot be accessed over the web, but is available to registered users of the EISCAT project computers at RAL. Registration is freely available to UK scientists and students. Once logged on, users can work with extensive software facilities to access, manipulate and analyse the data. The full UK database of EISCAT raw data (>2TB) is continuously available in this way.

UK special programmes are run for around 200 hours per year on the mainland radars and 100 hours per year on the ESR. UK time is awarded in peer-reviewed allocation rounds, which take place 3 times a year with deadlines for submission of proposals of 15 January, 15 May, and 15 September.

UK EISCAT experiments are normally collected into campaigns which take place 3 or 4 times per year. UK scientists can thus take a full part in running their own programmes under the supervision of a Campaign Manager responsible for co-ordinating the experiments.

Analysed data are generally distributed in a binary format based on that used by the CEDAR database at NCAR. The formats used in the Madrigal and RAL databases were both derived from this standard, and software to read them is available on the project computers at RAL. Programs are also available to produce the output in human-readable ascii form, or to read the data into C, FORTRAN, IDL and matlab programs. Raw data from all of the EISCAT radars consists of one file per dump in matlab format. A great deal of analysis, integration and visualisation software exists to support both the raw and analysed data formats. Other specialised formats have occasionally been produced according to the requirements of individual users.

The EISCAT project comprises all of the facilities referred to above i.e the EISCAT UHF radars, EISCAT VHF radar, EISCAT Svalbard radar, HP Heater and the Dynasonde. These facilities play a key role in ISTP studies and should thus be seen in the context of other international facilities such as satellites and ground-based radars.

The RAL database holds data from all the above facilities (UHF, VHF, ESR and Dynasonde) together with appropriate analysis software. There is no heater data as such. The heater is used for modification of the ionosphere which can then be observed using the other instruments.

Email to:Dr Ian McCrea