ENVRIplus Newsletter #3 (Nov 2016)

EISCAT_3D - Our eye on the environment between and space

Anders Tjulin is staff scientist at EISCAT Scientific Association. His scientific background lies in the in-situ exploration of ripples and waves in the solar and other space plasmas, but he has for the last seven years stayed closer to earth working towards the realisation of the EISCAT_3D system. Within ENVRIplus, Anders is the leader of Work Package 10.

The earth and the lap with many other areas of reliability of space and ground- science, such as atmospheric based technological systems The sun plays a fundamental physics and chemistry, solar and and services). The search for role in relations to the earth’s plasma physics. This presents us improvements in the prediction environment. Not only does it with several practical fields of and mitigation of provide direct heat and light, application, such as enhancing effects is now at the top of the it also provides the necessary models’ potential scientific and political agenda energy to power the convective for communications or global globally and solar-terrestrial motions in the atmosphere and positioning applications and physics thus stands to make a oceans, determining weather clarifying the natural variabil- significant contribution to XX- patterns and climates. ity’s short-term and long-term Ith century science. contributions to global change. Mostly invisible to the human A driving factor of progress eye, the sun also produces solar The search for improve- in the field of solar-terrestrial winds, that is, a fast stream of ments in the predic- physics lies in our ability to charged particles travelling from tion and mitigation of make observations. Continual the sun outwards, throughout variations in the solar-terrestrial the solar system. The magnetic space weather effectssystem and the complexity of field associated to solar winds is now at the top of the processes involved limit tour interacts with the earth's in- the scientific and po- capacity to apply current theo- herent magnetism to form the litical agenda globally retical models in predicting how . As a result, the environment will respond solar-terrestrial physics consist The world is increasingly de- to solar influence. This calls for in the scientific investigation of pendent on space-based sys- high-quality observational data, the diverse aspects of the con- tems for much of our everyday covering all key regions of the nection between the sun and the communications and travel sun-earth system, with particu- earth, including the processes while space weather processes lar focus on the ionosphere, as responsible for the conversion have come into focus to a larger it connects the earth's magneto- of energy from one form to extent. Space weather indeed sphere and lower atmosphere. another and how their combi- refers to conditions in the envi- nation might affect our environ- ronment of the magnetosphere To that end, systems applying ment. and ionosphere (ie. the upper- the incoherent scatter radar most part of the atmosphere technique are the most powerful In order to cover all implica- that is partially ionised by the instruments available for iono- tions of such a broad topic, sun and solar winds and has spheric observations. solar-terrestrial physics over- the potential to influence the Article

Incoherent scatter radar tech- provide detailed observations of Union of Radio Science (URSI). nique the state of the ionosphere in a Currently, EISCAT gathers Like all standard radar tech- volume well beyond the reach of associates amongst leading niques, the incoherent scatter a traditional system. research institutions and sci- radar technique involves the ence councils in , , transmission of a radio signal EISCAT Scientific Association , , and the towards a target and the detec- The EISCAT Scientific Associa- , while further tion and analysis of the return tion is an international research platforms in France, , signal. In our case, the targets organisation currently operating and also are ionospheric electrons, in three radar systems (in North- contribute to the operational sucha volume as to fill the ern Fenno- and the funding. As a result, scientists whole radar beam. The resulting archipelago), to pro- from more than fifty countries echo signal is very weak (only duce incoherent scatter meas- worldwide use EISCAT data. 0.0000000000000000001% of urements. Established in 1975 the transmitted power is typ- and headquartered in , EISCAT_3D ically returned), so that the Sweden itsthe radar operations The next step for EISCAT will transmitted radio pulse must be started in 1981. Since then, EIS- be to develop the EISCAT_3D powerful and the receivers sen- CAT facilities have been contin- system, which will enable sitive enough for the return sig- uously developed and extended. three-dimensional mapping of nal to be sufficiently strongand Thanks to successful operations, the dynamics of large volumes cancel out background noise. EISCAT has played a promi- in near-space and the upper High-power with a large nent role in the development of atmosphere. aperture (HPLA) are systems new and innovative techniques This is made possible by the fact fitted with the powerful trans- for radar experiments and data an EISCAT_3D radar site con- mitters and large antennas nec- analysis. EISCAT regularly par- sists of flexible arrays of anten- essary to satisfy such conditions ticipates in international cam- nas, in contrast to the very large and are as a result the preferred paigns involving other radars, instrument for incoherent scat- ground-based instrumentation ter radar measurements. and satellites -- noticeably the Figure 1: The present EISCAT Incoherent Scatter World Days radar facilities near Tromsø, The parameters typically ob- coordinated by the International Norway. (Photo: Craig Heinsel tained from an incoherent scatter radar measurement include as functions of time and distance from the receiv- er, electron density, electron and ion temperatures and bulk plasma velocity along the radar beam. By using three or more geographically separated receiv- ers looking at the same volume of the ionosphere, it is also possible to determine the full three-dimensional bulk plasma flow velocity within that shared volume. Thus, a radar system using the incoherent scatter radar technique may function as a plasma weather station and Article and slow-moving antenna dish- the transmitter. Each site will a result, optimizing data pro- es of present EISCAT systems. hold 9919 stationary antennas cessing and storage architecture This also allows the EISCAT_3D grouped into 109 hexagonal are prerequisites of any future system to produce continuous arrays, covering an area roughly development. measurements for the detection 70 m across. We anticipate the demand for of longer trends, to be compared At present, preparations for the data will be larger when EIS- with the mostly campaign-based three first EISCAT_3D sites CAT_3D goes online, partly observations offered by present have been initiated and a ten- because of its potential in systems. dering process is underway for providingcontinuous environ- As an integral part of the Scien- the construction of a first test mental monitoring data. In tific Association, EISCAT_3D sub-array dedicated to technical particular, the system will likely will be operated by EISCAT. It tests and evaluations. need to offer near real-time data will be located in the Northern The construction ofservices to fit into earth obser- auroral oval, where northern vations global systems. Simi- EISCAT_3D will gener- larly, the system’s extension of ate new technical and operation hours for monitoring organisational challeng- purposes hints to a larger need for systematic quality control of es for EISCAT, which data systems and their harmoni- is where ENVRIplus zation across all research infra- insight would be par- structures. ticularly valuable to us. It has been historically difficult EISCAT and ENVRIplus for EISCAT to keep track of The EISCAT Scientific Asso- where and how its data has been ciation has matured in terms used, which may be remedied of its access and data man- through the implementation agement practices and pro- of a system for data identifiers. cedures,through negotiations Streamlining processes for users conducted between members of will be necessary, to gain obser- the association spanning over vation time on the EISCAT_3D Figure 2: Sketch of a future EIS- the 35 years EISCAT has been system, in particular since it CAT_3D site. (Image: NIPR) operating radars. Nevertheless, may be possible to provide the construction of EISCAT_3D interleaved experiments, as lights are most prominent and will generate new technical well as access to more than one at the edge of the winter and organisational challenges experimenter at any giventime. vortex, one of the main features for EISCAT, which is where Finally, sharing best practic- controlling the atmosphere ENVRIplus insight would be es with other environmental over the Arctic and Northern particularly valuable to us. research infrastructures will Europe. In its fullest imple- An operational EISCAT_3D allow EISCAT to gain insights mentation, the radar system site will produce a lot more from areas of expertise outside will be distributed over five raw data than present EISCAT of its traditional activities. Such sites. A radio wave transmitter systems, due to the fact it will are some of the areas in which with several megawatts of peak demultiply data sources by a ENVRIplus recommendations, power will be placed at a site factor of around ten thousand. services and solutions would near Skibotn (Norway) and the In addition, the raw data pro- certainly serve EISCAT. return signal will be measured duced will also require signifi- from all sites, some of which are cantly more processing before located up to 250 km away from it can beuseful to scientists. As